In some examples, an electrical power system includes a differential bus, a power converter coupled to the differential bus, and a controller configured to control the power converter based on a first target value for the differential bus. The controller is also configured to sense that a ground fault has occurred in the electrical power system while controlling the power converter based on the first target value. The controller is further configured to, responsive to sensing that the ground fault has occurred, control the power converter based on a second target value for the differential bus, the second target value being different than the first target value.

An object of the present invention is to improve availability when a power is lost. In a power conversion device 1, a gate drive power supply circuit 50 can supply a gate drive power within a predetermined normal voltage range. A backup power supply circuit 70 supplies the gate drive power to a lower arm gate circuit 40 when a voltage of the gate drive power applied from the gate drive power supply circuit 50 to the lower arm gate circuit 40 falls below a normal voltage range. When the gate drive power is supplied from the backup power supply circuit 70, the lower arm gate circuit 40 drives a lower arm switching circuit 22 in a short state in which all switching elements of the lower arm switching circuit 22 are turned on.

In a motor driving apparatus including an inverter connectable to n motors (n being an integer not less than 2) each including a rotor having a permanent magnet, braking operation is performed on i (i being an integer from 1 to n1) of the n motors, and then braking operation is performed on j (j being an integer from 1 to ni) of the n motors other than the i motors. It is possible to reduce the risks of failure of the inverter and demagnetization of the motors due to overcurrent by reducing current flowing through the inverter and the motors when the braking operation is performed.

A switching circuit includes: a detection wiring configured to receive a potential changing depending on a current of a first switching element; a first circuit connected between the detection wiring and a first having a first time constant, and making the first wiring follow the potential of the detection wiring; a second circuit connected between the detection wiring and a second wiring, having a second time constant larger than the first time constant, and making the second wiring fellow the potential of the detection wiring; a potential maintaining circuit configured to maintain the second wiring at a potential higher than the potential of the first wiring while a current is not flow through the first switching element; and a control circuit configured to turn off the first switching element in a case where the potential of the first wiring exceeds the potential of the second wiring.

An overvoltage absorption circuit and a single-phase HERIC topology are provided. The overvoltage absorption circuit is applicable to the single-phase HERIC topology, and includes a clamping capacitor, an absorption resistor, a first diode, and a second diode. One terminal of the clamping capacitor and one terminal of the absorption resistor are each connected to collectors of two cross transistors in the single-phase HERIC topology. The other terminal of the clamping capacitor and the other terminal of the absorption resistor are each connected to the anodes of the first diode and the second diode. The cathode of the first diode is connected to the emitter of one of the two cross transistors. The cathode of the second diode is connected to the emitter of the other of the two cross transistors.

A half bridge circuit driver chip and the protection method thereof are provided. The high side voltage detecting circuit connects to a high side signal output terminal and detects the high side turn-on voltage of the high side transistor, so as to obtain a high side turn-on signal. The low side voltage detection circuit connects to a low side signal output terminal and detects a low side turn-on voltage of a low side transistor, so as to obtain a low side turn on signal. When the high side turn-on signal and the low side turn-on signal are received by a protection circuit, a reset signal is generated. The reset signal is sent to the high side driving circuit for turning off the high side transistor and to the low side driving circuit for turning off the low side transistor.

The present disclosure involves a two stage inverter, a system for electrical power conversation, and a method of converting electrical power using silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs). One example implementation includes using two or more SiC MOSFETs in series with each MOSFET having a gate terminal for triggering a state switch between an on (conducting) and off (non-conducting) state of the MOSFET. An AC terminal is connected between the series SiC MOSFETS, and the series SiC MOSFETs are connected across a DC bus and in parallel with one or more capacitors.

A communication system for use in a switching module includes a low-side control block coupled to control switching of a low-side switch of the switching module. The low-side control block is further coupled to be referenced with a low-side reference system ground. A high-side control block is coupled to control switching of a high-side switch of the switching module. The high-side control block is further coupled to be referenced with a floating node of the switching module. During steady state operation, the low-side control block is coupled to send signals during each switching cycle to the high-side control block to turn the high-side switch on and off. A status update is communicated from the high-side control block to the low-side control block through a first single-wire communication link.

A vehicle driving device includes an inverter which drives a motor. The inverter includes: a three-phase bridge circuit including a plurality of switching elements; a three-phase short circuit which short-circuits three phases of the motor via the three-phase bridge circuit; and a control circuit. The control circuit includes: a microprocessor which drives the three-phase bridge circuit; a malfunction notification circuit which outputs a malfunction notification signal when the microprocessor is malfunctioning; and a latch circuit which holds the malfunction notification signal outputted from the malfunction notification circuit. The control circuit outputs a three-phase short-circuit drive signal which drives the three-phase short circuit, based on the malfunction notification signal held by the latch circuit.

A system for testing a ground fault detection system in an electric circuit establishes a ground connection between a bus and the ground via an inverter and a load by closing an inverter switch of the inverter and a grounding switch disposed between the load and the ground, determines whether the ground connection is detected, and determines a fault in the ground fault detection system responsive to the first ground connection not being detected by the ground fault detection system. Optionally, a ground fault may be identified by determining three phase voltages provided from each of plural inverters, determining symmetrical components of the three phase voltages for each of the inverters, and identifying a ground fault in one or more of the inverters while powered by the power supply based on the symmetrical components.