Capacitor clamping-based trilevel railway power regulator

Abstract

The invention discloses a capacitor clamping-based trilevel railway power regulator which comprises two single phase transformers, two output reactors, a capacitor clamping trilevel power module and a direct-current side voltage sharing circuit, wherein primary sides of the two single phase reduction transformers are connected with two power supply arms in a three-phase tractive power supply system respectively, and secondary sides of the two single phase reduction transformers are connected with the capacitor clamping trilevel power module; and the voltage sharing control circuit is adopted at the direct current side, and the voltage of the direct-current side capacitor is shared through a small-capacity switching element and an inductor, thus the reliability of the device is improved. Compared with an RPC (remote procedure call), only one pair of high-power switching arms, two clamping capacitors and a group of direct-current side capacitors are needed, thus the capacitor clamping-based trilevel railway power regulator has the advantages of reducing the original active capacity cost, reducing the hardware cost and complexity of the compensation system in the premise of achieving the same functions, and improving the reliability of the compensation system.

Description

technical field [0001] The invention relates to a railway power regulator, in particular to a railway power regulator based on a capacitor-clamped three-level structure. Background technique [0002] Because the high-speed railway traction power supply system adopts single-phase power supply mode, negative sequence current is generated, which brings serious harm to the operation of power generation, transmission and transformation equipment in the power system, such as increasing the loss of generators, reducing the output of transformers, etc., seriously affecting Safe, efficient and economical operation of power systems. In addition, the harmonics generated by high-speed railway electric locomotives also reduce the reliability of its power supply system and upper-level power system. Therefore, effective measures must be taken to suppress the negative sequence and harmonic currents generated by the high-speed railway power supply system. [0003] Scholars at home and abro...

AI Technical Summary

Problems solved by technology

SVC is installed on the two power supply arms of the traction transformer for negative sequence compensation of electrified railways. Theoretically, the negative sequence can be fully compensated if the capacity of the traction transformer is allowed, but its dynamic compensation capability is limited and harmonics will be generated.

The use of active filters can achieve harmonic suppression for electrified railways, but cannot effectively compensate for negative sequence currents

For this reason, some high-voltage and large-capacity SATCOM devices are installed on the three-phase high-voltage side of the traction system to compensate for negative sequence and harmonics, but their large capacity and high cost

[0004] Since the traction power supply system is a high-voltage and large-capacity system, the pressure range of the existing switch tubes is limited. The traditional two-level PWM inverter relies on a single switch tube and obviously cannot withstand the high voltage of the DC side.

In addition to the high voltage defect, the traditional two-level inverter also has the following problems: 1) High frequency generates high dv / dt and surge voltage, which can easily cause insulation breakdown of the motor winding; 2) High frequency switching produces a large Device voltage stress and switching loss reduce efficiency; 3) High-frequency switching action generates broadband EMI to nearby communication or other electronic equipment; 4) Low power factor

However, this railway power conditioner contains 16 power switching devices, so there are many power devices, the cost is high, and the circuit is complicated

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