Power conversion device applied to high-speed flywheel energy storage system

Abstract

The invention relates to the technical field of motor control, in particular to a power conversion device applied to a high-speed flywheel energy storage system. The power conversion device comprises a half-bridge driving circuit, an energy feedback circuit, a bidirectional Buck-Boost conversion circuit and a wave circuit. The power conversion device has the advantages that the energy bidirectional flowing of the flywheel energy storage system can be realized; the four-quadrant operation of a high-speed flywheel energy storage motor can be realized; the energy feedback circuit is used, so that the utilization rate of energy is greatly improved; the operation efficiency of the flywheel energy storage system is improved; the structure is simple and reliable; the risk of through short circuit is avoided; the operation safety of the high-speed flywheel motor is improved.

Description

technical field [0001] The invention relates to the technical field of motor control, in particular to a power conversion device applied to a high-speed flywheel energy storage system. Background technique [0002] Flywheel energy storage system is a new type of electromechanical energy conversion and storage device, which has the advantages of long service life, high conversion efficiency, strong adaptability and no pollution. It has broad application prospects. [0003] The traditional iron-core brushless DC motor is used as a flywheel energy storage motor, which can have high operating efficiency after structural optimization design, but when running at high speed, the no-load loss of the motor is often very high; at the same time, its no-load and load The unbalanced magnetic pull during operation places high demands on the bearing capacity and stiffness of the magnetic bearing system. The coreless permanent magnet brushless DC motor can overcome the above-mentioned def...

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Problems solved by technology

[0005] Of course, compared with the full-bridge drive circuit, the half-bridge drive circuit also has certain shortcomings: (1) Due to the singleness of the winding current direction, this structure can only realize the unidirectional flow of energy, and cannot realize the four-quadrant operation of the motor ; (2) There is no freewheeling circuit in the half-bridge drive circuit, and the energy for switching off the switch tube is mainly absorbed by the RCD snubber circuit, which consumes the energy stored in the motor inductance, so the half-bridge drive circuit is not suitable for high-power applications

[0007] The half-bridge drive circuit is applied to the flywheel energy storage system, and there are several problems: (1) how to realize the bidirectional flow of energy in the flywheel energy storage system (that is, how to design the energy storage and energy release circuit); (2) the motor of the flywheel The rotation speed is very high, so it is not suitable to add PWM modulation signal to the switch tube drive signal, how to realize the speed control of the flywheel motor; (3) Since there is no freewheeling circuit, the energy of the switch tube off is mainly absorbed by the buffer circuit. This solution is feasible when the motor inductance is small (ironless structure) and the speed is low, but as the speed increases, the inductive energy storage will increase rapidly, and this part of the loss will increase sharply. How to use this part of energy

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