WO2012071502A2

WO2012071502A2 - System and method for controlling a power supply

Info

Publication number: WO2012071502A2
Application number: PCT/US2011/062026
Authority: WO
Inventors: Adam M. Gettings; Taylor J. Penn; Joel D. Brinton; Yi Zheng
Original assignee: Robotex Inc.
Priority date: 2010-11-23
Filing date: 2011-11-23
Publication date: 2012-05-31
Also published as: TW201250457A; WO2012071502A3

Abstract

A power monitor system and method are disclosed. The system can enable a self-regulating power supply to be used high current applications, but may be applicable to controlling any power supply. The power monitor system can include a power supply output sensor, a switching controller, and a reset circuit. The power monitor system can also include a charge storage device. A method of controlling a power supply can include the steps of monitoring the power supplied from the power supply, resetting the power supply, and maintaining power to the power supply monitor while the power supply resets.

Description

TITLE OF THE INVENTION

SYSTEM AND METHOD FOR CONTROLLING A POWER SUPPLY Adam M. Gettings

Taylor J. Penn

Joel Brinton

Yi Zheng CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to U.S Provisional Application No.

61/416,572, filed 23 November 2010 which is incorporated by reference herein in its entirety. TECHNICAL FIELD

[0002] This invention relates generally to the power regulation field, and more specifically to a system and method for controlling a power supply in the power regulation field. BACKGROUND

[0003] Some batteries, such as the BB-2590 Lithium-ion battery designed to be a multi- purpose military battery, are designed to have current output limitations. These batteries can have built-in current output-limiting electronics. The output-limiting electronics often have electronic circuitry that provides pack protection, charge equalization and battery management (fuel gauging). The current output limit prevents the battery from supplying power after the high current protection has been triggered. Applications known to require high current spikes, such as powering an electric motor (e.g., when a robotic vehicle or other device using an electric motor becomes jammed, dropped or otherwise stressed), currently requires multiple batteries or an alternative power supply. The system them needs to be reset manually, or the batteries must be removed and reinserted. Either of these solutions are burdensome, and even more so when during urgent situations such as during tactical use of a robot in a police or battlefield situation.

[0004] Thus, there is a need in the power regulation field to create a new and useful system and method for controlling a power supply. BRIEF DESCRIPTION OF THE FIGURES

[0005] Figure l is a schematic representation of a variation of a power supply and a power monitor system. [0006] Figure 2 is a schematic diagram of a variation of the power monitor system.

[0007] Figure 3 is a flowchart of a method of controlling a power supply.

[0008] Figure 4 is a schematic representation of a variation of the power supply, parallel electric current limiter and load.

[0009] Figure 5 is a schematic diagram of a variation of the power supply and a power monitor system.

[0010] Figure 6 is a state flow diagram of a variation of a method of controlling a power supply.

[0011] Figure 7 is a schematic diagram of a variation of the power supply and a power monitor system.

[0012] Figure 8 illustrates a variation of a method for the initial power-on process.

[0013] Figure 9 is a circuit diagram showing a variation of the cells, busses and filters of the power supply and a power monitor system.

[0014] Figure 10 is a graph of a variation of the timing and voltage during reset of the power supply. DETAILED DESCRIPTION

[0015] The power monitor system 100 can be used to control any power supply. For example, the power monitor system 100 can enable or permit a self-regulating power supply, such as a standard BB-2590 military battery, to be used high current applications.

[0016] Figures l and 2 illustrate variations of the power monitoring system 100 that can monitor and reset a power supply 1 10 if a power supply output parameter drops below and/or rises above a threshold. The power supply 1 10 can be a component within the power monitoring system 100 as shown in Figure 2, and/or an external component connected to the power monitoring system 100 as shown in Figure 1.

[0017] As shown in Figure 2, the circuit design of a power monitor system 100 can enable a power supply, for example a BB-2590 military battery, to continue providing normal currents after the high current protection has been triggered, enabling such a power supply to be used for applications using high currents , even if momentarily, such as driving an electric motor, or when a vehicle or device using an electric motor becomes jammed, dropped or otherwise stressed. As shown in Figure 3, a method of controlling a power supply can be used to extract high currents from a self-regulating power supply.

[0018] The power supply 1 10 can provide power for any suitable power application. The power supply 1 10 can be a BB-2590 military standard battery (by Bren-tronics, Inc. of Commack, NY), BA-5590 military standard battery, alkaline battery, lithium-ion battery, nuclear battery, any other type of battery, fuel cell, solar panel, power supply, or combinations thereof. Batteries can be manufactured by Bren-Tronics, Inc. (a field certified manufacturer known by those having ordinary skill in the art)', but also can be manufactured by SAFT, UltraLife, Golden Season, Valence

Technology, Inc., and ABSL. The Batteries can be batteries manufactured to any suitable specification, but also the following military (MIL STD) specifications: including BB-2590/U, BB- 2590, BB-2557, BB-2557/U, BA-5590, BA-5557, AB-2590.

[0019] The power supply 1 10 can be removable to allow repair, recharging, refueling, and/or replacement. The BB-2590 battery can be a multi-purpose military battery. The battery can have protection logic and/or circuitry that turns off the battery when a current output specification is exceeded. Dropping the current draw to below approximately 2 milliamps can reset the battery. After being reset, the battery can again output current after the battery's protection logic and/or circuitry senses a current draw below a limit, for example approximately 2 milliamps.

[0020] The power supply 1 10 can be connected to a power monitoring system 100 using one or more power supply connectors 1 1 1 , for example via one or more standard BB-2590 connectors (e.g., designed to interface with one or more BB-2590 standard military batteries, BA-5590 standard military batteries fuel cells, lithium batteries, rechargeable batteries, nuclear batteries, alkaline battery packs, solar panels, power cables, or any combination thereof. The connectors 1 1 1 can form a watertight connection with the power supply 110, and/or may occlude materials such as other liquids, gases, dirt, debris, and any other external or internal contaminants. The connectors 1 1 1 can act as removable attachment elements, for example allowing the power supply 1 10 to be removed and replaced from the power monitor system 100, or for the power monitor system 100 to be removed and replaced from the power supply 1 10.

[0021] As shown in Figure 1 , the power monitor system 100 can include a power supply output sensor 1 12, a switching controller 1 14, and a reset circuit 1 18. The power monitor system 100 can also include a charge storage device 1 16.

[0022] The power supply output sensor 1 12 can be directly connected to the power supply 1 10, a connector 1 1 1 , the charge storage device 1 16, the switching controller 1 14, the reset circuit 1 18, or a combination thereof. The power supply output sensor 1 12 can monitor the output of the power supply 1 10 and can output a signal or a change in a signal when the power supplied from the power supply 1 10 is below or above at least one threshold, or stops entirely. The measured output of the power supply 1 10 can be as voltage, current, temperature, capacitance, inductance, power, charge remaining, frequency (for example on an alternating. current (AC) power supply), or any combination thereof. The power supply output sensor 1 12 can be connected to the power supply 1 10 via a monitoring connection 109, which can be directly to the power supply or through one or more connectors 1 1 1.

[0023] The switching controller 1 14 can monitor and/or process information from the power supply output sensor 1 12, and can generate a reset signal for the power supply 1 10, and/or a notification signal to a user, for example a low battery signal or to change out a battery, and designate which of a number of batteries is being indicated (e.g., that the third battery in the system needs to be changed). The switching controller 1 14 can be an electronic circuit, such as a series of N-channel and P-channel mosfets, a PIC microcontroller, an FPGA, an ASIC, a microprocessor, or combinations thereof. The switching controller 1 14 can be programmed to perform the method described below, but can be programmed to execute any other program or function.

[0024] The reset circuit 1 18 can delay and/or reduce (or increase) the current draw from the power supply 1 10 to below (or above) a threshold. The reset circuit 1 18 may send a reset signal to the power supply 1 10, and may be connected to a reset pin on the microprocessor 114. The reset circuit 1 18 can be integrated into a microprocessor of the switching controller 1 14. The reset signal 108 for the power supply 1 10 can be connected to an output pin on a microprocessor of the switching controller 1 14. The reset circuit 1 18 can also be implemented with a circuit (or a microcontroller) that stays in a low power state for a certain amount of time after it is powered up. When the reset circuit controls the battery or power supply 110 to provide a smaller amount of power (i.e., a lower current or voltage than the original current draw before the reset) after resetting, the current drawn by the

f

microcontroller will be low enough to be acceptable for low power applications (e.g., operating system start-up, clock use). For example, the low power delivery from the battery of power supply 1 10 The battery or power supply 1 10 can return to delivering a higher (e.g., the original current draw before the reset) current after the low power delivery, for example after the operating system has rebooted (e.g., about 1 second, or about 3 seconds, or about 5 seconds, or about 10 seconds).

[0025] The charge storage unit 1 16 can provide uninterrupted power to the components of the power monitor system 100, which can include a power supply output sensor 1 12, a switching controller 1 14, and any other components (which may be external to the power monitor system 100). The continuous power provided by the charge storage unit 1 16 can maintain power and memory states of the switching controller 1 14 and/or at least one power supply output sensor 1 12 until the power supply 1 10 stabilizes. For example, the charge storage unit 1 16 can provide uninterrupted power to the power supply output sensor 1 12 (and can also provide uninterrupted power to the switching controller 1 14) during the time interval while the power supply 1 10 is not supplying power (e.g. during periods where the power supply 1 10 has stopped supplying power, and before the power supply 1 10 has been reset), or not supplying steady power, or when any other output from the power supply 1 10 is below (or above) an output threshold. If a power supply 1 10 is a battery and the battery is out of power, the charge storage unit 1 16 may allow the powered system to fail gracefully.

[0026] As shown in Figures 1 and 2, a power monitoring system 100 can be connected to a power supply 1 10, the power supply output sensor 1 12 can include a voltage monitor 93 may also include one cell protection circuit 91. The reset circuit 1 18 can include a delay circuit 92, a enable switch 94. The switching controller 1 14 can include a current throughput switch 95 and a charging circuit 96, and the circuits in the switching controller 1 14 may be controlled by a microprocessor.

[0027] As shown in Figure 2, the power supply 1 10 is shown as two batteries, for example each battery having four cells (e.g., such as in the standard BB-2590 battery). The cell protection circuit 91 can prevent the group of cells with the highest voltage from charging the group of cells with the lowest voltage, which could trigger the protection circuitry (e.g., of the BB-2590 battery). The cell protection circuit 91 can be at least one diode, for example one diode per group of four cells, but may be any suitable circuit.

[0028] A delay circuit 92 can reduce and/or turn off the current draw for a period of time, which can enable the power supply 1 10 to automatically reset. The delay circuit 92 can be controlled by a voltage monitor 93, which functions to monitor the voltage output from the power supply 1 10 and trigger a delay in the delay circuit 92 (for example, while a capacitor or battery in the delay circuit 92 charges from the power supply or elsewhere) to reset the power supply 110 when the power supply output drops below (or spikes above) a threshold. The delay circuit 92 can discharge (the charge from the capacitor or battery in the power monitor system) quickly and charge slowly, and can provide most of the delay while a capacitor charges. The power supply 1 10 can reset after a capacitor or battery in the delay circuit 92 has started recharging.

[0029] The voltage monitor 93 can include a voltage divider, which can control an N-channel mosfet controlling a P-channel mosfet. As shown in Figure 2, the P-channel mosfet of the voltage monitor 93 can output Vcontrol, which can power a system board or another application and may provide the voltage Vcontrol for the charging circuit 96. When the delay block is lowering the voltage across the voltage divider, the N-channel mosfet in the voltage monitor 93 turns off the P-channel mosfet, cutting off power to Vcontrol which can send a power off signal to a enable switch 94, cut off power to the application and may cut off power to the charging circuit 96, or combinations thereof.

[0030] The enable switch 94 can be an N-channel mosfet, a P-channel mosfet, any other suitable switch, or combinations thereof. The enable switch 94 can be connected to an N-channel mosfet of a current throughput switch 95.. The enable switch 94 can be an N-channel mosfet, which can override the signal to a current throughput switch 95, which can include another N-channel mosfet controlling at least one P-chahnel mosfet enabling a high powered output for an application such as driving electric motors. An N-channel mosfet of the current throughput switch 95 can control at least one P-channel mosfet, for example two P-channel mosfets as shown in Figure 2. The enable switch 94 can allow the mosfets switching Vout to turn off if the mosfet that switches Vcontrol turns off. For a hard reset, the power to Vcontrol and Vout can both be reset and/or cycled simultaneously.

[0031] Two P-channel mosfets, one per cell of a BB-2590 battery, can be more power efficient than a single P-Channel mosfet, however, any suitable configuration of N-channel and P- channel mosfets, or any other switching mechanism and/or circuit may be used. The current throughput switch 95 can include a diode, or two diodes, for example one diode connected to each P- channel mosfet. The diodes in the current throughput switch can be high-powered schotkey diodes, for example, rated for about 80-100 Amps. The current throughput switch 95 can include an enable signal, Vout enable, connected to a pin of the microprocessor 121. Vout_enable can enable the microprocessor 121 to control the output of the N-channel and P-Channel mosfets, for example, turning the voltage Vout on and off using an enable signal.

[0032] The charging circuit 96 can include a P-channel mosfet controlled by an N-channel mosfet. Any suitable combination of N-Channel and P-channel mosfets, or any other suitable switching device may be used. The charging circuit 96 can be controlled by an enable signal, Vcharge_enable, can be connected to a pin on a microprocessor. When the charging circuit 96 is enabled, the P-channel mosfet can allow current to flow through the resistor and the diode of the current throughput circuit 95, for example, to charge any capacitors connected to Vout, such as the capacitors of a motor controller, or an air compressor. However, capacitors connected to Vout can be charged without the charging circuit 96; the charging circuit 96 can function to limit the max current that the capacitors can draw from the power supply 1 10, otherwise each time the capacitors are charged, the protection circuitry of the power supply 1 10 (for example a BB-2590 battery) may be triggered. The charging circuit 96 can also pulse-width modulate the capacitor charge switches, to limit the average current (though the peak current will still be high). The charging circuit 96 can also use an inductor to limit current spikes.

[0033] The BB-2590 could be either inoperable, replaced, or has exceeded an output limit, not outputting power and requiring a low current draw below approximately 2 milliamps to be reset. The voltage Vbatjow current can be low and the delay circuit 92 can turn off the enable switch 94 and can turn off Vcontrol, power to a system. The current throughput switch 95 and the charging circuit 96 can be not powered while the BB-2590 battery is reset. Once the BB-2590 battery has been reset, the delay circuit 92 can be no longer providing a delay as the capacitor is recharging or has been recharged, and the voltage monitor 93 provides power output, and disables the enable switch 94. A microprocessor can enable the charging circuit 96 to charge any capacitors connected to Vout (e.g. motor controller applications require large electrolytic capacitors), but this may not be necessary if the application does not require capacitor charging. A microprocessor can disable the charging circuit 96 after an appropriate amount of charging time, and enable the current throughput switch 95, enabling high current flow to Vout. The entire process takes approximately 0.33 seconds, and a fast reset is potentially unnoticeable to the electronic system.

[0034] As shown in Figure 3, the method of controlling a power supply 200 can include monitoring the power supplied from the power supply S210, resetting the power supply S220, maintaining power to the power supply monitor while the power supply resets S230, or combinations thereof. The method 200 is shown in a particular order, but the actions may interact with each other in a different order, or may be performed in any order and still accomplish the same or similar results.

[0035] Step S210, which recites monitoring the power supplied from the power supply functions to monitor the output from the power supply for at least one specific output threshold. The output threshold can be voltage, current, temperature, capacitance, inductance, power, charge remaining, frequency (for example on an alternating current (AC) power supply), or any combination thereof. Step S210 can be performed by a voltage monitoring circuit 93 as shown in Figure 2. The step of monitoring power supplied from the power supply S210, can be executed at a regular interval, for example, step S210 can be executed at a frequency of 3 - 1000 Hz, but may also be executed by polling in a loop in a microprocessor (which would operate at a frequency inverse to the loop execution time, or a variable loop execution time), or at a reduced frequency which may depend upon the application. Step S210 can be performed by a power supply output sensor connected to a switching circuit and/or a microprocessor. The power supply can be a battery, such as a BB-2590 standard military battery, a BA-5590 standard military battery, a fuel cell, a lithium battery, a rechargeable battery, a nuclear battery, an alkaline battery pack, solar panels, power cables, multiple BB-2590 batteries, or any combination thereof.

[0036] Step S220, which recites resetting the power supply can include sending a reset signal to a power supply, and/or can include disconnecting and/or delaying the current draw from the power supply, which can also enable a power supply with self-limiting circuitry to reset itself. When the power supply output is detected below at least one output threshold (for example low voltage is detected), the power drawing circuits can be turned off or disabled, enabling the power draw to drop to below a threshold required to reset the power supply. For example, the BB-2590 will again output current after it senses a current draw below approximately 2 milliamps, so dropping the current draw to below approximately 2 milliamps can reset the BB-2590 battery. Step S220 can be performed by a delay circuit 92 as shown in Figure 2. The voltage Vbatjow current is low as detected by the voltage monitor 93 and the delay circuit 92 turns off the enable switch 94 and can turn off Vcontrol which powers an electronic system. If the power supply is a BB-2590 battery, since there is no current being drawn, the self-regulating circuitry of the BB-2590 battery reads a current draw below 2 mA and the battery resets and begins supplying current again.

[0037] Step S220 can also include additional steps of charging the capacitors S222 and/or enabling the power output S224. Step S222 which recites charging capacitors, can be necessary if a power application requires capacitors, such as an electric motor controller or an air compressor, which require large electrolytic capacitors. This step can be performed using a charging circuit 96 as shown in Figure 2. A microprocessor can disable the charging circuit 96 using Vcharge_enable after an appropriate amount of charging time for the capacitors.

[0038] Step S224, which recites enabling the power output, functions to enable the power to an application (for example a circuit board or a motor controller). As shown in Figure 2, once the BB- 2590 battery has been reset, the delay circuit 92 is no longer providing a delay as the capacitor is recharging or has been recharged, and the voltage monitor 93 disables the enable switch 94 and can enable the current throughput switch 95, enabling high current flow to Vout. For a full hard reset, the power to Vcontrol and Vout can both be reset and/or cycled simultaneously.

[0039] Step S220 can include sending a reset signal directly to a power supply. A reset signal (or a delay in the power draw from the power supply) may be sent preemptively, or response to an application event or interruption. For example, if a power supply with a fixed limited amount of charge capacity, such as a battery, is able to output acceptable voltages while at full charge capacity, but as the charge capacity reduces, the likelihood of a voltage below a threshold increases, the power output reliability and/or system reliability may be improved by resetting the power supply either before or after the performance of a frequently repeated power intensive task, such as the acceleration of an electric motor, transmission of data, or combinations thereof.

[0040] Method 200 may include Step S230, which recites maintaining power to the power supply monitor while the power supply is reset, functions to keep the monitor system operational while power to the rest of the components in the system may be lost during a time period where the power supply output is below a threshold, and while the reset signal is being generated and the power supply is resetting. If power to the power supply monitoring is lost, the system state may become unstable and unreliable, to prevent this, power can be maintained to the power supply monitor at all times. The maximum execution time of Step S210, S220, S222, and S224 or any combination thereof may be limited (and thus adjusted) by the maximum length of time step S230 may be performed, i.e. the maximum length of time that power to a power supply output monitoring system can be maintained. Step S230 can be performed by a charge storage device 1 16 as described above. [0041] High current Li+ rechargeable battery has become a standard commodity used in commercial and military applications. Many manufacturers implement in cell current limiting and reverse current protection. Exceeding these limits causes the internal battery circuitry to open causing power loss to the attached application. Most cells implement a timeout period plus current sense to return the battery to normal operating mode. The circuit described here can prevent both the over current and reverse current protection modes protecting vital low current applications on the battery bus. It also removes the need for inefficient Schottkey diodes protecting reverse current when cells are not balanced replacing them with low R_DS(on) MOSFETS.

[0042] Many applications have several Li+ rechargeable batteries in parallel configuration. Most manufactures implement internal battery protection to prevent damage to the highly volatile Li+ cells. While the protection can protect the battery against off-nominal conditions, this can be disadvantageous to end user applications. The following have been identified as issues with most cell manufacturers internal battery protection:

[0043] 1. Reverse current during parallel operation can drain batteries if one cell is damaged (charge imbalance).

[0044] 2. Internal manufacturer implemented over current protection is not ideal.

[0045] While connected in parallel, differences in charge can cause reverse current to flow into the lower voltage cell. If the forward or reverse current is above (or respectively below) the safety threshold set by the battery manufacturer, the cell will go into current protection mode. The standard solution for this is to connect the batteries together using Schottkey diodes. Under high current loads this causes large amounts of power dissipation.Jn addition to high current during parallel operation, off-nominal or peak loads may trip the batteries current protection circuitry. Most manufacturers do not implement control over the internal battery protection circuitry requiring the application to go into low current mode to resume normal operation. This is the case for the BB-2590 standard battery, but the method may be applied to any suitable battery or power supply.

[0046] As shown in Figures 4-6, a design for a microcontroller based Parallel Electric Current Limiter (PECL) includes a current limiter 420, a battery 410 and a load 430, as shown in Figures 4 and 5. The power (i.e., current and voltage) from the power supply 1 10 can be routed to the load 430. The load 430 can be an electrical component or system. For example, the load 430 can be one or more motors, solenoids, electro-magnets, motherboards, microprocessors, auxiliary components (e.g., weapons, cameras, speakers, microphones, robotic arms), or combinations thereof, in a vehicle, such as a robot, for example as described in U.S. Patent Application No. 12/755,264, filed April 6, 2010, which is herein incorporated by reference in its entirety. [0047] The current limiter 420 protects individual batteries 410 from overcurrent conditions, and prevents back current, which can extend battery life. An implementation is shown for 2-batteries with the time-invariant equations, such as Equations 1 -5:

V_BK - V; p

- 1* = 0.

^■Ak + R-Bk

[0048]

[Equation 1 ]

= v R Ak R Bk

Ak :k = o. i. , n

R ^■A, k

[0049]

[Equation 2]

[Equation 3]

VAO RAI + VAI RAO - IL AO RAI

[0051] RAI + RAQ [E uation 4]

[Equation 5]

[0053] The power supply can have any number of batteries 410 with any type of load conditions 430, for example about 1 , 2, 3, 4, 6, 10, 12, 15, 20, 24, or 25 batteries. The computational power of the microcontroller 421 can be adjusted to be increased with more batteries or decreased with fewer batteries. With a low-end microcontroller 421 , for example a 16-bit 12MHz microcontroller, the device can, for example, have about 2 batteries. [0054] A microcontroller algorithm .described below, can be executed by a microprocessor 421 , such as a microcontroller, a programmable interface controller, a programmable logic controller, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), an electronic and/or mechanical circuit including any number of electronic and/or mechanical components or any other suitable device or combination thereof.

[0055] For most loads and batteries it is not required to consider the dynamic loads 430. However, if the load 430 has very high capacitance and low Rc(ESR) compared to the rise in battery or if the load inductance, LL, is very low and the load resistance, Ri.(ESR), changes very quickly compared to Lu_{k d}i_(ty_dtthen it will be necessary to use the more computationally intensive time variant equations.

[0056] Figure 5 shows contributing components in a parallel battery powered system.

[0057] The cell voltage external to the cell, V_P, and load current, I₅, are telemeterized and available to the microcontroller 421 via analog inputs. High-side N-channel low R_Ds(on) MOSFETs are used to switch battery current. In DC operation the battery current can be described by equation 1.

[0058] The actual internal cell voltage can be previously unknown and solved in real-time, so the system can solve the internal battery voltage. Via can be set equal V_Bk - V_Pto simplify the circuit into a system of linear equations as shown in Equation 2.

[0059] Vp, the node voltage, can be determined as shown in Equation 3.

[0060] In the case of two batteries, the resulting V_P, the node voltage, can be that shown in Equation 4. With V_P, actual cell voltage can be solved and use this information in our state diagram, as shown in Figure 6. The equalities can then be developed, which prevent cell back current and overcurrent protection.

[0061] Algorithm: The microcontroller algorithm can be based on the state diagram 600 as shown in Figure 6. The inputs to the algorithm can be external cell voltage, V_Ak, and load current \_L. The microcontroller 421 can begin in the start state S610, which can configure the ADC registers and digital outputs for controlling at least one MOSFET. From here the state can transfer execution into the init state S620, which can initialize at least one MOSFET to off and can read all V_Ak values. The next state can be chosen by whichever V_Ak for 0≤ k < n is greater, and can utilize the battery with the most charge. These states can continually monitor current, and enter multiple cell states when the respective cells' voltage is greater than the node voltage, V_P. This can prevent backcharging of the batteries.

[0062] The Start State S610 can include the following steps, initializing all ADCs and digital outputs for control of the MOSFETS. Initialization of the digital I/O can be performed without actuating the MOSFETS, for example, when the system may not yet be active in the control loop. [0063] The init state S620 can include turning on the highest voltage cell. The init state may also include turning on a lower voltage cell, or a particular cell as needed in the application. This may also include sourcing power from an alternative power source.

[0064] The monitoring step S630 can include continuously checking three conditions relating to the power supplied from the battery 410. If the node voltage, V_P is greater than or equal to the battery voltage, V_Bk it can be safe to turn the cell on. If V_P is less than the battery voltage, V_Bk, the cell can be turned off because current would be flowing back into the battery 410. If the node voltage is much lower than the battery voltage, (V_Bk- V_P ) /R_Ak > I_k(peak), the program execution can enter into ^■ the short state S640.

[0065] The short state S640 can include immediately turning everything off and applying a timeout. The timeout period can be specific to the application, but is usually greater than 50ms.

[0066] The calibration state S605 can include identification of the values of R_l)k, the equivalent series resistance (ESR), and L_Bk, equivalent series inductance (ESL), of the battery. Other values such as R^, R_s, and maximum load characteristics compared to microcontroller 421 performance may need to be known by a programmer or system designer. To calculate ESR and ESL, a strictly resistive load may be attached to the output. The resistive load may be attached to the output electronically with the aid of additional MOSFETS, or connected as a test apparatus. Each cell external voltage can be measured before, several times during and after the load. The load may need not be applied for more than the time required for the current to stop rising. The load value should be only big enough to get enough signal to noise ratio for the range of values needed. The operation can be straightforward, sample V_Ak both with and without load and compute drop to get total resistance. Subtracting R_Ak then gives R_nk, which may be necessary for the calibration.

[0067] Power system high level design: a power supply, for example, a Li+ multipurpose battery (like BB-2590) has been widely used for an Unmanned Ground Vehicle (UGV), for safety concerns, power supply manufacturers usually include internal current surge protection circuitry which will prevent a battery from overheating, while at the same time can cause the whole system to lose power, a possibly undesirable effect for systems with a relatively long system initialization time. Also, face-to-face diodes are usually recommended when internal charge/discharge between cells can trigger the internal high current protection. Efficiency is usually not very good due to heat loss across diodes, especially for UGVs. MOSFETs can be more efficient but can require an active controller to turn on and/or off portions or all of the control circuit that need to be powered on first or in some special sequence for correct operation of the system. To solve this problem, the power system can include two different buses, one high current power bus(604) which supplies current for high power actuators like motors, and one lower current digital power bus(606) which can source current to all the low current consumption devices like a microcontroller unit (MCU) 607 and any other connected components, such as additional microcontrollers controlling power sub-systems for accessories or sensor systems. To control these buses, a combination of Low R_DS(ON) N-MOSFET(for high current power bus) and Schottky diodes(for the low current digital bus) can be used to maximize the system efficiency and/or performance. The whole system diagram is shown in Figure 7, including at least two cells in the power supply 612 and 61 1. However, the power supply can have one, two, or more than two cells, and each bus can have one or more switches 601 to connect to the power bus 604 and a diode 608 to connect to the digital bus 606). High current power bus switches 601 , 602 are controlled by an MCU 607.

Schottky diodes 608, 609 are connected to the low current digital bus. Diodes could be treated as an always on switch which can prevent internal charging/discharging between cells. However, since the current is usually low on the digital bus 606(less than 5A), the heat loss can be much lower. All sensors including a current sensor 603 and a temperature sensor 605 can assist the MCU(607) in controlling the power bus(604) by turning on and off the power bus cell switches 601 and 602.

[0068] Power bus switch design: As shown in Figure 9, power bus switches 901, 902 can be low R_DS(ON) N-MOSFETs and can be connected in a back-to-back structure with two FETs per side, four per cell which can reduce the total heat loss by approximately 50%. If the current flowing out of a cell through the switch is I, and R_DS(ON) of each MOSFET is R, a single FET per side with have a total DC heat loss of P=I²(R+R)=2I²R. As shown in Figure 9, a dual FET per side structure can have a total DC heat loss of P=I²(R||R)*2= I²R which can reduce heat loss by about 50% compared to a single FET per side structure.

[0069] Figure 8 illustrates a method for smart initial power-on process control Initially, when the battery is plugged in or start-up otherwise occurs, the MCU (607 in Figure 7) can be powered through the protection diodes 608 and 609 in the digital bus, as shown at 801 in Figure 8. After that, using current feedback from the power bus 606, a current sensor 603 can use PWM or another suitable modulation technique to turn on the power bus switches 601 and 602, as shown at 802 in Figure 8. The duty cycle can be determined by current controlling firmware in the Power

Initialization (PI) controller, 803 in Figure 8. This can be performed, for example, if there are some passive energy components such as large value capacitors which can require an initial charging, and the starting current could be large enough to trigger the internal protection circuits in a power supply, for example in a BB-2590 battery. With the PI controller managing the current control, the initial power-on process can be performed quickly and safely..

[0070] The system can utilize low power consumption, for example in a sleep mode, with a micro amp level current draw. As shown in Figure 9, cell voltage feedback can be used by an MCU to control a power bus switch, and/or a voltage divider can draw a milliamp level of current, so a high side MOSFET 905, 906 can be used to turn off these voltage sensors when necessary. When the system is in a low power (e.g., sleep) mode, the system can barely draw current and the power bus can be completely shut off.

[0071] Bus level current surge protection: As shown in Figure 10, a voltage waveform of a current surge occurs on the internal circuitry of a power supply (e.g., a battery) is followed by a complete power supply shut off. The surge occurs at SAT1 in Figure 10, but the power supply (e.g., battery) can wait or delay until SAT3 to shut itself off.

[0072] The firmware or operating software operating or executing in the power monitor system can include two levels of protection and can do some or all of the following steps in response to a current surge. When a current surge from current sensor 603 is detected by an MCU, the firmware can enter into a warning state and reduce, increase, or otherwise adjust the current consumption. The firmware can also start a timer. If a timer is used, when the timer expires (SAT2 in Figure 10) the firmware can turn off the power bus and the power supply (e.g., a battery) should reset and/or recover. This can maximize the system performance when compared to a direct shut off when a current surge occurs. In case there is a very big electrical load, like an electric motor stalling or a short circuit, the voltage of cell can drop very fast as shown in Figure 10, when it drops below SAV 1 , the firmware can receive this signal through a voltage divider and/or a low-pass filter 903, 904, as shown in Figure 9, and the firmware can ignore all other signals and turn off the power bus immediately. SAVl is determined by type of power supply used, which can be available to MCU through 610 (SMBus) in Figure 7, and also by the ambient temperature of the system which is available to MCU through the temperature sensor 605. The firmware program loop can be equal to or faster than about 5ms, for example as shown in the test illustrated in Figure 10.

[0073] To catch the start of SAT 1 in Figure 10 reliably, multiple data sensing and processing methods can be implemented in firmware or another equivalent real time system such as an electronic circuit. In addition to raw data measurements, such as the real time battery operating status of cell(s) and/or voltage(s) and/or overall consumed current, a combination of other data processing results (possibly computed or detected using a pattern recognition algorithm) based on original data can be used, such as the first and/or second order derivatives, and/or integration over certain number of sensing cycles. In order to achieve a faster processing speed and avoid data processing errors brought by digitalization of the analog data and firmware level algorithms, a hardware level solution can be used to directly provide processed data to firmware or an equivalent control system, for example, a derivative/integration circuit placed between raw data acquisition circuit and a control unit such as a microcontroller or FPGA or other suitable controller device . [0074] U.S. Patent Application No. 13/066,1 15, filed 6 April 201 1 , and U.S. Provisional application 61/321,383 filed 6 April 2010 are both incorporated by reference in their entireties.

[0075] As a person skilled in the art will recognize from the previous detailed description and from the figures and claims, modifications and changes can be made to the variations of the invention without departing from the scope of this invention defined in the following claims. Elements, characteristics and configurations of the various variations of the disclosure can be combined with one another and/or used in plural when described in singular or used in plural when described singularly.

Claims

CLAIMS We Claim:

1. A method of controlling a power delivery to an electrical component or system comprising:

drawing a first electrical current from a power supply;

delivering the first electrical current to the electrical component or system;

monitoring the first electrical current;

exceeding a current limit for the first electrical current from the power supply, wherein the exceeding of the current limit comprises automatically stopping by the power supply of the first electrical current;

resetting the power supply after the exceeding of the current limit; and

delivering a second electrical current to the electrical component or system after resetting the power supply, wherein the second electrical current is lower than the first electrical current, and wherein the second electrical current is configured to power low-power applications of the electrical component; and

delivering the first electrical current to the electrical component after delivering the second electrical current.

2. The method of Claim 1, further comprising delivering a second electrical current to the electrical component or system after the power supply stops the first electrical current and before the resetting of the power supply.

3. The method of Claim 2, wherein delivering the second electrical current comprises delivering the second electrical current from a charge storage device.

4. The method of Claim 3, wherein the charge storage device comprises a capacitor.

5. The method of Claim 3, further comprising charging the charge storage device by the power supply after the resetting of the power supply.

6. The method of Claim 2, wherein the delivering of the first electrical current and the delivering of the second electrical current provide uninterrupted current delivery to the electrical component or system.

7. The method of Claim I , wherein resetting comprises stopping the current draw from the power supply.

8. The method of Claim 1 , wherein resetting comprises resetting with a reset circuit in a power monitor system.

9. The method of Claim 1 , wherein monitoring the first electrical current comprises monitoring with a supply output sensor configured to transition to a current supplied by a stored charge device when the current limit is exceeded by the first electrical current.

10. The method of Claim 1 , wherein the charge storage device comprises a capacitor, and wherein the method further comprises limiting the first electrical current, and wherein limiting the first electrical current comprises pulse-width modulating the capacitor.

1 1. A method of controlling the delivery of current to an electrical component or system comprising: delivering a first electrical current to the electrical component or system;

monitoring the operating conditions of a power supply;

operating outside of the limit of the operating conditions, wherein operating outside of the limit comprises the stopping of the drawing of the first electrical current, wherein the operating outside of the limit of the operating conditions further comprises transitioning to a second electrical current to the electrical component or system before the resetting of the power supply;

resetting the power supply after operating outside of the operating conditions; and wherein the second electrical current is lower than the first electrical current, and wherein the second electrical current is configured to power low-power applications of the electrical component; and

12. The method of Claim 1 1 , wherein monitoring the operating conditions of a power supply further comprises monitoring a first electrical current, and wherein operating outside of the operating conditions further comprises exceeding a current limit for the first electrical current, wherein exceeding the current limit comprises the stopping of the drawing of the first electrical current, wherein the exceeding of the current limit further comprises transitioning to a second electrical current to the electrical component or system before the resetting of the power supply, and wherein resetting the power supply after operating outside of the operating conditions includes resetting the power supply after exceeding the current limit.

13. The method of Claim 1 1 , wherein monitoring the operating conditions of a power supply further comprises monitoring a temperature, and wherein operating outside of the operating conditions further comprises exceeding a temperature limit, wherein exceeding the temperature limit comprises the stopping of the drawing of the first electrical current, wherein the exceeding of the temperature limit further comprises transitioning to a second electrical current to the electrical component or system before the resetting of the power supply, and wherein resetting the power supply after operating outside of the operating conditions includes resetting the power supply after exceeding the temperature limit.

14. The method of Claim 1 1 , wherein the first electrical current charges a source of the second electrical current after the resetting of the power supply.

15. The method of Claim 1 1 , wherein the electrical component or system comprises a charge storage device, and the charge storage device comprises a capacitor, and wherein the method further comprises limiting the first electrical current, and wherein limiting the first electrical current comprises pulse-width modulating the capacitor.

16. A system for delivering electrical power comprising:

a power supply configured to stop an electric power delivery from the power supply when an output current from the power supply exceeds a current limit and/or an operating temperature of the power supply crosses a temperature threshold, and/or an output voltage from the power supply crosses a voltage threshold;

a power monitor system connected to the power supply, and wherein the power monitor system is configured to sense the output current and/or the output voltage, and wherein the power monitor system is configured to reset the power supply when the output current exceeds the current limit and/or an operating temperature of the power supply crosses a temperature threshold, and/or the output voltage crosses a voltage threshold; and

wherein the power monitor system comprises a charge storage device comprising a capacitor, and wherein the power monitor system is configured to limit the first electrical current by pulse-width modulating the capacitor; and

wherein the power supply is configured to deliver a load to the power monitor system.

17. The method of Claim 16, wherein the power monitor system comprises a reset circuit configured to reset the power supply after the electric power is stopped because the output current from the power supply exceeded a current limit and/or an operating temperature of the power supply crosses a temperature threshold, and/or an output voltage from the power supply crosses a voltage threshold.

18. The method of Claim 16, wherein the power supply comprises a first battery.

19. The method of Claim 16, wherein the power monitor system comprises a charge storage device configured to maintain power to the power monitor system.

20. The method of Claim 16, wherein the charge storage device comprises a second battery.