A fast on-grid switching method and system for an energy storage grid-connected converter
A converter and off-grid technology, applied in the direction of power network operating system integration, information technology support system, AC network load balancing, etc., can solve the problems of slow adjustment process, uneven transition, complicated control, etc., to achieve excessive smoothness, avoid Phase-lock failure, the effect of improving computing efficiency
Active Publication Date: 2021-11-23
SICHUAN HUATAI ELECTRIC
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Problems solved by technology
For example, one of the objectives of the present invention is to provide a fast grid-connected and off-grid switching method and system for energy storage grid-connected converters in view of problems such as slow adjustment process, complicated control, unsmooth transition, and switching failure due to sudden parameter changes.
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example 1
[0065] figure 1 It is a schematic circuit structure diagram of an energy storage grid-connected converter applicable to the present invention. Such as figure 1 As shown, the energy storage grid-connected converter includes a grid-connected switch S g , filter circuit, three-phase bridge circuit (including six switching tubes T 1 -T 6 ), the output capacitor C dc . The input side of the energy storage grid-connected converter is connected to the three-phase grid, and the output DC side can be directly connected to the battery, or it can be connected to the DC / DC converter and then connected to the battery. Depend on figure 1 It can be seen that the three-phase AC voltage of the grid is u ag , u bg , u cg , grid switch S g The voltage collected between the filter circuit and the three-phase AC voltage on the converter side u a , u b , u c .
[0066] Figure 2a and Figure 2b It is a schematic diagram of the filter circuit of the energy storage grid-co...
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The present invention provides a method and system for fast grid-connected and off-grid switching of an energy storage grid-connected converter. In the grid-connected working mode, the angular velocity increment is obtained through the first proportional integral operation, and then the sum of the angular velocity increment and the rated angular velocity is calculated. Integrate to obtain the updated phase-locked angle, and the updated phase-locked angle goes to the control of the converter; when the converter is off-grid, the rated angular velocity is integrated to obtain the phase-locked angle, and the voltage reference value is set to the rated voltage value to Used for subsequent voltage control; in the grid-connected pre-synchronization stage, the angular velocity increment is obtained through the second proportional integral operation, and then the updated phase-locked angle is obtained by integrating the sum of the angular velocity increment and the rated angular velocity, and the third proportional integral The updated system voltage reference value is obtained through calculation, so as to control the voltage and voltage phase of the converter to be consistent with the voltage and voltage phase of the grid. The command value of the invention is over-smooth, reduces the complexity of the system, and improves the grid-connected synchronization speed and operation efficiency.
Description
technical field [0001] The present invention relates to the technical field of circuit devices or systems for power supply or power distribution. Specifically, it relates to a method that can calculate the updated phase-locked angle and voltage reference value by combining the current phase-locked angle with a three-two transformation module, a proportional-integral module, etc. The on-grid and off-grid switching system of the energy storage grid-connected converter, and the fast on-off grid switching method of the energy storage grid-connected converter. Background technique [0002] With the substantial increase in wind power and photovoltaic installed capacity, the penetration rate of wind power and photovoltaics in the grid has further increased, and supporting energy storage equipment is needed to control the curtailment rate of wind and solar. Energy storage equipment is also needed in business parks to meet the needs of peak shaving and valley filling, capacity upgrad...
Claims
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IPC IPC(8): H02J3/14H02J3/40H02J3/32H02J3/01
CPCH02J3/01H02J3/14H02J3/32H02J3/40Y02B70/3225Y02E40/40Y04S20/222
Inventor 赵楠谢伟黄旭东郑泽东李驰刘建伟
Owner SICHUAN HUATAI ELECTRIC