Three-phase rectifier for high-frequency high-voltage DC power supply and its control method

Abstract

The invention relates to a three-phase rectifier for a high-frequency high-voltage direct current power source and a control method of the three-phase rectifier. The three-phase rectifier is characterized in that according to a circuit structure of the three-phase rectifier, one end of a first inductor L1 is connected with a first input port d of the three-phase rectifier, one end of a second inductor L2 is connected with a second input port e of the three-phase rectifier, and one end of a third inductor L3 is connected with a third input port f of the three-phase rectifier; a source of a switching tube Q1 and a drain of a switching tube Q2 are connected with the other end of the first inductor L1, and a source of a switching tube Q3 and a drain of a switching tube Q4 are connected with the other end of the second inductor L2; a source of a switching tube Q5 and a drain of a switching tube Q6 are connected with the other end of the third inductor L3; a drain of the first switching tube, a drain of the switching tube Q3, a drain of the switching tube Q5, a drain of a switching tube Q7 and a drain of a switching tube Q9 are connected, and a source of the switching tube Q2, a source of the switching tube Q4, a source of the switching tube Q6 and a source of a switching tube Q8 are connected; one end of a discharge resistor RS is connected with the source of the switching tube Q8, and the other end of the discharge resistor RS is connected with a source of the switching tube Q9.

Description

Technical field [0001] The invention relates to a three-phase rectifier used for high frequency and high voltage direct current power supply and a control method thereof. Background technique [0002] High-voltage DC power supplies have a wide range of applications, such as medical X-ray machines, industrial electrostatic precipitators, military radar generators, agricultural electrostatic flocking, etc., all of which require the use of high-power, high-frequency high-voltage DC power supplies . [0003] The high-frequency high-voltage DC power supply is mainly composed of a three-phase power supply, a three-phase rectifier, and a high-frequency boost circuit. The three-phase power supply, a three-phase rectifier, and a high-frequency boost circuit are all connected to the controller. The connection method is as follows figure 2 Shown. The working process of high-frequency high-voltage DC power supply has the following problems: (1) The use of high-frequency devices in the three-p...

AI Technical Summary

Problems solved by technology

The following problems exist in the working process of high-frequency high-voltage DC power supply: (1) The use of high-frequency devices in three-phase rectifiers and booster circuits has caused serious harmonic pollution to the power grid

(4) After the output voltage of the power supply rises to a certain value, it will break down the air and turn the air into a conductor. The existing technical data shows that it takes about 3kV to break through the air at a distance of 1mm, and the output of the high-frequency high-voltage DC power supply is several From ten kV to hundreds of kV, after air breakdown occurs, the output current changes suddenly and the power supply enters protection. At this time, the filter capacitor of the three-phase rectifier still has high electric energy. If the capacitor cannot be discharged in time, the power supply will be damaged. Threat to system and life safety

[0004] The three-phase rectifier widely used at present is a bridge type uncontrolled rectifier. This rectifier is composed of six diodes. It has the disadvantages of low power factor and uncontrollable output. It cannot overcome the above-mentioned problems when it is directly applied to the above-mentioned high-frequency high-voltage DC power supply.

[0005] Patent US 20090129124 A1 (May 21, 2009) discloses a high-frequency high-voltage DC power supply topology and its control method. The power supply still uses the traditional three-phase bridge uncontrolled rectifier, which also cannot achieve unity power factor correction. and filter capacitor voltage adjustment, but also does not solve the discharge problem of the filter capacitor

[0006] The paper "Electrostatic Precipitator Control Systems" (IEEE IndustryApplications Magazine, 2010, 16(4): 28-33.) replaced the three diodes of the upper bridge arm of the three-phase bridge uncontrolled rectifier with thyristors to realize power factor correction , but the adjustment of the filter capacitor voltage cannot be realized. In this paper, the purpose of adjusting the output voltage is achieved by controlling the switching tube of the back-stage inverter, but this adjustment method is obviously not flexible enough.

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