Variable topology thyristor rectifier

Abstract

The invention relates to a variable topology thyristor rectifier, which comprises two thyristor bridge rectifiers T1 and T2. The input ends of the T1 and T2 are connected with a single-phase or three-phase isolation alternating current voltage source respectively, and the voltage sources have an electrical angle difference. The negative pole of the output end of the T1 is connected with the positive pole of the output end of the T2 through a switch S1, and the positive pole of the output end of the T1 and the negative pole of the output end of the T2 are connected with an LC filter consisting of an inductor L and a capacitor C. The two ends of the capacitor C are connected with an inverter of which the output end is connected with a power grid. The T1 and the T2 run in different modes according to different electrical angles, the sinusoidal voltages of the two different electrical angles are superposed to form sinusoidal input voltage grades of different amplitudes, and input voltages are selected according to different load conditions to realize minimum voltage input under an on-load running condition; a trigger angle of a thyristor is as small as possible, so that a high-power factor running condition is created; and current peak prediction control is adopted for a plurality of running modes to realize the dynamic switching of an online mode.

Description

technical field [0001] The invention relates to a variable topology thyristor rectifier with large power capacity. Background technique [0002] Fully-controlled power electronic devices (the on and off of the device can be controlled by the gate signal), especially the power level of IGBT (Insulated Gate Bipolar Transistor, insulated gate transistor), restricts the further development of the capacity of power electronic devices. The withstand voltage level of the most widely used IGBT device at this stage is 1.7KV. Although 3.3KV and 6.5KV IGBTs have been put into commercial use, compared with 1.7KV devices, the price-capacity ratio is not high. In addition, the high withstand voltage requirement causes the on-state voltage drop and switching loss of the switching device to increase rapidly. The increase in the loss of the switching tube, in addition to the loss of efficiency, will also lead to a rapid increase in the heat dissipation cost of the device, and the loss of e...

AI Technical Summary

Problems solved by technology

Although 3.3KV and 6.5KV IGBTs have been put into commercial use, compared with 1.7KV devices, the price-capacity ratio is not high

[0005] However, the thyristor rectifier mainly has the following problems: 1. Due to the step-down characteristics of the thyristor rectifier bridge, it cannot be directly applied to the wind power generation system where the input voltage on the AC side changes greatly, but the DC bus voltage remains constant.

2. Since the thyristor rectifier adopts the phase control method, it will cause serious harmonic pollution under light load

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