Control method and control circuit of three-phase four-wire system static VAR generator

Abstract

The invention discloses a control method and a control circuit of a three-phase four-wire system static VAR generator. The control method includes respectively subjecting 0-axis rotational coordinateinductance real-time current value and 0-axis current directive value to robust control algorithm and repetitive control algorithm to obtain 0-axis current loop control output value; subjecting d-axiscurrent loop and q-axis current loop to PI control algorithm respectively to obtain d-axis current loop control output value and q-axis current loop control output value; calculating to obtain rotational coordinate modulation wave real-time value according to the d-axis current loop output value, the q-axis current loop control output value, the 0-axis current loop control output value, power grid voltage fundamental wave positive sequence angular velocity, rotational coordinate power grid real-time voltage value and the rotational coordinate inductance real-time current value, generating a real-time modulation signal by means of reverse-Park transform algorithm according to the rotational coordinate modulation wave real-time value and the power grid voltage fundamental wave positive sequence angular velocity, and according to the real-time modulation signal, effectively suppressing neutral conductor current harmonics injected into the power grid from the three-phase four-wire systemstatic VAR generator.

Description

technical field [0001] The invention relates to the technical field of reactive power compensation for distribution networks, in particular to a control method and a control circuit for a three-phase four-wire static var generator. Background technique [0002] The three-phase four-wire static var generator is an active power electronic device. The three-phase four-wire static var generator is used to compensate the reactive power of the distribution network, which can realize real-time fast and stepless compensation compensation. At the same time, it has the advantages of improving power factor and maintaining grid voltage stability. And with the advancement of technology and the reduction of the cost of core components, in my country's three-phase four-wire power supply system, the three-phase four-wire static var generator has a tendency to gradually replace the traditional capacitor compensation device. [0003] In the civil three-phase four-wire power supply mode, ther...

AI Technical Summary

Problems solved by technology

The traditional solution is generally to configure passive compensation equipment, such as: capacitance compensation device, to compensate the distribution network, but such devices have problems such as slow response speed, poor compensation accuracy, and easy resonance with the system

[0004] However, due to the adjustment effect of the three-phase switch of the static var generator of the three-phase four-wire system, it is easy to cause zero-sequence harmonic components in the neutral line, such as the 3rd harmonic and the 9th harmonic, etc., making the three-phase four-wire system The output current distortion rate of the static var generator increases, causing additional harmonic pollution to the power grid, and even causing the device to fail to operate stably in severe cases

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