an AC chopper

Abstract

An AC chopper is connected between an AC power supply and a load circuit, comprising: a switch group, a voltage polarity detector and a switch control logic unit. Among them, the voltage polarity detector is connected to both ends of the AC power supply, and is used to detect the voltage polarity of the chopper input AC power supply when the switch is switched; the switch control logic unit receives the voltage polarity sent by the voltage polarity detector Signal, and send different control signals to the switch group according to the voltage polarity signal to control the state switching sequence of the switch group, and finally make the circuit switch between the freewheeling mode and the active mode. Because the switching method of the present invention is only when the circuit freewheeling mode and the active mode are converted, the state of the switch group is related to the input AC power voltage polarity signal, so the safety and reliability of the system are high; and, due to the method's The voltage polarity signal is fed back to the switch control logic unit discontinuously, so the system is not easy to generate oscillation.

Description

1. Technical field [0001] The invention relates to an AC converter device, in particular to an AC chopper device for controlling the switching sequence of switches by feeding back the polarity of the AC power supply voltage to realize power conversion. 2. Technical Background [0002] As a relatively mature AC voltage regulation technology, phase-controlled rectification technology has replaced electromagnetic voltage regulation technology in many occasions and has been widely used. However, the phase-controlled rectification technology has many insurmountable defects, such as low power factor affected by the firing angle, slow dynamic response, rich output low-order harmonics, and serious grid harmonic current pollution. In recent years, the AC chopper based on the simple topology of the DC chopper has become a new research hotspot. The AC chopper control voltage regulation technology has the advantages of only depending on the power factor of the load, fast dynamic respon...

AI Technical Summary

Problems solved by technology

Moreover, since this switch control strategy needs to continuously feed back the voltage polarity signal to the switch controller, the fluctuation of the AC power supply voltage at the zero-crossing point can easily cause system oscillation, and the stability of the control system is poor.

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