Hybrid parallel type high-voltage direct current traction power supply current transformer and control method thereof

Abstract

The invention relates to a hybrid parallel type high-voltage direct current traction power supply current transformer and a control method thereof. The hybrid parallel type high-voltage direct current traction power supply current transformer is characterized by comprising a set of pulse width modulation (PWM) rectifier units and a set of diode rectifier units, wherein both an input end of the PWM rectifier units and an input end of the diode rectifier units are connected with an alternating current electric network, and an output end of the PWM rectifier units and an output end of the diode rectifier units are connected in parallel to realize high-voltage direct current output. Because the PWM rectifier units and the diode rectifier units are connected in series, the direct current output voltage of the entire current transformer is improved, the power supply distance is prolonged, and the contact net loss is reduced. Meanwhile, equipment investment is reduced, and the reliability of a system is improved. The hybrid parallel type high-voltage direct current traction power supply current transformer and the control method thereof can be widely applied to urban railway transit traction power supply systems.

Description

technical field [0001] The invention relates to a high-voltage direct current traction power supply conversion device and a control method thereof, in particular to a hybrid parallel high-voltage direct current traction power supply conversion device and a control method for supplying power to urban rail transit vehicles. Background technique [0002] At present, the traction power supply conversion device of urban rail transit in my country still uses diode rectifiers, and the power supply voltage is 750V or 1500V. This power supply method has been used for decades. Its biggest advantage is that the device structure is simple and the technology is relatively mature. However, this traditional power supply scheme also has the following problems: 1. Due to the use of diode rectifiers, the energy can only be unidirectional Therefore, the energy generated by vehicle braking cannot be fed back to the grid, and is usually consumed by resistors, resulting in a great waste of energy...

AI Technical Summary

Problems solved by technology

This power supply method has been used for decades. Its biggest advantage is that the device structure is simple and the technology is relatively mature. However, this traditional power supply scheme also has the following problems: 1. Due to the use of diode rectifiers, the energy can only be unidirectional flow, so the energy generated by vehicle braking cannot be fed back to the grid, and is usually consumed by resistors, resulting in a great waste of energy

2. The DC output voltage is uncontrollable and has a large fluctuation range, which is not conducive to the safe, reliable and economical operation of the vehicle

3. The catenary network has a large voltage drop, and the distance between power supply stations is short, usually no more than 3 to 4 kilometers, resulting in a large number of required power supply stations and a large construction investment

Applying the PWM rectifier to the urban rail transit traction power supply system can not only realize the feedback of train braking energy, save electric energy, and keep the DC voltage stable; at the same time, if the DC power supply can be increased to more than 1.5kV, the power supply distance can also be extended. Reducing the number of power supply stations and catenary loss has great practical application value, but compared with traditional diode rectifiers, PWM rectifiers are at a disadvantage in terms of price, reliability, maintenance, and overload capacity

In fact, for urban rail transit traction power supply systems, the required traction capacity is usually more than twice the braking capacity, so from the perspective of economy, the power supply scheme based on full PWM rectifier is not cost-effective

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