A power conversion circuit having a solid-state circuit breaker integrated therein is disclosed. With a disconnect switch between a utility source and the power conversion apparatus described for meeting UL489, the power conversion circuit includes an input connectable to an AC source, a rectifier circuit connected to the input to convert an AC power input to a DC power, and a DC link coupled to the rectifier circuit to receive the DC power therefrom. The rectifier circuit comprises a plurality of phase legs each including thereon an upper switching unit and a lower switching unit, wherein at least one of the upper and lower switching units on each phase leg comprises a bi-directional switching unit that selectively controls current and withstands voltage in both directions, so as to provide a circuit breaking capability that selectively interrupts current flow through the rectifier circuit, while maintaining original power conversion functionalities.

An electrical system includes a ground fault detection unit including a low frequency ground fault detection circuit and a high frequency ground fault detection circuit, and/or a ground fault control unit connected to the low frequency ground fault detection circuit and the high frequency ground fault detection circuit. The ground fault unit may be configured to detect a ground fault according to an output of the low frequency ground fault detection circuit and/or an output of the high frequency ground fault detection circuit. The electrical system may include a first current sensor connected to the low frequency ground fault detection circuit and/or a second current sensor connected to the high frequency ground fault detection circuit.

Provided is a method for determination of a location of a short circuit fault in a generator arrangement, wherein the generator arrangement includes an electrical machine and at least one channel, wherein the or each channel includes a breaker, a converter unit and a set of stator windings of the electrical machine connected to the converter unit via the breaker, wherein upon an occurrence of a short circuit in a channel, the connection between the set of stator windings and the converter unit interrupted by opening the breaker, wherein depending on at least one measured signal of a measurand, wherein the measured signal is measured by at least one sensor of the electric machine and wherein the measurand describes a torque ripple of the electrical machine, either the electrical machine or the converter unit of the channel is determined as location of the short circuit fault.

A protection circuit including an inrush current detector operable to detect an inrush current from a DC link is disclosed herein. The inrush current detector includes a transistor switch that is turned on in normal operation of the protection circuit. The protection circuit operates to detect when the voltage across the transistor switch exceeds a threshold voltage in response to a detected inrush current, and in response operates to turn off the transistor switch.

A power conversion system including: a self-excited power converter that converts power between an alternating-current (AC) power system and a direct-current (DC) line; an AC circuit breaker disposed between the AC power system and the self-excited power converter; an arrester connected between the DC line and a ground or between an AC line and the ground, the AC line connecting the AC circuit breaker and the self-excited power converter; and a control device. The control device causes the self-excited power converter to stop a switching operation when the control device detects a ground fault accident on the DC line, and opens the AC circuit breaker after the self-excited power converter stops the switching operation.

A motor drive system includes: an inverter that drives a motor; a current detector that detects and outputs the first signal that is a current value of a current flowing through the inverter; a first low-pass filter that removes a noise frequency component from the first signal and outputs a second signal that is a current value after the noise frequency component has been removed; a demagnetization current determiner that compares a demagnetization current threshold with the second signal, and outputs a demagnetization protection signal when the second signal takes a value larger than the demagnetization current threshold; and a short circuit determiner that compares a third signal with a short circuit and outputs an anomaly signal for stopping the inverter when the third signal takes a value larger than or equal to the short circuit threshold.

A protection device provided between a synchronous motor having a plurality of windings and a motor driving device for driving the synchronous motor includes: a switching unit for making and breaking the connection between the motor driving device and the synchronous motor; a dynamic brake circuit including resistors and switches, to short-circuit the plurality of windings between the switching unit and the synchronous motor via the resistors; and a control device for controlling the switching unit and the dynamic brake circuit. The control device controls the switches in the dynamic brake circuit to short-circuit the plurality of windings, and then controls the switching unit to cut off the connection between the motor driving device and the synchronous motor.

The present disclosure relates to a conversion circuit, an inverter, and a method of driving the inverter, wherein a switch is provided at an input terminal of a direct current (DC) link capacitor, so that power is charged in the DC link capacitor through a switching element at initial driving and charged in the DC link capacitor through a rectifier when a voltage level of the DC link capacitor is equal to or higher than a preset reference level, thereby limiting inrush current caused in the DC link capacitor through the switching element when the inrush current is caused.

Apparatus and methods for supplying DC power to control circuitry of a matrix converter is provided. In certain embodiments, a matrix converter includes an array of switches having AC inputs for receiving a multi-phase AC input voltage and AC outputs for providing a multi-phase AC output voltage to a load, such as an electric motor. The matrix converter further includes control circuitry for opening or closing individual switches of the array, and a clamp circuit connected between the AC inputs and AC outputs of the array and operable to dissipate energy of the load in response to an overvoltage condition, such as an overvoltage condition arising during shutdown. The clamp circuit includes a switched mode power supply operable to generate a DC supply voltage for the control circuitry.

A fault detection method is used to determine whether a power switch coupled to a DC bus of a power conversion circuit is faulted. The method includes: detecting a bus voltage to provide a voltage signal and acquiring at least one detection value according to the voltage signal; providing control signals sequentially to turn off or turn on the power switch; determining that the power switch is a short-circuit fault if a first detection value is greater than or equal to a first threshold value when the power switch is turned off; determining that the power switch is an open-circuit fault if a second detection value is less than a second threshold value when the power switch is turned on; and providing an alarm signal or a disable signal when the power switch is the short-circuit fault or the open-circuit fault.