10 results about "Cycloconverter" patented technology

Provided are a method for controlling a cycloconverter circuit, a cycloconverter circuit, and an isolated converter. The cycloconverter circuit is configured to perform alternating current to alternating current conversion and includes a plurality of switch elements connected in a plurality of current paths. The plurality of switch elements are divided into a plurality of groups of switch elements. Each group of switch elements includes at least one switch element disposed in each current path. The method includes: when the cycloconverter circuit is in a zero-crossing detection stage, controlling a first group of switch elements to be turned on complementarily and a second group of switch elements to switch between an on state and an off state. During a dead time between drive signals for the first group of switch elements, a first target switch element in the second group of switch elements is turned on.

The invention discloses a redecoupling method and system under asymmetry of bridge arm inductance of a bipolar AC-AC frequency converter. The bipolar AC-AC frequency converter is of an ABC three-phase structure, each phase comprises an upper bridge arm and a lower bridge arm, each of the upper bridge arm and the lower bridge arm comprises n full-bridge sub-modules connected in series and a bridge arm inductor, and the inductance parameters of the upper bridge arm and the lower bridge arm are different. Single-frequency output of a power frequency side and single-frequency output of a low-frequency side are achieved by applying the processing frequency difference mode reference voltage and the low-frequency common mode reference voltage to the upper bridge arm and the lower bridge arm, and mutual coupling of the power frequency side and the low-frequency side caused by asymmetry of bridge arm inductance is eliminated by applying the processing frequency common mode reference voltage and the low-frequency difference mode reference voltage to the upper bridge arm and the lower bridge arm. According to the invention, by introducing a re-decoupling control strategy based on a common mode and a differential mode, re-decoupling of the bipolar AC-AC frequency converter under the condition of asymmetric parameters is realized, unexpected harmonic components are eliminated, and the safety and reliability of the bipolar AC-AC frequency converter are effectively improved.

The present invention provides a wide-range soft-switching full-bridge inverter circuit and device based on controllable inductance. By changing the inductance values ​​of a first variable inductance unit and a second variable inductance unit during the process of inverting the DC power supply module by a phase-shifted full-bridge converter and a cycloconverter, the circuit achieves wide-range soft-switching operation of the phase-shifted full-bridge converter, thereby reducing switching losses of the inverter during operation and improving system conversion efficiency.

The present invention discloses a bidirectional WPT AC-AC frequency conversion system based on a variable-topology bidirectional AC / AC system. The system comprises a variable-topology bidirectional AC / AC-1 unit, a wireless power transmission unit, and a variable-topology bidirectional AC / AC-2 unit, which are connected in sequence. The circuit has two energy transmission modes: forward energy transmission and reverse energy transmission. During forward energy transmission, the energy transmission path is: AB side → MN side of the variable-topology bidirectional AC / AC-1 unit → OP side of the wireless power transmission unit → variable-topology bidirectional AC / AC-2 unit → GH side; during reverse energy transmission, the energy transmission path is: GH side → OP side of the variable-topology bidirectional AC / AC-2 unit → MN side of the wireless power transmission unit → variable-topology bidirectional AC / AC-1 unit → AB side. The circuit of the present invention is capable of achieving efficient bidirectional wireless power transmission. Both the front and rear stages of the wireless power transmission circuit adopt a variable-topology bidirectional AC / AC solution to achieve a wireless power transmission frequency conversion output function, thereby improving system efficiency and reducing costs. The circuit is novel, reliable, and practical, and the control scheme is novel.

A cycloconverter configured for use with a power converter is provided herein and comprises a bidirectional switch operable in a first mode of operation when an AC mains voltage is equal to or greater than a predetermined voltage and a second mode of operation when the AC mains voltage is less than the predetermined voltage, such that during zero voltage switching (ZVS) commutations a first Gate of a first pair of Gallium-Nitride (GaN) High Electron Mobility Transistors is on, a second Gate of the first pair of Gallium-Nitride (GaN) High Electron Mobility Transistors is off, and the first Gate and the second Gate of a second pair of Gallium-Nitride (GaN) High Electron Mobility Transistors are off.

The present invention discloses a modulation system and method for a cycloconverter-type high-frequency link inverter, which includes a main circuit topology, a dual closed-loop controller, and a switch modulation strategy module. The method is as follows: starting from the voltage stress of the switch tube, the relationship between the voltage stress and the switch timing is analyzed, and the switch combination under different modulation strategies is obtained through the state of the transformer leakage inductance current under different modulation strategies, so as to realize the energy transmission between the primary and secondary sides of the converter; then, a dynamic mathematical model of the converter is established to obtain the transfer function of the system; a discrete controller is designed to obtain a reference modulation wave, and finally, by designing the logical relationship between the corresponding switch tubes, the safe soft commutation and converter function of the cycloconverter are realized. The present invention provides an effective modulation strategy for the high-frequency link inverter, and the transformer leakage inductance current naturally drops to zero, which can reduce the voltage stress generated by the discontinuous inductance current when the switch tube is commutated, and can realize the soft switching of the converter, which has high practicality.

The invention provides a cycle frequency converter fault-tolerant control method and system based on redundant bridge arms, and belongs to the technical field of frequency converter fault-tolerant control. The device comprises an AC-AC frequency conversion circuit formed by three N-phase input-single-phase output frequency conversion circuits, a j-phase unit comprises N normal working bridge arms, a redundant bridge arm and N bidirectional controllable normally-open switches, and each bidirectional controllable normally-open switch connects the midpoint o of the redundant bridge arm to the midpoints of the other N bridge arms; when a rear open-circuit fault occurs in the thyristor, the corresponding switch is closed, a trigger signal on the thyristor is transferred to the corresponding redundant thyristor, and the redundant thyristor is used for replacing the fault thyristor to conduct the circuit, so that smooth redundant switching of the frequency converter is realized, zero clearance and accuracy of redundant switching are realized, and the reliability of the frequency converter is improved.

An energy conversion device with an integrated active cell balancing circuit. The energy conversion device comprising a cell balancing circuit adapted to be connected to a plurality of cells of a battery, where the cell balancing circuit forms a DC bridge. A transformer, having a primary winding forming a portion of the cell balancing circuit, couples energy to a secondary winding. The secondary winding forms a portion of a resonant cycloconverter configured to convert the coupled energy to an AC output.

Method and apparatus for providing surge protection in a power conversion device. The apparatus comprises a surge protector, coupled to a resonant circuit of a cycloconverter, to bypass a tank current from the resonant circuit away from the cycloconverter when the power conversion device is being shut down.

The embodiment of the invention provides a control method of a cyclic wave conversion device, an inversion system and a storage medium, and belongs to the technical field of power electronics. The method comprises the following steps: acquiring a sampling alternating-current voltage corresponding to an alternating-current voltage output by a cyclic wave conversion device at the current moment and a zero-crossover interval; determining a first switch element and a second switch element of the cyclic wave conversion device under the condition that the sampled alternating current voltage is in the zero-crossover interval, each first switch element is in a high-frequency complementary switching state, each second switch element is controlled to perform high-frequency switching, and the high-frequency switching phase of the second switch element is the same as the high-frequency switching phase of the first switch element in one-to-one correspondence; the duty cycle of each second switching element is greater than the duty cycle of the first switching element. And the first switch element is a switch element for performing high-frequency complementation in a time interval except a zero-crossover interval in an alternating current half cycle. Through the method, the output reliability of the cyclic wave conversion device can be improved.