H-bridge parallel reconnection topology and system

Abstract

The utility model provides an H-bridge parallel re-topology, which comprises an H-bridge formed by N groups of IGBTs and N corresponding current-sharing inductors, each group of H-bridges has the same structure and is controlled by an independent current-sharing loop, the midpoint of the left bridge arm of each group of H-bridge is connected with one end of the corresponding current-sharing inductor, the other end of each current-sharing inductor is connected with one end of a capacitor C1, and the other end of the capacitor C1 is connected with the other end of the capacitor C1. The other end of the capacitor C1 is connected with the midpoint of the right bridge arm of each group of H bridges; and two ends of each group of H bridges are connected in parallel with bus voltage. According to the H-bridge parallel re-topology and the current sharing control loop thereof provided by the utility model, the defect of multi-path parallel connection of IGBTs is avoided, and current multiplication output of H-bridge parallel connection is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of grid feedback analog power supply, in particular to an H-bridge parallel heavy topology and current sharing control loop. BACKGROUND

[0002] With the continuous development of new energy and power electronics industry, more power electronic equipment is introduced in the grid connection, transmission and consumption of new energy. The grid-connected inverter technology fails frequently and cannot meet the safety and stability requirements of the grid. Since 2021, the United Kingdom, Australia, the United States and other countries have issued corresponding power guidelines, requiring grid-connected inverters to have the ability of rapid fault injection, phase jump support, rapid frequency response, dynamic reactive power compensation, etc., and responding within 5ms after the grid fault or disturbance. Domestic and foreign grid-connected energy storage demonstration projects have been developed, and related research and large-scale applications have been promoted.

[0003] As a test power supply for grid-connected energy storage converters (PCS), the grid feedback analog power supply must meet the standard requirement of 5ms current switching to a maximum of 3 times the reactive current in grid-connected testing, and have the corresponding voltage rapid regulation capability.

[0004] Currently, the grid feedback analog power supply in the industry mainly uses "H-bridge topology + LC filter circuit" output to realize high and low voltage ride-through, zero ride-through, etc. However, in the face of low-voltage and high-current scenarios, it can only use multiple parallel machines and IGBT module parallel methods. Due to the multi-parallel connection of IGBT, uneven current problems are prone to occur, and the response rate and consistency of the driver are required to be high. The commonly used IGBT driver on the market mostly supports 2 IGBT modules in parallel, and the cost is high, which is limited to the improvement of output current.

[0005] The existing H-bridge parallel scheme mostly relies on the output transformer leakage inductance to realize current sharing of multiple bridge arms. The grid feedback analog power supply needs to realize the phase angle ride-through function. Due to the volt-second characteristic of the transformer, magnetic saturation will occur in this function, causing bridge arm short circuit protection. SUMMARY

[0006] The purpose of the present application is to provide an H-bridge parallel heavy topology and system, which can realize current multiplication output of multiple H-bridges without relying on transformer leakage inductance.

[0007] To achieve the above purpose, the following technical solutions are used:

[0008] An H-bridge parallel heavy topology, comprising N groups of IGBTs forming H-bridges and corresponding N current sharing inductors, N being a positive integer;

[0009] Each group of H-bridge has the same structure, the midpoint of the left bridge arm of each group of H-bridge is connected with one end of the corresponding current-sharing inductor, the other end of each current-sharing inductor is connected with one end of the capacitor C1, the other end of the capacitor C1 is connected with the midpoint of the right bridge arm of each group of H-bridge;

[0010] The capacitor C1 is connected in parallel with the load, and each group of H-bridge is connected in parallel with the bus voltage.

[0011] Preferably, the inductance values of the N current-sharing inductors are equal.

[0012] Preferably, each group of H-bridge includes four switching tubes, the left bridge arm includes two series-connected switching tubes, the right bridge arm includes two series-connected switching tubes, and each switching tube is connected in parallel with a body diode.

[0013] Preferably, N is 2, including two groups of H-bridge composed of IGBT, inductors L1 and L2, and capacitor C1, the first group of H-bridge includes switching tubes V1-V4 and their respective parallel body diodes, the second group of H-bridge includes switching tubes V1'-V4' and their respective parallel body diodes, switching tube V1 and switching tube V2 are connected in series to form the left bridge arm of the first group of H-bridge, switching tube V3 and switching tube V4 are connected in series to form the right bridge arm of the first group of H-bridge, the connection point of switching tube V1 and switching tube V2 is the midpoint of the left bridge arm of the first group of H-bridge, the connection point of switching tube V3 and switching tube V4 is the midpoint of the right bridge arm of the first group of H-bridge, switching tube V1' and switching tube V2' are connected in series to form the left bridge arm of the second group of H-bridge, switching tube V3' and switching tube V4' are connected in series to form the right bridge arm of the second group of H-bridge, the connection point of switching tube V1' and switching tube V2' is the midpoint of the left bridge arm of the second group of H-bridge, and the connection point of switching tube V3' and switching tube V4' is the midpoint of the right bridge arm of the second group of H-bridge.

[0014] An H-bridge parallel heavy system includes the above-mentioned H-bridge parallel heavy topology and N current-sharing control loops, the current-sharing control loops have the same structure and are used to generate a modulation wave for modulating the corresponding H-bridge, and each current-sharing control loop includes an average circuit module, a first subtractor, an amplifier, a second subtractor, and a modulation wave generator;

[0015] The input end of the average circuit module is connected with the bridge arm current sampling end of each group of H-bridge;

[0016] The first input end of the first subtractor is connected with the bridge arm current sampling end of the corresponding H-bridge, and the second input end is connected with the output end of the average circuit module;

[0017] The input end of the amplifier is connected with the output end of the first subtractor;

[0018] The first input end of the second subtractor is connected with a given signal Ug, and the second input end is connected with the output end of the amplifier;

[0019] The input end of the modulation wave generator is connected with the output end of the second subtractor.

[0020] The advantages of the present application are that the defects that IGBT cannot be multi-parallel connected are avoided, current multiplication output of H-bridge parallel connection is realized, the equivalent switching frequency of output is improved through carrier phase-shift modulation, and the voltage and current harmonic distortion of output is reduced.

[0021] Through independent current sharing loop control, the circulating current between bridge arms is effectively inhibited, and the stability of the power supply is improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is an H-bridge parallel heavy load circuit topology diagram in the embodiment 1 of the present application.

[0023] Figure 2 It is a system block diagram of the H-bridge parallel heavy load system in the embodiment 2 of the present application. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be clearly and completely described in combination with the drawings in the embodiments of the present application.

[0025] Embodiment 1

[0026] The present embodiment discloses an H-bridge parallel heavy load topology, which comprises two groups of H-bridges composed of IGBTs, inductors L1 and L2, and a capacitor C1.

[0027] Please refer to Figure 1 The first group of H-bridges comprises switch tubes V1-V4 and their respective parallel body diodes, and the second group of H-bridges comprises switch tubes V1'-V4' and their respective parallel body diodes. Switch tube V1 and switch tube V2 are connected in series to form the left bridge arm of the first group of H-bridges, and switch tube V3 and switch tube V4 are connected in series to form the right bridge arm of the first group of H-bridges. The connection point of switch tube V1 and switch tube V2 is the midpoint of the left bridge arm of the first group of H-bridges, and the connection point of switch tube V3 and switch tube V4 is the midpoint of the right bridge arm of the first group of H-bridges. Switch tube V1' and switch tube V2' are connected in series to form the left bridge arm of the second group of H-bridges, and switch tube V3' and switch tube V4' are connected in series to form the right bridge arm of the second group of H-bridges. The connection point of switch tube V1' and switch tube V2' is the midpoint of the left bridge arm of the second group of H-bridges, and the connection point of switch tube V3' and switch tube V4' is the midpoint of the right bridge arm of the second group of H-bridges.

[0028] The midpoint of the left bridge arm of the first group of H-bridges is connected with the left end of inductor L1, the right end of L1 is connected with the upper end of capacitor C1, and the lower end of capacitor C1 is connected with the midpoint of the right bridge arm of the first group of H-bridges. The midpoint of the left bridge arm of the second group of H-bridges is connected with the left end of inductor L2, the right end of L2 is connected with the upper end of capacitor C1, and the lower end of capacitor C1 is connected with the midpoint of the right bridge arm of the second group of H-bridges.

[0029] The capacitor C1 is connected in parallel with the load R1. Each H-bridge is connected in parallel with an independent bus voltage Udc (there is no parallel connection between DC buses). Each Udc has the same amplitude. The front end is a DC / DC isolation topology.

[0030] The inductance values ​​of inductor L1 and inductor L2 are equal.

[0031] Example 2

[0032] This embodiment discloses an H-bridge parallel reconfiguration system, taking phase A as an example, including the H-bridge parallel reconfiguration topology of Embodiment 1 and two current sharing control loops. Please refer to... Figure 2 The two current sharing control loops have the same structure and are used to generate the modulation wave corresponding to the H bridge.

[0033] The following explanation uses the current sharing control loop of the first H-bridge as an example.

[0034] The current sharing control loop includes an averaging circuit module, a first subtractor, an amplifier, a second subtractor, and a modulation wave generator. The input of the averaging circuit module is connected to the current sampling terminals of the right bridge arms of inductors L1 and L2. The first input of the first subtractor is connected to the current sampling terminal of the right bridge arm of inductor L1, and its second input is connected to the output of the averaging circuit module. The input of the amplifier is connected to the output of the first subtractor. The first input of the second subtractor is connected to the given signal Ug, and its second input is connected to the output of the amplifier. The input of the modulation wave generator is connected to the output of the second subtractor.

[0035] The bridge arm current is sampled by a Hall current transformer, filtered, and then the average value of the two bridge arm currents is calculated using an averaging circuit. Therefore, the actual modulation waves of the two H-bridges are:

[0036]

[0037]

[0038] in, The first set of H-bridge arm current sampling values The average value of the current samples of all H-bridge arms is given by k, which is the amplifier's amplification factor. In actual operation, the value of k should not be too large, as excessive harmonics will cause system instability.

[0039] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A H-bridge parallel heavy-duty topology, characterized in that, The H-bridge comprises N groups of IGBTs, and N equal inductors, where N is a positive integer. Each group of H-bridge has the same structure, and the midpoint of the left bridge arm of each group of H-bridge is connected to one end of the corresponding inductor, and the other end of each inductor is connected to one end of the capacitor C1, and the other end of the capacitor C1 is connected to the midpoint of the right bridge arm of each group of H-bridge. The capacitor C1 is connected in parallel with the load, and each group of H-bridge is connected in parallel with the bus voltage.

2. The H-bridge parallel reconfiguration topology of claim 1, wherein, The inductance of the N equal inductors is equal.

3. The H-bridge parallel reconfiguration topology of claim 1, wherein, Each group of H-bridge comprises four switching tubes, the left bridge arm comprises two series-connected switching tubes, the right bridge arm comprises two series-connected switching tubes, and each switching tube is connected in parallel with a body diode.

4. The H-bridge parallel reconfiguration topology of claim 1, wherein, N is equal to 2, the H-bridge comprises two groups of IGBTs, inductors L1 and L2, and a capacitor C1, the first group of H-bridge comprises switching tubes V1-V4 and their respective parallel body diodes, the second group of H-bridge comprises switching tubes V1'-V4' and their respective parallel body diodes, switching tube V1 and switching tube V2 are connected in series to form the left bridge arm of the first group of H-bridge, switching tube V3 and switching tube V4 are connected in series to form the right bridge arm of the first group of H-bridge, the connection point of switching tube V1 and switching tube V2 is the midpoint of the left bridge arm of the first group of H-bridge, the connection point of switching tube V3 and switching tube V4 is the midpoint of the right bridge arm of the first group of H-bridge, switching tube V1' and switching tube V2' are connected in series to form the left bridge arm of the second group of H-bridge, switching tube V3' and switching tube V4' are connected in series to form the right bridge arm of the second group of H-bridge, the connection point of switching tube V1' and switching tube V2' is the midpoint of the left bridge arm of the second group of H-bridge, and the connection point of switching tube V3' and switching tube V4' is the midpoint of the right bridge arm of the second group of H-bridge.

5. A H-bridge parallel heavy system, characterized in that, The parallel heavy topology comprises the H-bridge of any one of claims 1-4 and N equal current control loops, the current control loops have the same structure and are used to generate a modulation wave for modulating the corresponding H-bridge, and each current control loop comprises an average circuit module, a first subtractor, an amplifier, a second subtractor, and a modulation wave generator. The input end of the average circuit module is connected to the bridge arm current sampling end of each group of H-bridge. The first input end of the first subtractor is connected to the bridge arm current sampling end of the corresponding H-bridge, and the second input end is connected to the output end of the average circuit module. The input end of the amplifier is connected to the output end of the first subtractor. The first input end of the second subtractor is connected to a given signal Ug, and the second input end is connected to the output end of the amplifier. The input end of the modulation wave generator is connected to the output end of the second subtractor.

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