CN203813692U - Hybrid energy storage inverter system based on storage battery and super capacitor - Google Patents

Abstract

A hybrid energy storage inverter system based on batteries and supercapacitors, a filter composed of circuit breaker QF1, isolation transformer T, reactor L1 and capacitor C1, pre-stage H-bridge converters A, B, C, bidirectional Composed of DC/DC converters D, E, reactors L2, L3 and DC circuit breakers QF2, QF3; the input end of the circuit breaker QF1 is connected to the AC power grid (5), and the output end is connected to the primary side of the transformer T; The two independent windings are respectively connected to the AC sides of the H-bridge converters A, B, and C through the filter composed of L1 and C1; the DC sides of the H-bridge converters A, B, and C are converted to DC/DC through the DC bus The input terminals of converter D and E are connected; the output terminal of D converter is connected to lithium battery (7) through DC circuit breaker QF2; the output terminal of E converter is connected to supercapacitor (6) through DC circuit breaker QF3. The utility model can realize grid-connected operation, and can also perform isolated island monitoring and off-grid operation; it can complete energy storage and feedback of the system, and realize two-way operation.

Description

A hybrid energy storage inverter system based on batteries and supercapacitors

technical field

The utility model relates to a hybrid energy storage inverter system based on batteries and supercapacitors, which belongs to the technical field of power electronics.

Background technique

With the continuous increase of electricity load, the old pattern of centralized and unified large power grid makes the power grid more fragile. Therefore, it is necessary to increase the distributed energy structure to improve the reliability of the power grid and ensure the daily electricity consumption of the public and industrial and agricultural electricity consumption. In addition; distributed energy can better achieve energy saving and consumption reduction, which is conducive to the utilization and promotion of clean energy and renewable energy. However, when the power system fails, the distributed power generation must be out of operation immediately. This greatly limits the full play of distributed energy efficiency. In order to coordinate the contradiction between the large power grid and the distributed power supply, people put forward the concept of microgrid. The microgrid consists of distributed power supply, distributed energy storage and energy management modules to form a load power supply system, which together with the load form an independent controllable system, which completely solves the contradiction between the large power grid and distributed power supply. The energy storage system is an important link to adjust the performance of the micro power supply and ensure the quality of power supply to the load.

Supercapacitors and batteries are typical representatives of power-type energy storage components and energy-type energy storage components. They have strong complementarity in key characteristics such as power density, energy density, cycle life, and high and low temperature performance. Mixing the two It has the potential to greatly improve the performance of energy storage systems. The hybrid energy storage inverter based on batteries and supercapacitors mainly realizes the two-way transmission of energy between the AC power grid and the energy storage system. The acceptance capacity of large-scale renewable energy generation (wind energy, photovoltaic), and can accept dispatching instructions, absorb or supplement the peak and valley power of the grid, and provide reactive power to improve the power supply quality and economic benefits of the grid. In the event of grid failure or power outage, it also has the function of independent network power supply to improve the safety of power supply for loads.

Contents of the invention

The purpose of this utility model is to provide a hybrid energy storage inverter system based on batteries and supercapacitors, through the combination of three-phase H-bridge converters and two sets of bidirectional DC/DC converters, to realize lithium batteries and supercapacitors Coordinate energy storage and energy feedback.

The technical scheme of the utility model is that the hybrid energy storage inverter system based on batteries and supercapacitors of the present invention is composed of a circuit breaker QF1, an isolation transformer T, a filter composed of a reactor L1 and a capacitor C1, and the front stage H bridge converter A, B, C, bidirectional DC/DC converters D, E, reactors L2, L3 and DC circuit breakers QF2, QF3. The input end of the circuit breaker QF1 is connected to the AC grid, and the output end is connected to the primary side of the transformer T. The three independent windings on the secondary side of the transformer are respectively connected to the AC sides of the H-bridge converters A, B, and C through the filter composed of L1 and C1; the DC sides of the H-bridge converters A, B, and C pass through the DC bus It is connected to the input terminals of DC/DC converters D and E; the output terminal of D converter is connected to the lithium battery through DC circuit breaker QF2; the output terminal of E converter is connected to the supercapacitor through DC circuit breaker QF3.

The three-phase H-bridge converter composed of A, B, and C adopts the SPWM modulation method. In the energy storage mode, the three-phase alternating current can be converted into direct current. Charging; in the feedback mode, the energy released by the lithium battery and the supercapacitor is converted by the bidirectional DC/DC circuit to provide DC power for the DC busbar, and the H-bridge converter (A, B, C) inverts and isolates the Energy is fed back to the grid.

The effect and benefit of the utility model are that the main circuit topology adopts a three-phase H-bridge converter, so that the voltage of each phase can be adjusted independently, and the voltage distortion caused by the unbalanced load is overcome. The equivalent switching frequency of the system is twice that of the IGBT switching frequency, which further reduces the system harmonics; it can realize grid-connected operation, and can also perform island monitoring and realize off-grid operation; the four-quadrant H-bridge of the front stage performs bidirectional DC The combination of /DC converter can complete the energy storage and feedback of the whole system to realize bidirectional operation.

The utility model is suitable for verification and application of energy storage equipment and technologies of scientific research institutions and enterprises.

Description of drawings

Figure 1 is a block diagram of a hybrid energy storage inverter system based on batteries and supercapacitors;

Fig. 2 is the H bridge circuit diagram;

Figure 3 is a DC/DC circuit diagram;

Figure numbers in the figure: 1 and 2 are the input terminals of the H-bridge converter, 3 and 4 are the output terminals of the H-bridge converter; 5 is the AC grid; 6 is the supercapacitor; 7 is the lithium battery.

Detailed ways

The specific embodiment of the utility model is shown in Fig. 1, Fig. 2 and Fig. 3.

Fig. 1 is a system principle block diagram of the technical solution of the utility model.

The main circuit of the microgrid energy storage inverter system in this embodiment includes: a circuit breaker QF1, an isolation transformer T, a filter composed of a reactor L1 and a capacitor C1, and the circuits of the front-stage H-bridge converters A, B, and C As shown in Figure 2, 1 and 2 are the input terminals of the H-bridge converter, and 3 and 4 are the output terminals of the H-bridge converter; the latter stage is the circuit of the buck-boost bidirectional DC/DC converter D and E As shown in Figure 3, reactors L2, L3 and DC circuit breakers QF2, QF3.

The input end of the circuit breaker QF1 is connected to the AC power grid 5, and the output end is connected to the primary side of the transformer T. On the one hand, the transformer plays an isolation role, and on the other hand, it increases the input voltage to increase the rear-end DC bus voltage. The three independent windings on the secondary side of the transformer are connected to the H-bridge converter after the filter. The H-bridge converter is connected to the D and E converters through the DC bus, and the D converter is connected to the lithium battery 7 through the DC circuit breaker QF2; the E converter is connected to the supercapacitor 6 through the DC circuit breaker QF3.

The three-phase H-bridge converter composed of A, B, and C adopts the SPWM modulation method. In the energy storage mode, the three-phase alternating current can be converted into direct current. Charging; in the feedback mode, the lithium battery and supercapacitor release energy to provide DC power for the DC busbar after being transformed by a bidirectional DC/DC circuit, and the energy is fed back to the grid after being inverted and isolated by the H-bridge converter.

Claims (1)

1. A hybrid energy storage inverter system based on batteries and supercapacitors, characterized in that the system is composed of a circuit breaker QF1, an isolation transformer T, a reactor L1 and a filter composed of a capacitor C1, and the pre-stage H bridge transformer Current converters A, B, C, bidirectional DC/DC converters D, E, reactors L2, L3 and DC circuit breakers QF2, QF3; the input end of the circuit breaker QF1 is connected to the AC power grid, and the output end is connected to the primary side of the transformer T ; The three independent windings on the secondary side of the transformer are respectively connected to the AC sides of the H-bridge converters A, B, and C through the filter composed of L1 and C1; the DC sides of the H-bridge converters A, B, and C pass through the DC The bus bar is connected to the input terminals of DC/DC converters D and E; the output terminal of the D converter is connected to the lithium battery through the DC circuit breaker QF2; the output terminal of the E converter is connected to the supercapacitor through the DC circuit breaker QF3.