A vehicle power conversion system includes an input power supply including an AC power input, a battery, a power factor correction circuit connected to the input power supply, a power transmission unit including an inverter connected in parallel to the battery, a three-phase motor connected to the inverter, and at least one relay connected to the three-phase motor and configured to transfer power between the input power supply and the battery, and a buck converter including a first switching element and a second switching element, connected in parallel to the power factor correction circuit, wherein an end of the second switching element is connected in parallel to the power transmission unit, and wherein the buck converter is configured to step down an output voltage of the power factor correction circuit and transfer the stepped down output voltage.

A line interface filter apparatus to couple a drive or group of drives to a shared multiphase AC bus, including individual phase circuits having an inductor coupled between a respective bus and drive phase lines, a tapped resistor coupled to the respective drive phase line, and a capacitor coupled between the resistor and a common connection of the capacitors of the individual phase circuits, where the capacitance of the capacitors is 5 to 15 times a per-phase equivalent capacitance of the drive or group of drives, and the resistance of the resistors is two times a damping ratio times a square root of a ratio of the filter inductance to the filter capacitance, where the damping ratio ζ is greater than or equal to 1.0 and less than or equal to 2.0.

An power converter includes an unfolder connected to a three-phase source and has an output connection with a positive terminal, a negative terminal and a neutral terminal. The unfolder creates two unipolar piece-wise sinusoidal DC voltage waveforms offset by a half of a period. A three-input converter connected to the unfolder produces a quasi-sinusoidal output voltage across output terminals. Switches of the converter selectively connect the positive, negative and neutral inputs across the output terminals. A PWM controller controls a first duty ratio and a second duty ratio for the converter based on a phase angle of the source and a modulation index generated from an error signal related to a control variable. The duty ratios are time varying with a fundamental frequency of the source. The modulation index relates to output voltage of the converter, peak voltage or current of the source and/or peak current at the output terminals.

Disclosed is a method and apparatus. The method includes detecting an operating state of a current source converter that comprises a current source rectifier (1), a current source inverter (2), and an inductor circuit (3) connected between an output (p, n) of the current source rectifier (1) and an input (q, r) of the current source inverter (2); and dependent on the detected operating state, operating the current source converter in a first operating mode or a second operating mode. Operating the current source converter in the first operating mode comprises operating the current source rectifier (1) in a 2/3 mode and operating the current source inverter in a 3/3 mode, and operating the current source converter in the second operating mode comprises operating the current source inverter (2) in the 2/3 mode and operating the current source rectifier in the 3/3 mode.

A conveyance system includes a machine having a motor; a source of AC power; a drive system coupled to the source of AC power, the drive system to provide multi-phase drive signals to the motor, the drive system including: a first drive having a first converter and a first inverter, the first convertor including a first positive DC bus and a first negative DC bus; a second drive having a second converter and a second inverter, the second convertor including a second positive DC bus and a second negative DC bus; wherein the first positive DC bus and the second DC positive bus are electrically connected and the first negative DC bus and the second negative DC bus are electrically connected.

A method of monitoring a split wind-turbine-converter system with at least one generator-side converter and at least one grid-side converter arranged at distant locations, and a DC-link in the form of an elongated conductor arrangement with at least one positive and at least one negative conductor. The impedance of the DC-link conductor arrangement is determined by means of DC-voltage sensors. The voltages between the positive and the negative conductors are determined at the generator-side converter and at the grid-side converter, and the difference between the voltages is determined. The impedance of the DC-link conductor arrangement is determined by putting the determined voltage difference in relation to the DC current flowing through the DC-link conductor arrangement. If the impedance exceeds a given impedance threshold a fault state is recognized.

A method according to an exemplary aspect of the present disclosure includes, among other things, controlling a power supply system to avoid an over-voltage event across one or more switching devices of the power supply system, the controlling step based on switching overlap information that includes instructions for either advancing or retarding a switching signal associated with at least one of the switching devices.

A device for generating alternating electric field of low frequency, a system for generating alternating electric field of low frequency, and a signal regulating method are provided. According to implementations herein, a device for generating alternating electric field of low frequency may comprise an input control module, a transformer, an output control module, and an electric discharge module. In one aspect, an input end of the input control module is configured to be coupled with an external AC power supply, the input control module is coupled with a primary side winding of the transformer, one end of a secondary side winding of the transformer is coupled with the output control module, the output control module is coupled with the electric discharge module, and the other end of the secondary side winding of the transformer is coupled with ground potential.

A control facility for a DC link converter includes a power regulator, which determines, based on an actual power determined at least partially at the feed converter, a power-based desired moment component for a kinetic energy store. The invention also relates to a DC link converter controlled by the control facility and to a forming machine, such as a press, with a DC link converter controlled by the control facility.

A source-network coordination type direct-current (DC) circuit breaker based on pre-charged capacitors for an MMC based DC grid is provided. The MMC based DC grid is provided with four converter stations, each having two converters, which are in loop connection through a double-loop DC overhead line. Two ends of each DC line connecting the converters are separately equipped with DC circuit breakers for isolating a fault of the DC line. An MMC active voltage adjusting control strategy is matched with pre-charged capacitor voltage in the self-adaptive mode to provide a beneficial breaking condition for a quick mechanical switch branch, so that the fault line is effectively cut off.