CN218102571U - Overcurrent protection circuit of off-grid inverter and full-bridge inverter circuit - Google Patents
Overcurrent protection circuit of off-grid inverter and full-bridge inverter circuit Download PDFInfo
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- CN218102571U CN218102571U CN202222334070.3U CN202222334070U CN218102571U CN 218102571 U CN218102571 U CN 218102571U CN 202222334070 U CN202222334070 U CN 202222334070U CN 218102571 U CN218102571 U CN 218102571U
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Abstract
The utility model relates to an overcurrent protection circuit and full-bridge inverter circuit of an off-grid inverter, wherein the overcurrent protection circuit comprises a current sampling module, an overcurrent protection module and a controller, and the overcurrent protection module comprises a first overcurrent protection unit, a second overcurrent protection unit and a third overcurrent protection unit; the current sampling module is connected with the negative end of the off-grid inverter to obtain sampling current; the first overcurrent protection unit outputs the sampling current as an overload protection signal; the second overcurrent protection unit outputs the sampling current as an overcurrent protection signal; the third overcurrent protection unit outputs the sampling current as a short-circuit protection signal; the controller shuts down the off-grid inverter based on any one or more of the overload protection signal, the overcurrent protection signal, and the short-circuit protection signal. When the current in the off-grid inverter is overlarge, the overcurrent protection circuit protects the full-bridge inverter transistor and protects the off-grid inverter.
Description
Technical Field
The utility model relates to a power electronic technology field especially relates to an overcurrent protection circuit and full-bridge inverter circuit of off-grid inverter.
Background
An off-grid inverter is a conversion device for converting direct current into alternating current (DC/AC), and is a conversion device with high voltage and large current, so that overcurrent protection of the off-grid inverter is very important. If the protection is not timely or not, circuit faults, power devices are damaged, conversion equipment cannot work, and very large menses loss is brought to users.
Therefore, an overcurrent protection circuit which is simple, reliable, accurate in protection and timely in response is needed to protect the off-grid inverter.
SUMMERY OF THE UTILITY MODEL
Therefore, it is necessary to provide an overcurrent protection circuit and a full-bridge inverter circuit of an off-grid inverter to solve the above technical problems, and when an excessive current occurs in the off-grid inverter, a corresponding overcurrent protection action is timely performed, so that a full-bridge inverter transistor is protected, and the off-grid inverter is protected.
An overcurrent protection circuit of an off-grid inverter comprises a current sampling module, an overcurrent protection module and a controller, wherein the overcurrent protection module comprises a first overcurrent protection unit, a second overcurrent protection unit and a third overcurrent protection unit;
the current sampling module is connected with the negative end of the off-grid inverter and is used for collecting the output current of the off-grid inverter to obtain a sampling current;
the first overcurrent protection unit is connected with the output end of the current sampling module and used for outputting the sampling current as an overload protection signal; the second overcurrent protection unit is connected with the output end of the current sampling module and used for outputting the sampling current as an overcurrent protection signal; the third overcurrent protection unit is connected with the output end of the current sampling module and used for outputting the sampling current as a short-circuit protection signal;
the first overcurrent protection unit, the second overcurrent protection unit and the third overcurrent protection unit are respectively connected with the controller, and the controller closes the off-grid inverter based on any one or more of the overload protection signal, the overcurrent protection signal and the short-circuit protection signal.
In one embodiment, the current sampling module comprises a sampling resistor, one end of the sampling resistor is connected with the negative end of the off-grid inverter, and the other end of the sampling resistor is grounded.
In one embodiment, the first overcurrent protection unit includes a differential operational amplifier, a first input end of the differential operational amplifier is connected to one end of the sampling resistor, a second input end of the differential operational amplifier is connected to the other end of the sampling resistor, and an output end of the differential operational amplifier is connected to the first overcurrent protection unit, the second overcurrent protection unit, and the third overcurrent protection unit, respectively.
In one embodiment, the first overcurrent protection unit comprises an in-phase operational amplifier, an input end of the in-phase operational amplifier is connected with an output end of the differential operational amplifier, and an output end of the in-phase operational amplifier is connected with the controller.
In one embodiment, the second overcurrent protection unit includes a first voltage comparator, a non-inverting input terminal of the first voltage comparator is connected to the output terminal of the differential operational amplifier, an inverting input terminal of the first voltage comparator is configured to receive a first set voltage value, and an output terminal of the first voltage comparator is connected to the controller.
In one embodiment, the third overcurrent protection unit includes a second voltage comparator, a non-inverting input terminal of the second voltage comparator is connected to the output terminal of the differential operational amplifier, an inverting input terminal of the second voltage comparator is configured to receive a second set voltage value, and an output terminal of the second voltage comparator is connected to the controller.
In one embodiment, the over-current protection circuit comprises an LC filter module, and the LC filter module is connected with the negative terminal and the positive terminal of the off-grid inverter.
In one embodiment, the LC filter module includes a capacitor and an inductor, one end of the inductor is connected to the positive terminal, the other end of the inductor is connected to one end of the capacitor, and the other end of the capacitor is connected to the negative terminal.
A full-bridge inverter circuit comprises an off-grid inverter and the overcurrent protection circuit in any embodiment.
In one embodiment, the off-grid inverter comprises four inverting power tubes and two groups of high-frequency switching tubes.
The overcurrent protection circuit comprises a current sampling module, an overcurrent protection module and a controller, wherein the overcurrent protection module comprises a first overcurrent protection unit, a second overcurrent protection unit and a third overcurrent protection unit; the current sampling module is connected with the negative end of the off-grid inverter and is used for collecting the output current of the off-grid inverter to obtain a sampling current; the first overcurrent protection unit is connected with the output end of the current sampling module and used for outputting the sampling current as an overload protection signal; the second overcurrent protection unit is connected with the output end of the current sampling module and used for outputting the sampling current as an overcurrent protection signal; the third overcurrent protection unit is connected with the output end of the current sampling module and used for outputting the sampling current as a short-circuit protection signal; the first overcurrent protection unit, the second overcurrent protection unit and the third overcurrent protection unit are respectively connected with the controller, and the controller closes the off-grid inverter based on any one or more of the overload protection signal, the overcurrent protection signal and the short-circuit protection signal
Therefore, when the off-grid inverter outputs overload, overcurrent and short circuit, the first overcurrent protection unit, the second overcurrent protection unit and the third overcurrent protection unit in the overcurrent protection circuit can timely detect corresponding overload protection signals, overcurrent protection signals and short circuit protection signals, and output the corresponding signals to the controller, so that the controller can timely control the off-grid inverter to be closed, thereby protecting the full-bridge inverter transistor and protecting the off-grid inverter.
Drawings
Fig. 1 is a block diagram of an overcurrent protection circuit of an off-grid inverter according to an embodiment;
FIG. 2 is a schematic diagram of the circuit connections of an off-grid inverter and a sampling resistor in one embodiment;
fig. 3 is a schematic circuit connection diagram of the overcurrent protection module in an embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the following description of the present invention will be made in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The utility model provides an overcurrent protection circuit from net dc-to-ac converter. In one embodiment, as shown in fig. 1, the overcurrent protection circuit 20 includes a current sampling module 202, an overcurrent protection module 204 and a controller 206, where the overcurrent protection module 204 includes a first overcurrent protection unit 2042, a second overcurrent protection unit 2044 and a third overcurrent protection unit 2046; the current sampling module 202 is connected to the negative end of the off-grid inverter 10, and is configured to collect an output current of the off-grid inverter 10 to obtain a sampled current; the first overcurrent protection unit 2042 is connected to the output end of the current sampling module 202, and is configured to output the sampled current as an overload protection signal; the second overcurrent protection unit 2044 is connected to the output end of the current sampling module 202, and is configured to output the sampled current as an overcurrent protection signal; the third overcurrent protection unit 2046 is connected to the output end of the current sampling module 202, and is configured to output the sampled current as a short-circuit protection signal; the first overcurrent protection unit 2042, the second overcurrent protection unit 2044, and the third overcurrent protection unit 2046 are respectively connected to the controller 206, and the controller 206 turns off the off-grid inverter 10 based on any one or more of the overload protection signal, the overcurrent protection signal, and the short-circuit protection signal.
In one embodiment, the current sampling module 202 includes a sampling resistor, one end of the sampling resistor is connected to the negative terminal of the off-grid inverter 10, and the other end of the sampling resistor is grounded.
Specifically, as shown in fig. 2, the sampling resistor is a resistor RX1. And the resistor RX1 is connected in series with the negative end of the off-grid inverter circuit and used for current detection. And the power resistor is adopted for current sampling, so that the cost is low. When the inverter outputs, the magnitude of the output current can be accurately detected on line.
In one embodiment, the first overcurrent protection unit includes a differential operational amplifier, a first input end of the differential operational amplifier is connected to one end of the sampling resistor, a second input end of the differential operational amplifier is connected to the other end of the sampling resistor, and an output end of the differential operational amplifier is connected to the first overcurrent protection unit, the second overcurrent protection unit, and the third overcurrent protection unit, respectively.
In one embodiment, the first over-current protection unit includes an in-phase operational amplifier circuit, an input terminal of the in-phase operational amplifier is connected with an output terminal of the differential operational amplifier, and an output terminal of the in-phase operational amplifier is connected with the controller.
In one embodiment, the second overcurrent protection unit includes a first voltage comparator, a non-inverting input terminal of the first voltage comparator is connected to the output terminal of the differential operational amplifier, an inverting input terminal of the first voltage comparator is configured to receive a first set voltage value, and an output terminal of the first voltage comparator is connected to the controller.
In one embodiment, the third overcurrent protection unit includes a second voltage comparator, a non-inverting input terminal of the second voltage comparator is connected to the output terminal of the differential operational amplifier, an inverting input terminal of the second voltage comparator is configured to receive a second set voltage value, and an output terminal of the second voltage comparator is connected to the controller.
Specifically, as shown in fig. 3, the differential operational amplifier is a differential operational amplifier U5A, the non-inverting operational amplifier is a non-inverting operational amplifier follower U5B, the first voltage comparator is a voltage comparator U4A, and the second voltage comparator is a voltage comparator U4B. As shown in fig. 2, the positive terminal CT-and the negative terminal CT + of the resistor RX1. And current sampling signals are output through a positive terminal CT-and a negative terminal CT +. As shown in fig. 3, the current sampling signal is converted into a voltage signal, which is amplified by a differential operational amplifier U5A and divided into three paths, one of which is sent to a controller CPU for processing after passing through an in-phase operational amplifier follower U5B, and is used as a current signal detection, and is used as a third overcurrent protection signal detection as shown in fig. 3. The third over-current protection signal is typically used for power signal and overload signal detection. The overload rated power is detected by time delay, the time delay is generally 2-5 minutes, and an overload protection signal is sent out. The CPU sends an overload protection signal to shut down the off-grid inverter circuit. As shown in fig. 3, the other two paths are respectively sent to the non-inverting input terminals of two independent high-precision voltage comparators for comparison with the set values of the inverting terminals. As shown in fig. 3, the voltage comparator U4A outputs a second overcurrent protection signal of the off-grid inverter, which is slow protection, such as overcurrent protection. The voltage comparator U4B outputs a first overcurrent protection signal of the off-grid inverter, i.e., fast protection, such as short-circuit protection. The overcurrent voltage signals obtained by sampling are respectively compared with voltage values set by a voltage comparator U4A and a voltage comparator U4B, and the voltage comparator U4A and the voltage comparator U4B timely and accurately output corresponding overcurrent protection signals to an inverter chip CPU and a corresponding full-bridge driving switch circuit, so that an off-grid inverter circuit is closed, and the off-grid inverter is protected.
In one embodiment, the over-current protection circuit comprises an LC filter module, and the LC filter module is connected with the negative terminal and the positive terminal of the off-grid inverter.
Specifically, the LC filter module includes a capacitor and an inductor, one end of the inductor is connected to the positive terminal, the other end of the inductor is connected to one end of the capacitor, and the other end of the capacitor is connected to the negative terminal. As shown in fig. 2, the capacitor is a capacitor C2, and the inductor is an inductor L2. The off-grid inverter outputs positive and negative half cycle SPWM modulated wave voltage to LC filtering constructed by a capacitor C2 and an inductor L2, and then alternating current pure sine wave voltage is obtained.
The application also provides a full-bridge inverter circuit, the full-bridge inverter circuit includes the off-grid inverter, and any one of the above embodiments the overcurrent protection circuit.
As shown in fig. 2, the off-grid inverter includes four inverter power transistors and two sets of high-frequency switching transistors. The off-grid inverter converts the high-voltage direct-current voltage into an SPWM high-frequency modulation wave voltage with 50HZ positive and negative half cycles for output.
The utility model has the advantages that: combine 3 layers of overcurrent protection device, protection that can be timely accurate leaves the net dc-to-ac converter, can let again and leave the net dc-to-ac converter area load ability and strengthen, let the user area load more heterogeneous loads, bring more practical and economic value for the user, be particularly suitable for middle-size and small-size power and leave net dc-to-ac converter.
The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.
Claims (10)
1. The over-current protection circuit of the off-grid inverter is characterized by comprising a current sampling module, an over-current protection module and a controller, wherein the over-current protection module comprises a first over-current protection unit, a second over-current protection unit and a third over-current protection unit;
the current sampling module is connected with the negative end of the off-grid inverter and is used for collecting the output current of the off-grid inverter to obtain a sampling current;
the first overcurrent protection unit is connected with the output end of the current sampling module and used for outputting the sampling current as an overload protection signal; the second overcurrent protection unit is connected with the output end of the current sampling module and used for outputting the sampling current as an overcurrent protection signal; the third overcurrent protection unit is connected with the output end of the current sampling module and used for outputting the sampling current as a short-circuit protection signal;
the first overcurrent protection unit, the second overcurrent protection unit and the third overcurrent protection unit are respectively connected with the controller, and the controller closes the off-grid inverter based on any one or more of the overload protection signal, the overcurrent protection signal and the short-circuit protection signal.
2. The overcurrent protection circuit of claim 1, wherein the current sampling module comprises a sampling resistor, one end of the sampling resistor is connected to a negative terminal of the off-grid inverter, and the other end of the sampling resistor is grounded.
3. The over-current protection circuit according to claim 2, wherein the first over-current protection unit comprises a differential operational amplifier, a first input end of the differential operational amplifier is connected with one end of the sampling resistor, a second input end of the differential operational amplifier is connected with the other end of the sampling resistor, and an output end of the differential operational amplifier is respectively connected with the first over-current protection unit, the second over-current protection unit and the third over-current protection unit.
4. The over-current protection circuit according to claim 3, wherein the first over-current protection unit comprises a non-inverting operational amplifier, an input end of the non-inverting operational amplifier is connected with an output end of the differential operational amplifier, and an output end of the non-inverting operational amplifier is connected with the controller.
5. The over-current protection circuit according to claim 3, wherein the second over-current protection unit comprises a first voltage comparator, a non-inverting input terminal of the first voltage comparator is connected to the output terminal of the differential operational amplifier, an inverting input terminal of the first voltage comparator is configured to receive a first set voltage value, and an output terminal of the first voltage comparator is connected to the controller.
6. The over-current protection circuit according to claim 3, wherein the third over-current protection unit comprises a second voltage comparator, a non-inverting input terminal of the second voltage comparator is connected to the output terminal of the differential operational amplifier, an inverting input terminal of the second voltage comparator is configured to receive a second set voltage value, and an output terminal of the second voltage comparator is connected to the controller.
7. The over-current protection circuit according to claim 1, wherein the over-current protection circuit comprises an LC filter module, and the LC filter module is connected with a negative terminal and a positive terminal of the off-grid inverter.
8. The overcurrent protection circuit of claim 7, wherein the LC filter module comprises a capacitor and an inductor, one end of the inductor is connected to the positive terminal, the other end of the inductor is connected to one end of the capacitor, and the other end of the capacitor is connected to the negative terminal.
9. A full-bridge inverter circuit is characterized by comprising an off-grid inverter and the overcurrent protection circuit in any one of the above 1-8.
10. The full-bridge inverter circuit according to claim 9, wherein the off-grid inverter comprises four inverter power transistors and two sets of high-frequency switching transistors.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222334070.3U CN218102571U (en) | 2022-09-01 | 2022-09-01 | Overcurrent protection circuit of off-grid inverter and full-bridge inverter circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222334070.3U CN218102571U (en) | 2022-09-01 | 2022-09-01 | Overcurrent protection circuit of off-grid inverter and full-bridge inverter circuit |
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| Publication Number | Publication Date |
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| CN218102571U true CN218102571U (en) | 2022-12-20 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202222334070.3U Active CN218102571U (en) | 2022-09-01 | 2022-09-01 | Overcurrent protection circuit of off-grid inverter and full-bridge inverter circuit |
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| CN (1) | CN218102571U (en) |
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- 2022-09-01 CN CN202222334070.3U patent/CN218102571U/en active Active
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