Current hysteresis control digital implementation system for PWM rectifier

Abstract

The invention discloses a current hysteresis control digital implementation system for a PWM rectifier. TMS320F28069 DSP of Piccolo series of TI is adopted to achieve current hysteresis control, the functions of a chip dual-core processor are fully utilized, logic control, communication and three-phase current given generation for the PWM rectifier are achieved in a main CPU, a current hysteresis control strategy is achieved in a control rate accelerator, PWM pulses are generated to drive a power switch tube of a major loop, and the functions of the PWM rectifier are achieved. The control rate accelerator introduces the concurrent control loop execution function into a C28x series device. In this way, time delay existing from ADC damping to output is greatly reduced, and faster system response and a higher-frequency control loop are achieved. CLA is used for providing services for the control loop with strict time requirements, so that the main CPU freely processes other system tasks such as communication and diagnosis.

Description

technical field [0001] The invention relates to the technical field of power electronic control, in particular to a digital implementation system for current hysteresis control of a PWM rectifier. Background technique [0002] The current PWM rectifier has been widely used in AC speed regulation, uninterruptible power supply, reactive power compensation, new energy and other fields due to its many advantages such as bidirectional flow of power, unit power factor operation at the grid side, and good sine degree of input current. Commonly used control strategies for PWM rectifiers include current hysteresis control, sinusoidal PWM control, and space vector PWM control. The current hysteresis control method has the advantages of simple control, fast response, high tracking accuracy, and good system stability, so it is a commonly used control method in the control link of the output current of the PWM rectifier. Traditional current hysteresis control is generally realized by an...

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Problems solved by technology

Traditional current hysteresis control is generally realized by analog circuits, but compared with digital circuits, analog circuits have obvious defects, such as zero drift of the circuit, noise interference, false triggering, etc.

At present, the most widely used method is to use conventional fixed-frequency sampling for hysteresis control. The control cycle is about tens to hundreds of microseconds. However, due to the fixed switching time, the same command can only be tracked once, resulting in the actual current glitch. Small, the current control accuracy is not high, and the control effect is not ideal; conventional digital sampling, each operation control module cannot be adjusted according to the response requirements, the stability and anti-disturbance ability of the control system are not high; and, conventional control, the main loop operation of DSP If the cooperation with interrupt operation is not good, it will seriously affect the real-time of current control and the synchronization of current hysteresis tracking

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