Parabola method current tracking pulse width modulation controller

Abstract

This invention provides parabolic method current tracking pulse width modulation controller, which contains parabolic wave generator with reset, analogy phase inverter, comparator, reset signal generator and analog selector, wherein the output signal shape of parabolic wave generator determined by the ratio of time and switch cycle subtracting the square value of said ratio, the analog phase inverter making phase inverting to the output signal of parabolic wave generator, then transmitting the inverted signal with no inverted signal to analog selector to be selected one from two signal, transmitting to input of comparator whose first way output controlling action signal of main circuit switch, second way controlling analog selector and third way used as input of reset signal generator. Said invented controller is easily integrated, capable of making the output current of pulse width modulation inverter continuous tracking instruction current value and keeping switch frequency basically constant.

Description

(1) Technical field [0001] The invention relates to a current tracking PWM controller. It is suitable for current tracking control of various voltage-type pulse-width modulation (pulse-width modulation, PWM for short) converters. (2) Background technology [0002] For voltage-type PWM converters with high dynamic performance requirements, such as motor drives, power active filters (APF), power factor correctors (PFC) and UPS, etc., current tracking direct control is most suitable. Current control can be achieved by methods such as triangular wave comparison or hysteresis control. The biggest advantage of triangular wave compared to PWM current control is that it has a fixed switching frequency, but the system response is limited by the stability of its current feedback and is easily affected by load parameters. The advantage of the hysteresis control PWM method is that it has no stability problem, is simple and easy to implement, has a fast response speed, and has the abil...

AI Technical Summary

Problems solved by technology

The biggest advantage of triangular wave compared to PWM current control is that it has a fixed switching frequency, but the system response is limited by its current feedback stability and is easily affected by load parameters.

However, the traditional hysteresis control will cause a large change in the switching frequency due to its fixed hysteresis bandwidth, which also limits its application.

In order to overcome this shortcoming, various current control schemes with variable hysteresis loops have been proposed successively, such as phase-locked loop (PLL) fixed-frequency control, adaptive hysteresis bandwidth control, and lock-in control with switching frequency forward prediction technology. Phase loop (PLL) fixed-frequency control, dead-beat (dead-beat) hysteresis control, etc., realize the fixed-frequency hysteresis current tracking control by predicting or calculating the hysteresis loop band, but because the hysteresis loop band is related to There is a nonlinear functional relationship between the measurement signals, which can only be realized with the help of a single-chip microcomputer or DSP combined with complex hardware circuits, which greatly increases the difficulty of application

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