Controllable rectifier control method, rectification controller, frequency converter and storage medium

Abstract

The embodiment of the invention relates to the field of control, and discloses a controllable rectifier control method, a rectification controller, a frequency converter and a storage medium. The method is applied to the rectification controller, the rectification controller is connected to a controllable rectifier, and the controllable rectifier is connected to a power grid through an inductor. The method comprises the following steps: obtaining the power grid voltage; and when the power grid voltage is higher than a first preset threshold value, reducing the switching frequency of the controllable rectifier to obtain a target switching frequency which is higher than a preset frequency. Compared with the prior art, the direct current side of the controllable rectifier is provided with the electrolytic capacitor with the large capacitance value, the stability of the modulation voltage output by the controllable rectifier in the over-modulation state is improved only through the large capacitance value of the electrolytic capacitor, and then the stability of the frequency converter is improved; and the stability of the frequency converter is improved by reducing the high-frequency voltage at the two ends of the inductor, the attribute of the electrolytic capacitor does not need to be limited, and the stability of the frequency converter is better guaranteed.

Description

technical field [0001] The embodiments of the present invention relate to the field of control, and in particular, to a control method of a controllable rectifier, a rectifier controller, a frequency converter and a storage medium. Background technique [0002] Four-quadrant inverter is a new type of inverter that can transmit electric energy in both directions. It can be used in elevators and other fields. It can not only convert grid electric energy into electric energy with variable frequency, and then convert electric energy into mechanical energy (in electric state) through the motor. It can also convert the mechanical energy of the motor into electrical energy and send it back to the power grid (in the power generation state), which is characterized by high operating efficiency and little harmonic pollution to the power grid. Compared with the two-quadrant inverter that can only be in the electric state and cannot be in the power generation state, the four-quadrant inv...

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Problems solved by technology

[0003] Under the working condition of high input grid voltage, the controllable rectifier is easy to enter the over-modulation state, and entering the over-modulation state will lead to the weakening of the controllable rectifier's ability to stabilize the output DC voltage, resulting in large fluctuations in the output DC voltage , so that the stability of the four-quadrant inverter system is not high, and in severe cases, the four-quadrant inverter may even fail to shut down

[0004] At present, in response to this problem, technicians will install electrolytic capacitors on the DC side of the controllable rectifier to use the larger capacitance of the electrolytic capacitor to stabilize the DC voltage output by the controllable rectifier. The larger the capacitance of the electrolytic capacitor, the more stable it will be. The stronger the DC voltage capability, but at the same time the volume of the electrolytic capacitor will increase sharply, and the cost will also rise sharply, which limits the ability of the electrolytic capacitor to stabilize the DC voltage. Considering the size and cost of the inverter, the inverter The stability of the

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