Patent Publication Number: US-10316568-B2

Title: Power boost module for a door closer

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. No. 62/264,055 filed on Dec. 7, 2015, the contents of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     The present application generally relates to a door closer, and more particularly, but not exclusively, relates to a door closer that harvests energy which is subsequently used to boost terminal shutting of the door. 
     Doors may not fully close for a number of reasons. Many hydraulic door closers are set to meet the Americans with Disabilities Act (“ADA”) requirement of 5 lbs. force to open the door. Due to this limited opening force, the amount of energy that can be stored in the hydraulic door closer is also limited. This may cause the door to have insufficient closing force to overcome adverse conditions such as pressure fluctuation due to operation of heating, ventilation, and air conditioning (“HVAC”) systems, friction forces, poor condition of door hardware, weather stripping, etc. In these situations, the user must either increase the closer spring force (which may in turn cause the door to not meet the ADA requirement), leave the door in a possible non-secure state, or invest in a powered door closing device such as an auto operator. Therefore, a need exists for further technological developments in the area of door closers. 
     SUMMARY 
     According to one aspect, an apparatus is provided including a door closer and a power boost module. The door closer is adapted to be operably coupled to a door and may have a pinion adapted to rotate in a first direction in response to an opening of the door, and in a second direction, opposite the first direction, in response to a closing of the door. The power boost module may be operably coupled to the pinion and may include a motor adapted to generate electrical energy from rotational movement of the pinion and to supply a boost force to the pinion to assist closing of the door, a gearing operably coupled to the pinion and the motor and structured to back drive the motor to generate the electrical energy in response to rotation of the pinion, and an energy storage device adapted to store the electrical energy generated by the motor and supply stored electrical energy to the motor for the boost force. 
     According to another aspect, a power boost module is provided which is attachable to a door closer for supplying a boost force to assist in closing the door, and may include a motor adapted to generate electrical energy from rotational movement of a pinion of the door closer and to supply a boost force to the pinion to assist the closing of the door, a gearing operably coupled to the pinion and the motor and structured to back drive the motor to generate the electrical energy in response to rotation of the pinion, and an energy storage device adapted to store the electrical energy generated by the motor and supply stored electrical energy to the motor for the boost force. 
     According to yet another embodiment, a method is provided for retrofitting a door closer with a power boost module, and may include operably coupling a pinion of the door closer to a gearing of the power boost module while the door closer is attached to a door, wherein the gearing is positioned within a housing of the power boost module, the power boost module capable of harvesting energy and boosting terminal closing of the door using the harvested energy, and fastening the housing of the power boost module to the door closer. 
     Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for a door closer. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. Further embodiments, forms, features, and aspects of the present application shall become apparent from the description and figures provided herewith. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       The concepts described herein are illustrative by way of example and not by way of limitation in the accompanying figures. For simplicity and clarity of illustration, elements illustrated in the figures are not necessarily drawn to scale. Where considered appropriate, references labels have been repeated among the figures to indicate corresponding or analogous elements. 
         FIG. 1  is an exploded, partial cutaway front perspective view of at least one embodiment of a door closer system; 
         FIG. 2  is a cutaway front perspective view of at least one embodiment of a power boost assembly of  FIG. 1 ; 
         FIG. 3  is a front perspective view of the door closer system of  FIG. 2 ; 
         FIG. 4  is a rear perspective view of the door closer system of  FIG. 2 ; 
         FIG. 5  is a front perspective view of at least one embodiment of another door closer system; 
         FIG. 6  is a cross-sectional view of a power boost assembly of the door closer system of  FIG. 5 ; 
         FIG. 7  is a front perspective view of a completed retrofit to an existing door closer with a power boost assembly; 
         FIG. 8  is a simplified block diagram of at least one embodiment of an electronic controller associated with a power boost assembly; 
         FIG. 9  is a simplified block diagram of an least one embodiment of a method for harvesting energy and providing a power boost using a power boost assembly; 
         FIG. 10  is a simplified block diagram of at least one embodiment of an architecture of a power boost assembly; 
         FIGS. 11A-11C  are simplified schematics of at least one embodiment of an electrical circuit of a power boost assembly including a brushless motor; 
         FIGS. 12A-12C  are simplified schematics of at least one other embodiment of an electrical circuit of a power boost assembly including a brushed motor; 
         FIG. 13  is a simplified block diagram of at least one embodiment of a method for retrofitting a door closer with a power boost assembly; 
         FIG. 14  is a front perspective view of at least one other embodiment of a door closer system; 
         FIG. 15  is a front, cutaway view of the door closer system of  FIG. 14  when the door is closed; and 
         FIG. 16  is a front, cutaway view of the door closer system of  FIG. 14  when the door is opened. 
     
    
    
     DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     Although the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described herein in detail. It should be understood, however, that there is no intent to limit the concepts of the present disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives consistent with the present disclosure and the appended claims. 
     References in the specification to “one embodiment,” “an embodiment,” “an illustrative embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may or may not necessarily include that particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. It should further be appreciated that although reference to a “preferred” component or feature may indicate the desirability of a particular component or feature with respect to an embodiment, the disclosure is not so limiting with respect to other embodiments, which may omit such a component or feature. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to implement such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. 
     Additionally, it should be appreciated that items included in a list in the form of “at least one of A, B, and C” can mean (A); (B); (C); (A and B); (B and C); (A and C); or (A, B, and C). Similarly, items listed in the form of “at least one of A, B, or C” can mean (A); (B); (C); (A and B); (B and C); (A and C); or (A, B, and C). Further, with respect to the claims, the use of words and phrases such as “a,” “an,” “at least one,” and/or “at least one portion” should not be interpreted so as to be limiting to only one such element unless specifically stated to the contrary, and the use of phrases such as “at least a portion” and/or “a portion” should be interpreted as encompassing both embodiments including only a portion of such element and embodiments including the entirety of such element unless specifically stated to the contrary. 
     The disclosed embodiments may, in some cases, be implemented in hardware, firmware, software, or a combination thereof. The disclosed embodiments may also be implemented as instructions carried by or stored on one or more transitory or non-transitory machine-readable (e.g., computer-readable) storage media, which may be read and executed by one or more processors. A machine-readable storage medium may be embodied as any storage device, mechanism, or other physical structure for storing or transmitting information in a form readable by a machine (e.g., a volatile or non-volatile memory, a media disc, or other media device). 
     In the drawings, some structural or method features may be shown in specific arrangements and/or orderings. However, it should be appreciated that such specific arrangements and/or orderings may not be required. Rather, in some embodiments, such features may be arranged in a different manner and/or order than shown in the illustrative figures unless indicated to the contrary. Additionally, the inclusion of a structural or method feature in a particular figure is not meant to imply that such feature is required in all embodiments and, in some embodiments, need not be included or may be combined with other features. 
     Referring now to  FIGS. 1-4 , illustrated therein is at least one embodiment of a door closer system  100  which is structured and configured to harvest energy (e.g., by generating and storing the energy) via a person pushing on the door and/or via the closing force generated by a door closer, and subsequently using that harvested energy to boost the door shut (i.e., terminal shutting of the door).  FIGS. 1-4  show various views of the door closer system  100  and/or the components/devices thereof. In particular,  FIG. 1  illustrates an exploded, partial cutaway view of the door closer system  100 . As shown, the door closer system  100  includes a door closer  102  and an electrical power boost assembly  104 . In the illustrative embodiment, the door closer  102  is embodied as a hydraulic door closer  102 . However, it should be appreciated that the door closer  102  may be embodied as another suitable type of closer in other embodiments. The power boost assembly  104  is configured to modularly attach to the door closer  102  and be positioned in powered or driving communication with the door closer  102  via a pinion  103  of the door closer  102 . As such, in some embodiments, the power boost assembly  104  may be referred to herein as a power boost module  104 . 
       FIG. 2  illustrates a perspective, cutaway view of the power boost assembly  104  of the door closer system  100 . As shown, the illustrative power boost assembly  104  includes a motor  106 , a gear train or gearing  108 , an energy storage device  110  (e.g., one or more capacitor(s) or batteries), a printed circuit board assembly (“PCBA”)  112 , a magnet  114 , a position sensor  116  (e.g., a Hall-effect sensor, a magnetometer, a reed switch, potentiometer, capacitive sensor, analog inductive sense, or other suitable position sensors), and/or discrete components  118  (e.g., adjust potentiometers, user interface, etc.). The PCBA  112  may include the hardware, firmware, and/or software (e.g., logic) for operating the power boost assembly  104 . For example, the PCBA  112  may include a processing device (e.g., one or more microprocessors and/or microcontrollers) or electronic circuitry (e.g., analog and/or digital). 
       FIG. 3  illustrates a front view of the door closer system  100  in which the door closer  102  is coupled to the power boost assembly  104 , and  FIG. 4  illustrates a rear or back view of the door closer system  100  in which the door closer  102  is coupled to the power boost assembly  104 . 
     The power boost assembly  104  may include a housing  105  that may be attached to the door closer  102 . In particular, the power boost assembly  104  may be operably attached to the pinion  103  of the door closer  102 . For example, the pinion  103  may be adapted to mate with a bore  109  defined in a gear of the gearing  108  of the power boost assembly  104 . As such, it should be appreciated that, in some embodiments, the pinion  103  of the door closer  102  is exposed and positioned opposite the close arm(s)  111  such as, for example, an LCN 4040XP. Further, in some embodiments, the housing  105  of the power boost assembly  104  may also be secured to the door closer  102  via one or more fasteners  107  (e.g., threaded fasteners). 
     In the illustrative embodiment, by virtue of the connection with the pinion  103  of the door closer  102 , the power boost assembly  104 , in operation, receives rotational motion/torque as an input to drive the motor  106 , and the motor  106  provides rotational motion/torque to the door closer  102  to boost the door shut in certain circumstances. That is, the motor  106  may be used to act as a generator during energy harvesting and to drive the door (not shown) while providing a power boost to fully close the door. As such, the pinion  103  rotates in one direction when the door is opened and the opposite direction when the door is closed. The gear train  108  is operably coupled between the motor  106  and the pinion  103 , and it structured to increase the speed of the input from the pinion  103  to drive the motor  106  at a sufficient speed (RPM) to harvest energy, and to increase the boost power or potential boost force of the motor  106 . As indicated above, the power boost assembly  104  may also include a PCBA  112  including the energy storage device, a user interface, a door position or landmark sensor, and/or a microcontroller. In some embodiments, the motor  106  is embodied as a DC brushless motor. In other embodiments, the motor  106  may be embodied as any type of motor suitable for performing the functions described herein (e.g., brushed motor, stepper motor, etc.). 
     In some embodiments, the door closer  102  may be a non-handed door closer mounted to a door using a standard mounting template. The door closer  102  may be non-handed so as to include an exposed end of the door closer pinion to actuate the electrical boost mechanism. As indicated above, the power boost assembly  104  may be fastened to the door closer  102  via fasteners. For example, mounting screws may attach directly to threaded holes in the door closer  102  such as, for example, cover mounting screw holes. In some embodiments, an existing door closer  102  can be left on the door, and the power boost assembly  104  can be attached or bolted on in the field (i.e., with the door closer  102  still attached to the door). In other embodiments in which threaded holes are unavailable or otherwise unusable, a mounting plate may be used. The mounting plate could be mounted to the door, behind the door closer  102 , or to the door closer  102  in some other fashion. The power boost assembly  104  can then be mounted to the mounting plate. In some embodiments, a mounting plate (not shown) is mounted between the door closer  102  and the power boost assembly  104 , for example, to deal with variability in manufacturing tolerances. In such embodiments, the mounting plate may include an aperture defined therein to permit the operable connection between the pinion  103  and the gearing  108 . In some embodiments, other mounting methods may be used to attach the power boost assembly  104  to the door. The door closer  102  may be mounted to the door frame via one or more closer arms  111 . 
     As shown in  FIG. 7 , the door closer  102  and the power boost assembly  104  may be secured by a cover  120  after the power boost assembly  104  has been secured to the door closer  102 . In some embodiments, it should be appreciated that the cover  120  may be fastened to the door closer  102  using the same fastening mechanism used to fasten a previous cover used to house only the door closer  102  (e.g., prior to the retrofit). As shown, the door closer system  100  is mounted to the door  122 , and the closer arm(s)  111  secure the door closer  102  to the door frame  122 . 
     As the door opens or closes, the door closer  102  may operate normally. As the pinion  103  rotates, the pinion  103  actuates the gearing  108  inside the power boost assembly  104 . The gearing  108  is used to back drive the motor  106  to thereby generate electrical energy. The generated electrical energy is stored in an energy storage device  110  such as, for example, one or more capacitors (e.g., a supercapacitor or capacitor bank) or one or more batteries. It should be appreciated that the energy storage device  110  may be embodied as any one or more energy storage devices suitable for performing the functions described herein. For example, in some embodiments, the energy storage device  110  may include one or more capacitors, supercapacitors, Ultracapacitors, Electric Double Layer Capacitor (ELDC) devices, etc. In particular, the energy storage device  110  may be any type of capacitor characterized by high energy densities, low ESR, and low leakage performance. Depending on the particular embodiment, the power boost assembly  104  can be configured to harvest energy (e.g., by electrical and/or mechanical means) only on door opening, only on door closing, during both door opening/closing, or portions thereof. The motor  106  acts as a brake while harvesting such that the harvesting function can be used to control the door in the back-check zone and on door closing. 
     As the door closes, the door closer  102  may operate normally. Logic in the PCBA  112  may monitor the door angle, or may look for a landmark point and hold the stored electrical energy until the door angle reaches an appropriate angle where the door requires additional closing force or torque. To do so, the PCBA  112  may utilize sensor data generated by the sensor  116  (e.g., a hall-effect sensor) and the magnet  114 . In other embodiments, the power boost assembly  104  may utilize other sensors and/or techniques to determine the door angle. The additional force/torque required to shut a particular door could be due to HVAC pressure fluctuations, door alignment/misalignment, weather stripping, latch forces, or other forces that hinder door closing. Regardless of the cause, in some embodiments, the electrical energy is used to power the motor  106  and provide a “power boost” to the door closer  102  to provide a higher than normal closing force (e.g., a boost force) to fully close/shut the door. 
     By continuously or periodically monitoring the door angle, the PCBA  112  can monitor door position and speed. If the door gets to an almost closed state (e.g., fifteen degrees from closed), but begins to abnormally slowdown, then a power boost may be initiated. If the door is cycling correctly, no boost may be needed, and the harvested energy can be stored for a future boost cycle and/or to perform other functions or operations. In some embodiments, it should be appreciated that the PCBA  112  may only cause a power boost if the amount of energy stored in the energy storage device  110  exceeds a threshold amount of electrical energy necessary to boost the door to the closed position. That is, the power boost assembly  104  does not waste electrically energy by boosting the door toward the closed position if the boost force that can be accomplished using the stored electrical energy is insufficient to actually close the door. As such, unnecessary depletion of stored energy may be avoided. It should be appreciated that the threshold amount of electrical energy to boost the door may be predetermined, static or dynamic, determined based on sensor data, or otherwise determined based on the particular embodiment. Further, in some embodiment, the latch zone (e.g., between zero and fifteen degrees) at which the door is to the almost closed state may vary depending on the particular embodiment and, in some embodiments, may be modified by a user via a user interface of the power boost assembly  104 . 
     Using a landmark point method, a specific pinion angle may be detected. To do so, the power boost assembly module  104  may utilize a snap switch, a reed switch, a Hall-effect sensor, or other suitable position sensors or switches. The landmark angle can be a designator when the door has reached the latch zone. When the door is in the latch zone, the PCBA  112  may provide a signal to boost the door closed on every cycle. The PCBA  112  may also look at motor voltage while harvesting to determine door speed and use the sensed door speed value to determine if a power boost is needed (e.g., boosting only if the door is moving slowly or is stopped). This allows the power boost assembly  104  to selectively provide a power boost, and to be able to store energy if a boost is not needed. 
     Door closers may be used in a variety of applications which can cause a relatively large variation of pinion travel. In some embodiments, this may require calibration or setup by the user. The landmark detection embodiment, however, may require no setup/calibration or minimal setup/calibration. This method may function similar to a mechanical closer wherein the latch zone corresponds to a set amount of pinion rotation. This method may require the installer to attach the unit to the closer pinion  103  in an orientation where the landmark sensor will be in the correct position while the door cycles. This may be accomplished by having marks on the pinion attachment that must be correctly orientated prior to installation. 
     Referring now to  FIGS. 5-6 , at least one other embodiment of a door closer system  100  that includes a landmark sensor  121  or landmark detection system for determining whether the door is within the latch zone. The door closer system  100  of  FIGS. 5-6  may be configured similar to the door closer system  100  of  FIGS. 1-4 . However, the door closer system  100  includes a landmark sensor  121  that is provided with a target board  113  and an antenna  115 . As shown, the target board  113  is secured to a rotor  117  of the motor  106  for rotation therewith (e.g., about an axis  119  shared with the pinion  103 ). The antenna  115  is secured to the PCBA  112 , which may in turn be offset from the target board  113 . Further the target board  113  includes a landmark point (e.g., a copper mark on the target board  113 ) that may be sensed by the antenna  115  when the landmark point crosses the antenna  115 . The landmark sensor  121  may be used to detect when the door is within the latch zone, which may be modified by the user in some embodiments. 
     In another embodiment, a landmark position is not used. Instead, a speed detection algorithm may be used to regulate the power boost assembly  104  to a specific speed, harvesting when the door is moving too fast, and boosting when the door is moving too slow. This may accomplished by monitoring the back-EMF of the motor  106 , and regulating the voltage within a specific voltage window. 
     In embodiments that continuously monitor pinion position, such as using a potentiometer or encoder, calibration may be needed to determine door position. This can be accomplished by having a procedure performed by the installer so that the unit correlates door position to the sensor readings. One method for accomplishing this feature includes having the user perform a calibration routine after installation involving pressing a button when the door is closed, then opening the door to 90 degrees, and then pressing the button again. Furthermore, additional steps involving pressing the button at the fully opened position, latch zone, or a power boost zone can be added to further define the door angles and refine operation. Other calibration techniques may be used in other embodiments. 
     The harvesting and braking functions can be performed automatically, or can be set up for manual adjustment by the user. For automatic operation, the power boost assembly  104  may be factory setup to perform at levels that will work for all applications. By adding user inputs (e.g., potentiometers, dip switches, and push buttons), energy harvesting by the power boost assembly  104  may be refined for a particular application. For example, in such embodiments, the braking function of the closer may be turned down, and the harvesting/braking of the power boost assembly  104  may be increased to allow more energy to be harvested for subsequent power boosting. This may add relatively significant energy, especially if the closer size is increased. 
     In some embodiments, the power boost function may also be user modified. For example, the power boost may be set at the factory at a safe level for all applications. Further, adjustments may also be made, in some embodiments, so that the installer can set the boost level in the field. Such features can be particularly useful for heavy or large doors where additional closing force may be required. 
     To maximize efficiency and reduce cost, gearbox tooth contact points (e.g., using smaller gears) may be minimized, which may in turn result in a weaker gearbox. In order to handle these abusive torques, multiple methods of torque reduction may be used including, for example, torque-limiting the motor/generator by using current-limits on the control circuitry, and/or by current limiting the power boost assembly  104 , and/or having the user set the hydraulics to compensate for any lack of breaking done by the power boost assembly  104 . 
     It should be understood that multiple techniques may be utilized for maximizing the harvested energy while reducing gear torques including, for example, constant current harvest (always attempt to harvest at a specific point), constant voltage harvest (harvest all energy above a specific voltage), constant resistance harvest (vary harvesting proportionally to the motor RPM), fixed-PWM with current limit (apply a fixed PWM to the motor H-bridge, and cutoff the PWM output when the current exceeds the predetermined torque value), and/or variable-PWM with current limit (apply a variable PWM to the motor H-bridge, and cutoff the PWM output when the current exceeds a predetermined torque value). A microcontroller may vary the duty cycle when required. 
     Energy storage may be accomplished via an energy storage device  110 , thereby allowing for “infinite” cycling of the device without replacing the storage device or any electronics. In particular, organic electrolytic, double-layer capacitors may be used which can handle the relatively wide temperature range and relatively high capacitance demands of the system. 
     The power boost assembly  104  electrically harvests energy on door opening but, in some embodiments, a majority of the energy is being stored in a spring in the door closer  102 . By storing the energy in the spring first, the power boost assembly  104  can control the speed at which the door closes, thereby allowing the power boost assembly  104  to tune the system for efficient energy storage. 
     An H-bridge driver may have a high enough voltage rating to handle the events, but devices down-stream need only handle voltages around the maximum capacitor storage voltage. By taking advantage of the winding resistance and winding inductance, this energy can be shunted into the energy storage device  110  rather to ground. If the energy storage device  110  is fully charged, then energy may be shunted into ground. By appropriately segmenting these methods, the proper amount of energy may be shunted without overrating the other devices. 
     The power boost assembly  104  may use a dynamic control scheme based on a set of rules that maximize efficiency while controlling movement of a door. The feedback system may be based on the input instead of the output. 
     As an external force starts to open the door, the spring in the door closer  102  compresses and the motor  106  starts rotating. The power boost assembly  104  may store all low-RPM energy in the spring. Once the motor back-EMF is high enough to start harvesting (as low as 3V turn-on), the power boost assembly  104  may or may not start harvesting a small amount of electrical energy. All other energy is generally stored in the spring. 
     When door movement experiences high speeds, the power boost assembly  104  may increase the energy harvesting amount. The power boost assembly  104  may limit the current harvested so that the power boost assembly  104  can reduce the torque or rotational force on the gearbox  108 . As the motor  106  is harvesting energy, the motor  106  also acts as a brake to slow movement of the door. 
     As the door hits “backcheck”, the power boost assembly  104  may maximize the energy harvested to slow down moment of the door. As the external force stops opening the door, the energy stored in the momentum of the door may be transferred into the spring and into the motor  106 . When the door stops moving, all energy harvesting may stop, and the power boost assembly  104  may use the harvested/stored energy in the spring to start pushing the door closed. 
     Once the spring has inserted enough energy into the door, and the door&#39;s kinetic energy is sufficient for the user&#39;s application, the power boost assembly  104  starts siphoning the spring energy into electrochemical energy. If there is an abusive situation, the power boost assembly  104  may harvest some of that energy, and the other portion of the energy may or may not go into the hydraulics to be expended as heat. 
     If the spring is unable to insert enough energy into the door, or if the door kinetic energy drops sufficiently low, the power boost assembly  104  uses the stored reserve of the electrochemical energy through the motor  106 , thereby controlling the current and/or voltage flowing through the motor  106  to control movement of the door. 
     If the power boost assembly  104  detects an abnormality during the closing, such as a human pushing on the door, the power boost assembly  104  may reduce the amount of boost the power boost assembly  104  provides, if any. If the power boost assembly  104  detects an abnormality or obstruction, such as a door frame, the power boost assembly  104  may increase the boost energy to place the door into its final/terminal closed position. Alternatively, the power boost assembly  104  may refrain from supplying the boost force as the obstruction may be an object propping the door. 
     Once the power boost assembly  104  is in its final position, the power boost assembly  104  may start the shutdown sequence, which may or may not include storage and/or communication of the door&#39;s statistics via Bluetooth to a mobile device or a gateway to a back-end device such as a server. 
     Since the power boost assembly  104  is operating at relatively low voltages, the power boost assembly  104  may be operating an H-bridge as an energy boost converter, which may allow the power boost assembly  104  to operate the system at relatively low RPMs, and the down-stream electronics may manage any high-voltage scenarios. The impedance of the capacitors and the motors may be adjusted to allow the system to behave as a synchronous or asynchronous boost converter, synchronous or asynchronous buck converter, or a pass-through charger, depending on the state/configuration of the system. 
     When boosting the door shut, the power boost assembly  104  typically will control the power entering the system. The microcontroller may regulate the power supply voltage rather than the power into the motor  106 . This may decrease the efficiency losses in the system as well as stability problems related to having two switching supplies placed in series with one another. 
     Referring now to  FIG. 8 , a simplified block diagram of at least one embodiment of a control system  800  of the power boost assembly  104  is shown. As indicated above, it should be appreciated that the control system may include or be embodied as a PCBA device in some embodiments. The illustrative control system  800  includes a processing device  802  that executes algorithms and/or processes data in accordance with operating logic  808 , an input/output device  804  that enables communication between the control system  800  and one or more external devices  810 , and memory  806  which stores data. It should be appreciated that the control system  800  may include multiple input/output devices  804 , memories  806 , and/or operating logics  808  in some embodiments. Similarly, the control system  800  may be configured to communicate with multiple external devices  810  in some embodiments. 
     The input/output device  804  allows the control system  800  to communicate with the external device  810 . For example, the input/output device  804  may include a transceiver (e.g., Bluetooth and/or Wi-Fi), a network adapter, a network card, an interface, one or more communication ports (e.g., a USB port, serial port, parallel port, an analog port, a digital port, VGA, DVI, HDMI, FireWire, CAT 5, or any other type of communication port or interface), and/or other communication circuitry. Communication circuitry may be configured to use any one or more communication technologies (e.g., wireless or wired communications) and associated protocols (e.g., Ethernet, Bluetooth®, Wi-Fi®, WiMAX, etc.) to effect such communication depending on the particular control system  800 . Additionally, in some embodiments, the input/output device  804  may allow power transfer between the control system  800  and other devices (e.g., to power an electronic lock). The input/output device  804  may include hardware, software, and/or firmware suitable for performing the techniques described herein. 
     The external device  810  may be any type of device that allows data to be inputted or outputted from the control system  800 . For example, in various embodiments, the external device  810  may be embodied as an access control device, server (e.g., in a cloud computing environment, desktop computer, laptop computer, tablet computer, notebook, netbook, Ultrabook™, mobile computing device, cellular phone, smartphone, wearable computing device, personal digital assistant, Internet of Things (IoT) device, processing system, router, switch, diagnostic tool, controller, printer, display, alarm, illuminated indicator (e.g., a status indicator), peripheral device (e.g., keyboard, mouse, touch screen display, etc.), and/or any other computing, processing, and/or communication device capable of performing the functions described herein. Furthermore, in some embodiments, it should be appreciated that the external device  810  may be integrated into the control system  800 . 
     The processing device  802  may be embodied as any type of processor(s) capable of performing the functions described herein. In particular, the processing device  802  may be embodied as one or more single or multi-core processors, microcontrollers, or other processor or processing/controlling circuits. For example, in some embodiments, the processing device  802  may include or be embodied as an arithmetic logic unit (ALU), central processing unit (CPU), digital signal processor (DSP), and/or another suitable processor(s). The processing device  802  may be a programmable type, a dedicated hardwired state machine, or a combination thereof. Processing devices  802  with multiple processing units may utilize distributed, pipelined, and/or parallel processing in various embodiments. Further, the processing device  802  may be dedicated to performance of just the operations described herein, or may be utilized in one or more additional applications. In the illustrative embodiment, the processing device  802  is of a programmable variety that executes algorithms and/or processes data in accordance with operating logic  808  as defined by programming instructions (such as software or firmware) stored in memory  806 . Additionally or alternatively, the operating logic  208  for processing device  802  may be at least partially defined by hardwired logic or other hardware. Further, the processing device  802  may include one or more components of any type suitable to process the signals received from input/output device  804  or from other components or devices and to provide desired output signals. Such components may include digital circuitry, analog circuitry, or a combination thereof. 
     The memory  806  may be of one or more types of non-transitory computer-readable media, such as a solid-state memory, electromagnetic memory, optical memory, or a combination thereof. Furthermore, the memory  806  may be volatile and/or nonvolatile and, in some embodiments, some or all of the memory  806  may be of a portable variety, such as a disk, tape, memory stick, cartridge, and/or other suitable portable memory. In operation, the memory  206  may store various data and software used during operation of the control system  800  such as operating systems, applications, programs, libraries, and drivers. It should be appreciated that the memory  806  may store data that is manipulated by the operating logic  808  of processing device  802 , such as, for example, data representative of signals received from and/or sent to the input/output device  804  in addition to or in lieu of storing programming instructions defining operating logic  808 . As shown in  FIG. 2 , the memory  806  may be included with the processing device  802  and/or coupled to the processing device  802  depending on the particular embodiment. For example, in some embodiments, the processing device  802 , the memory  806 , and/or other components of the control system  800  may form a portion of a system-on-a-chip (SoC) and be incorporated on a single integrated circuit chip. 
     Referring now to  FIG. 9 , in use, the power boost assembly  104 , or more particularly the control system  800 , may execute a method  900  for harvesting energy and providing a power boost. It should be appreciated that the particular blocks of the method  900  are illustrated by way of example, and such blocks may be combined or divided, added or removed, and/or reordered in whole or in part depending on the particular embodiment, unless stated to the contrary. As shown, the blocks shown in the left column (blocks  902 ,  906 ,  910 ,  914 ,  920 ,  924 ,  930 ,  934 ,  940 ) indicate what is occurring with the door physically at a given point in time, and the blocks shown in the right column (blocks  904 ,  908 ,  912 ,  916 ,  918 ,  922 ,  926 ,  928 ,  932 ,  936 ,  938 ,  942 ) indicate the core focus of the electronics of the power boost assembly  104  in response to the corresponding physical status of the door. 
     The illustrative method  900  begins with block  902  in which the door opens very slowly. It should be appreciated that the door may open at various speeds (e.g., very slow speed, slow speed, normal speed, high speed, very high speed). Further, the particular speeds associated with the speed ranges may vary depending on the particular embodiment. If the door is opening very slowly (e.g., less than 1.5 RPM), then in block  904 , the power boost assembly  104  may not harvest electrical energy and the electronics may not wake up. If the power boost assembly  104  determines in block  906  that the door is opening slowly (e.g., above 1.5 RPM but still below normal speed), a jumpstart circuit may be used in block  908 , which may effectively function as a boost converter that helps generate enough energy to fully turn on the electronics, for example, for harvesting. 
     If the power boost assembly  104  determines in block  910  that the door is opening at a normal speed, then in block  912 , the power boost assembly  104  harvests electrical energy based on the movement of the door. If the power boost assembly  104  determines in block  914  that the door is opening at a high speed, the power boost assembly  104  continues to harvest the electrical energy in block  916 . Further, in some embodiments, it should be appreciated that the power boost assembly  104  harvests only up to a current limit in block  918 . In embodiments in which the door closer  102  is a hydraulic door closer, the power boost assembly  104  may “back off” on harvesting to let the hydraulics take over. As such, the power boost module  104  electronics and the hydraulics system may work with one another and rely on each other&#39;s operation. In some embodiments, it should be appreciated that the motor  106  is designed such that it is physically unable to provide enough torque for the door to move in an unsafe manner, so electronic control over the torque is unnecessary. If the power boost assembly  104  determines in block  920  that the door is opening at a very high speed, a protection circuit is engaged in block  922 , for example, to protect the electronics. 
     In block  924 , the door may reach a back check position (e.g., at seventy degrees). If so, at block  926 , the power boost assembly  104  continues to harvest extra electrical energy. Further, in block  928 , the power boost assembly  104  may apply a current limit similar to block  918  in some embodiments. If the power boost assembly  104  determines that the door is shutting (e.g., via a spring in the door) in block  930 , the power boost assembly  104  continues to harvest electrical energy in block  932 . If the power boost assembly  104  determines that a force (e.g., wind, a person, etc.) is pushing the door shut, the power boost assembly  104  continues to harvest electrical energy. However, in block  938 , in some embodiments, the power boost assembly  104  may harvest only until a current limit is reached. If the power boost assembly  104  determines in block  940  that a latch zone has been reached (e.g., zero to fifteen degrees, a user-adjusted position, etc.), the power door assembly  104  provides a boost force to the motor  106  to boost the door shut in block  942 . As indicated above, in some embodiments, the power door assembly  104  may also consider the speed of the door such that a fast-moving door does not receive an additional boost force to boost the door shut. 
     As described herein, the motor  106  generates electrical energy at certain points in time and provides a boost force (using stored electrical energy) at other points in time. In particular, the motor  106  may be adapted to supply the boost force only when the door is within the latch zone (e.g., between zero and fifteen degrees) and only when the door is moving in a closing direction. Further, the motor  106  may provide the boost force only when the door is moving at a speed below a threshold speed (e.g., too slowly to shut on its own) and/or the electrical energy stored in the energy storage device is sufficient (e.g., estimated to be sufficient) that the boost force is capable of driving the door to a closed position. Depending on the particular embodiment, the motor  106  may be configured to generate electrical energy at any time the door is moving fast enough to harvest energy (e.g., above a threshold speed) or only within a particular range/direction of motion. For example, in some embodiments, the motor  106  may generate electrical energy when the door is moving in an opening direction whereas, in other embodiments, the motor  106  may generate electrical energy regardless of the direction of the door movement. It should be appreciated that the threshold speeds described herein may vary depending on the particular embodiment (e.g., 500 RPM). Similarly, in some embodiments, the motor  106  may generate electrical energy only if the door is outside the latch zone (e.g., between fifteen degrees and ninety degrees). It should be appreciated that the door swing/opening range may vary depending on the particular embodiment. For example, in various embodiments, the door may be capable of opening only to 90 degrees, 120 degrees, 180 degrees, or another suitable maximum door opening angle. 
     Referring now to  FIG. 10 , at least one embodiment of an architecture  1000  of the power boost assembly  104  is shown. As shown, the illustrative architecture  1000  includes a header  1002  (including the motor  106  and an encoder  1004 ), a motor controller  1006  (including the jumpstart circuit  1008 ), a current sense circuitry  1010 , an over-voltage protection circuitry  1012 , a two-quadrant power controller  1014 , the energy storage device  110 , a low-voltage (LV) regulation circuitry  1016 , a microcontroller  1018 , the landmark sensor  121 , and an external interface  1020 . 
     It should be appreciated that the motor encoder  1004  may include an encoder comparator and encoder lines. Further, in some embodiments, the motor  106  and the encoder  1004  may be on a printed circuit board (PCB) separate from the other electronics of the architecture  1000 . The illustrative motor controller  1006  receives signals from the motor  106 , which are fed into the jumpstart circuit  1008  for power boosting when needed. Additionally, the motor controller  1006  includes an H-bridge and a corresponding driver for the H-bridge. The H-bridge driver and the jumpstart circuit  1008  may communicate with the microcontroller (e.g., the PCBA  112 ). 
     In the illustrative embodiment, the current sense circuitry  1010  includes a voltage reference, one or more current sense op-amps, and a current sense. Further, the current sense circuitry  1010  may include or interact with the LV regulation circuitry  1016  and transmit analog outputs the microcontroller. The over-voltage protection circuitry  1012  functions to protect against overly high voltages in the power boost assembly  104 . The architecture  1000  includes a high current path from the over-voltage protection circuitry  1012  to the two-quadrant power controller  1014  and a low current path from the over-voltage protection circuitry  1012  to the LV regulation circuitry  1016 . The two-quadrant power controller  1014  includes a buck controller, boost controller and drivers and is configured to convert electrical energy into a form usable by the energy storage device  110 . The energy storage device  110  circuit may include one or more energy storage devices  110  (e.g., capacitors, supercapacitors, ultracapacitors, etc.), overvoltage protection, enablement/disablement circuitry, and voltage monitoring circuitry and enablement circuitry. Further, the energy storage device  110  circuit may receive instructions from and/or transmit data to the microcontroller. In some embodiments, a set of electrical switches function to prevent leakage in the energy storage device  110 . 
     The LV regulation circuitry  1016  may include a low voltage power supply and a bypass circuit. In some embodiments, the LV regulation circuitry  1016  may be embodied as a 50V to 3.3V power converter. However, the LV regulation circuitry  1016  may include the bypass circuit to, at voltages below 3.3V, allow power to the microcontroller and avoid powering off of the microcontroller that may occur without the bypass circuit. Accordingly, the jumpstart circuitry  1008  may be powered by virtue of power supplied through the bypass to boost the power and jumpstart the microcontroller. In the illustrative embodiment, the jumpstart circuitry  1008  may be configured to receive an input voltage generated by the motor  106  that is unusable to power the microcontroller and boost the input voltage to an activation power useful to power the microcontroller. In other words, the jumpstart circuitry  1008  boosts ultra-low voltages from the motor  106  into usable energy for higher-efficiency motor control systems (e.g., the microcontroller). 
     As indicated above, in some embodiments, the microcontroller  1018  may be embodied as, or include, the PCBA  112 . The external interface  1020  may include mechanisms by which a user or technician may access the microcontroller  1018  (e.g., for reprogramming, updates, set). As such, the external interface  1020  may include, for example, user interface switches (e.g., potentiometers, lever switches, buttons, etc.), user interface LEDs or other output devices, and/or a programming header. 
     It should be appreciated that the architecture  1000  may include additional, or alternative, components in other embodiments. Further, in some embodiments, one or more of the components described in reference to the architecture  1000  may be omitted in some embodiments. 
     Referring now to  FIGS. 11A-C , at least one embodiment of an electrical circuit  1100  of the power boost assembly  104  is shown. It should be appreciated that the electrical circuit  1100  corresponds with embodiments of the power boost assembly  104  in which the motor  106  is a DC brushless motor. As shown, the electrical circuit  1100  includes a brushless motor  1102  (or, more specifically, a brushless motor equivalent circuit), a current sense circuitry  1104 , a three-phase H-bridge  1106 , a low voltage power supply  1108 , a high power over-voltage protection circuitry  1110 , a charge circuitry  1112 , the energy storage device  110 , the motor power supply boost circuitry  1114 , and the jumpstart circuitry  1116 . It should be appreciated that these components may perform functions similar to the similarly named components described above. 
     In some embodiments, the electrical circuit  1100  may use motor winding losses as the inductor for a boost converter, which may in turn be utilized to harvest energy from the motor  106 . In other words, the motor H-bridge  1106  may be treated as a boost converter. In operation, the microcontroller may pulse the low side FETs of the H-bridge  1106 , and the inductive “kick back” may go through the high side to charge the system. Further, one of the low side FETs may be pulsed to determine the amount of torque applied to the door (along with door speed) and provide braking independent of the energy harvesting. 
     In some embodiments, the charge circuitry  1112  is adapted to supply the harvested energy to the energy storage device  110  (e.g., a bank of supercapacitors), and the motor power supply boost circuitry  1114  is adapted to provide the power boost to the motor  106  in response to a command received from the microcontroller (e.g., a switching signal received by the FET of the circuitry  1114 ). Further, it should be appreciated that, in some embodiments, the jumpstart circuitry  1116  may be replaced with a boost converter electrically wired to the low voltage power supply  1108 . 
     Referring now to  FIGS. 12A-C , at least one other embodiment of an electrical circuit  1200  of the power boost assembly  104  is shown. It should be appreciated that the electrical circuit  1200  is similar to the electrical circuit  1100  of  FIGS. 11A-C . However, unlike the electrical circuit  1100 , the electrical circuit  1200  corresponds with embodiments of the power boost assembly  104  in which the motor  106  is a brushed motor. As shown, the electrical circuit  1200  includes a brushed motor  1202  (or, more specifically, a brushed motor equivalent circuit), a current sense circuitry  1204 , an H-bridge  1206 , a low voltage power supply  1208 , a high power over-voltage protection circuitry  1210 , a charge circuitry  1212 , the energy storage device  110 , the motor power supply boost circuitry  1214 , and the jumpstart circuitry  1216 . It should be appreciated that these components may perform functions similar to the similarly named components described above. 
     As described herein, the motor power supply boost circuitry  1214  may function essentially as a boost converter. When the microcontroller intends to drive the motor  106  with a power boost, the microcontroller may turn off M 12  of the charge circuitry  1212  and turn on M 13  of the motor power supply boost circuitry  1213  (and use pulse width modulation), which may create a stable rail that can be supplied to the motor to drive the door shut. 
     Referring now to  FIG. 13 , at least one embodiment of a method  1300  for retrofitting a door closer  102  with a power boost assembly  104  is shown. As described above, it should be appreciated that a door closer  102  may be assembled to a particular door in the field without a power boost assembly  104  or similar features thereof. Rather, the door closer  102  may simply be secured to the door  122  and door frame  124  and housed within a cover large enough to secure the door closer  102 . In such circumstances, it may be beneficial to retrofit the door closer system  100  with a power boost assembly  104  to provide the benefits of assisting the door in closing described herein. In doing so, a technician may retrofit the door closer system  100  while the door closer  102  stays attached to the door  122 . 
     As such, the illustrative method  1300  begins with block  1302  in which the technician may remove an existing cover from the existing door closer  102 . Of course, it should be appreciated that the door closer  102  need not include a cover in some embodiments. In block  1304 , in some embodiments, the technician may attach a mounting plate to the door closer  102  as described above. In such embodiments, the mounting plate must include an aperture or other feature by which the power boost assembly  104  may be operably connected to the pinion  103  of the door closer  102 . 
     In block  1306 , the technician operably couples the gearing  108  of the power boost converter  104  with the pinion  103  of the door closer  102 . In particular, the pinion  103  may be inserted into a bore  109  defined within a particular gear of the gearing  108 , as described above. It should be appreciated that the operable connection is such that rotation of the pinion  103  resulting from movement of the door  122  causes a corresponding rotation of the gear of the gearing  108 . 
     In block  1308 , the technician may fasten the power boost assembly  104 , or more particularly the housing  105  of the power boost assembly  104 , to the door closer  102 . For example, in some embodiments, the technician may use the fasteners  107  to secure the two components to one another as described above. In other embodiments, the power boost assembly  104  and the door closer  102  may be secured to one another via another suitable mechanism. In yet other embodiments, the power boost assembly  104  and the door closer  102  need not be secured to one another (other than the pinion  103  and gearing  108  connection). Instead, in such embodiments, the power boost assembly  104  and/or the door closer  102  may be secured in place, for example, to the door  122  or a mounting plate secured to the door  122 . 
     In block  1310 , the technician may secure a new cover  120  (e.g., a different/larger cover) to the door closer system  100  that now includes both the door closer  102  and the power boost assembly  104 . As discussed above, in some embodiments, the cover  120  may be fastened to the door closer  102  using the same fastening mechanism used to fasten the previous cover used to house only the door closer  102 . In other embodiments, the technician need not secure a cover to house the door closer  102  and/or the power boost assembly  104 . 
     Referring now to  FIGS. 14-16 , illustrated therein is at least one other embodiment of a door closer system  1400 . The door closer system  1400  is structured and configured to harvest energy (e.g., by generating and storing the energy) via a person pushing on the door and/or via the closing force generated by a door closer, and subsequently using that harvested energy to boost the door shut (i.e., terminal shutting of the door). It should be appreciated that the door closer system  1400  may include one or more of the components or features of the door closer systems described above. Therefore, the description of such components/features is not described herein in detail for brevity and clarity. 
       FIGS. 14-16  show various views of the door closer system  1400  and/or the components/devices thereof. In particular,  FIG. 14  illustrates a front view of the door closer system  1400 , and  FIGS. 15-16  show cutaway views of the door closer system  1400  when the door is closed ( FIG. 15 ) and when the door is opened ( FIG. 16 ). As shown, the door closer system  1400  includes a door closer  1402  and a power boost assembly  1404 . 
     In the illustrative embodiment, the door closer  1402  is embodied as a hydraulic door closer. However, it should be appreciated that the door closer  1402  may be embodied as another suitable type of closer in other embodiments. As shown in  FIGS. 15-16 , the door closer  1402  includes a pinion  103 , a piston  1412 , and a spring  1414  that contacts and applies a force (when compressed) to the piston  1412  at an end  1418  of the piston  1412 . The illustrative piston  1412  and the spring  1414  are positioned with a housing  1422  of the door closer  1402  along a longitudinal axis  1416  defined by the door closer  1402 . The longitudinal axis  1416  defines a fist direction  1424  and a second direction  1426 . It should be appreciated that the closer arm  111  is operably coupled to the pinion  103  and the pinion  103  is operably coupled to the piston  1412  (either directly or indirectly) such that movement of the closer arm  111  drives rotational movement of the pinion  103  about an axis  1428 , which in turn drives movement of the piston  1412  along the longitudinal axis  1416 . In particular, when the door is moving in an opening direction, the piston  1412  is driven in the second direction  1426 . However, when the door is moving in a closing direction, the piston  1412  is driven in the first direction  1424 . Further, movement of the piston  1412  in the second direction  1426  compresses the spring  1414 , which applies a force to the piston  1412  in the first direction  1424 , thereby assisting with the closing of the door. 
     The power boost assembly  1404  includes a motor  1406 , a lead screw  1408 , and a PCBA  1410 . In the illustrative embodiment, the motor  1402  is embodied as a lead screw stepper motor. However, it should be appreciated that, in other embodiments, the motor  1402  may be embodied as any type of motor capable of performing the techniques described herein. In particular, the motor  1402  may be embodied as a type of motor with a motor-gear-screw drive type arrangement that provides linear motion and is capable of being attached to an end of the door closer  1402 . The lead screw  1408  is attached to an end  1420  of the piston  1412  opposite the end  1418  that contacts the spring  1414  such that the lead screw  1408  extends from the end  1420  along the longitudinal axis  1416 . In the illustrative embodiment, the motor  1406  is operably connected to the lead screw  1408  via a suitable driving mechanism. For example, in some embodiments, the motor  1406  and the lead screw  1408  may operably connect to one another via a rack and pinion mechanism. In other embodiments, the motor  1406  and the lead screw  1408  may be operably connected via another suitable mechanism that permits the motor  1406  to apply, directly or indirectly, a driving force to the lead screw  1408  in the first direction  1424  and allows the motor  1406  to be back driven to harvest electrical energy. 
     The PCBA  1410  may be configured similar to the PCBA  112  of the door closer system  100 . As such, the PCBA  1410  may include the hardware, firmware, and/or software (e.g., logic) for operating the power boost assembly  1404 . For example, the PCBA  1410  may include a processing device (e.g., one or more microprocessors and/or microcontrollers) or electronic circuitry (e.g., analog and/or digital). Further, in some embodiments, the PCBA  1410  may include a user interface that permits the user to adjust one or more settings of the power boost assembly  1404 . It should be appreciated that the power boost assembly  1404 , or more particularly the PCBA  1410 , may use any suitable technique for determining, for example, whether the door is in a boost region (e.g., the latch region) and/or other determinations described above in reference to the door closer system  100 . 
     In operation, as the door is opened, the linear movement of the piston  1412  in the second direction  1426  back drives the motor  1406 , which allows the harvesting of electrical energy according to principles similar to those described above. As the door closes, the motor  1402  is back driven in the opposite direction, which also allows electrical energy to be harvested. When the boost region or latch region is region is reached, the motor  1406  may be driven to pull the piston  1412  in the closing direction (i.e., in the first direction  1424 ), thereby supplying a power boost or boost force to the piston  1412 . As indicated above, the PCBA  1410  may analyze various data to determine when to harvest energy and/or when to supply electrical energy to the motor  1406  to provide a boost force. For example, in some embodiments, the motor  1406  only provides a boost force if the current closing speed of the door is insufficient to result in terminal closing of the door.