Ac motor system and method for controlling same, and related power conversion device

Abstract

The objective of the invention is to provide a power conversion device for reliably restrain the switching of the dc voltage, even if in the harsh operation such as rapid acceleration-deceleration. In order to restrain the excessive inverter output power generated by flux control delay due to urgent acceleration-deceleration at the inverter side to the value corresponding to the rectifier. The processing comprises: setting the inverter output power maximum depended on the rectifier control capacity at power limiting set device, inputting the setting value of the power limiting set device, current detecting value detecting by the inverter output current detector and voltage detecting value detected by inverter output voltage detector to the power limiting calculator, calculating the torque current limiting value calculated by current detecting value and voltage detecting value, not exceeding the setting value, inputting the limiting value after calculation to the torque current order limiter, restraining the torque current order value based on the input limiting value in the torque current order limiter.

Description

technical field [0001] The present invention relates to an AC motor system, a control method of the AC motor system, and a power conversion device having a rectifier (converter) and an inverter (inverter) for driving an AC motor, and particularly relates to an AC motor system that is also suitable for harsh operations such as sudden acceleration and deceleration. An AC motor system that drives the system stably without stopping the device, a control method of the AC motor system, and a power conversion device related thereto. Background technique [0002] As a power conversion device for driving an AC motor, etc., a rectifier is used to convert the power of the AC power supply to DC, and an inverter is used to convert the DC to AC. The DC part between the rectifier and the inverter is connected. smoothing capacitor. Moreover, the control device for controlling the rectifier controls the output current of the rectifier so that the voltage across the smoothing capacitor conne...

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Problems solved by technology

In addition, if the rectifier cannot cope with the excessive power of the transitional method at this time, there will be inconsistency in the transmission and reception of power, and there may be a problem that the DC voltage fluctuates greatly.

[0006] In order to stabilize the operation of the system, it is important to control the DC voltage to be constant. In the prior art, by adding the power of the inverter to the rectifier in a feed-forward manner, it is possible to suppress the delay caused by the control delay of the rectifier. However, it is ineffective to control the above-mentioned DC voltage fluctuation caused by the inverter power exceeding the control capability of the rectifier.

In order to stabilize the system even under severe operation such as sudden acceleration and deceleration, it is necessary to increase the capacity of the rectifier to cope with the above-mentioned transient excess power, or to increase the capacity of the inverter to rapidly change the magnetic flux of the motor, But every method is uneconomical

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