VACUUM PUMP

A battery pack powered device includes a housing including a battery pack interface configured to receive a battery pack, a first sensing circuit configured to detect a battery pack voltage of the battery pack, a second sensing circuit configured to detect a current from the battery pack, and a controller. The controller includes a processor and a memory. The controller is configured to receive a first signal from the first sensing circuit related to the battery pack voltage, receive a second signal from the second sensing circuit related to the current from the battery pack, determine a battery pack impedance based on the battery pack voltage and the current from the battery pack, determine a battery pack type of the battery pack based on the battery pack impedance, and set a voltage threshold for the battery pack based on the battery pack type.

FIELD

Embodiments described herein relate to a pump, and more particularly to a vacuum pump.

SUMMARY

Vacuum pumps may be used to remove or evacuate material, such as unwanted air, gas, and non-condensables (e.g., water vapor), from an external system (e.g., an air conditioning system, a refrigeration system, etc.). Vacuum pumps may be used to evacuate the external system before the system is charged with refrigerant or when the existing system is undergoing repair (e.g., the refrigerant is already recovered). The vacuum pump may be connected to high- and low-pressure sides of the external system via hoses and a manifold. During operation, the vacuum pump creates a low-pressure zone that draws the unwanted materials, such as air and non-condensables, out of the external system, which has a high pressure, and into the vacuum pump.

Embodiments described herein provide a device, such as a battery pack power device. Battery pack powered devices or vacuum pumps disclosed herein are connectable to an external system and configured to evacuate material from the external system. The vacuum pumps include a housing including a battery pack interface configured to receive a battery pack, a first sensing circuit configured to detect a battery pack voltage of the battery pack, a second sensing circuit configured to detect a current from the battery pack, and a controller. The controller includes a processor and a memory. The controller is configured to receive a first signal from the first sensing circuit related to the battery pack voltage, receive a second signal from the second sensing circuit related to the current from the battery pack, determine a battery pack impedance based on the battery pack voltage and the current from the battery pack, determine a battery pack type of the battery pack based on the battery pack impedance, and set a voltage threshold for the battery pack based on the battery pack type.

Embodiments described herein provide methods of operating a battery pack powered device. The methods include receiving, by a controller from a first sensing circuit, a first signal related to a battery pack voltage of a battery pack of the battery pack powered device, receiving, by the controller from a second sensing circuit, a second signal related to a current from the battery pack, determining, by the controller, a battery pack impedance based on the battery pack voltage and the current from the battery pack, determining, by the controller, a battery pack type of the battery pack based on the battery pack impedance, and setting, by the controller, a voltage threshold for the battery pack based on the battery pack type.

Embodiments described herein provide systems. The systems include a battery pack powered device, a first sensor, a second sensor, one or more indicators, and a controller. The battery pack powered device includes a battery pack. The first sensor is configured to detect a battery pack voltage of the battery pack. The second sensor is configured to detect a current from the battery pack. The controller is communicably coupled to the battery pack powered device, the first sensor, and the second sensor. The controller includes a processor and a memory. The controller is configured to receive a first signal from the first sensor representative of the battery pack voltage, receive a second signal from the second sensor representative of the current from the battery pack, determine an amount of energy the battery pack discharges over a defined time period based on at least one of the battery pack voltage and the current from the battery pack, determine a battery pack type of the battery pack based on the amount of energy the battery pack discharges over the defined time period and the current from the battery pack, and control operation of the one or more indicators based on a voltage threshold for the battery pack type that is determined and the battery pack voltage.

It should be understood that although certain drawings illustrate hardware and software located within particular devices, these depictions are for illustrative purposes only. Functionality described herein as being performed by one component may be performed by multiple components in a distributed manner. Likewise, functionality performed by multiple components may be consolidated and performed by a single component. In some embodiments, the illustrated components may be combined or divided into separate software, firmware and/or hardware. For example, instead of being located within and performed by a single electronic processor, logic and processing may be distributed among multiple electronic processors. Regardless of how they are combined or divided, hardware and software components may be located on the same computing device or may be distributed among different computing devices connected by one or more networks or other suitable communication links. Similarly, a component described as performing particular functionality may also perform additional functionality not described herein. For example, a device or structure that is “configured” in a certain way is configured in at least that way but may also be configured in ways that are not explicitly listed.

DETAILED DESCRIPTION

FIGS.1-4illustrate a vacuum pump10including a housing14, a handle18coupled to an upper portion of the housing14, and a base22coupled to a lower portion of the housing14to support the vacuum pump10relative to the ground. The housing14defines an internal cavity (seeFIG.3) that has a first chamber26that houses, protects, and/or conceals a motor assembly an electronic control unit34, and other electronic components. The internal cavity of the housing14also defines a second chamber (e.g., a compression chamber38) that houses a pump assembly42.

With reference toFIG.1, an inlet44is positioned on an upper portion of the housing14and is in communication with the pump assembly42. The inlet44is fluidly connected to a hose40that connects the vacuum pump10to an external system46(e.g., an air conditioning system, a refrigeration system, etc.). In the illustrated embodiment, the inlet44includes multiple connection ports48that are sized to connect to the hose40of the external system46. For example, the connection ports48may have various sizes (e.g., ½ inch, ¼ inch, etc.).

A battery pack50is removably coupled to an end portion of the housing14via a battery receptacle52. The battery pack50provides electrical current to the motor assembly30that drives the pump assembly42to remove or evacuate material such as air, gas, and non-condensables (e.g., water vapor) from the external system46. The vacuum pump10includes a control panel54on a sidewall of the housing14. In the illustrated embodiment, the control panel54includes a power switch56that selectively activates the vacuum pump10and a Universal Serial Bus (“USB”) port58. In some embodiments, an external display may be connected to the USB port58to display information related to the operation of the vacuum pump (e.g., battery life remaining, micron gauge, etc.). In other embodiments, the control panel54may include a display (e.g., a liquid crystal display).

With reference toFIG.3, the compression chamber38is sealed relative to the first chamber26via a partition wall60so the compression chamber38can hold lubrication fluid (e.g., oil). In the illustrated embodiment, the partition wall60defines a fluid pathway68that extends between the inlet44and the pump assembly42. The lubrication fluid positioned within the compression chamber38is used to lubricate and cool the pump assembly42during operation of the vacuum pump10.

With reference toFIG.2, the compression chamber38further includes a fluid port62having a removable cap66, a fluid gauge70positioned on a sidewall of the housing14, a release valve74positioned on the upper portion of the housing14, and a fluid drain valve78positioned at the bottom of the compression chamber38adjacent the base22. In the illustrated embodiment, a user may remove the removable cap66to fill the compression chamber38with lubrication fluid via the fluid port62. The fluid port62and the removable cap66may also function as an exhaust during operation of the vacuum pump10. The fluid gauge70may be transparent to allow a user to determine the amount of lubrication fluid that is held within the compression chamber38. Also, the fluid drain valve78allows the user to drain the lubrication fluid from the compression chamber38.

With reference toFIG.4, the motor assembly30is positioned within the first chamber26and is coupled to the partition wall60via a support bracket80. The motor assembly includes a motor82and a fan86driven by the motor82. In the illustrated embodiment, the motor82is a brushless direct current (“BLDC”) motor that has a motor shaft90having a first end coupled to the fan86and a second end coupled to the pump assembly42, a rotor94coupled to the motor shaft90, and a stator98surrounding the rotor94. During operation of the motor82, an electrical current flows through coils of the stator98to produce a magnetic field around the rotor94, which causes the motor shaft90to rotate about a drive axis100and drive the pump assembly42. The fan86is positioned between the electronic control unit34and the motor assembly30. The fan86removes heat from the electronic control unit34and provides air to the motor assembly30to prevent overheating of each of the electronic control unit34and the motor assembly30. Although the motor82of the illustrated embodiment is a BLDC motor, in other embodiments, the motor82may alternatively be a brushed direct current motor or any other type of DC motor.

With reference toFIG.4, the pump assembly42is a two-stage pump that has a first pump chamber102and a second pump chamber106in series with the first pump chamber102. The first pump chamber102has a pump inlet104in communication with the fluid pathway68. The first pump chamber102is in fluid communication with the second pump chamber106. The second pump chamber106has a pump outlet110that releases the pressure from the pump assembly42to the compression chamber38. Specifically, the pump chambers102,106create low-pressure zones within the pump assembly42, which draws material out of the external system46(seeFIG.1) and into the pump assembly42. The evacuated material is transferred from the first pump chamber102to the second pump chamber106, at which point the evacuated material is discharged into the compression chamber38via the second pump outlet110. In the illustrated embodiment, the second pump outlet110includes a valve (e.g., a reed valve, etc.) that selectively releases the evacuated material into the compression chamber38before being released from the vacuum pump10through the exhaust (e.g., via the cap66) of the compression chamber38. Although the illustrated pump assembly42is a two-stage pump (e.g., has first and second pump chambers), in other embodiments, the pump assembly42may only include a single stage or chamber.

During operation, a user may attach the battery pack50to the battery receptacle52of the vacuum pump10, and fluidly connect the external system46to the vacuum pump10via the inlet44(e.g., with the hose40). The user may activate the vacuum pump10with the control panel54(e.g., by depressing the power switch56) to activate the motor assembly30and begin evacuating material from the external system46. When the vacuum pump10is activated, the first and second pump chambers102,106create a low-pressure zone to evacuate material from the external system46.

FIG.5illustrates a control system for the vacuum pump10. The control system includes the electronic control unit34. The electronic control unit34is electrically and/or communicatively connected to a variety of modules or components of the vacuum pump10. For example, the illustrated electronic control unit34is electrically connected to the motor82, the batter receptacle52(e.g., battery pack interface), a switch500(connected to the power switch56), one or more sensors or sensing circuits505, one or more indicators510, the control panel54(e.g., a user input module), a wireless communication controller515, a power input module520, and a switching module525(e.g., including a plurality of switching FETs). The electronic control unit34includes combinations of hardware and software that are operable to, among other things, control the operation of the vacuum pump10, monitor the operation of the vacuum pump10, activate the one or more indicators510(e.g., an LED), etc.

The electronic control unit34includes a plurality of electrical and electronic components that provide power, operational control, and protection to the components and modules within the electronic control unit34and/or the vacuum pump10. For example, the electronic control unit34includes, among other things, a processing unit530(e.g., a microprocessor, a microcontroller, an electronic processor, an electronic controller, or another suitable programmable device), a memory535, input units540, and output units545. The processing unit530includes, among other things, a control unit550, an arithmetic logic unit (“ALU”)555, and a plurality of registers560(shown as a group of registers inFIG.5), and is implemented using a known computer architecture (e.g., a modified Harvard architecture, a von Neumann architecture, etc.). The processing unit530, the memory535, the input units540, and the output units545, as well as the various modules or circuits connected to the electronic control unit34are connected by one or more control and/or data buses (e.g., common bus565). The control and/or data buses are shown generally inFIG.5for illustrative purposes. The use of one or more control and/or data buses for the interconnection between and communication among the various modules, circuits, and components would be known to a person skilled in the art in view of the invention described herein.

The memory535is a non-transitory computer readable medium and includes, for example, a program storage area and a data storage area. The program storage area and the data storage area can include combinations of different types of memory, such as a ROM, a RAM (e.g., DRAM, SDRAM, etc.), EEPROM, flash memory, a hard disk, an SD card, or other suitable magnetic, optical, physical, or electronic memory devices. The processing unit530is connected to the memory535and executes software instructions that are capable of being stored in a RAM of the memory535(e.g., during execution), a ROM of the memory535(e.g., on a generally permanent basis), or another non-transitory computer readable medium such as another memory or a disc. Software included in the implementation of the vacuum pump10can be stored in the memory535of the electronic control unit34. The software includes, for example, firmware, one or more applications, program data, filters, rules, one or more program modules, and other executable instructions. The electronic control unit34is configured to retrieve from the memory535and execute, among other things, instructions related to the control processes and methods described herein. In other constructions, the electronic control unit34includes additional, fewer, or different components.

The battery receptacle or battery pack interface52includes a combination of mechanical components (e.g., rails, grooves, latches, etc.) and electrical components (e.g., one or more terminals) configured to and operable for interfacing (e.g., mechanically, electrically, and communicatively connecting) the vacuum pump10with a battery pack (e.g., the battery pack For example, power provided by the battery pack50to the vacuum pump10is provided through the battery receptacle52to the power input module520. The power input module520includes combinations of active and passive components to regulate or control the power received from the battery pack50prior to power being provided to the electronic control unit34. The battery receptacle52also supplies power to the FET switching module525to provide power to the motor82. The battery receptacle52also includes, for example, a communication line570for providing a communication line or link between the electronic control unit34and the battery pack50.

The indicators510include, for example, one or more light-emitting diodes (“LEDs”) and/or audio signaling devices. The indicators510can be configured to display or indicate conditions of, or information associated with, the vacuum pump10. For example, the indicators510are configured to indicate measured electrical characteristics of the vacuum pump10, the status of the vacuum pump10, etc. The control panel54is operably coupled to the electronic control unit34to, for example, select an operating mode (e.g., a boost mode of operation or an eco mode of operation), a torque and/or speed setting for the vacuum pump10(e.g., using torque and/or speed switches), etc. In some embodiments, the control panel54includes a combination of digital (see, e.g., user interface800ofFIG.8) and analog input or output devices required to achieve a desired level of operation for the vacuum pump10, such as one or more knobs, one or more dials, one or more switches, one or more buttons, etc.

The electronic control unit34is configured to determine a battery pack type of the battery pack50of the vacuum pump10. In some embodiments, the electronic control unit34sets a voltage threshold based on the battery pack type and controls the one or more indicators510using the voltage threshold. Additionally, the electronic control unit34is configured to control the operating speed of the vacuum pump10to reduce the amount of current drawn from the battery pack50based on a set voltage threshold associated with a determined battery pack type and/or user selected operating mode.

FIG.5provides an illustration of the wireless communication controller515that includes a processor600, a memory605, a real-time clock (“RTC”)610, and an antenna and transceiver615, as shown inFIG.6. The wireless communication controller515enables the vacuum pump10to communicate with an external device705(see, e.g.,FIG.7). The radio antenna and transceiver615operate together to send and receive wireless messages to and from the external device705and the processor600. The memory605can store instructions to be implemented by the processor600and/or may store data related to communications between the vacuum pump10and the external device705or the like. The RTC610can increment and keep time independently of the other device components. The RTC610can receive power from the battery pack50when the battery pack50is connected to the vacuum pump10. The processor600for the wireless communication controller515controls wireless communications between the vacuum pump10and the external device705. For example, the processor600associated with the wireless communication controller515buffers incoming and/or outgoing data, communicates with the electronic control unit34, and determines the communication protocol and/or settings to use in wireless communications. The communication via the wireless communication controller515can be encrypted to protect the data exchanged between the vacuum pump10and the external device705from third parties.

In the illustrated embodiment, the wireless communication controller515is a Bluetooth® controller. The Bluetooth® controller communicates with the external device705employing the Bluetooth® protocol. Therefore, in the illustrated embodiment, the external device705and the vacuum pump10are within a communication range (i.e., in proximity) of each other while they exchange data. In other embodiments, the wireless communication controller515communicates using other protocols (e.g., Wi-Fi, ZigBee, a proprietary protocol, etc.) over different types of wireless networks. For example, the wireless communication controller515may be configured to communicate via Wi-Fi through a wide area network such as the Internet or a local area network, or to communicate through a piconet (e.g., using infrared or NFC communications).

In some embodiments, the network is a cellular network, such as, for example, a Global System for Mobile Communications (“GSM”) network, a General Packet Radio Service (“GPRS”) network, a Code Division Multiple Access (“CDMA”) network, an Evolution-Data Optimized (“EV-DO”) network, an Enhanced Data Rates for GSM Evolution (“EDGE”) network, a 3GSM network, a 4GSM network, a 4G LTE network, 5G New Radio, a Digital Enhanced Cordless Telecommunications (“DECT”) network, a Digital AMPS (“IS-136/TDMA”) network, or an Integrated Digital Enhanced Network (“iDEN”) network, etc.

The wireless communication controller515is configured to receive data from the electronic control unit34and relay the information to the external device705via the antenna and transceiver615. In a similar manner, the wireless communication controller515is configured to receive information (e.g., configuration and programming information) from the external device705via the antenna and transceiver615and relay the information to the electronic control unit34.

FIG.7illustrates a communication system700. The communication system700includes at least one of the vacuum pump10(illustrated as a power tool device) and the external device705. The vacuum pump10and the external device705can communicate wirelessly while they are within a communication range of each other. The vacuum pump10may communicate a status, operation statistics, sensor data, stored usage information, and the like associated with the vacuum pump10.

More specifically, the vacuum pump10can monitor, log, and/or communicate various operational parameters. The external device705can also transmit data to the vacuum pump10for pump configuration, firmware updates, or to send commands. The external device705also allows a user to set operational parameters, safety parameters, select tool modes, and the like for the vacuum pump10.

The external device705is, for example, a smart phone (as illustrated), a laptop computer, a tablet computer, a personal digital assistant (“PDA”), or another electronic device capable of communicating wirelessly with the vacuum pump10and providing the user interface800(see, e.g.,FIG.8). The external device705provides the user interface800and allows a user to access and interact with the vacuum pump10. The external device705can receive user inputs to determine operational parameters, enable or disable features, and the like. The user interface800of the external device705provides an easy-to-use interface for the user to control and customize operation of the vacuum pump10.

In addition, as shown inFIG.7, the external device705can also share the operational data obtained from the vacuum pump10with a remote server725connected through a network715. The remote server725may be used to store the operational data obtained from the external device705, provide additional functionality and services to the user, or a combination thereof. In some embodiments, storing the information on the remote server725allows a user to access the information from a plurality of different locations. In some embodiments, the remote server725collects information from various users regarding their power tool devices and provide statistics or statistical measures to the user based on information obtained from the different power tools. The network715may include various networking elements (routers710, hubs, switches, cellular towers720, wired connections, wireless connections, etc.) for connecting to, for example, the Internet, a cellular data network, a local network, or a combination thereof, as previously described. In some embodiments, the vacuum pump10is configured to communicate directly with the server725through an additional wireless interface or with the same wireless interface that the vacuum pump10uses to communicate with the external device705.

FIG.8illustrates the user interface800for the vacuum pump10. In some embodiments, the user interface800is included in the external device705. The user interface800includes a plurality of graphical user interface elements, such as, a power control input805, a first operating mode input810, a second operating mode input815, and a user selection mode input820. The power control input805is configured to enable a user to activate and deactivate (e.g., turn ON and OFF) the vacuum pump10. The first operating mode input810is configured to enable a user to control performance of the vacuum pump10according to a first set of operating parameters. For example, the first operating mode input810provides operating parameters to reduce pump speed of the vacuum pump10based on a determination that a voltage of the battery pack50has reached a set threshold. In some embodiments the first operating mode input810is configured to control operation of the vacuum pump10into a “boost” or high-power mode of operation. The second operating mode input815is configured to enable a user to control performance of the vacuum pump10according to a second set of operating parameters. For example, the second operating mode input815provides operating parameters to reduce pump speed of the vacuum pump10based on a determination that a timer associated with the second operating mode has elapsed and/or an atmospheric pressure of the vacuum pump10has reached a set threshold. In some embodiments the second operating mode input815is configured to control operation of the vacuum pump10into an “eco” or economy mode of operation. The user selection mode input820is configured to enable a user to control performance of the vacuum pump10according to a set of operating parameters provided by the user. For example, the user selection mode input820provides operating parameters to adjust pump speed of the vacuum pump10based on a user selection of one of multiple operating speeds of the vacuum pump10.

FIG.9illustrates a circuit diagram900of the FET switching module525. The FET switching module525includes a number of high side power switching elements902and a number of low side power switching elements904. The electronic control unit34provides the control signals to control the high side FETs902and the low side FETs904to drive the motor82based on the motor feedback information and user controls, as described above. For example, in response to detecting activation of the power switch56, the electronic control unit34provides the control signals to selectively enable and disable the FETs902and904(e.g., sequentially, in pairs) resulting in power from the power source910(e.g., battery pack50) to be selectively applied to stator coils of the motor82to cause rotation of a rotor. More particularly, to drive the motor82, the electronic control unit34enables a first high side FET902and first low side FET904pair (e.g., by providing a voltage at a gate terminal of the FETs) for a first period of time. In response to determining that the rotor of the motor82has rotated based on a pulse from the sensing circuits505, the electronic control unit34disables the first FET pair, and enables a second high side FET902and a second low side FET904. In response to determining that the rotor of the motor82has rotated based on pulse(s) from the sensing circuits505, the electronic control unit34disables the second FET pair, and enables a third high side FET902and a third low side FET904. This sequence of cyclically enabling pairs of high side FET902and low side FET904repeats to drive the motor82. Further, in some embodiments, the control signals include pulse width modulated (PWM) signals having a duty cycle that is set based on the power switch56, to thereby control the speed or torque of the motor82.

FIG.10Aillustrates a current flow diagram1000of the FET switching module525for using current to determine battery pack impedance. The FET switching module525includes the plurality of high side power switching elements902and the plurality of low side power switching elements904, as described above. For example, in response to detecting activation of the power switch56, the electronic control unit34provides the control signals to selectively enable and disable the FETs902and904(e.g., sequentially, in pairs) resulting in power being provided from the power source (e.g., battery pack50). Current1010travels from the power source910through one of the high side power switching elements902to stator coils of the motor82. The current1010then travels from the motor82to one of the low side power switching elements904before completing a path of connection1015of the power source910.

FIG.10Billustrates another embodiment of a current flow diagram1020of the FET switching module525for using current to determine battery pack impedance. The FET switching module525includes the plurality of high side power switching elements902and the plurality of low side power switching elements904, as described above. For example, in response to detecting activation of the power switch56, the electronic control unit34provides the control signals to selectively enable and disable the FETs902and904(e.g., sequentially, in pairs) resulting in power being provided from the power source910(e.g., the battery pack50). Current1010travels from the power source910through one high side power switching elements902, to one low side power switching elements904. The current1010closes the circuit by then returning to the power source910. This reduced current1010path only travels through two switching FETs and completes a shorter portion of the path of connection1015of the power source910. In some embodiments, one or more high side power switching elements902and/or one or more low side power switching elements904are enabled at the same time. Such control may decrease the overall resistance of the system and enable higher current flow and distributing the load of the system through the FETs902and904to reduce FET902and904burnup.

FIG.10Cillustrates another embodiment of a current flow diagram1025of the FET switching module525for using current to determine battery pack impedance. In this embodiment, an additional switching module1030is connected to the path of connection1015. In addition to the additional switching module1030, an additional resistor is connected to the path of connection1015. For example, in response to detecting activation of the power switch56, the electronic control unit34provides the control signals to selectively enable and disable the switching module1030resulting in power being provided from the power source910(e.g., the battery pack50). Current1010travels from the power source910through the additional resistor, then through the additional switching module1030. The current1010only travels through the additional resistor and the additional switching module1030then returns to the power source910to close the circuit. In other embodiments, an inductor can be used for similar purposes as the additional resistor. Additionally, other circuitry configurations may be configured in such a way that other components can be used (e.g., a capacitor).

FIG.10Dillustrates yet another embodiment of a current flow diagram1035of the FET switching module525for using current to determine battery pack impedance. In this embodiment, only one power switching module904is used. For example, in response to detecting activation of the power switch56, the electronic control unit34provides the control signals to selectively enable and disable the power switching element904resulting in power being provided from the power source910(e.g., the battery pack50). Current1010travels from the power source910to the motor82(e.g., a brushed motor), then to the power switching element904before closing the path of connection1015.

FIG.11Aillustrates a method1100executed by the electronic control unit34of the vacuum pump10. The vacuum pump10is activated (STEP1105) to initialize the method1100by the electronic control unit34. For example, the vacuum pump10may be activated by detecting activation of the power switch56, which causes the battery pack50to deliver power to the vacuum pump10. The electronic control unit34receives or measures the battery pack voltage from the battery pack50, and the electronic control unit34determines or calculates a starting battery pack voltage (STEP1110). The vacuum pump10then receives one or more signals from the plurality of sensing circuits505(e.g., Hall Effect sensors) related to a rotational position of the motor82(i.e., the rotor). Data corresponding to the one or more signals are stored within the memory535for determining rotor position (STEP1115). In some embodiments, the power tool does not include Hall Effect sensors. Instead, the power tool uses back-emf to determine the position of the motor. In other embodiments, an inrush technique by enabling the high side switching elements902and the low side switching elements904can derive the position of the motor (e.g., through back-emf, Hall transition, etc.). In other embodiments, the motor82position may be ascertained by conducting multiple quick inrush pulses and comparing relative impedances. In other embodiments, the position of the motor is not used in the case where the inductance is similar regardless of motor rotation.

In some embodiments, STEPS1115and1120may be optional. If the location of the rotor is known, the current may flow through a path with ideal inductance. Higher inductance corresponds to a slower rise in current. This allows more time for the rise in current, which helps to take the measurement. If there is a fixed time period delay (described in further detail below), it also avoids draining too much current that might damage electrical components.

Using the data received from the aforementioned sensing circuits505, the vacuum pump10initiates power to one or more high side power switches modules902, and one or more low side switching modules904, which consequently conducts current through the motor82(STEP1120). A delay is then instituted to allow for a flow of current through the system (STEP1125). The delay allows for the current to rise to a level that can be reliably read with sufficient resolution. Without the delay, there may not be a significant enough change in voltage or current. The length of the delay prevents burning up an electrical component (e.g., an FET902and904), as well as not allowing the motor to over significantly rotate. In some embodiments, the method is delayed approximately 40 μs. In other embodiments, longer or shorter delays can be implemented to avoid transient voltage or current spikes. In some embodiments, one of a hard busy wait is used. In some embodiments, a measurement includes multiple samples (e.g., of current and voltage).

FIG.11Billustrates a continuation of the method1100executed by the electronic control unit34. After implementing a delay at STEP1125, the electronic control unit34is configured to sample a current sense input to an analog-to-digital converter (“ADC”) and receives or measures a second voltage (e.g., sampling a voltage sense input to an ADC). In some embodiments, multiple samples are taken within a measurement. The electronic control unit34uses the sampled current sense input to then calculate the current of the battery pack50, Ibat, and the second voltage measurement, Vend(STEP1130). The electronic control unit34is then configured to turn off the low side power switches904to allow the high side power switches902to freewheel current (STEP1135). Another delay is used to allow the high side power switches902to freewheel current for an amount of time (STEP1140). In some embodiments, the method is delayed approximately 100 μs. In other embodiments, longer or shorter delays can be implemented. After the second delay of the method1100, the high side power switching902is turned off.

Using the starting battery voltage from STEP1110, the second battery voltage from STEP1130, and the calculated current of the battery pack50from STEP1130, the electronic control unit34is configured to determine the impedance of the battery pack50. The impedance of the battery pack50can be calculated by the electronic control unit34using, for example, the following equation:

Although EQN. 1 provides one example of how battery pack impedance can be determined, other techniques for determining battery pack impedance can also be used.

In another embodiment of estimating impedance of the battery pack, the rate of voltage drop and rate of current increase can be used in relation of the inductance of the system. The voltage drop is measured at least twice, and assumes a fixed inductance. In another embodiment of estimating impedance of the battery pack, the measurement of current alone may also be used to estimate general impedance of the battery pack. In another embodiment of estimating impedance of the battery pack, the integration of measured current over time may be used to find an estimation of the impedance of the battery pack. Similarly, the integration of voltage over time may be used to find an estimation of the impedance of the battery pack. Similarly, the derivative of the rising current and/or the derivative of the falling voltage may also be used to find an estimation of the impedance of the battery pack.

In another embodiment of estimating impedance of the battery pack, during an inrush current technique, voltage and current samples are measured to perform a slope calculation to find impedance. The slope calculation can feed into another algorithm (e.g., a neutral net, filter functions, etc.) to derive multiple aspects of the impedance (e.g., resistance, capacitance, inductive loading, etc.). Additionally, the inrush technique could be used with multiple inrush spikes and the results can be combined for a more precise output.

FIG.11Cis a continuation of method1100. If, at STEP1150, the calculated impedance is greater than or equal to a certain predetermined value (e.g., a value of 50 to 80 milli-Ohms), the electronic control unit34is configured to determine that the battery pack50is a particular type of battery pack (STEP1155). The electronic control unit34then proceeds to control the vacuum pump10(e.g., to control current drawn from the battery pack50) based on the determination of the particular type of battery pack and the calculated impedance. If, at STEP1150, the calculated impedance is less than the certain predetermined value, the electronic control unit34is configured to determine that the battery pack50is a second particular type of battery pack (STEP1160). The electronic control unit34then proceeds to control the vacuum pump10(e.g., to control current drawn from the battery pack50) based on the determination of the second particular type of battery pack and/or the calculated impedance. In other embodiments, any number of different types of battery packs can be identified (e.g., three or more, between three and 20, etc.). In some embodiments, multiple impedance thresholds are included for determining the type of battery pack. In some embodiments, the impedance is a continuous parameter that is used to identify the type of battery pack (e.g., using a lookup table). In another embodiment, the voltage and/or current of the system may be measured by the battery pack. In other embodiments, the voltage and/or current measurements may be communicated to the tool (e.g., via digital or analog interface). In other embodiments, the battery pack may self-calculate its own impedance. The battery pack may communicate the self-calculated impedance of the battery pack to the power tool. In another embodiment, the power tool may calculate the impedance of the battery pack, then communicate the result of the calculation to the battery pack.

In some embodiments, the determination of the type of the battery pack may be probabilistic. In some embodiments, the type of the battery pack may be found by a thermal measurement. The thermal measurement of the battery pack may be found using a temperature sensor (e.g., a thermistor, thermocouple, etc.). Because impedance changes with temperature, the thermal measurement can be used to identify the most probable battery pack type.

FIG.12illustrates a method1200executed by the electronic control unit34of the vacuum pump10. The vacuum pump10is powered on (STEP1205) to initialize the method1200by the electronic control unit34. For example, the vacuum pump10may be activated by detecting activation of the power switch56, which causes the battery pack50to deliver power to the vacuum pump10. The electronic control unit34then initiates an impedance check to determine an impedance of the battery pack50(e.g., using one of the methods described above) (STEP1210). For example, the electronic control unit34receives a user selection of an operating mode via the control panel54. The electronic control unit34then proceeds to control the vacuum pump10based on the operating parameters of the user selection (STEP1215). The electronic control unit34receives or measures the battery pack50voltage from the battery pack50, and the electronic control unit34determines or calculates a starting battery pack voltage. The electronic control unit34then receives one or more signals (e.g., current and voltage measurements associated with the battery pack50) from the sensing circuits505(STEP1220). In some embodiments, the electronic control unit34logs data corresponding to the one or more signals in the memory535for determining a battery pack impedance and a battery pack type of the battery pack50. The electronic control unit34then identifies the battery pack50based on an impedance of the battery pack using one of the methods described above (STEP1220). In addition to, or alternatively, in some embodiments, the electronic control unit34uses the data (e.g., energy discharged, energy discharge time, battery pack voltage, current) logged in the memory535to determine a battery type. Using the starting battery voltage from STEP1210, the starting battery pack voltage and the current of the battery pack from STEP1220the electronic control unit34is configured to determine the energy discharged by the battery pack50. The electronic control unit34sets a voltage threshold based on the battery pack type of the battery pack50(STEP1235). For example, the electronic control unit34sets a low battery alert based on a determined battery pack type of the battery pack50connected to the vacuum pump10.

The electronic control unit34compares the battery pack voltage to the voltage threshold (STEP1240). If, at STEP1240, the battery pack voltage is greater than a voltage threshold of the battery pack50, the electronic control unit34is configured to continue to monitor the voltage of the battery pack50(STEP1240). The electronic control unit34then proceeds to control the vacuum pump10(e.g., to control current drawn from the battery pack50) based on a first set of operating parameters of the selected operating mode. If, at STEP1240, the battery pack voltage is less than or equal to a voltage threshold of the battery pack50, the electronic control unit34is configured to perform a defined action (STEP1245). The defined action can include the electronic control unit34proceeding to control the vacuum pump10(e.g., to control current drawn from the battery pack50) based on a second set of operating parameters of the selected operating mode. In some embodiments the electronic control unit34reduces the speed of the motor82to decrease the discharge rate of the battery pack50and reduce airflow, which extends runtime of the vacuum pump10, while maintaining performance conditions provided by the vacuum pump10. In some implementations, the electronic control unit34activates the indicators510. For example, one or more LEDs can be turned on or a buzzer can be triggered to indicate a battery pack state of charge or remaining run time.

FIG.13illustrates a method1300for controlling the vacuum pump10executed by the electronic control unit34. The vacuum pump10is powered on to initialize the method1300by the electronic control unit34. For example, the vacuum pump10may be activated by receiving a signal from the control panel54associated with a user selection to power on the vacuum pump10, which causes the battery pack50to deliver power to the vacuum pump10. In another example, the signal is associated with a mode of operation set using the user interface800, as shown inFIG.8. The electronic control unit34controls the current the battery pack50provides to the motor assembly30that drives the pump assembly42that removes or evacuates material from the external system46at first flowrate (STEP1305). For example, the first flowrate may be associated with a default flowrate of the vacuum pump10. The electronic control unit34initiates a timer associated with a start time of the pump assembly42and/or the first flowrate (STEP1310).

The electronic control unit34receives a signal associated with a user selection from the control panel54(STEP1315). In some embodiments, STEP1315is optional. The electronic control unit34receives a signal that indicates a defined time period from initiation of the start time has elapsed (STEP1320). In some embodiments, the timer in STEP1310is not initiated until after the user selection from the control panel54is received. The electronic control unit34is configured to control the vacuum pump10(e.g., to control the speed of the motor82) based on operating parameters (e.g., flowrate) associated with the user selection of a second operating mode (STEP1325). For example, the electronic control unit34drives the pump assembly42at a first flowrate, such as, for example a default flow rate of five (5) cubic feet per minute (CFM) (e.g., corresponding to 2,500 motor rotations per minute [“RPM”]. In this example, after the electronic control unit34receives an operation mode selection, the electronic control unit34can reduce or increase a flowrate of the vacuum pump10based on the operation mode selection. In an “eco” or economy mode, the flowrate of the vacuum pump10is reduced (e.g., from 5 CFM to 3 CFM). As indicated above, the eco mode can be entered after an amount of time (e.g., a predetermined amount of time) has elapsed or immediately upon receiving a corresponding user input (e.g., from user interface800). In a “boost” or high-power mode, the flowrate of the vacuum pump10is increased (e.g., from 5 CFM to 7 CFM). As indicated above, the boost mode can be entered after an amount of time (e.g., a predetermined amount of time) has elapsed or immediately upon receiving a corresponding user input (e.g., from user interface800). In some embodiments, the user interface800is used to select specific values for either the RPM of the motor82or specific values for CFM. In some embodiments, the defined time period from initiation of the start time has elapsed, and then the electronic control unit34receives a signal associated with the second operating mode, the electronic control unit34immediately reduces (eco mode) or increases (boost mode) a flowrate of the vacuum pump10.

FIG.14Aillustrates a method1400for controlling a low battery notification of the vacuum pump10executed by the electronic control unit34. The vacuum pump10is powered on to initialize the method1400by the electronic control unit34. The electronic control unit34determines a battery pack voltage and an impedance of the battery pack50using one of the methods described above (STEP1405). In some embodiments, the electronic control unit34determines the current the battery pack50provides to the vacuum pump10. The method1400then proceeds toFIG.14B.FIG.14Bis a continuation of the method1400. Using the determined battery pack voltage from STEP1405, the electronic control unit34determines whether the determined battery pack voltage is greater than a default threshold voltage (STEP1410). If, at STEP1410, the determined battery pack voltage is less than or equal to the default threshold voltage, then electronic control unit34proceeds to control the indicators510of the vacuum pump10(STEP1450) (seeFIG.14A). For example, the default threshold voltage is associated with an initial startup voltage of the battery pack50(e.g., a near dead battery) and the electronic control unit34enables the indicators510to notify a user of the status of the battery pack50. If, at STEP1410, the determined battery pack voltage is greater than the default threshold voltage, then electronic control unit34proceeds to determine whether the battery pack provides a measurable voltage, such as, for example a check voltage (STEP1415).

If, at STEP1415, the determined battery pack voltage is less than or equal to the check threshold, then electronic control unit34proceeds to control the indicators510of the vacuum pump10(STEP1450) (seeFIG.14A). For example, the check voltage is associated with a voltage of the battery pack50(e.g., a low battery) that the sensors505are capable of sensing for an accurate measurement, and the electronic control unit34enables the indicators510to notify a user of the status of the battery pack50after, for example, expiration of a time threshold (e.g., eight minutes of discharge for a 12.0 AH battery pack). If, at STEP1415, the determined battery pack voltage is greater than the check threshold, the electronic control unit34is configured to log the battery pack voltage and the current of the battery pack50in, for example, the memory535(STEP1420) (seeFIG.14A).

Using the battery voltage and current from STEP1420, the electronic control unit34is configured to determine an amount of energy discharged from the battery pack50over a defined time period (STEP1425). The amount of energy discharged from the battery pack50can be calculated by the electronic control unit34. In some embodiments of estimating the discharged energy of the battery pack50, the electronic control unit34determines a moving average of the current and voltage of the battery pack50, and uses a Riemann sum to integrate for a value of energy to change in voltage. In another embodiment of estimating the discharged energy of the battery pack50, the measurement of current or voltage alone may also be used to estimate the discharged energy of the battery pack50.

Using logged data from STEP1420and the discharged energy from STEP1425, the electronic control unit34compares the logged data in the memory535to profiles of identified battery packs in the memory535(STEP1430). The logged data includes, for example, a time related to a voltage drop of the battery pack50, the average current of the battery pack50over the time related to the voltage drop (e.g., from 16.5V to 16.0V), etc. In some embodiments, in addition to the logged data, the electronic control unit34compares the impedance of the battery pack50and the impedance of the profiles of identified battery packs in the memory535. For example, larger battery packs output greater amounts of energy over a smaller change in voltage than smaller battery packs.

If, at STEP1435, the discharged energy of the battery pack50is approximately equivalent to a discharged energy value in a profile of a first battery type (e.g., 6.0 Ampere hour [Ah] battery pack), the electronic control unit34is configured to determine that the battery pack is a battery of the first battery type. The electronic control unit34then proceeds to control the indicators510of the vacuum pump10to indicate a state of charge of the battery pack50based on the first battery type and the battery pack voltage of the battery pack50(STEP1450). In some embodiments, a buzzer can be sounded or the indicators510can be activated to indicate that the battery pack50has reached a low battery level.

FIG.14Cis a continuation of the method1400. If, at STEP1435, the electronic control unit34determines that the battery pack50is not a battery of the first battery type, the electronic control unit34is configured to determine whether the battery pack50is a battery of a second battery type (STEP1440). If, at STEP1440, the discharged energy of the battery pack50is approximately equivalent to a discharged energy value in a profile of the second battery type (e.g., 12.0 Ampere hour [Ah] battery pack), the electronic control unit34is configured to determine that the battery pack50is a battery of the second battery type (STEP1440). The electronic control unit34then proceeds to control the indicators510of the vacuum pump10to indicate a state of charge of the battery pack50based on the second battery type and the battery pack voltage of the battery pack50while monitoring the voltage of the battery pack50(STEP1445). In some embodiments, the electronic control unit waits until after, for example, expiration of the time threshold (e.g., eight minutes of discharge for a 12.0 AH battery pack). For example, the electronic control unit34monitors the voltage of the battery pack50(e.g., waiting until the voltage reaches the set voltage threshold to enable a buzzer or indicators510). If, at STEP1440, the discharged energy of the battery pack50is not approximately equivalent to a discharged energy value in a profile of the second battery type (e.g., 12.0 Ampere hour [Ah] battery pack), the electronic control unit34is configured to control the indicators510of the vacuum pump10(e.g., enable a buzzer based on the battery pack voltage).

Thus, embodiments described herein provide, among other things, a vacuum pump that can determine an impedance of a battery pack, a discharged energy of the battery pack, and control the speed of a motor in the pump. Various features and advantages are set forth in the following claims.