Abstract: An inverter and driving method of the inverter are disclosed. The inverter includes an active clamp forward (ACF) converter and a flyback converter. One of a forwarding operation of delivering current from a primary side to a secondary side by using the ACF converter and a backwarding operation of delivering current from the secondary side to the primary side by using the flyback converter is selected to generate a rectified AC.

Abstract: A multilevel inverter circuit includes an inverter control circuit that controls switching of main and neutral switches. The inverter control circuit receives current vector information indicating flow direction of an AC current output of the multilevel inverter circuit. The inverter control circuit eliminates dead time between switching of a neutral switch and a main switch depending on whether the AC current output is flowing towards a load or away from the load. Among other advantages, elimination of dead time improves the total harmonic distortion of the sinusoidal AC voltage output of the multilevel inverter circuit.

Abstract: According to one embodiment, a power supply system includes a switching device operable to be turned on and off for causing power to be delivered to a load. The switching device has a control terminal. Driver circuitry, coupled to the control terminal of the switching device, is operable to drive the switching device. The driver circuitry further operable to detect a fault condition in the power supply system. If the switching device is turned on when the fault condition is detected, the driver circuitry reduces the voltage at the control terminal of the switching device to a level just above the threshold voltage for the switching device, and holds the voltage at the control terminal to the level just above the threshold voltage for a controlled duration, thereby reducing the saturation current flowing through the switching device. The driver circuitry further reduces the voltage at the control terminal of the switching device after the controlled duration, thereby safely turning off the switching device.

Abstract: A multilevel inverter circuit includes an inverter control circuit that controls switching of main and neutral switches. The inverter control circuit receives current vector information indicating flow direction of an AC current output of the multilevel inverter circuit. The inverter control circuit eliminates dead time between switching of a neutral switch and a main switch depending on whether the AC current output is flowing towards a load or away from the load. Among other advantages, elimination of dead time improves the total harmonic distortion of the sinusoidal AC voltage output of the multilevel inverter circuit.

Abstract: In one embodiment, a method is provided for a power converter system comprising a switching circuit having a plurality of switches operable to be turned on and off to cause current to flow to deliver power to a load. The method includes the following: generating PWM control signals for turning on and off the switches in the switching circuit; sensing the direction of current flow, wherein the direction of current flow is related to a likelihood of shoot-through in the switching circuit; providing a current vector signal indicative of the direction of current flow; and enabling or disabling introduction of a dead time into the PWM control signals for the switches in the switching circuit in response the current vector signal.

Abstract: An inverter and driving method of the inverter are disclosed. The inverter includes an active clamp forward (ACF) converter and a flyback converter. One of a forwarding operation of delivering current from a primary side to a secondary side by using the ACF converter and a backwarding operation of delivering current from the secondary side to the primary side by using the flyback converter is selected to generate a rectified AC.

Abstract: In one embodiment, a power converter system comprises an input terminal operable to connect to a DC power source and an output terminal at which an output voltage can be provided. An active clamped forward converter is operable to provide forward power flow from the DC power source to the output terminal. A flyback converter is operable to provide backward power flow from the output terminal to the DC power source. The active clamped forward converter and the flyback converter cooperate to generate a rectified sinusoidal waveform at the output terminal.

Abstract: In an embodiment, a power converter system is provided for AC voltage regulation. The power converter system receives an AC input voltage at an input terminal and provides an AC output voltage to a load at an output terminal. A main bi-directional switch is coupled between the input terminal and the output terminal. The main bi-directional switch is operable to control the provision of the AC output voltage. A reactive current flows through the main bi-directional switch if the load is reactive. An auxiliary bi-directional switch is coupled to the output terminal. The auxiliary bi-directional switch is operable to circulate the reactive current due to the reactive load, thereby reducing any voltage spikes in the power converter system.

Abstract: In an embodiment, a power converter system is provided for AC voltage regulation. The power converter system receives an AC input voltage at an input terminal and provides an AC output voltage to a load at an output terminal. A main bi-directional switch is coupled between the input terminal and the output terminal. The main bi-directional switch is operable to control the provision of the AC output voltage. A reactive current flows through the main bi-directional switch if the load is reactive. An auxiliary bi-directional switch is coupled to the output terminal. The auxiliary bi-directional switch is operable to circulate the reactive current due to the reactive load, thereby reducing any voltage spikes in the power converter system.

Abstract: In one embodiment, a power converter system includes a first input terminal and a second input terminal operable to connect to an alternating current (AC) power source, and an output terminal at which an output voltage can be provided to a load. A first inductor and a first diode are connected in series between the first input terminal and the output terminal. A second inductor and a second diode are connected in series between the second input terminal and the output terminal. A first switch is connected to the first inductor and the first diode, and a second switch is connected to the second inductor and the second diode. The first switch and the second switch alternately function as a boost switch and a synchronous rectifier for charging and discharging the first and second inductors during operation of the power converter system.

Abstract: In one embodiment, a power converter system includes a first input terminal and a second input terminal operable to connect to an alternating current (AC) power source, and an output terminal at which an output voltage can be provided to a load. A first inductor and a first diode are connected in series between the first input terminal and the output terminal. A second inductor and a second diode are connected in series between the second input terminal and the output terminal. A first switch is connected to the first inductor and the first diode, and a second switch is connected to the second inductor and the second diode. The first switch and the second switch alternately function as a boost switch and a synchronous rectifier for charging and discharging the first and second inductors during operation of the power converter system.

Abstract: A synchronous full bridge rectifier is controlled to provide a power factor near unity. The full bridge rectifiers are transistors each with a controlling input. The AC input signal and currents within the circuit are sensed and sent to a controller. In response, the controller output control signals to turn on/off the rectifying MOSFETS on a timely basis to form a power factor of near one with respect to the AC input signal. The full wave rectifier is made of N-channel MOSFET's, some with fast body diodes. The MOSFET's are rectifiers and PFC control elements. The result is a one stage synchronous rectifier with PFC. A solid state precision analog differential amplifier senses the AC line waveform and high frequency current transformers sense the currents. The controller accepts the inputs of the amplifier and the sensed currents and outputs control signals that turn on and off the four MOSFET's.

Abstract: A synchronous full bridge rectifier is controlled to provide a power factor near unity. The full bridge rectifiers are transistors each with a controlling input. The AC input signal and currents within the circuit are sensed and sent to a controller. In response, the controller output control signals to turn on/off the rectifying MOSFETS on a timely basis to form a power factor of near one with respect to the AC input signal. The full wave rectifier is made of N-channel MOSFET's, some with fast body diodes. The MOSFET's are rectifiers and PFC control elements. The result is a one stage synchronous rectifier with PFC. A solid state precision analog differential amplifier senses the AC line waveform and high frequency current transformers sense the currents. The controller accepts the inputs of the amplifier and the sensed currents and outputs control signals that turn on and off the four MOSFET's.

Abstract: A quick punch-through integrated gate bipolar transistor (IGBT) includes a drift region and a gate. The drift region has a drift region dopant concentration and a drift region thickness. The gate has a gate capacitance. The drift region dopant concentration, drift region thickness and gate capacitance are adjusted dependent at least in part upon the PNP gain of the IGBT to maintain the potential difference between the gate and emitter at a level greater than the IGBT threshold voltage when the collector voltage reaches the bus voltage. This insures that the hole carrier concentration remains approximately equal to or greater than the drift region dopant concentration when the depletion layer punches through to the buffer region during the turn-off delay. Thus, the collector voltage overshoot and the rate of change of voltage and current are controlled, and electromagnetic interference is reduced, during turn off.

Abstract: A quick punch-through integrated gate bipolar transistor (IGBT) includes a drift region and a gate. The drift region has a drift region dopant concentration and a drift region thickness. The gate has a gate capacitance. The drift region dopant concentration, drift region thickness and gate capacitance are adjusted dependent at least in part upon the PNP gain of the IGBT to maintain the potential difference between the gate and emitter at a level greater than the IGBT threshold voltage when the collector voltage reaches the bus voltage. This insures that the hole carrier concentration remains approximately equal to or greater than the drift region dopant concentration when the depletion layer punches through to the buffer region during the turn-off delay. Thus, the collector voltage overshoot and the rate of change of voltage and current are controlled, and electromagnetic interference is reduced, during turn off.

Abstract: A control scheme for a wound rotor synchronous generator whereby feedback signals corresponding to the exciter field current and the generator output voltage potential combine together to control the generator output voltage in such a way that at lower generator speeds and lower load requirements, exciter field current saturation is eliminated by reducing generator output voltage. The generator control scheme includes a circuit for sensing exciter field current in logic cooperation with a circuit for sensing generator voltage. Both sensing circuits regulate the current applied to the exciter field which corresponds to the rectified current applied to the field windings of the power generator. During steady state operations the generator output voltage is regulated using the generator output voltage as a feedback signal.

Abstract: An aircraft engine start system eliminates the need of a separate exciter field inverter by rearranging the exciter field windings and by utilizing external AC power. The aircraft engine is started by external AC power and once the engine has started, the engine can supply power back to a variable frequency AC bus as well as back to a constant frequency AC bus through the start/generator converter mode.

Abstract: A plurality of power semiconductor switching devices are included in a circuit module in a pattern whereby interconnecting lead lengths are minimized to provide improved circuit characteristics and to insure uniform current sharing when said devices are paralleled during switch-on, switch-off and steady state conditions.

Abstract: This invention provides for an enabling circuit that ensures a positive turn-on of semiconductor switches configured for the generation of a synthesized waveform, thereby eliminating misfiring of the switches due to electronic noise or logic malfunction. The circuit is configured to separately compare a sample waveform with a positive reference voltage and a negative reference voltage. The two results are directed to separate logic AND gates which have respective control signal inputs that regulate the formation of the positive and negative portion of a synthesized waveform. The output signals from the two AND gates connect to logic means to control the firing of the semiconductor switches.

Abstract: A multi-step, alternating current power supply that provides for a failed-operation redundancy safety system that compensates for a short-circuited power switch and maintains an AC regulated output voltage without introducing undesirable harmonic components. The firing and logic controller 33 senses a short-circuited power switch 46 within an inverter bridge 32 and disables all complementary power switches 48 within the faulted bridge and enables the remaining power switches 50 in the faulted bridge. The firing sequence is adjusted for the remaining healthy power switches 52 by increasing the phase shift of the individual waveforms 54. The generator voltage is increased as required to maintain the desired AC voltage output level 56.