CN220440374U - Overcurrent detection circuit - Google Patents
Overcurrent detection circuit Download PDFInfo
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- CN220440374U CN220440374U CN202322058878.8U CN202322058878U CN220440374U CN 220440374 U CN220440374 U CN 220440374U CN 202322058878 U CN202322058878 U CN 202322058878U CN 220440374 U CN220440374 U CN 220440374U
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Abstract
The utility model discloses an overcurrent detection circuit, which relates to the field of overcurrent protection of inverters, and is characterized in that a first output current of the inverter sampled by a first sampling circuit is a sine wave, and a phase inversion circuit inverts a negative half period in the sine wave corresponding to the first output current, so that all currents of the negative half period are inverted into positive currents under the condition that the values of the currents are unchanged, namely the values received by a current comparison circuit are positive values, the inversion result is accurate, and the reliability of the overcurrent detection circuit is improved; at the moment, only one preset peak current value is set through the current comparison circuit, so that the positive peak current corresponding to the current of the positive half period and the negative peak current corresponding to the current of the negative half period can be protected completely, the circuit structure is simple, and the cost is saved.
Description
Technical Field
The utility model relates to the field of overcurrent protection of inverters, in particular to an overcurrent detection circuit.
Background
The inverter is a converter for converting direct current electric energy into alternating current electric energy with fixed frequency and fixed voltage or with frequency and voltage modulation and regulation, and the direct current voltage on the direct current network is converted into sine waves through the cooperation of devices such as an alternating current sensor and the like in the inverter. Because of the adoption of more power switching devices and pulse modulation technology, when the load of the inverter is suddenly connected or the load connected with the inverter is too much, the output current of the inverter may exceed the rated current of the inverter, so that the power switching devices are burnt out. Therefore, it is necessary to perform overcurrent protection on the output current of the inverter, that is, to collect the output current of the inverter by the sensor, to compare the detected output current with a preset peak current, and to trigger a protection operation such as pulse blocking when the output current is greater than the preset peak current.
However, since the inverter outputs a sine wave, the peak value of the positive half cycle and the peak value of the negative half cycle need to be considered, respectively. In the prior art, the circuit for detecting the overcurrent of the output current of the inverter generally sets peak currents for the positive half period and the negative half period of the sine wave respectively, namely, the positive peak current and the negative peak current corresponding to the positive half period and the negative half period of the sine wave are detected to be overcurrent respectively, so that the whole inverter is complex in integral structure and high in cost.
Disclosure of Invention
The utility model aims to provide an overcurrent detection circuit, which improves the reliability of the overcurrent detection circuit, and can fully protect the positive peak current corresponding to the current of a positive half period and the negative peak current corresponding to the current of a negative half period by only setting a preset peak current value through a current comparison circuit, so that the circuit has a simple structure and saves the cost.
In order to solve the above technical problems, the present utility model provides an overcurrent detection circuit, including:
the input end of the first sampling circuit is respectively connected with the forward output end and the reverse output end of an alternating current sensor in the inverter, and the output end of the first sampling circuit is connected with the input end of the phase inversion circuit and is used for obtaining a first output current of the inverter;
the output end of the phase reversal circuit is connected with the input end of the current comparison circuit, and is used for outputting the current of the positive half period of the first output current to the current comparison circuit, reversing the current of the negative half period of the first output current and outputting the reversed current to the current comparison circuit;
the output end of the current comparison circuit is connected with the overcurrent protection circuit and is used for comparing the current output by the phase reversal circuit with a preset peak current;
and the overcurrent protection circuit is used for carrying out overcurrent protection on the inverter when the current output by the phase reversal circuit is larger than a preset peak current.
In one aspect, the first sampling circuit includes:
the first end of the first resistor is connected with the positive output end of the alternating current sensor in the inverter, and the second end of the first resistor is respectively connected with the positive input end of the first operational amplifier and the first end of the fourth resistor;
the first end of the second resistor is connected with the reverse output end of the alternating current sensor in the inverter, and the second end of the second resistor is respectively connected with the reverse input end of the first operational amplifier and the first end of the third resistor;
the output end of the first operational amplifier is respectively connected with the second end of the third resistor and the input end of the phase reversal circuit;
the third resistor;
and the second end of the fourth resistor is grounded.
In another aspect, the first sampling circuit further includes:
the first end of the first capacitor is respectively connected with the first end of the third resistor, the reverse input end of the first operational amplifier and the second end of the second resistor, and the second end of the first capacitor is respectively connected with the second end of the third resistor, the output end of the first operational amplifier and the input end of the phase reversal circuit.
In one aspect, the phase inversion circuit includes:
the positive electrode of the first diode is respectively connected with the output end of the first sampling circuit and the reverse input end of the reverse phase proportional operational amplifier circuit, and the negative electrode of the first diode is respectively connected with the input end of the current comparison circuit and the negative electrode of the second diode;
the output end of the inverting proportion operational amplifier circuit is connected with the positive electrode of the second diode and is used for inverting the current of the negative half period of the first output current;
the second diode.
In one aspect, the inverting proportional operational amplifier circuit includes:
the first end of the fifth resistor is connected with the output end of the first sampling circuit, and the second end of the fifth resistor is respectively connected with the first end of the sixth resistor and the reverse input end of the second operational amplifier;
the positive input end of the second operational amplifier is connected with the first end of the seventh resistor, and the output end of the second operational amplifier is respectively connected with the second end of the sixth resistor and the positive electrode of the second diode;
the sixth resistor;
the second end of the seventh resistor is grounded.
In one aspect, the current comparison circuit includes:
the first end of the eighth resistor is connected with the preset peak current input end, and the second end of the eighth resistor is respectively connected with the first end of the ninth resistor and the positive input end of the comparator;
the reverse input end of the comparator is connected with the output end of the phase reversal circuit, and the output end of the comparator is connected with the overcurrent protection circuit and is used for comparing the current output by the phase reversal circuit with the preset peak current of the preset peak current input end;
the second end of the ninth resistor is grounded.
In one aspect, the method further comprises:
the input end of the second sampling circuit is respectively connected with the output end of the first sampling circuit and the input end of the phase inversion circuit, and the output end of the second sampling circuit is connected with the digital signal controller and is used for acquiring the first output current of the inverter and lifting the first output current to be a second output current, and the current value of the second output current is a positive value.
In one aspect, the second sampling circuit includes:
a tenth resistor, wherein a first end of the tenth resistor is connected with the reference voltage input end, and a second end of the tenth resistor is respectively connected with a second end of the eleventh resistor and a positive input end of the third operational amplifier;
the first end of the eleventh resistor is connected with the output end of the first sampling circuit and the input end of the phase inversion circuit respectively;
a twelfth resistor, wherein a first end of the twelfth resistor is grounded, and a second end of the twelfth resistor is respectively connected with an inverted input end of the third operational amplifier and a first end of the thirteenth resistor;
the output end of the third operational amplifier is respectively connected with the second end of the thirteenth resistor and the digital signal controller;
the thirteenth resistor.
In one aspect, the second sampling circuit further includes:
and the first end of the second capacitor is respectively connected with the first end of the tenth resistor and the reference voltage input end, and the second end of the second capacitor is respectively connected with the second end of the tenth resistor, the second end of the eleventh resistor and the positive input end of the third operational amplifier.
In another aspect, the second sampling circuit further includes:
and the first end of the third capacitor is respectively connected with the first end of the thirteenth resistor and the reverse input end of the third operational amplifier, and the second end of the third capacitor is respectively connected with the second end of the thirteenth resistor, the output end of the third operational amplifier and the input end of the phase reversal circuit.
The utility model provides an overcurrent detection circuit, wherein the first output current of an inverter sampled by a first sampling circuit is a sine wave, and the phase inversion circuit inverts a negative half period in the sine wave corresponding to the first output current, so that all the currents in the negative half period are inverted to positive currents under the condition that the values are unchanged, namely the values received by a current comparison circuit are positive values, the inversion result is accurate, and the reliability of the overcurrent detection circuit is improved; at the moment, only one preset peak current value is set through the current comparison circuit, so that the positive peak current corresponding to the current of the positive half period and the negative peak current corresponding to the current of the negative half period can be protected completely, the circuit structure is simple, and the cost is saved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required in the prior art and the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of an overcurrent detection circuit according to an embodiment of the present utility model;
fig. 2 is a waveform diagram of an output of a first sampling circuit according to an embodiment of the present utility model;
FIG. 3 is a waveform diagram of the output of the phase inversion circuit according to an embodiment of the present utility model;
fig. 4 is a schematic diagram of a connection relationship of an overcurrent detection circuit according to an embodiment of the present utility model;
FIG. 5 is a schematic diagram of a connection relationship of another overcurrent detection circuit according to an embodiment of the present utility model;
fig. 6 is a waveform diagram of an output of the second sampling circuit according to an embodiment of the present utility model.
Detailed Description
The core of the utility model is to provide an overcurrent detection circuit, which improves the reliability of the overcurrent detection circuit, and can protect all positive peak current corresponding to the current of a positive half period and all negative peak current corresponding to the current of a negative half period by only setting a preset peak current value through a current comparison circuit, so that the circuit has a simple structure and saves the cost.
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments of the present utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.
Referring to fig. 1, fig. 1 is a schematic structural diagram of an overcurrent detection circuit according to an embodiment of the present utility model, including:
the input end of the first sampling circuit 101 is respectively connected with the forward output end and the reverse output end of an alternating current sensor in the inverter, and the output end of the first sampling circuit 101 is connected with the input end of the phase reversal circuit 102 and is used for obtaining a first output current of the inverter;
the output end of the phase inversion circuit 102 is connected with the input end of the current comparison circuit 103, and is used for outputting the current of the positive half period of the first output current to the current comparison circuit 103, inverting the current of the negative half period of the first output current, and outputting the inverted current to the current comparison circuit 103;
the output end of the current comparison circuit 103 is connected with the overcurrent protection circuit 104 and is used for comparing the current output by the phase reversal circuit 102 with a preset peak current;
the overcurrent protection circuit 104 is configured to perform overcurrent protection on the inverter when the current output by the phase inversion circuit 102 is greater than a preset peak current.
In a specific embodiment, the first sampling circuit 101 samples a current signal output by the inverter, and maintains the original sine wave characteristic of the current, that is, the original numerical characteristic of the positive and negative half periods, and referring to fig. 2, fig. 2 is a waveform chart output by the first sampling circuit 101 according to the embodiment of the present utility model; the current in the negative half period of the sine wave corresponding to the first output current is inverted by the phase inversion circuit 102, that is, the original negative half period is inverted to a positive value, the value is unchanged, the current in the original positive half period is unchanged, referring to fig. 3 specifically, fig. 3 is a waveform chart output by the phase inversion circuit 102 according to the embodiment of the present utility model; the currents each having a positive value are input to the current comparison circuit 103, the current output from the phase inversion circuit 102 is compared with a predetermined peak current value, and when the current output from the phase inversion circuit 102 is greater than the predetermined peak current value, the overcurrent protection circuit 104 performs overcurrent protection on the inverter.
The embodiment is not limited to the specific structure of the first sampling circuit 101, and can be a current sampling circuit for directly collecting the current signal output by the inverter, or a voltage collecting circuit for sensing the current through a series resistor so as to sample the current. Further, the present embodiment is not limited to the specific configuration of the current comparing circuit 103, as long as the comparing function can be realized, and the current may be mainly constituted by a hall sensor, or may be converted into a voltage, and then compared with a threshold voltage defining the magnitude of the current by the comparator Q3.
The embodiment is not limited to the specific structure and specific function of the overcurrent protection circuit 104, for example, when the current output by the phase reversal circuit 102 is greater than the preset peak current, the overcurrent protection circuit 104 may report an overcurrent fault signal, and trigger the fuse to blow to protect the inverter.
The utility model provides an overcurrent detection circuit, because the first output current of an inverter sampled by a first sampling circuit 101 is a sine wave, the phase inversion circuit 102 inverts the negative half period in the sine wave corresponding to the first output current, so that the current of the negative half period is all inverted into positive current under the condition that the value is unchanged, namely, the values received by a current comparison circuit 103 are all positive values, the inversion result is accurate, and the reliability of the overcurrent detection circuit is improved; at this time, only one preset peak current value is set through the current comparison circuit 103, so that the positive peak current corresponding to the current of the positive half period and the negative peak current corresponding to the current of the negative half period can be all protected, the circuit structure is simple, and the cost is saved.
Based on the above embodiments:
referring to fig. 4, fig. 4 is a schematic diagram illustrating a connection relationship of an overcurrent detection circuit according to an embodiment of the present utility model:
in some embodiments, the first sampling circuit 101 includes:
the first end of the first resistor R1 is connected with the positive output end of an alternating current sensor in the inverter, and the second end of the first resistor R1 is respectively connected with the positive input end of the first operational amplifier Q1 and the first end of the fourth resistor R4;
the first end of the second resistor R2 is connected with the reverse output end of the alternating current sensor in the inverter, and the second end of the second resistor R2 is respectively connected with the reverse input end of the first operational amplifier Q1 and the first end of the third resistor R3;
the output end of the first operational amplifier Q1 is respectively connected with the second end of the third resistor R3 and the input end of the phase reversal circuit 102;
a third resistor R3;
the second end of the fourth resistor R4 is grounded.
In a specific embodiment, input impedance matching is performed through a first resistor R1 and a second resistor R2, so that total offset voltage caused by bias current is prevented; the third resistor R3 acts as a feedback resistor that sets the closed loop dynamic range and affects both bandwidth and stability. One of the greatest advantages of current feedback is the very large signal bandwidth. Based on the application of the feedback resistor, the device has high slew rate and adjustable bandwidth, so that the large signal bandwidth of the device is very close to the small signal bandwidth.
According to the embodiment, the sampling function is realized through the cooperation of the first operational amplifier Q1 and the resistor, the sampling rate is high, the precision is high, the sampling is accurate, the peak interference can be restrained, the sampling switching noise is attenuated, the anti-interference capability of a sampling circuit is improved, the fourth resistor R4 is used as a balance resistor, the static working point is automatically adjusted, the influence of the static base current on the output voltage is eliminated, the error caused by the static input voltage formed by the operational amplifier input bias current on the resistor is reduced, the offset voltage is avoided, the first operational amplifier Q1 is protected, and the first operational amplifier Q1 is prevented from being burnt due to faults.
In other embodiments, the first sampling circuit 101 further comprises:
the first end of the first capacitor C1 is connected to the first end of the third resistor R3, the inverting input end of the first operational amplifier Q1, and the second end of the second resistor R2, respectively, and the second end of the first capacitor C1 is connected to the second end of the third resistor R3, the output end of the first operational amplifier Q1, and the input end of the phase inversion circuit 102, respectively.
In the embodiment, the first capacitor C1 and the third resistor R3 are connected in parallel to form a high-pass filter, so that the filtering function is realized, and the anti-interference capability of the sampling circuit is improved; prevent self-excitation and improve the safety of the circuit.
In some embodiments, phase inversion circuit 102 includes:
the positive electrode of the first diode D1 is respectively connected with the output end of the first sampling circuit 101 and the reverse input end of the reverse phase proportional operational amplifier circuit, and the negative electrode of the first diode D1 is respectively connected with the input end of the current comparison circuit 103 and the negative electrode of the second diode D2;
the output end of the inverting proportion operational amplifier circuit is connected with the positive electrode of the second diode D2 and is used for inverting the current of the negative half period of the first output current;
and a second diode D2.
In a specific embodiment, a forward current in the first output current passes through the first diode D1, and then the negative half-cycle current is reversed through the inverting proportional operational amplifier circuit, that is, the original negative half-cycle is changed into a positive value and the original positive half-axis is changed into a negative value, and then the reversed current of the negative half-cycle of the first output current passes through the second diode D2; thus, the sampling waveforms of positive and negative half cycles are input to the input terminal of the current comparing circuit 103 while the magnitude of the sampling value is ensured to be unchanged.
According to the embodiment, the inversion of the current signal is realized through the cooperation of the inverse proportion operational amplifier circuit and the diode, only the differential mode signal exists, and the anti-interference capability is strong.
In some embodiments, the inverting proportional operational amplifier circuit includes:
the first end of the fifth resistor R5 is connected with the output end of the first sampling circuit 101, and the second end of the fifth resistor R5 is respectively connected with the first end of the sixth resistor R6 and the reverse input end of the second operational amplifier Q2;
the positive input end of the second operational amplifier Q2 is connected with the first end of the seventh resistor R7, and the output end of the second operational amplifier Q2 is respectively connected with the second end of the sixth resistor R6 and the positive electrode of the second diode D2;
a sixth resistor R6;
and the second end of the seventh resistor R7 is grounded.
In the embodiment, the second operational amplifier Q2 and the resistor are used for inverting the current of the negative half period of the first output current, wherein the fifth resistor R5 is used as an input resistor and the sixth resistor R6 is used as a feedback resistor to jointly form a proportional resistor, the voltage gain of the inverting proportional operational amplifier circuit is determined, the seventh resistor R7 is used as a balance resistor, the resistance value is equal to that of the fifth resistor R5, the effect of balancing the influence of the input bias current on the input signal voltage is achieved, the noise is low, the precision is high, the cost and the power consumption are low, and the cost performance and the anti-interference capability of the overcurrent detection circuit are improved.
In some embodiments, the current comparison circuit 103 includes:
the first end of the eighth resistor R8 is connected with a preset peak current input end, and the second end of the eighth resistor R8 is respectively connected with the first end of the ninth resistor R9 and the positive input end of the comparator Q3;
the reverse input end of the comparator Q3 is connected with the output end of the phase reversal circuit 102, and the output end of the comparator Q3 is connected with the overcurrent protection circuit 104 and is used for comparing the current output by the phase reversal circuit 102 with the preset peak current of the preset peak current input end;
and a second end of the ninth resistor R9 is grounded.
In a specific embodiment, the current output by the phase inversion circuit 102 is compared with a preset peak current at the preset peak current input end by the comparator Q3, wherein the current output by the phase inversion circuit 102 includes a peak current corresponding to a positive half period in a current signal output by the inverter and also includes a peak current corresponding to a negative half period after inversion, and as long as one of the two peak currents exceeds the preset peak current, the comparator Q3 converts a state of continuously outputting a high potential into outputting a low potential signal to trigger the overcurrent protection circuit 104 to perform a corresponding overcurrent protection operation.
In this embodiment, the comparison between the current output by the phase inversion circuit 102 and the preset peak current at the preset peak current input end is realized through the comparator Q3, which gives consideration to the sampling efficiency, the quality and precision of the sampling signal, and the cost, and meanwhile, the beneficial effects of high sampling efficiency, high sampling quality and low cost are obtained, and the reference voltage value at the preset peak current input end is divided through the eighth resistor R8 and the ninth resistor R9, so as to obtain the preset peak current, that is, the current is converted into the voltage, and then compared with the threshold voltage limiting the current through the comparator Q3, so that the speed is fast, the precision is high, and the connection is convenient.
Referring to fig. 5, fig. 5 is a schematic diagram illustrating a connection relationship of another overcurrent detection circuit according to an embodiment of the present utility model:
in some embodiments, further comprising:
and the input end of the second sampling circuit 105 is respectively connected with the output end of the first sampling circuit 101 and the input end of the phase reversal circuit 102, and the output end of the second sampling circuit 105 is connected with the digital signal controller and is used for acquiring the first output current of the inverter and lifting the first output current to be a second output current, and the current value of the second output current is a positive value.
Since the DSP (Digital Signal Processing ) cannot input negative voltage, the output voltage and current of the inverter can be sent to the DSP only through signal conditioning, that is, the first output current is lifted to the second output current by the second sampling circuit 105, and the current values of the second output current are all positive values, referring to fig. 6, fig. 6 is a waveform chart output by the second sampling circuit 105 according to the embodiment of the present utility model.
In this embodiment, the second sampling circuit 105 is used to raise the first output current of the inverter to the second output current, so that the DSP can detect the period and the current value of the current, and the reliability of the inverter is improved.
In some embodiments, the second sampling circuit 105 includes:
a tenth resistor R10, a first end of the tenth resistor R10 is connected to the reference voltage input terminal, and a second end of the tenth resistor R10 is connected to a second end of the eleventh resistor R11 and a positive input terminal of the third operational amplifier Q4, respectively;
an eleventh resistor R11, wherein a first end of the eleventh resistor R11 is connected to the output end of the first sampling circuit 101 and the input end of the phase inversion circuit 102, respectively;
a twelfth resistor R12, the first end of the twelfth resistor R12 is grounded, and the second end of the twelfth resistor R12 is connected to the inverting input end of the third operational amplifier Q4 and the first end of the thirteenth resistor R13, respectively;
the output end of the third operational amplifier Q4 is respectively connected with the second end of the thirteenth resistor R13 and the digital signal controller;
thirteenth resistor R13.
In this embodiment, the third operational amplifier Q4 and the resistor are matched to form the in-phase adder, so that the signal output by the third operational amplifier Q4 to the digital signal controller overlaps the ac amount sampled by the first sampling circuit 101 with the dc amount of the reference voltage, so that no phase difference is generated, the DSP is convenient to detect the period and the current value of the current, and the reliability of the inverter is improved.
In some embodiments, the second sampling circuit 105 further comprises:
and a first end of the second capacitor C2 is respectively connected with the first end of the tenth resistor R10 and the reference voltage input end, and a second end of the second capacitor C2 is respectively connected with the second end of the tenth resistor R10, the second end of the eleventh resistor R11 and the positive input end of the third operational amplifier Q4.
In the embodiment, the second capacitor C2 and the tenth resistor R10 are connected in parallel to form a high-pass filter, so as to realize a filtering function and improve the anti-interference capability of the second sampling circuit 105 in the process of sampling the reference voltage; prevent self-excitation and improve the safety of the circuit.
In some embodiments, the second sampling circuit 105 further comprises:
and a first end of the third capacitor C3 is connected to the first end of the thirteenth resistor R13 and the inverting input end of the third operational amplifier Q4, and a second end of the third capacitor C3 is connected to the second end of the thirteenth resistor R13, the output end of the third operational amplifier Q4, and the input end of the phase inversion circuit 102.
In the embodiment, the third capacitor C3 and the thirteenth resistor R13 are connected in parallel to form a high-pass filter, so that the filtering function is realized, and the anti-interference capability of the sampling circuit is improved; prevent self-excitation and improve the safety of the circuit.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant points refer to the description of the method section.
It should also be noted that in this specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present utility model. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the utility model. Thus, the present utility model is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. An overcurrent detection circuit, comprising:
the input end of the first sampling circuit is respectively connected with the forward output end and the reverse output end of an alternating current sensor in the inverter, and the output end of the first sampling circuit is connected with the input end of the phase inversion circuit and is used for obtaining a first output current of the inverter;
the output end of the phase reversal circuit is connected with the input end of the current comparison circuit, and is used for outputting the current of the positive half period of the first output current to the current comparison circuit, reversing the current of the negative half period of the first output current and outputting the reversed current to the current comparison circuit;
the output end of the current comparison circuit is connected with the overcurrent protection circuit and is used for comparing the current output by the phase reversal circuit with a preset peak current;
and the overcurrent protection circuit is used for carrying out overcurrent protection on the inverter when the current output by the phase reversal circuit is larger than a preset peak current.
2. The overcurrent detection circuit of claim 1, wherein the first sampling circuit comprises:
the first end of the first resistor is connected with the positive output end of the alternating current sensor in the inverter, and the second end of the first resistor is respectively connected with the positive input end of the first operational amplifier and the first end of the fourth resistor;
the first end of the second resistor is connected with the reverse output end of the alternating current sensor in the inverter, and the second end of the second resistor is respectively connected with the reverse input end of the first operational amplifier and the first end of the third resistor;
the output end of the first operational amplifier is respectively connected with the second end of the third resistor and the input end of the phase reversal circuit;
the third resistor;
and the second end of the fourth resistor is grounded.
3. The overcurrent detection circuit of claim 2, wherein the first sampling circuit further comprises:
the first end of the first capacitor is respectively connected with the first end of the third resistor, the reverse input end of the first operational amplifier and the second end of the second resistor, and the second end of the first capacitor is respectively connected with the second end of the third resistor, the output end of the first operational amplifier and the input end of the phase reversal circuit.
4. The overcurrent detection circuit of claim 1, wherein the phase inversion circuit comprises:
the positive electrode of the first diode is respectively connected with the output end of the first sampling circuit and the reverse input end of the reverse phase proportional operational amplifier circuit, and the negative electrode of the first diode is respectively connected with the input end of the current comparison circuit and the negative electrode of the second diode;
the output end of the inverting proportion operational amplifier circuit is connected with the positive electrode of the second diode and is used for inverting the current of the negative half period of the first output current;
the second diode.
5. The overcurrent detection circuit of claim 4, wherein the inverting proportional operational amplifier circuit comprises:
the first end of the fifth resistor is connected with the output end of the first sampling circuit, and the second end of the fifth resistor is respectively connected with the first end of the sixth resistor and the reverse input end of the second operational amplifier;
the positive input end of the second operational amplifier is connected with the first end of the seventh resistor, and the output end of the second operational amplifier is respectively connected with the second end of the sixth resistor and the positive electrode of the second diode;
the sixth resistor;
the second end of the seventh resistor is grounded.
6. The overcurrent detection circuit of claim 1, wherein the current comparison circuit comprises:
the first end of the eighth resistor is connected with the preset peak current input end, and the second end of the eighth resistor is respectively connected with the first end of the ninth resistor and the positive input end of the comparator;
the reverse input end of the comparator is connected with the output end of the phase reversal circuit, and the output end of the comparator is connected with the overcurrent protection circuit and is used for comparing the current output by the phase reversal circuit with the preset peak current of the preset peak current input end;
the second end of the ninth resistor is grounded.
7. The overcurrent detection circuit according to any one of claims 1 to 6, further comprising:
the input end of the second sampling circuit is respectively connected with the output end of the first sampling circuit and the input end of the phase inversion circuit, and the output end of the second sampling circuit is connected with the digital signal controller and is used for acquiring the first output current of the inverter and lifting the first output current to be a second output current, and the current value of the second output current is a positive value.
8. The overcurrent detection circuit of claim 7, wherein the second sampling circuit comprises:
a tenth resistor, wherein a first end of the tenth resistor is connected with the reference voltage input end, and a second end of the tenth resistor is respectively connected with a second end of the eleventh resistor and a positive input end of the third operational amplifier;
the first end of the eleventh resistor is connected with the output end of the first sampling circuit and the input end of the phase inversion circuit respectively;
a twelfth resistor, wherein a first end of the twelfth resistor is grounded, and a second end of the twelfth resistor is respectively connected with an inverted input end of the third operational amplifier and a first end of the thirteenth resistor;
the output end of the third operational amplifier is respectively connected with the second end of the thirteenth resistor and the digital signal controller;
the thirteenth resistor.
9. The overcurrent detection circuit of claim 8, wherein the second sampling circuit further comprises:
and the first end of the second capacitor is respectively connected with the first end of the tenth resistor and the reference voltage input end, and the second end of the second capacitor is respectively connected with the second end of the tenth resistor, the second end of the eleventh resistor and the positive input end of the third operational amplifier.
10. The overcurrent detection circuit of claim 8, wherein the second sampling circuit further comprises:
and the first end of the third capacitor is respectively connected with the first end of the thirteenth resistor and the reverse input end of the third operational amplifier, and the second end of the third capacitor is respectively connected with the second end of the thirteenth resistor, the output end of the third operational amplifier and the input end of the phase reversal circuit.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202322058878.8U CN220440374U (en) | 2023-08-02 | 2023-08-02 | Overcurrent detection circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322058878.8U CN220440374U (en) | 2023-08-02 | 2023-08-02 | Overcurrent detection circuit |
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