INTELLIGENT SWITCH FOR POWER MANAGEMENT

Abstract: A method and system for managing power in a device having a power source (30) is described. The system includes a switch (26) and at least one controller (22). The switch is coupled with the power source and a portion of the device (32, 34, 36, 38). The at least one controller is coupled with the switch and is for controlling the switch to be open or closed based on instructions provided to the controller. Thus, the switch and controller can manage the power provided to the portion of the device.

Description: INTELLIGENT SWITCH FOR POWER MANAGEMENT FIELD OF THE INVENTION The present invention relates to systems which may have a limited power supply and more particularly to a method and system for providing an intelligent switch to provide power management in such as system. BACKGROUND OF THE INVENTION Many systems utilize a power supply which may have a limited capacity. For example, truck tractors, boats, golf carts, and satellites may utilize a battery or other energy storage apparatus for DC electrical power. These devices may have a mechanism for recharging the battery, such as an alternator. However, on occasion these devices operate on the stored power from the battery. For example, a truck tractor typically includes an alternator for generating power, a battery for storing power, and various subsystems which may consume power. These power consumers include a cranking system; lights; computers; communication devices electronics for the engine, brakes, steering and other subsystems; and comfort devices such as heating cooling, ventilation, refrigeration, microwaves, and televisions. Many of the power consumers can operate on the stored power of the battery alone when the alternator is not generating power. Breakdown of the electrical system can be the primary cause of failure for many of these devices, such as the tractor trailer. Even where the electrical system is less subject to malfunctions, breakdown of the electrical system can cause the device to be unable to function. Such a failure of the device may be expensive, both to repair and in other costs absorbed by the user. For example, a failure of the electrical system which drains the battery of a truck tractor may be costly not only because the truck tractor must be towed to another location and repaired, but also because time and perishable cargo may be lost. Consequently, the ability to predict, diagnose, and avoid such failures is desirable. Mechanisms for avoiding such failure are disclosed in U.S. Patent No. 5,871,858 by Thomsen et al. ("Thomsen") and U.S. Patent No. 5,798,577 by Lesesky et al. ("Lesesky"). Thomsen and Lesesky treat one problem that has been diagnosed in devices such as a truck tractor, the problem of overcranking. Consequently, Thomsen discloses cutting off power to the cranking system of a truck tractor when the current flowing and time for which the current flows exceed a particular level. Similarly, Lesesky discloses cutting off power to the cranking system of a truck tractor when a user has provided a cranking signal for greater than a particular time. Furthermore, Thomsen treats the problem of theft using solid state switches controlled using a micro-computer and a code input by a user. Based on whether a code is provided to the system, whether the internal temperature of a switch is above a particular value, and whether a particular current has been provided for a particular time, Thomsen allows power to be provided to the cranking motor. However, it would still be desirable to be capable of diagnosing impending failures, avoiding failures, providing power to consumers in a more optimal manner. Accordingly, what is needed is a system and method for providing intelligent power management. The present invention addresses such a need. SUMMARY OF THE INVENTION The present invention provides a method and system for managing power in a device having a power source is described. The system comprises a switch and at least one controller. The switch is coupled with the power source and a portion of the device. The at least one controller is coupled with the switch and is for controlling the switch to be open or closed based on instructions provided to the controller. Thus, the switch and controller can manage the power provided to the portion of the device. According to the system and method disclosed herein, the present invention provides an intelligent switch which is capable of managing power provided to a subsystem within a device. Thus, many aspects of device performance can be improved. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1A is a high-level block diagram of one embodiment of an intelligent power management system in accordance with the present invention. Figure IB is a block diagram of one embodiment of an intelligent power management system in accordance with the present invention. Figure 2 A is a block diagram of one embodiment of the intelligent power management system as coupled with a device. Figure 2B is a block diagram of one embodiment of how a switch of the intelligent power management system is coupled with a portion of a device. Figure 2C is a block diagram of one embodiment of how a switch of the intelligent power management system is coupled with a portion of a particular device. Figure 3 is a high-level flow chart of the functions of the power management module in accordance with the present invention. Figure 4A is a flow chart depicting one embodiment of a method for stepping down the power using the power management module in accordance with the present invention. Figure 4B is a flow chart depicting another embodiment of a method for stepping down the power using the power management module in accordance with the present invention. Figure 4C depicts one embodiment of a method for cutting off power due to power supply voltage level using the power management module in accordance with the present invention. Figure 5 A depicts one embodiment of a system for cutting off power based on priority due to power supply voltage level using the power management module in accordance with the present invention. Figure 5B depicts one embodiment of a method for cutting off power based on priority due to power supply voltage level using the power management module in accordance with the present invention. Figure 5C depicts another embodiment of a method for cutting off power based on priority due to power supply voltage level using the power management module in accordance with the present invention. Figure 6A is a high-level block diagram of one embodiment of a power management module in accordance with the present invention is used in a truck tractor. Figure 6B is another high-level block diagram of one embodiment of a power management module in accordance with the present invention is used in a truck tractor. Figure 7 is a more detailed block diagram of one embodiment of a power management module in accordance with the present invention is used in a truck tractor. Figure 8 depicts one embodiment of a system for using the using the power management module in accordance with the present invention in conjunction with a manual cut-off switch. DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in power management technology, particularly for DC electrical power sources which may have limited capacity. The following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements. Various modifications to the preferred embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. Thus, the present invention is not intended to be limited to the embodiment shown, but is to be accorded the widest scope consistent with the principles and features described herein. The present invention will be described in terms of a particular configuration and particular devices. However, one of ordinary skill in the art will readily recognize that this method and system will operate effectively for other configurations, including other connections with power sources and power consumers. Furthermore, one of ordinary skill in the art will readily recognize that the present invention can be used in a variety of other devices, such as satellites, boats, or other devices. The present invention provides a method and system for managing power in a device having a power source is described. The system comprises a switch and at least one controller. The switch is coupled with the power source and a portion of the device. The at least one controller is coupled with the switch and is for controlling the switch to be open or closed based on instructions provided to the controller. Thus, the switch and controller can manage the power provided to the portion of the device. To more particularly illustrate the method and system in accordance with the present invention, refer now to 1 A, which depicts a high-level block diagram of one embodiment of an intelligent power management system, or power management module ("PMM") 10 in accordance with the present invention. The PMM 10 depicted is essentially an intelligent switch which can be considered to include at least a controller 22 and switches 26. The controller 22 and switches 26 are preferably integrated together in a single module. The switches 26 are preferably devices such as MOSFET switches. The controller 22 is preferably a programmable microcomputer. Thus, the controller 22 may be individually tailored for functions desired by a user of the PMM 10. The controller 22 can receive input signals from in order to aid in controlling the switches 26. For example, the controller 22 can receive signals from a device with which the PMM 10 is being used or from internal sensors which may be coupled to one or more of the switches 26. The switches 26 are coupled with a power supply and a portion of the device, such as a subsystem. Thus, depending upon whether a particular switch 26 is closed, power may be provided to a subsystem of the device. Using the intelligence in the controller 22 and the switches 26, the PMM 10 can control the switching of power to portions of the device in which the PMM 10 is used. Thus, the PMM 10 can act as an intelligent switch. As a result, power management in the device can be improved. Figure IB depicts a more detailed diagram of one embodiment of an intelligent PMM 10 in accordance with the present invention. The PMM 10 includes power input 12, power output 16, signal inputs 18, signal outputs 14, internal sensors 20, a controller 22, switches 26 and, preferably, control gates 24 for the switches 26. The power input 12, power output 16, signal inputs 18, signal outputs 14, internal sensors 20, a controller 22, switches 26 and, preferably, control gates 24 for the switches 26 are preferably integrated together into a single module that can be used within a device. The switches 26 are preferably devices such as MOSFET switches. The controller 22 is preferably a programmable microcomputer. Thus, the controller 22 may be individually tailored for functions desired by a user of the PMM 10. The controller 22 can communicate with portions of the device in which the PMM 10 is used via the signal input 18 and signal output 14. Thus, the controller can receive signals from a device with which the PMM 10 is being used through the signal input 18. Furthermore, the controller 22 can provide data and commands to the device through the signal output 14. The internal sensors 20 monitor the condition of the PMM 10. For example, the internal sensors 20 could include temperature sensors for various portions of the PMM 10, such as the switches 26, as well as current and voltage sensors for the switches 26. The internal sensors 20 may also include a timer, or clock, (not explicitly shown in Figure IB). In a preferred embodiment, the internal sensors 20 include temperature, voltage, and current sensors for each of the switches 26. Figure 2 A depicts an embodiment of the PMM 100 coupled with subsystems of a device. The PMM 100 is substantially the same as the PMM 10. The PMM 100 still includes the signal input 18, the signal output 14, the power input 12, the power output 16, the internal sensors 20, the controller 22 and switches 26. Not depicted are the control gates 24 which may be provided. The PMM 100 is coupled to a power supply 30 through the power input 12. The power supply 30 includes at least one or more power storage devices (not explicitly shown), such as a battery, and may also include power generating devices (not explicitly shown), such as one or more alternators. In a preferred embodiment, the PMM 100 is separately coupled to the alternator and battery. The PMM 100 receives signals from subsystem A 32 and subsystem B 34 through the signal input 18. The PMM 100 provides signals to subsystem A 32 and a subsystem C 36 using the signal output 14. The PMM 100 is also coupled to subsystem A 32, subsystem B 34, subsystem C 36 and subsystem D 38. The PMM 100 is capable of a variety of functions, including but not limited to one or more of the following: managing the generation and storage of power, monitoring and controlling power consumption, cutting off power to one or more consumers based on a variety of programmable factors, providing step down power conversion of the power supplied by the power source 30, providing protection against spikes, providing protection against shorts, providing reverse polarity protection, providing a self learning capability, learning the signatures of one or more subsystems, diagnosing potential failures based on the signatures of one or more subsystems, protecting against potential failures based on the signatures of one or more subsystems, and protecting against drainage of the power source 30. Figure 2B depicts one embodiment of a portion of the PMM 10 or 100 and the device to which the PMM 10 is coupled. The switch 26, which is one of the switches of the PMM 10, is connected between the power supply 30 of the device and the subsystem A 32 of the device. Consequently, when the switch 26 is open, as depicted in Figure 2B, no power is provided to the subsystem A 32. However, when the switch 26 is closed, power is provided to the subsystem A 32. Also depicted are the controller 22 and internal sensor 19 coupled with the switch 26. Other or different components internal to the PMM 10 or 100 can be coupled with the switch 26. For example, in a preferred embodiment, current, voltage and temperature through the switch 26 are also monitored. The internal sensor 19 provides to the controller 22 an electrical signal indicating a property of one or more of the switches 26. Using the signal from the internal sensor 19 and/or other signals input to the controller 22 and based on the instructions provided to the controller 22, the controller 22 can control the switch to be open or closed. For example, Figure 2C depicts one embodiment of a portion of the PMM 10 or 100 and the device to which the PMM 10 is coupled. Figure 2C is substantially the same as Figure 2B, however, specific internal sensors are depicted for ease of explanation. The switch 26, which is one of the switches of the PMM 10 or 100, is connected between the power supply 30 of the device and the subsystem A 32 of the device. Consequently, when the switch 26 is open, as depicted in Figure 2C, no power is provided to the subsystem A 32. However, when the switch 26 is closed, power is provided to the subsystem A 32. Also depicted are the controller 22, temperature sensor 20 and clock 21 coupled with the switch 26. Other or different components internal to the PMM 10 or 100 can be coupled with the switch 26. For example, in a preferred embodiment, current and voltage through the switch 26 are also monitored. The temperature sensor 20 is thermally coupled with the switch 26 and coupled with the controller 22. Preferably, the temperature sensor 20 provides to the controller 22 an electrical signal indicating the temperature of the switch 26. The clock 21 is coupled to the controller 22 and can provide an indication of how long the switch 26 has been open or closed. Figure 3 depicts a high-level flow chart of one embodiment of a method 50 for using the PMM 10 or 100 in accordance with the present invention. One or more control programs are provided to the controller 22, via step 52. The controller 22 then controls the power supplied to different power consumers based on the program and other inputs to the PMM 10 or 100, via step 54. Thus, the controller 22 opens or closes the switches 26 under certain conditions. The data provided by the internal sensors 20, an internal clock or information provided by the subsystems of the device that are connected to the signal input 18 inform the controller 22 as to the condition of the PMM 10 or 100 and the device to which the PMM 10 or 100 is connected. Figure 4A depicts one embodiment of a method 450 for stepping down the power provided by a voltage source using the PMM 10 or 100. The method 450 can be used with any PMM 10 or 100 which steps down the voltage provided by a power supply. For example, the PMMs 10 and 100 depicted in Figures 1A-B, 2 A and 6 A may utilize the method 450 for providing PWM. PWM may also be provided in other instances, such as stepping down the voltage of a power supply for providing power to lights or other systems in a device such as a truck tractor. PWM can also be used to regulate the power from the alternator or other power generator, as described below with respect to Figure 7. In such a case, the switch which is toggled may be coupled between the alternator and the other portions of the device. PWM helps prevent the device from drawing too much power from the alternator during starting. In such a case, the power output by the power source (e.g. alternator), rather than the power input to a power consumer, is desired to be regulated. PWM can also help prevent spikes. For example, when a component like the cranking subsystem of a truck tractor is started, the current drawn rises to a high spike is unregulated. The peak current could be four times the average current. This high current rush puts stress on the electrical system. The PMM 10 or 100 can limit the peak rush-in current by turning on and off the switches, in a manner similar to PWM. Thus, current spikes are reduced in magnitude. Referring to Figures 4A and 2 A, the controller for the PMM 100 determines whether the voltage provided by the power supply for a particular subsystem is at the desired level, via step 451. Step 451 may be performed by comparing the voltage provided to the subsystem to a particular level at a particular time or by determining that the voltage is to be stepped down at a particular time. If the voltage is at the desired level, then the switch for the subsystem is closed, via step 452. If the voltage is not at the desired level, then the controller provides pulse with modulation by commanding the appropriate switch to open and close at the rate desired for the stepped down voltage, via step 453. In one embodiment, the rate at which the switch should be opened and closed is previously known. In such an embodiment, step 453 can include simply opening and closing the switch at the known rate. Figure 4B depicts one embodiment of the step 453, providing PWM for the desired voltage. The desired voltage is determined, via step 454. The desired rate at which the switch should be opened and closed based on the current voltage and the desired voltage is determined, via step 455. The switch is then opened and closed at the desired rate, via step 456. The PWM 10 or 100 in accordance with the present invention can also control the power supply to help prevent the power supply from being unduly drained or to manage the state of the power supply. Figure 4C depicts one embodiment of a method 460 for cutting off power due to power supply voltage level using the power management module in accordance with the present invention. It is determined whether the voltage of the power supply, particularly the battery which stores power, is above a particular level, via step 461. The level might differ for a variety of reasons. For example the level may be higher when a power generator, such as the alternator, is operating. The voltage determined in step 461 may also represent an alternator. Thus, if the alternator stops functioning, it will be ensured that the battery does not become discharged. If the voltage level is not above the level, then at least one switch in the PMM 10 or 100 that couples the power supply to a power consumer is open or forced to remain open (not allowed to close), via step 462. If, however, the voltage of the power supply is above the particular level, then the switch is closed or allowed to remain closed, via step 463. The voltage of the power supply is then continued to be monitored by returning to step 461. Figure 5 A depicts one embodiment of a system 465 which cuts off power based on priority due to power supply voltage level using the PMM 10 or 100 in accordance with the present invention. The system 465 will be described in the context of a truck tractor which includes a battery and alternator as a power source and which utilizes the PMM 10 or 100. Power is provided from a battery and, if the engine is running, an alternator via lines 466. Power is provided to loads via lines 467, 468 and 469. The switches 470, 471, and 472, which are part of a PMM 100 (other components of which are not explicitly shown) determine whether power is provided to the lines 467, 468, and 469. The lines 467 supply power to a power consumer that is a priority one, or highest priority, load. The lines 468 supply power to a power consumer that is a priority two, or next highest priority, load. The lines 469 supply power to a power consumer that is a priority three, or lowest priority, load. When the voltage of the battery drops below a certain level, the loads are disconnected based on their priority. Thus, the lines 469 will be disconnected first, by opening the switch 472. The lines 468 will be disconnected next, by opening the switch 471. The lines 467 will be disconnected last, by opening the switch 470. Note criteria other than or in addition to the voltage of the battery could be used in cutting off power to the power consumers. For example, power could be cut off to loads based on the ability of the alternator to charge the battery. A controller (not shown in Figure 5 A) determines which, if any, switch to close and ensures that the switches are closed in order of priority. There are many methods which can be used in conjunction with the system 465 for disconnecting power to power consumers based on their priority. Furthermore, one or more voltage levels at which loads of particular priorities are cut off. For example, Figures 5B-5C depict two methods for disconnecting power consumers based on their priority. Prioritization is desired so that loads which a user deems less important, such as a microwave or cooling can be shut off before loads which are deemed more important. Furthermore, a user may be allowed to set the priorities of different power consumers as well as the voltage level(s) above which the battery is desired to be kept. Figure 5B depicts one embodiment of a method 475 for cutting off power based on priority due to power supply voltage level using the PMM 100 in accordance with the present invention. It is determined whether the voltage of the battery is above a desired level, via step 475. The desired level is preferably predetermined and programmed into the controller. Step 475 is preferably performed by measuring the voltage of the battery and using the controller to compare the measured voltage with the desired level. If the voltage of the battery has not dropped below the desired level, step 475 is repeated. Thus, the voltage of the battery continues to be monitored. If the voltage of the battery has dropped below the desired level, then one or more power consumers, or loads, are cut off based on their priority, via step 477. Figure 5C is a more detailed flow chart of one embodiment of a method 478 for cutting off power based on priority due to power supply voltage level using the PMM 100 in accordance with the present invention. It is determined whether the voltage of the battery is above a desired level, via step 479. The desired level is preferably predetermined and programmed into the controller. Step 479 is preferably performed by measuring the voltage of the battery and using the controller to compare the measured voltage with the desired level. If the voltage of the battery is still above the desired level, step 479 is repeated. Thus, the voltage of the battery continues to be monitored. If the voltage of the battery has dropped below the desired level, then the lowest priority load (power consumer) currently receiving power is determined, via step 480. Power is then cut off to the lowest priority load, via step 481. Step 481 is performed by the controller of the PMM 100 opening the appropriate switch in the PMM 100 for the lowest priority load. It is then determined if all loads have been cut off, via step 482. If so, then no more loads can be cut off, and the method terminates. If not, then step 479 and appropriate additional steps are repeated. Because the loads can be cut off using the mechanisms depicted in Figures 4-5C, the performance and lifetime of the battery may be extended. In addition, the minimum charge required to crank the engine may be preserved. To further illustrate the structure, functions, and capabilities of the present invention, reference will be made to the use of a PMM 100 in the context of a particular device, a truck tractor. However, one of ordinary skill in the art will readily realize that analogous or functions may be provided by a PMM 10 or 100 in other devices. Figure 6A depicts a PMM 100 as it is coupled with subsystems in a truck tractor. Although numbered differently, components of the PMM 100 shown in Figure 6A correspond to similarly named components in the PMM 10 and 100 shown in Figures 1 A-2A. Referring back to Figure 6 A, The truck tractor includes two power supplies, an alternator 101 which generates power and a battery pack 102 which stores power. The truck tractor also includes various subsystems such as a local area network 103, and LED indicator 104, comfort devices 105, lights 106, a starter 107, critical components 108, a start key switch 109 and a manual battery disconnect switch 110. The comfort devices 105 may include components such as a radio, refrigerator, or other devices. The critical components 108 include the engine, brakes, and other components. Figure 6B is another high-level diagram of the PMM 100 as coupled with certain subsystems in a device such as a truck tractor. The PMM 100 is depicted as being coupled to the batteries 102 and the alternator 101, the starter 107, other power consumers, and the LAN 103. Based on communication with the batteries 102, alternator 101, and various subsystems of the truck tractor, the PMM 100 can control switches (not explicitly shown in Figure 6B) within the PMM 100 and can communicate with portions of the truck tractor so that a variety of functions are performed. These functions include but are not limited to those disclosed in the present application. As depicted in Figure 6B, the PMM 100 may recognize differing power requirements for the batteries 102 under different conditions and determine the power drawn by the subsystems of the truck tractor. For example, the PMM 100 may recognize the ideal charge for the batteries 102 over a range of battery temperatures, battery capacity, and various requirements of the starter, such as voltage and current. The PMM 100 may also communicate with the batteries 102 to determine the remaining life in the batteries 102. Consequently, the PMM 100 may control other portions of the truck tractor and the power provided to the batteries 102 to meet the requirements of the batteries 102. Thus, the PMM 100 may ensure that the batteries 102 are charged close to the ideal level and may regulate power to power consumers to extend the life of the batteries 102 or ensure that the batteries 102 have sufficient power for critical applications. Consequently, the PMM 100 may identify and prevent potential failure of the batteries 102. The PMM 100 also receives signals from and provides signals to the alternator 101. Thus, potential failures of the alternator 101 or harm due to problems within the alternator 101 or other portions of the truck tractor may be prevented. The output of the alternator 101 may also be controlled based on signals provided from the PMM 100, for example to optimize battery power. In addition, switches between the alternator 101 and other portions of the truck tractor, including the batteries 102, may be provided. The PMM 100 may control these switches to provide the desired power to other portions of the truck tractor. Furthermore, the PMM 100 communicates with the starter (cranking) subsystem 107, identifying impending failure and preventing harm to the starter 107 due to system failure or user abuse. The power to the starter 107 may also be controlled based on other factors, such as the power remaining in the batteries 102 or the temperature of switches in the PMM 100. The PMM 100 also communicates with the LAN 103 for the truck tractor and other power consumes. Information relating to the status of the truck tractor may be communicated between the LAN 103 and the PMM 100. In addition to communicating with various other subsystems, the PMM 100 may control each subsystem's power consumption. For example, the PMM 100 may cut off power to the subsystems or reduce power to the subsystem. The PMM 100 may also control power to the subsystems to ensure that power in the batteries 102 or alternator 101 exists for critical needs and to ensure that the subsystems receive the appropriate amount of power. The PMM 100 may also monitor the subsystems to prevent harm from short circuits, spikes, or failures. The PMM 100 can also control and regulate power output to power sensitive devices, such as light bulbs. Figure 7 more particularly illustrates the connections between the PMM 100 and subsystems of the truck tractor. Although numbered differently, components of the PMM 100 shown in Figure 7 correspond to similarly named components in the PMM 100 shown in Figure 6 A. Referring back to Figure 7, the PMM 100 includes signal inputs 222, signal outputs 223, power inputs 224 and power outputs 225. The PMM 100 also includes MOSFET switches 200, control gates 201 and a controller 202. The control gates 201 control the switches 200. The controller 202 controls the control gates 201 and, therefore, controls the switches 200. The controller 202 is preferably a programmable microcomputer. The PMM 100 also includes an internal timer 203, current sensors 204, voltage sensors 205 and temperature sensors 206. The current sensors 204, voltage sensor 205, and temperature sensors 206 monitor the current through, voltage across and temperature of, respectively, the switches 200. Preferably each of the switches 200 includes a current sensor 204, a voltage sensor 205, and a temperature sensor 206. In addition, the PMM 100 includes components for monitoring various portions of the truck tractor. For example, the PMM 100 may monitor the voltage across and current through certain power consumers and may monitor the charge level, rate of charge and rate of discharge of the battery 207. The PMM 100 is coupled to two power supplies, battery 207 and the alternator 208. The PMM 100 receives signals from a local area network (LAN) line 221, a manual disconnect line 220, a starter key line 219, an engine running signal line 218, and a battery temperature sensor line 217 provided from a LAN (not shown), a manual disconnect switch (not shown), a starter key (not shown), an sensor indicating whether the engine is running (not shown) and a battery temperature sensor (not shown), respectively. The PMM 100 provides signals to a LAN, the alternator 208, and an LED via a communication to LAN line 221, a input to alternator output voltage regulation line 209, and an LED fault indication line 210. Consequently, the PMM 100 can receive data from, provide data to, and provide commands to different subsystems of the truck tractor. For example, the manual disconnect line 220 indicates whether the battery 207 and alternator 208 should be cut off by the PMM 100. The starter key line 219 indicates whether a user has turned a starter key to start up the engine of the truck tractor. The engine running signal line 218 indicates to the PMM 100 whether the engine is already running, allowing the PMM 100 to prevent power from flowing to the cranking subsystem when the engine is already on. The PMM 100 can monitor the temperature of the battery via line 217, and can monitor the voltage across the battery 207, for example to control charging of the battery 207. Furthermore, the PMM 100 can control output of the alternator 208 through the input to alternator output voltage regulation line 209. The PMM 100 can also indicate to the user if a fault has occurred via LED fault indication line 210. The temperature sensors 206 provide an indication of the temperature of the switches 200. This allows the controller to open one or more of the switches when their temperature is too high. A typical alternator, such as the alternator 208, is three-phase alternating current generator. The rectifier circuit (not shown) in the alternator 208 converts alternating current (AC) to direct current (DC). Important components in the rectifier are diodes. When a diode or other component fails in one phase of the alternator 208, the alternator 208 will generate only two-thirds of the power. This will put significant stress on the two working phases of the alternator 208. This leads to quick and progressive failure of all phases of the alternator 208. Currently, conventional devices in the market place cannot detect the loss of a phase and prevent the rapid and eminent failure of the other phases. The PMM 100 can detect the loss of a phase through alternator signature recognition. In response, the PMM 100 can reduce the demand on the alternator 208. This will give time to fix the alternator at the next scheduled maintenance rather failing unexpectedly on a high way where the maintenance and downtime costs are excessive. The alternator 208 has both stator and rotor windings. Any one of these windings can develop electrical short or open condition. When shorted or open condition develops, the alternator 208 will generate reduced electrical power. This will put significant stress on windings that are normal. Progressive failure of other components rapidly follows. Currently no conventional devices detect a short or open condition to prevent the failure of other components. The PMM 100 can detect the loss of a phase through alternator signature recognition, and reduces the demand on alternator 208. This will give time to fix the alternator 208 at the next scheduled maintenance rather failing unexpectedly, resulting in excessive maintenance and downtime costs. Furthermore the PMM can detect and account for the failure of the belt and pulley system driving the alternator. When the belt or pulley slips, the alternator cannot generate power that it is designed to generate. The slip condition heats up the belt, pulley, alternator bearings and other portions of the truck tractor. The PMM 100 can detect the existence of these conditions, using communication with the truck tractor and monitoring the difference between the behavior of the alternator and its signature. PMM can then take appropriate action, for example by providing an alarm to the user. The PMM 100 can also monitor the power consumers and supplies. Thus, the PMM 100 is coupled with several subsystems that act as power consumers. For example, the PMM 100 is coupled with the lights, a cranking motor latch/hold coil, a cranking motor winding, other devices in the truck tractor, the engine and brakes, and comfort appliances via the lights line 211, a cranking motor latch/hold coil line 212, a cranking motor winding line 213, other devices in the truck tractor line 214, engine and brakes line 215, and comfort appliances line 216. Thus, in the embodiment shown in Figure 7, the PMM 100 is coupled to the cranking subsystem through two lines 212 and 213. Using the lines 211, 212, 213, 214, 215, and 216, the PMM 100 can monitor and control power to various subsystems of the truck tractor, such as the lights, components of the cranking subsystem, the engine and brakes, comfort appliances, and other subsystems. For example, the PMM 100 can provide pulse width modulation (PWM) to control the magnitude of the power supplied to a particular subsystem. Thus, the voltage applied to the lights, the engine, and the brakes can be decreased as desired to extend the life of or better control components. The PMM 100 can also monitor and regulate the demand on the alternator, preferably by using PWM. For example, when the engine is started when the whether is cold, the battery charge is low and the power use is high, the electrical system will try to draw as much current as possible from the alternator 208 instantaneously. This condition puts high stress on and reduces the life of the alternator 208. The PMM 100 monitors and regulates the demand on the alternator 208 such that the stress on alternator is moderated and maintained at an optimum level. This is accomplished through PWM of alternator output. The PMM 100 is also capable of keeping track of these information for various components such as starter (cranking subsystem), battery 207, alternator 208, light bulbs and others subsystems. Knowing the cycles and severity of operation is the accurate way of knowing the actual usage of these components. By knowing this, most optimum maintenance schedule can be used. This will avoid servicing or changing components before its time. This will also help to avoid not serving or changing components when it is time. Figure 8 depicts one embodiment of a system using the PMM 100 in conjunction with a manual on/off, or cut-off, switch 500. For clarity, only a portion of the PMM 100, which includes the controller 501 and the switch 504, is depicted. Thus, cut-off of the intelligent switch is highlighted. The manual on/off switch 500 is used so that when open, power cannot be provided to any portion of the truck tractor. The manual on/off switch 500 may be used in cases where providing power to any system is dangerous, such as when an accident has occurred. Normally, the manual on/off switch 500 is closed, as shown in Figure 8. Consequently, the controller 501 controls the switch 504 so that the switch 504 is closed. Thus, power can be provided to any of the subsystems of the truck tractor. If the manual on/off switch is opened, then the controller 501 ensures that the switch 504 is open. When the switch 504 is open, no power can flow to the subsystems of the truck tractor. Furthermore, the switch to the LED 502 is closed. Thus, a small amount of power is provided to the LED 502, which indicates that manual cut-off of power to the subsystems of the truck tractor has been engaged. Thus, the PMM can utilize its controller, switches, internal sensors or other components to function as an intelligent switch. Thus, the PMM can control power to the various portions of the device in which the PMM is used based on a variety of factors. As a result, performance of the power supply is improved, reliability of the power supply and other portions of the device are improved, and failures are reduced. A method and system has been disclosed for an intelligent power management system. Although the present invention has been described in accordance with the embodiments shown, one of ordinary skill in the art will readily recognize that there could be variations to the embodiments and those variations would be within the spirit and scope of the present invention. Accordingly, many modifications may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended claims.

Claims: CLAIMS What is claimed is: 1. A system for managing power in a device having a power source, the system comprising: a switch coupled with the power source and a portion of the device; and at least one controller, coupled with the switch, for controlling the switch to be open or closed based on instructions provided to the at least one controller; and wherein the switch and the at least one controller can manage the power provided to the portion of the device. 2. The system of claim 1 wherein the switch further includes a solid-state switch. 3. The system of claim 2 wherein the switch further includes a mosfet. 4. The system of claim 1 further comprising: a control gate for controlling the switch, the control gate being controlled by the at least one controller. 5. The system of claim 1 further comprising at least one internal sensor, the at least one internal sensor for monitoring at least one property of the switch. 6. The system of claim 1 further comprising at least one internal sensor coupled with the switch and the at least one controller, the at least one internal sensor for monitoring at least one property of the switch and allowing the at least one controller to control the switch based on the at least one property. 7. The system of claim 1 wherein the at least one controller controls the switch to provide pulse- width modulation of the power provided to the portion of the device. 8. The system of claim 7 wherein the at least one controller controls the switch to provide pulse-width modulation to provide a particular voltage to the portion of the device. 9. The system of claim 1 further comprising a manual switch coupled with the switch, the manual switch for allowing a user to ensure that the switch cannot be closed to cut off power to the portion of the device. 10. The system of claim 1 wherein the at least one controller controls the switch based on at least one signal input to the at least one controller. 11. The system of claim 1 wherein the at least one controller and the switch are integrated together into a module. 12. The system of claim 1 wherein the at least one controller is capable of controlling the switch to cut off the power to the portion of the device based on a priority for the portion of the device. 13. The system of claim 1 wherein the at least one controller controls the switch based on at least one instruction provided to the at least one controller. 14. The system of claim 13 wherein the at least one controller is a programmable microcomputer. 15. A method for managing power in a device having a power source, the method comprising the steps of: providing a switch coupled with the power source and a portion of the device; providing at least one controller, coupled with the switch, for controlling the switch to be open or closed based on instructions provided to the at least one controller; and allowing the at least one controller to be used to control the switch in order to manage the power provided to the portion of the device. 16. The method of claim 15 wherein the switch further includes a solid-state switch. 17. The method of claim 16 wherein the switch further includes a mosfet. 18. The method of claim 15 further comprising the step of: providing a control gate for controlling the switch, the control gate being controlled by the at least one controller. 19. The method of claim 15 further comprising the step of: providing at least one internal sensor coupled with the switch and the at least one controller, the at least one internal sensor for monitoring at least one property of the switch and allowing the at least one controller to control the switch based on the at least one property. 20. The method of claim 15 further comprising at least one sensor coupled to the device and to the at least one controller, the at least one sensor for providing data to the at least one controller for controlling the switch. 21. The method of claim 15 wherein the at least one controller controls the switch to provide pulse- width modification of the power provided to the portion of the device. 22. The method of claim 21 wherein the at least one controller controls the switch to provide pulse-width modification to provide a particular voltage to the portion of the device. 23. The method of claim 15 further comprising a manual switch coupled with the switch, the manual switch for allowing a user to ensure that the switch cannot be closed to cut off power to the portion of the device. 24. The method of claim 15 wherein the at least one controller controls the switch based on at least one signal input to the at least one controller. 25. The method of claim 15 wherein the at least one controller and the switch are integrated together into a module. 26. The method of claim 15 wherein the at least one controller is capable of controlling the switch to cut off the power to the portion of the device based on a priority for the portion of the device. 27. The method of claim 15 wherein the at least one controller controls the switch based on at least one instruction provided to the at least one controller. 28. The method of claim 27 wherein the at least one controller is a programmable microcomputer. 29. A method for managing power in a device having a power source utilizing a system, the system comprising a switch coupled with the power source and a portion of the device and at least one controller, coupled with the switch, for controlling the switch to be open or closed based on instructions provided to the at least one controller, the method comprising the steps of providing a instructions to the at least on controller, at least a portion of the instructions indicating how the switch is to be controlled; and managing the power provided to the portion of the device using the switch and the at least one controller.

Inventors: JETHA ALY AMIRALI, KARUPPANA SAMY V, THOMSEN JES, JETHA, ALY, AMIRALI, KARUPPANA, SAMY, V., THOMSEN, JES
Applicants: INTRA INTERNAT AB, JETHA ALY AMIRALI, KARUPPANA SAMY V, THOMSEN JES, INTRA INTERNATIONAL AB, JETHA, ALY, AMIRALI, KARUPPANA, SAMY, V., THOMSEN, JES
Application year: 2000
Main classification: H02M1
IPC codes: G05F1, H02J1, H02J7