High-voltage frequency conversion all-in-one machine adopting trapezoidal modulation waves and control method thereof

Abstract

The invention discloses a high-voltage frequency conversion all-in-one machine adopting trapezoidal modulation waves. The all-in-one machine comprises a rectification part, power units, a multi-winding motor and a control circuit, wherein the n power units are sequentially connected in series and then connected to a DC voltage bus; the multi-winding motor is provided with n three-phase motor windings, and the outputs of the n three-phase inversion units are connected to the n three-phase motor windings respectively. The control method of the high-voltage frequency conversion all-in-one machinecomprises the following steps: a) generating trapezoidal modulation waves; b) sending a modulation wave; c) generating a driving signal; (c-1) performing frequency conversion starting control; c-2) performing rated frequency control. According to the invention, when the voltage output by the frequency converter is equal to or close to the rated voltage of the motor, the IGBT driving signal generated by comparing the trapezoidal wave with the triangular wave is equal to the rated frequency (such as 50Hz) of the motor, so the switching frequency of the power device is greatly reduced, the lossis reduced, and the service life of the power device is prolonged.

Description

technical field [0001] The present invention relates to a high-voltage frequency conversion integrated machine and a control method thereof, more specifically, to a high-voltage frequency conversion integrated machine using trapezoidal modulation waves and a control method thereof. Background technique [0002] At present, high-voltage motor speed regulation generally adopts high-voltage inverters with cascaded multi-level technology. The input side must have an isolation phase-shifting transformer to provide voltage clamping for the power units of the cascaded inverters and protect the power devices used inside the power units. IGBT. [0003] From the perspective of the entire system, the isolation phase-shifting transformer has performed an electromagnetic conversion, and the motor itself has also performed electromagnetic conversion, which is equivalent to two electromagnetic conversions, which makes the efficiency of the entire system low. At the same time, due to the l...

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Problems solved by technology

[0003] From the perspective of the whole system, the isolation phase-shifting transformer performs an electromagnetic conversion, and the motor itself also performs electromagnetic conversion, which is equivalent to two electromagnetic conversions, which makes the efficiency of the entire system low.

At the same time, due to the large volume of the isolation phase-shifting transformer itself, the final volume or footprint of the entire system is large

[0004] In addition, under normal circumstances, the motor and the frequency converter are arranged separately, and there is a certain distance between them. Long-distance frequency conversion power supply will produce the reflection effect of the cable, causing the motor terminal voltage to be too large, which will have a great impact on the life of the motor.

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