Photovoltaic power generation split-phase control method for power supply system and photovoltaic traction power supply system

Abstract

The invention discloses a photovoltaic power generation split-phase control method for a power supply system, and the method comprises the steps: collecting three-phase voltage and three-phase currentinstantaneous values of a photovoltaic inverter, and obtaining the active power and reactive power of the photovoltaic inverter through phase voltage and phase current injection into a traction sidethrough calculation; determining an output strategy of the photovoltaic inverter based on the voltage and current relationship between the traction side and a photovoltaic low-voltage side and the locomotive load state of the traction side, and generating a three-phase current per unit value injected into the traction side; and based on the output strategy and the three-phase current per unit value injected into the traction side, controlling the output current of each phase current of the photovoltaic inverter to track the three-phase current per unit value so as to complete power supply to atraction side load. According to the method, the intuition, rapidity and stability of a traction side photovoltaic inverter system are improved. The invention further discloses a photovoltaic traction power supply system, the three-phase photovoltaic power generation system can be directly connected into a three-phase power system, and unbalanced current, reactive circulation and oscillation power, caused by a single-phase transformer, of the three-phase system are avoided.

Description

technical field [0001] The invention relates to the technical field of traction power supply, in particular to a photovoltaic power generation phase-separation control method for a power supply system and a photovoltaic traction power supply system. Background technique [0002] Under the dual pressure of energy crisis and environmental pollution, renewable energy represented by photovoltaics has developed rapidly. Photovoltaic power generation has the characteristics of cleanness, no pollution, no noise, and scalable scale. It is one of the best choices to solve the energy crisis. . At present, the development of photovoltaic power generation is being strongly supported by national policies, and the rapid development of photovoltaic power generation technology provides an opportunity for its promotion and application in the railway field. The scale of railway transportation enterprises is huge, with a large number of station buildings, warehouses, real estate, etc. If thes...

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Problems solved by technology

[0003] The back-to-back photovoltaic integrated structure uses two single-phase transformers to complete the transformation of the grid voltage and the traction side voltage. When a locomotive is loaded on a traction arm, the power is transmitted through the corresponding converter connected to the specific traction arm. However, in the traction arm In the case of no vehicle load, photovoltaic power generation is transmitted to the grid by one or two single-phase transformers through unbalanced current and oscillating power, which has problems of complex structure, non-centralized integration, unbalanced current on the high-voltage side, and unstable power oscillation

[0004] At the same time, when supplying power to the single-phase load on the two power supply arms, the phase-separated current control method based on the αβ0 rotating coordinate system and the stationary coordinate system is usually adopted. The phase-separated current control method of the αβ0 rotating coordinate system is to use the abc coordinate system The three-phase instantaneous voltage below is mapped to the instantaneous voltage in the αβ0 coordinate system, one of its advantages is to separate the zero-sequence component from the abc coordinate system, so as to use fewer variables to complete the control of different objectives, but this method has a complex structure , control parameters are difficult to adjust and other shortcomings, and are easily affected by input voltage fluctuations and output current changes; and the phase-separated current control method based on the αβ static coordinate system is to transform the phase voltage and line current instantaneous values ​​​​under the abc static coordinate system into In the αβ static coordinate system, this method improves the anti-interference ability of the rectifier to a certain extent, but the control parameters are not intuitive, and the coordinate transformation increases the control time. Therefore, the above two methods are flexible based on two independent adjustable parameters The control of multiple different objectives, and the method of sequential control, there will also be the problem that the positive and negative sequence current values ​​​​only consider the three-phase load, which is not suitable for the electrified train of the traction power supply system for single-phase loads.

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