A system and method for combining power from DC power sources. Each power source is coupled to a converter. Each converter converts input power to output power by monitoring and maintaining the input power at a maximum power point. Substantially all input power is converted to the output power, and the controlling is performed by allowing output voltage of the converter to vary. The converters are coupled in series. An inverter is connected in parallel with the series connection of the converters and inverts a DC input to the inverter from the converters into an AC output. The inverter maintains the voltage at the inverter input at a desirable voltage by varying the amount of the series current drawn from the converters. The series current and the output power of the converters, determine the output voltage at each converter.

Distributed Power Harvesting Systems Using DC Power Sources

A battery monitor is provided for use with a battery of an automotive vehicle. The battery monitor can provide real time battery condition measurements and can selectively control the charging of the battery through an alternator of the vehicle based upon the measured battery condition.

Energy management system for automotive vehicle

An uninterruptible power system has a transformer with a primary connected to input terminals, a secondary connected to output terminals, a static switch connected between the input terminals and the primary, and an auxiliary primary connected to an inverter which is supplied by a battery to provide output voltage to the output terminals when a main AC power system connected to the input terminals has failed. The primary has multiple taps at different voltage levels and a buck-boost winding. The taps of the transformer are switched and the buck-boost winding is controlled to provide either buck, boost, or pass-by to allow control of the output voltage from the transformer to within a few percent of a desired voltage level despite large changes in the input voltage. A battery charger coupled to the auxiliary primary operates as a boost converter to provide current to charge the battery at a current level which tracks the input voltage from the AC power system, thereby providing a substantially unity power factor to the AC power system. The voltage control of the output voltage also controls the voltage at the output of the auxiliary primary to which the battery charger is connected, whereby the voltage applied to the charger is substantially regulated and the output power of the charger itself is substantially regulated. The charger can be operated in programmable modes to provide a desired charge configuration for the battery. Detection of faults in the AC power system is enhanced by accurate detection of the zero crossings of the input voltage from the AC power system, and by comparison of the AC input power waveform with an adaptive reference.

Uninterruptible power system

An electronic battery tester for testing a storage battery includes test circuitry configured to provide an output based upon a selected test criteria. Additionally, circuitry is provided to assist in balancing batteries used in a string of multiple batteries.

Electronic battery tester

A monitoring system and method for monitoring performance of individual powers sources in a distributed power source system A monitoring module is coupled to each of the power sources, or to each string of serially connected power sources, to monitor and collect data regarding current, voltage, temperature and other environmental factors at the power source The collected data is transmitted over a power line to a central analysis station for analysis Data collected from each source indicates malfunction or degradation at the source Comparison of data collected from adjacent sources filters for environmental factors impacting neighboring sources such as cloudy days for a solar panel Comparison of data collected from the same source at different times indicates soiling or degradation of the source with time or periodic events such as a moving shade from an adjacent building

Monitoring of Distributed Power Harvesting Systems Using DC Power Sources

A microprocessor-based electronic voltage regulation system for controlling the charging of the battery in a vehicle. The conventional voltage regulator is eliminated and the intelligence of the microprocessor already present on the vehicle for controlling engine operation is used to regulate the output of the alternator. The battery temperature signal from a temperature transducer and a battery voltage signal from a sense line connected directly to the positive terminal of the battery are supplied to the microprocessor through an analog-to-digital converter. The microprocessor is programmed to ascertain from the battery temperature signal the desired set point voltage based upon an inverse first order relationship between battery temperature and desired battery voltage with preset maximum and minimum voltage set point levels. Energization of the field windings is controlled in accordance with a comparison between the desired set point voltage and the battery voltage signal on the battery sense line and is implemented in response to a control signal from the microprocessor by a solid-state power switching circuit which interfaces with the alternator field windings. In addition, the microprocessor is provided with additional feedback information relating to various driving conditions, such as vehicle deceleration, throttle position, engine RPM, and elapsed time since ignition, and is further programmed to modify the desired voltage set point or modify engine RPM in accordance with such driving conditions. Overcurrent protection for the logic circuitry and improved diagnostic capabilities are also provided.

Microcomputer controlled electronic alternator for vehicles

A regulated power supply for supplying DC output voltage and current to an electronic control system of an internal combustion engine, designed especially for automotive applications and cold cranking conditions encountered therein, is disclosed. The power supply has a series switching regulator section having a transformer provided with two windings, and a shunt switching regulator section that shares the transformer with the series regulator section. When normal battery voltages are available, the power supply through its series regulator section operates in a voltage dropping mode, intermittently passing current through the primary winding of the transformer to maintain the desired output voltage. When low battery voltages are encountered, such as during cold cranking conditions, the shunt regulator section of the power supply operates in a voltage boosting mode to maintain the desired output voltage. The voltage boosting function is accomplished by intermittently shunting current from the primary winding towards ground, and utilizing the resultant magnetic energy stored in the core of the transformer to boost the voltage available to the load. Mutual inductance between the primary and secondary windings allows energy stored in the core of the transformer as a result of current flowing through the primary winding to be beneficially delivered through the secondary winding to the output of the power supply during both modes of power supply operation, thereby improving overall power supply efficiency and reducing power supply cost and complexity.

Buck-boost regulated D.C. to D.C. power supply

A method of and apparatus for controlling the energization of an electromagnetic fuel injection valve in response to the production of an injector control pulse in an electronic fuel injection system. The driver circuit operates a current regulating power transistor into saturation until the current through the solenoid coil of the injector valve attains a predetermined peak current value. A comparator circuit deactivates the power transistor to stop the build-up of current through the coil. A switched free-wheeling circuit is enabled, remains activated, and starts conducting when the power transistor is deactivated by the comparator circuit so that some current continues to be supplied to the solenoid coil when the power transistor is off, thereby causing the current through the coil to decay slowly. When the solenoid current has decayed to a predetermined hold current level, the comparator circuit reactivates the power transistor and thereafter, due to hysteresis in the comparator circuit, cycles the power transistor on and off to substantially maintain the current through the coil at the predetermined hold current level. At the end of the injector control pulse, both the current regulating power transistor and the switched free-wheeling circuit are deactivated. Then, through multiple power dissipation pathways momentarily activated by the avalanching of a zener diode in series with the injector's solenoid coil, the energy stored in the solenoid coil and the current through the coil diminish rapidly to zero.

Electronic fuel injector driver circuit

A method to disengage an electronic speed control as a function of the condition of the park/neutral gear or manual clutch If the automatic transmission lever is bumped from "drive" or the manual transmission clutch is depressed while the electronic speed control is operating, the method will sense this by detecting a difference in the ratio of engine speed to vehicle speed If the ratio changes by ±25 percent, the electronic speed control is disengaged

Electronic speed control system for vehicles, a method of determining the condition of a manual transmission clutch and of a park/neutral gear in an automatic transmission

A circuit and method, for use with an electronically controlled load network for diagnosing short-circuit and open-circuit conditions and for protecting loads affected by those conditions by using positive feedback in cooperation with a microprocessor controlled tri-state input/output port pin.

William R. Kissel

Papers

Microcomputer controlled electronic alternator for vehicles

Buck-boost regulated D.C. to D.C. power supply

Electronic fuel injector driver circuit

Electronic speed control system for vehicles, a method of determining the condition of a manual transmission clutch and of a park/neutral gear in an automatic transmission

Diagnostic protection circuit and method using tri-state control and positive feedback