High-low-voltage conversion star multi-phase variable-frequency drive system

Abstract

The present invention provides a high-low-voltage conversion star multi-phase variable-frequency drive system and relates to a high-voltage high-power motor and drive control thereof. The variable-frequency drive technical solution which is commonly used at present mainly has the disadvantages that a frequency converter is added to a common motor, the insulation life of the motor is short and the heat dissipating ability of the motor is poor. The system comprises a phase-shifting transformer, rectifying circuits, inverter circuits, a multi-phase motor, and a control circuit connected with the phase-shifting transformer, the rectifying circuits, the inverter circuits and the multi-phase motor, wherein primary windings of the phase-shifting transformer are connected with an alternating-current power source, and secondary windings of the phase-shifting transformer are connected with the rectifying circuits; and is characterized in that the number of the secondary windings is the same as the number of the rectifying circuits, one secondary winding is connected with one rectifying circuit, all rectifying circuits are in common-ground connection to form a common-ground direct-current power source, and output ends of the rectifying circuits are connected with the inverter circuits. By adopting the technical solution, high voltage and large currents are realized, simultaneously the structure is simple, the insulation requirement is lowered, the heat dissipating ability of the motor is improved and the power density is increased.