Miniature inverter secondary side overcurrent protection circuit

Abstract

The utility model relates to a secondary side overcurrent protection circuit of a micro inverter, and belongs to the technical field of circuit structures. According to the secondary side overcurrent protection circuit of the micro inverter, the overcurrent comparators in the two groups of H bridges respectively generate a first overcurrent signal OCS0 and a second overcurrent signal OCS1, and the first overcurrent signal OCS0 and the second overcurrent signal OCS1 are both connected with the driving chips corresponding to the two groups of H bridges at the same time so as to control the turn-off of the switching devices in the two groups of H bridges. Therefore, when one group of H bridges is over-current, the MOS tubes on the two groups of H bridges are turned off at the same time, and the MOS tubes of the other group of H bridges are prevented from being damaged due to large impact instantly. The secondary side overcurrent protection circuit of the micro inverter is simple in structure and wide in application range.

Description

TECHNICAL FIELD

[0001] The utility model relates to circuit structure technical field, especially micro inverter circuit structure technical field, specifically points to a kind of micro inverter secondary side overcurrent protection circuit. BACKGROUND

[0002] The micro inverter secondary side overcurrent control in prior art is as shown in Figure 1 Each group of H bridge corresponds to respective overcurrent comparator and drive chip, i.e. when overcurrent occurs in a group of H bridge, the group of H bridge is controlled to be turned off by drive chip, while another group of bridge can normally operate, and then based on software control, when detecting that overcurrent occurs in any one group of H bridge, all drive outputs are turned off. When OC_S0 is pulled low due to overcurrent, corresponding drive chip U17 quickly turns off drive output, but U16 is not turned off until triggering secondary MCU software protection to stop output, so that the corresponding bridge tube is turned off, and there is the condition of another group of bridge tube delayed turn-off

[0003] Therefore, when a group of H bridge is turned off while another group is normally operated, the energy on two groups of H bridge flows through a MOS tube of a group of H bridge at the same time, causing instantaneous larger impact, which can lead to the damage of the MOS tube.

[0004] Therefore, how to provide a kind of overcurrent protection circuit for simultaneously turning off all drive outputs when overcurrent occurs in any one group of H bridge becomes the problem to be solved in the field. UTILITY MODEL CONTENT

[0005] The utility model aims at overcoming the above-mentioned shortcomings in prior art, and provides a kind of micro inverter secondary side overcurrent protection circuit, which simultaneously gives the overcurrent signal of a group of H bridge to the drive chip corresponding to two groups of H bridge, so that the MOS tube on two groups of H bridge is turned off simultaneously.

[0006] In order to achieve the above-mentioned purpose, the micro inverter secondary side overcurrent protection circuit of the utility model has the following composition:

[0007] The micro-inverter secondary side overcurrent protection circuit includes two groups of H-bridges connected to the micro-inverter secondary side, each group of H-bridges is connected with a corresponding overcurrent comparator and a driving chip, the first overcurrent comparator connected to the first H-bridge in the two groups of H-bridges compares the input voltage with the reference voltage to generate a first overcurrent signal OC_S0, the second overcurrent comparator connected to the second H-bridge compares the input voltage with the reference voltage to generate a second overcurrent signal OC_S1, wherein the first overcurrent signal OC_S0 and the second overcurrent signal OC_S1 are simultaneously connected to the first driving chip U16 and the second driving chip U17 corresponding to the two groups of H-bridges, the first driving chip U16 controls the conduction and turn-off of the switching device connected to the secondary side ground in the first H-bridge according to the first overcurrent signal OC_S0 or the second overcurrent signal OC_S1, and the second driving chip U17 controls the turn-off of the switching device connected to the secondary side ground in the second H-bridge according to the first overcurrent signal OC_S0 or the second overcurrent signal OC_S1.

[0008] In the micro-inverter secondary side overcurrent protection circuit, the output end of the second driving chip U17 includes a first control signal GS1 and a second control signal GS2, the first H-bridge is connected with a switching device QS1 and a switching device QS2, the gate of the switching device QS1 is connected to the first control signal GS1, the source thereof is connected to a voltage VH-, and the drain thereof is connected to the secondary side ground; the gate of the switching device QS2 is connected to the second control signal GS2, the source thereof is connected to the voltage VH-, and the drain thereof is connected to the secondary side ground; the output end of the first driving chip U16 includes a third control signal GS3 and a fourth control signal GS4, the second H-bridge is connected with a switching device QS3 and a switching device QS4, the gate of the switching device QS3 is connected to the third control signal GS3, the source thereof is connected to the voltage VH-, and the drain thereof is connected to the secondary side ground; the gate of the switching device QS4 is connected to the fourth control signal GS4, the source thereof is connected to the voltage VH-, and the drain thereof is connected to the secondary side ground.

[0009] In the micro-inverter secondary side overcurrent protection circuit, the input end of the second driving chip U17 is connected to the first overcurrent signal OC_S0 and the second overcurrent signal OC_S1, and is also connected to a first pulse width modulation signal PWM1 and a second pulse width modulation signal PWM2; the input end of the first driving chip U16 is connected to the first overcurrent signal OC_S0 and the second overcurrent signal OC_S1, and is also connected to a third pulse width modulation signal PWM3 and a fourth pulse width modulation signal PWM4.

[0010] The micro-inverter auxiliary side overcurrent protection circuit of the utility model, the overcurrent comparators in the two groups of H bridges generate first overcurrent signal OC_S0 and second overcurrent signal OC_S1 respectively, and the first overcurrent signal OC_S0 and the second overcurrent signal OC_S1 are connected to the driving chips corresponding to the two groups of H bridges at the same time, and then the switching devices in the two groups of H bridges are controlled to be turned off. Therefore, the overcurrent signal of one group of H bridges is simultaneously given to the driving chips corresponding to the two groups of H bridges, so that when the overcurrent of one group of H bridges occurs, the MOS tubes on the two groups of H bridges are turned off at the same time, thereby avoiding the MOS tube of the other group of H bridges from being subjected to a large impact instantaneously and avoiding the damage of the MOS tube. The micro-inverter auxiliary side overcurrent protection circuit of the utility model has simple structure and is quite widely used. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is a micro-inverter auxiliary side overcurrent control circuit schematic diagram in the prior art;

[0012] Figure 2 It is a micro-inverter auxiliary side overcurrent protection circuit turn-off time comparison schematic diagram of the utility model and the prior art;

[0013] Figure 3 It is a circuit structure schematic diagram of two groups of H bridges of the micro-inverter auxiliary side;

[0014] Figure 4 It is a micro-inverter auxiliary side overcurrent protection circuit structure schematic diagram of the utility model. DETAILED DESCRIPTION

[0015] In order to make the technical content of the utility model more clearly understood, the following embodiments are used for detailed description.

[0016] Please refer to Figure 3 It is a circuit structure schematic diagram of two groups of H bridges of the micro-inverter auxiliary side, Figure 4 It is a micro-inverter auxiliary side overcurrent protection circuit structure schematic diagram of the utility model.

[0017] In one embodiment, the micro-inverter secondary side over-current protection circuit includes two groups of H-bridges connected to the micro-inverter secondary side, each group of H-bridges is connected with a corresponding over-current comparator and a driving chip, the first over-current comparator connected to the first H-bridge compares the input voltage with the reference voltage to generate a first over-current signal OC_S0, the second over-current comparator connected to the second H-bridge compares the input voltage with the reference voltage to generate a second over-current signal OC_S1, wherein the first over-current signal OC_S0 and the second over-current signal OC_S1 are simultaneously connected to the first driving chip U16 and the second driving chip U17 corresponding to the two groups of H-bridges, the first driving chip U16 controls the conduction and turn-off of the switching device connected to the secondary side ground in the first H-bridge according to the first over-current signal OC_S0 or the second over-current signal OC_S1, and the second driving chip U17 controls the turn-off of the switching device connected to the secondary side ground in the second H-bridge according to the first over-current signal OC_S0 or the second over-current signal OC_S1.

[0018] In a preferred embodiment, the output end of the second driving chip U17 includes a first control signal GS1 and a second control signal GS2, the first H-bridge is connected with a switching device QS1 and a switching device QS2, the gate of the switching device QS1 is connected to the first control signal GS1, the source thereof is connected to the voltage VH-, and the drain thereof is connected to the secondary side ground; the gate of the switching device QS2 is connected to the second control signal GS2, the source thereof is connected to the voltage VH-, and the drain thereof is connected to the secondary side ground.

[0019] The output end of the first driving chip U16 includes a third control signal GS3 and a fourth control signal GS4, the second H-bridge is connected with a switching device QS3 and a switching device QS4, the gate of the switching device QS3 is connected to the third control signal GS3, the source thereof is connected to the voltage VH-, and the drain thereof is connected to the secondary side ground; the gate of the switching device QS4 is connected to the fourth control signal GS4, the source thereof is connected to the voltage VH-, and the drain thereof is connected to the secondary side ground.

[0020] In a more preferred embodiment, the input end of the second driving chip U17 is connected to the first over-current signal OC_S0 and the second over-current signal OC_S1, and is also connected to a first pulse width modulation signal PWM1 and a second pulse width modulation signal PWM2; the input end of the first driving chip U16 is connected to the first over-current signal OC_S0 and the second over-current signal OC_S1, and is also connected to a third pulse width modulation signal PWM3 and a fourth pulse width modulation signal PWM4.

[0021] As Figure 2 and Figure 3As shown, assuming that when the switching device QS1 is off due to overcurrent, if the prior art is adopted, the energy on the two groups of H-bridges all flows through the switching device QS3 before triggering the software protection off switching device QS3, that is, as shown in the upper half of the figure, Figure 3 As shown by the arrow direction, VH0 and VH1 flow out through VH+, and VH- returns, and returns to the secondary side ground through the switching device QS3, forming a loop. Figure 2 As shown in the lower half of the figure. This case can easily cause damage to the switching device QS3, and the same applies to other MOS tubes.

[0022] In order to solve the above problems, in the circuit of the utility model, hardware protection is added, as shown in the figure, Figure 4 The overcurrent signals OC_S0 and OC_S1 are simultaneously given to the two drive chips, so that the MOS tubes QS1 and QS3 on the two groups of H-bridges are simultaneously turned off, and the current waveform is as shown in the upper half of the figure. Figure 2 Thus, the damage to the switching device QS3 is effectively avoided.

[0023] The micro-inverter secondary side overcurrent protection circuit of the utility model, the overcurrent comparators in the two groups of H-bridges generate a first overcurrent signal OC_S0 and a second overcurrent signal OC_S1, and the first overcurrent signal OC_S0 and the second overcurrent signal OC_S1 are simultaneously connected to the drive chips corresponding to the two groups of H-bridges, thereby controlling the off of the switching devices in the two groups of H-bridges. Therefore, the overcurrent signal of one group of H-bridges is simultaneously given to the drive chips corresponding to the two groups of H-bridges, so that when one group of H-bridges overflows, the MOS tubes on the two groups of H-bridges are simultaneously turned off, thereby avoiding that the MOS tubes in the other group of H-bridges receive a large impact instantaneously, and avoiding damage to the MOS tubes. The micro-inverter secondary side overcurrent protection circuit of the utility model has a simple structure and is quite widely applicable.

[0024] In this specification, the utility model has been described with reference to its specific embodiments. However, it is obvious that various modifications and changes can be made without departing from the spirit and scope of the utility model. Therefore, the specification and drawings should be considered illustrative rather than limiting.

Claims

1.A micro-inverter secondary side over-current protection circuit, comprising two groups of H-bridges connected to the micro-inverter secondary side, each group of H-bridges is connected with a corresponding over-current comparator and a driving chip, the first over-current comparator connected to the first H-bridge in the two groups of H-bridges compares the input voltage with the reference voltage to generate a first over-current signal OC_S0, and the second over-current comparator connected to the second H-bridge compares the input voltage with the reference voltage to generate a second over-current signal OC_S1, characterized in that, the first over-current signal OC_S0 and the second over-current signal OC_S1 are simultaneously connected to the first driving chip U16 and the second driving chip U17 corresponding to the two groups of H-bridges, the first driving chip U16 controls the conduction and turn-off of the switching device connected to the secondary side ground in the first H-bridge according to the first over-current signal OC_S0 or the second over-current signal OC_S1, and the second driving chip U17 controls the turn-off of the switching device connected to the secondary side ground in the second H-bridge according to the first over-current signal OC_S0 or the second over-current signal OC_S1. 2.The micro-inverter secondary side over-current protection circuit according to claim 1, characterized in that, the output end of the second driving chip U17 comprises a first control signal GS1 and a second control signal GS2, the first H-bridge is connected with a switching device QS1 and a switching device QS2, the gate of the switching device QS1 is connected to the first control signal GS1, the source thereof is connected to the voltage VH-, and the drain thereof is connected to the secondary side ground; the gate of the switching device QS2 is connected to the second control signal GS2, the source thereof is connected to the voltage VH-, and the drain thereof is connected to the secondary side ground; the output end of the first driving chip U16 comprises a third control signal GS3 and a fourth control signal GS4, the second H-bridge is connected with a switching device QS3 and a switching device QS4, the gate of the switching device QS3 is connected to the third control signal GS3, the source thereof is connected to the voltage VH-, and the drain thereof is connected to the secondary side ground; the gate of the switching device QS4 is connected to the fourth control signal GS4, the source thereof is connected to the voltage VH-, and the drain thereof is connected to the secondary side ground. 3.The micro-inverter secondary side over-current protection circuit according to claim 2, characterized in that, the input end of the second driving chip U17 is connected to the first over-current signal OC_S0 and the second over-current signal OC_S1, and is also connected to a first pulse width modulation signal PWM1 and a second pulse width modulation signal PWM2; the input end of the first driving chip U16 is connected to the first over-current signal OC_S0 and the second over-current signal OC_S1, and is also connected to a third pulse width modulation signal PWM3 and a fourth pulse width modulation signal PWM4. ​ ​ ​ ​ ​

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