CN118487492A - Current sampling circuit applied to bidirectional converter and bidirectional converter - Google Patents
Current sampling circuit applied to bidirectional converter and bidirectional converter Download PDFInfo
- Publication number
- CN118487492A CN118487492A CN202410941422.2A CN202410941422A CN118487492A CN 118487492 A CN118487492 A CN 118487492A CN 202410941422 A CN202410941422 A CN 202410941422A CN 118487492 A CN118487492 A CN 118487492A
- Authority
- CN
- China
- Prior art keywords
- output end
- circuit
- negative
- sampling
- current
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000005070 sampling Methods 0.000 title claims abstract description 158
- 230000002457 bidirectional effect Effects 0.000 title abstract description 35
- 239000003990 capacitor Substances 0.000 claims description 27
- 230000000087 stabilizing effect Effects 0.000 claims description 4
- 238000010586 diagram Methods 0.000 description 19
- 238000004590 computer program Methods 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 230000006870 function Effects 0.000 description 6
- 238000012986 modification Methods 0.000 description 5
- 230000004048 modification Effects 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- 230000004075 alteration Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
Landscapes
- Measurement Of Current Or Voltage (AREA)
Abstract
The invention provides a current sampling circuit applied to a bidirectional converter and the bidirectional converter, wherein the sampling circuit comprises a positive half-wave rectifying circuit, a negative half-wave rectifying circuit and a sampling channel switching control circuit; the input end of the positive half-wave rectification circuit, the input end of the negative half-wave rectification circuit and the first input end of the sampling channel switching control circuit are respectively connected with the differential voltage output end; the positive channel output end of the positive half-wave rectification circuit and the negative channel output end of the negative half-wave rectification circuit are respectively connected with the second input end of the sampling channel switching control circuit; when the input current is positive, selecting the output end of the positive channel of the positive half-wave rectification circuit as output; and when the input current is negative, selecting a negative channel output end of the negative half-wave rectification circuit as output. Thereby reliably achieving accurate sampling of the full load segment.
Description
Technical Field
The invention relates to the technical field of power electronic equipment, in particular to a current sampling circuit applied to a bidirectional converter and the bidirectional converter.
Background
The bidirectional converter works in the principle that the bidirectional conversion of energy between two directions is realized by controlling the on and off of a switching device. The method has wide application fields in the field of energy conversion and control, in particular to an electric automobile, a solar power generation system, an energy storage system and the like. In these applications, the bi-directional converter can achieve efficient conversion and flexible switching of electrical energy, improving energy utilization and system stability.
The bidirectional converter has two working modes of positive and negative directions, and the working current of the bidirectional converter also has positive and negative directions. A classical BUCK/BOOST circuit is shown in fig. 1, which has a positive and negative sign due to the bi-directional operation mode, although its current inductance falls into the DC current range. Assuming that the inductor current in the BUCK/BOOST circuit of FIG. 1 is positive to the right and negative to the left; the peak value of the inductance current is 100A, the positive direction is 0A-100A, the negative direction is-100A-0A, the inductance current range is-100A to +100A, and compared with the unidirectional operation, the current range needs 2 times, and the current range reaches 200A. Fig. 2 is a schematic diagram of a conventional bi-directional current sampling circuit in the prior art. V_idc+ and v_idc-in fig. 2 are differential voltages from the corresponding currents of the current sensor of fig. 1, which are re-biased by 3.3V/2 via differential proportional circuits and fed into the AD sampling port of the DSP/MCU. Wherein, the voltage of the AD port corresponding to the current of-100A to 0A is 0 to 1.65V; the current of 0A-100A corresponds to the AD port voltage of 1.65V-3.3V. That is, the voltage of the AD port 0-3.3V corresponds to the measuring range of 200A, and the offset voltage of 3.3V/2 is required due to the existence of positive and negative current sampling, which leads to the increase of the measuring range; the increase in range will directly affect the accuracy of the sampling.
In order to solve the problem of poor sampling precision of the bidirectional current sampling circuit of fig. 2, the prior art proposes an improved bidirectional current sampling circuit of fig. 3, which adopts two independent sampling circuits with large and small ranges. When the current is greater than a certain specific threshold value, a wide-range current sampling circuit channel V_IDC_AD1 is used, and when the current is less than a certain specific threshold value, a small-range current sampling circuit channel V_IDC_AD2 is used (for example, -50A current uses a small-range sampling circuit, and-100A-50A and 50A-100A use a large-range sampling circuit); the sampling channel v_idc_ad1 or v_idc_ad2 is then selected by software.
The improved bidirectional current sampling circuit of fig. 3 has the fatal disadvantage that the sampling accuracy is improved as compared with the conventional scheme of fig. 2, because each of the AD ports corresponds to 100A range of 0-3.3 v: when the device works in a working condition that the load frequently fluctuates in a large range for a long time, the two current sampling channels with large and small measuring ranges need to be frequently switched, so that the current sampling precision cannot be improved, and even accurate current sampling cannot be realized. The bi-directional current sampling circuit of fig. 3 is thus not suitable for applications where the load frequently fluctuates widely.
Disclosure of Invention
The present invention aims to solve at least to some extent one of the technical problems in the above-described technology. Therefore, a first object of the present invention is to provide a current sampling circuit for a bidirectional converter, which can reliably realize full-load segment sampling; and the sampling precision of the full load section can be effectively improved.
The second object of the present invention is to provide a bidirectional converter, which can significantly improve the sampling precision of the full-load section, and is better applied to the scene of frequent and large-range fluctuation of load.
To achieve the above object, an embodiment of a first aspect of the present invention provides a current sampling circuit for a bidirectional converter, including: the sampling channel switching control circuit comprises a positive half-wave rectification circuit, a negative half-wave rectification circuit and a sampling channel switching control circuit; the input end of the positive half-wave rectification circuit, the input end of the negative half-wave rectification circuit and the first input end of the sampling channel switching control circuit are respectively connected with a differential voltage output end; the positive channel output end of the positive half-wave rectification circuit and the negative channel output end of the negative half-wave rectification circuit are respectively connected with the second input end of the sampling channel switching control circuit;
The sampling channel switching control circuit is configured to select the forward channel output end of the forward half-wave rectification circuit as output when the output current of the differential voltage output end is positive; and when the output current of the differential voltage output end is negative, selecting the negative channel output end of the negative half-wave rectification circuit as output.
According to the current sampling circuit applied to the bidirectional converter, the positive current and the negative current are independently sampled respectively, so that the range optimization of the sampling circuit is reduced by half, and the current sampling precision in the full load range can be effectively improved on the premise of not sacrificing the load range; meanwhile, the sampling channel switching control circuit which is purely controlled in an analog mode is matched to realize the automatic switching of the sampling channels for output according to positive and negative currents, the full-load section sampling can be reliably realized, and the structure is simple and practical.
In addition, the current sampling circuit for a bidirectional converter according to the embodiment of the present invention may further have the following additional technical features:
Optionally, the sampling channel switching control circuit comprises a comparator U5, a gating chip U6, a gating chip U7, an electrical interlocking circuit and a sampling output end; the positive electrode input end of the comparator U5 is connected with the differential voltage output end, the negative electrode input end is grounded, and the output end is connected with the electrical interlocking circuit; the first input end of the gating chip U6 is connected with the output end of the forward channel, the second input end of the gating chip U6 is connected with the electrical interlocking circuit, and the output end of the gating chip U6 is connected with the sampling output end; the first input end of the gating chip U7 is connected with the negative channel output end, the second input end of the gating chip U7 is connected with the electric interlocking circuit, and the output end of the gating chip U7 is connected with the sampling output end;
The comparator U5 is configured to judge whether the output current of the differential voltage output end is positive current or negative current;
The electrical interlocking circuit is configured to control the gating chip U6 to be conducted when the judgment result of the comparator U5 is forward current, and lock the gating chip U7 in a cut-off state; when the judgment result of the comparator U5 is negative current, the gating chip U7 is controlled to be conducted, and meanwhile the gating chip U6 is locked in a cut-off state.
Optionally, the electrical interlock circuit includes a transistor Q1 and a transistor Q2; the base electrode of the triode Q1 is respectively connected with the output end and the grounding end of the comparator U5, the emitter electrode is connected with the grounding end, and the collector electrode is respectively connected with the second input end of the gating chip U7, the power supply VCC and the base electrode of the triode Q2; the base electrode of the triode Q2 is connected with the collector electrode of the triode Q1, the emitter electrode is connected with the power supply VCC, and the collector electrode is respectively connected with the second input end and the grounding end of the gating chip U6.
Optionally, the sampling channel switching control circuit further includes a resistor R3; the resistor R3 is connected in parallel between the positive input and the output of the comparator U5.
Optionally, the sampling channel switching control circuit further includes a diode D5 and a voltage regulator ZD1; the cathode of the diode D5 is connected with the output end of the comparator U5, and the cathode is connected with the grounding end; the output end of the comparator U5 is connected with the electric interlocking circuit through the voltage stabilizing tube ZD 1.
Optionally, the forward half-wave rectification circuit includes an operational amplifier U2, an operational amplifier U3, a diode D1, and a diode D2; the negative input end of the operational amplifier U2 is connected with the differential voltage output end, the positive input end is connected with the grounding end, and the output end is connected with the cathode of the diode D2; the anode of the diode D2 is respectively connected with the grounding end, the negative electrode input end and the positive electrode input end of the operational amplifier U3; the output end of the operational amplifier U3 is used as a forward channel output end; the anode of the diode D1 is connected with the output end of the operational amplifier U2, and the cathode is connected with the negative input end of the operational amplifier U2.
Optionally, the negative half-wave rectification circuit includes an operational amplifier U4, a diode D3, and a diode D4; the negative input end of the operational amplifier U4 is connected with the differential voltage output end, the positive input end is connected with the grounding end, and the output end is connected with the anode of the diode D4; the cathode of the diode D4 is connected with the grounding end and is used as a negative channel output end; the anode of the diode D3 is connected with the negative input end of the operational amplifier U4, and the cathode is connected with the output end of the operational amplifier U4.
Optionally, a differential circuit is also included; the input end of the differential circuit is connected with the output end of the Hall current sensor HCT or the output end of the current transformer CT, and the output end is used as the differential voltage output end.
Optionally, the differential circuit includes an input terminal v_idc+, an input terminal v_idc-, an operational amplifier U1, a capacitor C2, a resistor R1, a resistor R2, and a resistor R3; the input end V_IDC+ is connected with the positive electrode input end of the operational amplifier U1; the input end V_IDC-is connected with the negative electrode input end of the operational amplifier U1; one end of the capacitor C1 is grounded after the capacitor C1 and the capacitor R1 are connected in parallel, and the other end of the capacitor C1 is connected with the positive input end of the operational amplifier U1; one end of the capacitor C2 and one end of the capacitor R2 are connected in parallel, and then the other end of the capacitor C2 is connected with the negative input end of the operational amplifier U1, and the other end of the capacitor C2 is connected with the output end of the operational amplifier U1; the output end of the operational amplifier U1 is used as the differential voltage output end.
In order to achieve the above object, a second embodiment of the present invention provides a bidirectional converter, which includes a current sampling circuit for the bidirectional converter.
According to the bidirectional converter provided by the embodiment, the current sampling circuit provided by the embodiment is adopted, so that full-load section sampling can be reliably realized; and the sampling precision of the full load section can be effectively improved. Thus being better applied to the scene of frequent and wide-range fluctuation of load.
Drawings
FIG. 1 is a schematic diagram of a typical BUCK/BOOST circuit in the prior art;
FIG. 2 is a schematic diagram of a conventional bidirectional current sampling circuit in the prior art;
FIG. 3 is a schematic diagram of a prior art improved bidirectional current sampling circuit;
Fig. 4 is a schematic diagram of a circuit module of a current sampling circuit applied to a bidirectional converter according to an embodiment of the present invention;
FIG. 5 is a diagram illustrating sampling of A, C and D-point voltages when a current sampling circuit according to an embodiment of the present invention samples BUCK/BOOST forward inductor current;
FIG. 6 is a diagram illustrating exemplary sampling voltages at A, C and D points when a current sampling circuit according to an embodiment of the present invention samples BUCK/BOOST negative inductor current;
FIG. 7 is a schematic diagram of a circuit structure of a current sampling circuit for a bi-directional converter according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of a Hall (HCT) output as an input to a differential circuit in an embodiment of the invention;
FIG. 9 is a schematic diagram of a Current Transformer (CT) output as an input to a differential circuit in accordance with an embodiment of the present invention;
Fig. 10 is a diagram showing an example of sampling voltages at A, C points and D points when an alternating AC current is sampled by the current sampling circuit according to the embodiment of the present invention.
Reference numerals illustrate:
100. a current sampling circuit;
101. a forward half-wave rectifier circuit;
102. a negative half-wave rectification circuit;
103. a sampling channel switching control circuit;
31. An electrical interlock circuit;
104. a differential circuit.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.
Compared with the prior art, the method and the device determine the sampling by using a sampling circuit with a large/small range through comparison with a threshold value, and can not only improve the sampling precision and even realize accurate current sampling when working in a large-range frequent fluctuation working condition of a load for a long time.
In order that the above-described aspects may be better understood, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
In order to better understand the above technical solutions, the following detailed description will refer to the accompanying drawings and specific embodiments.
Fig. 4 is a schematic diagram of a circuit module of a current sampling circuit applied to a bidirectional converter according to an embodiment of the present invention.
As shown in fig. 4, an embodiment of the present invention provides a current sampling circuit 100 for a bidirectional converter, including: a positive half-wave rectifier circuit 101, a negative half-wave rectifier circuit 102, and a sampling channel switching control circuit 103; the input end of the positive half-wave rectification circuit 101, the input end of the negative half-wave rectification circuit 102 and the first input end of the sampling channel switching control circuit 103 are respectively connected with a differential voltage output end; the positive channel output end of the positive half-wave rectification circuit 101 and the negative channel output end of the negative half-wave rectification circuit 102 are respectively connected with the second input end of the sampling channel switching control circuit 103;
The positive half-wave rectification circuit is configured to filter a negative half wave of the input current and output a positive half wave when the output current of the differential voltage output end is positive;
the negative half-wave rectification circuit is configured to filter positive half waves of the input current and turn the negative half waves into positive half waves for output processing when the output current of the differential voltage output end is negative;
The sampling channel switching control circuit is configured to select the forward channel output end of the forward half-wave rectification circuit as output when the output current of the differential voltage output end is positive; and when the output current of the differential voltage output end is negative, selecting the negative channel output end of the negative half-wave rectification circuit as output.
The current sampling circuit applied to the bidirectional converter provided by the embodiment has the following working principle:
(1) When the output current of the differential voltage output end is positive, the voltage V_A of the point A is larger than 0; at the moment, the negative half-wave rectification circuit is cut off and does not work, and the voltage V_D=0 of the point D at the output end of the negative channel; the forward half-wave rectification circuit conducts work, negative half waves are filtered out of input current, positive half waves are output, and voltage V_C=K×V_A at a point C of an output end of a forward channel is processed; the sampling channel switching control circuit selects a forward channel output terminal of the forward half-wave rectification circuit as an output, i.e., v_i_dc_ad=v_c+v_d=k×v_a.
Taking the BUCK/BOOST forward inductor current as an example, k=1, and the point a is the sampling voltage corresponding to the positive inductor current, the sampling examples of the point a voltage, the point C voltage and the point D voltage are shown in fig. 5.
(2) When the output current of the differential voltage output end is negative, the voltage V_A of the point A is smaller than 0; at the moment, the forward half-wave rectification circuit is cut off and does not work, and the voltage V_C=0 at the point C of the output end of the forward channel; the negative half-wave rectification circuit conducts, positive half waves are filtered out of input current, the negative half waves are turned over to be positive half waves, then output processing is carried out, and the voltage V_C= -K multiplied by V_A at the point D of the output end of the negative channel; the sampling channel switching control circuit selects a negative channel output end of the negative half-wave rectification circuit as an output, namely V_I_DC_AD=V_C+V_D= -K×V_A.
Taking the negative inductor current of BUCK/BOOST, k=1 as an example, and the point a is the sampling voltage corresponding to the negative inductor current, the sampling examples of the point a voltage, the point C voltage and the point D voltage are shown in fig. 6.
The current sampling circuit applied to the bidirectional converter can automatically match a corresponding positive half-wave rectifying circuit/negative half-wave rectifying circuit according to positive/negative directions of input current sampling to rectify and output the rectified current, the voltage of 0-3.3V of an AD port of an output end corresponds to a measuring range of 100A, the measuring range is reduced to half of the original range, and the current sampling precision in a full-load range is effectively improved on the premise of not sacrificing the load measuring range; furthermore, a gating mode adopting pure analog control is combined, so that accurate sampling of the full-load section is reliably realized, the sampling precision of the full-load section is effectively improved, and the method is simple, reliable and practical.
Preferably, the forward half-wave rectification circuit in this embodiment is a forward precise half-wave rectification circuit; the negative-direction half-wave rectification circuit is a negative-direction precise half-wave rectification circuit, so that the influence of diode voltage drop in the voltage sampling process is removed to the greatest extent, the accuracy of sampling is ensured, and the high-precision rectification requirement of voltage sampling is better adapted.
In some implementations of the present embodiment, as shown in fig. 7, the sampling channel switching control circuit 103 includes a comparator U5, a strobe chip U6, a strobe chip U7, an electrical interlock circuit 31, and a sampling output terminal v_i_dc_ad; the positive input end of the comparator U5 is connected with the differential voltage output end, the negative input end is grounded, and the output end is connected with the electrical interlocking circuit 31; the first input end of the gating chip U6 is connected with the output end of the forward channel, the second input end of the gating chip U6 is connected with the electrical interlocking circuit 31, and the output end of the gating chip U6 is connected with the sampling output end; the first input end of the gating chip U7 is connected with the negative channel output end, the second input end is connected with the electric interlocking circuit 31, and the output end is connected with the sampling output end V_I_DC_AD;
The comparator U5 is configured to judge whether the output current of the differential voltage output end is positive current or negative current;
The electrical interlocking circuit is configured to control the gating chip U6 to be conducted when the judgment result of the comparator U5 is forward current, and lock the gating chip U7 in a cut-off state; when the judgment result of the comparator U5 is negative current, the gating chip U7 is controlled to be conducted, and meanwhile the gating chip U6 is locked in a cut-off state. That is, the two-way multiplexing strobe chip U6 and strobe chip U7 can only be selectively turned on under the control of the electrical interlock circuit, so that only one sampling channel can be used as an output at the same time.
As a specific example, as shown in fig. 7, the electrical interlock circuit 31 is mainly composed of a transistor Q1 and a transistor Q2; the base electrode of the triode Q1 is respectively connected with the output end and the grounding end of the comparator U5, the emitter electrode is connected with the grounding end, and the collector electrode is respectively connected with the second input end of the gating chip U7, the power supply VCC and the base electrode of the triode Q2; the base electrode of the triode Q2 is connected with the collector electrode of the triode Q1, the emitter electrode is connected with the power supply VCC, and the collector electrode is respectively connected with the second input end and the grounding end of the gating chip U6.
The working principle of the sampling channel switching control circuit is as follows:
(1) When the output current of the differential voltage output end is forward current, the sampling voltage corresponding to the point A is positive, the output of the comparator U5 is high, the triode Q1 is conducted, the second input end CS_EN_2 of the gating chip U7 is low, and the gating chip U7 is turned off; simultaneously, the triode Q2 is conducted, the second input end CS_EN_1 of the gating chip U6 is set high, and the gating chip U6 is turned on; at this time, the voltage at the output terminal point C of the forward half-wave rectification circuit is the final output voltage, i.e., v_idc_ad=v_c.
(2) When the output current of the differential voltage output end is negative current, the sampling voltage corresponding to the point A is negative, the output of the comparator U5 is low, the triode Q1 is cut off, the second input end CS_EN_2 of the gating chip U7 is high, and the gating chip U7 is turned on; meanwhile, the triode Q2 is cut off, the second input end CS_EN_1 of the gating chip U6 is set low, and the gating chip U6 is cut off; the D-point voltage of the negative half-wave rectifier circuit is the final output voltage, i.e., v_idc_ad=v_d.
The sampling channel switching control circuit realizes that only one sampling channel is used as output at the same time through an electric interlocking circuit formed by the triode Q1 and the triode Q2. That is, the sampling channel switching control circuit functions to control which one of the channels is used as an output according to the positive and negative directions of the current.
In summary, the operating principle of the sampling channel switching control circuit can be summarized as follows:
When the input current is sampled positively, the gating chip U6 is turned on, the gating chip U7 is turned off, and the forward rectifying channel is used as a final output V_IDC_AD=V_C;
when the input current sample is negative, the gating chip U6 is turned off, the gating chip U7 is turned on, and the negative rectification channel serves as the final output v_idc_ad=v_d.
As yet another specific example, the sampling channel switching control circuit further includes a resistor R3; the resistor R3 is connected in parallel between the positive input and the output of the comparator U5.
Here, the resistor R3 can be used as a feedback voltage to increase positive feedback in the comparator U5 to generate a return difference, so that the influence of frequent automatic switching of the sampling channel on the sampling precision can be effectively avoided, and the anti-interference effect is achieved.
Specifically, when the input current of the current sampling circuit is sampled to 0, that is, when the a-point sampling voltage is 0 or is in an idle state close to 0, positive feedback is added to the comparator U5 to generate a return difference, so that the positive channel output voltage v_c of the positive half-wave rectification circuit and the negative channel output voltage v_d of the negative half-wave rectification circuit are both close to 0, and at this time, the final output v_idc_ad=v_c+v_d=0, no matter which sampling channel is selected, the final sampling value is not affected.
As still another specific example, as shown in fig. 7, the sampling channel switching control circuit further includes a diode D5 and a regulator tube ZD1; the cathode of the diode D5 is connected with the output end of the comparator U5, and the cathode is connected with the grounding end; the output end of the comparator U5 is connected with the electric interlocking circuit through the voltage stabilizing tube ZD 1.
Here, the diode D5 is used for clamping to ensure that the output of the comparator U5 is equal to or greater than the GND level; the voltage stabilizing tube ZD1 is used for limiting output voltage anti-interference processing and avoiding misleading of the triode Q1.
In further specific implementations of the present embodiment, as shown in fig. 7, the forward half-wave rectification circuit 101 includes an operational amplifier U2, an operational amplifier U3, a diode D1, and a diode D2; the negative input end of the operational amplifier U2 is connected with the differential voltage output end, the positive input end is connected with the grounding end, and the output end is connected with the cathode of the diode D2; the anode of the diode D2 is respectively connected with the grounding end, the negative electrode input end and the positive electrode input end of the operational amplifier U3; the output end of the operational amplifier U3 is used as a forward channel output end; the anode of the diode D1 is connected with the output end of the operational amplifier U2, and the cathode is connected with the negative input end of the operational amplifier U2.
The working principle of the forward half-wave rectification circuit is as follows:
(1) When the output current of the differential voltage output end is in the forward direction, the sampling voltage V_A corresponding to the point A is larger than 0, the diode D1 is turned off, the diode D2 is turned on, the operational amplifier U2 is equivalent to an inverse proportion operational amplifier circuit, and the point B voltage V_B= -K multiplied by V_A; after the operational amplifier U3 performs the inverse proportion operational amplification processing, the voltage V_C= -V_B=K×V_A of the point C at the output end;
(2) When the output current of the differential voltage output end is negative, the sampling voltage V_A corresponding to the point A is smaller than 0, the diode D1 is turned on, the diode D2 is turned off, and the point B voltage is clamped to be 0, namely V_B=0; after the inverting proportion operational amplifier of the U3 operational amplifier is processed, the voltage V_C= -V_B=0 at the point C of the output end;
Thus, the negative half wave (negative half wave clamp output is 0) in the input current is removed by the processing of the positive half wave rectifying circuit, and only the positive half wave is output.
In yet other implementations of this embodiment, as shown in fig. 7, the negative half-wave rectifier circuit 102 includes an operational amplifier U4, a diode D3, and a diode D4; the negative input end of the operational amplifier U4 is connected with the differential voltage output end, the positive input end is connected with the grounding end, and the output end is connected with the anode of the diode D4; the cathode of the diode D4 is connected with the grounding end and is used as a negative channel output end; the anode of the diode D3 is connected with the negative input end of the operational amplifier U4, and the cathode is connected with the output end of the operational amplifier U4.
The working principle of the negative half-wave rectification circuit is as follows:
(1) When the output current of the differential voltage output end is in the forward direction, the sampling voltage V_A corresponding to the point A is larger than 0, the diode D3 is turned on, the diode D4 is turned off, the voltage of the point D is clamped to be 0, and V_D=0;
(2) When the output current of the differential voltage output end is negative, the sampling voltage V_A corresponding to the point A is smaller than 0, the diode D3 is turned off, the diode D4 is turned on, the operational amplifier U4 is equivalent to an inverting proportion operational amplifier circuit, and the voltage V_D= -K multiplied by V_A of the point D; the negative voltage is flipped positive.
Therefore, through the processing of the negative half-wave rectifying circuit, the positive half wave (the positive half-wave clamping output is 0) in the input current is removed, and only the negative half wave is inverted to be output after being positive.
In still other embodiments, the current sampling circuit for a bidirectional converter according to the present embodiment, as shown in fig. 7, further includes a differential circuit 104; the input end of the differential circuit 104 is connected with the output end of the hall current sensor HCT or the output end of the current transformer CT, and the output end is used as the differential voltage output end and is respectively connected with the positive half-wave rectifying circuit 101, the negative half-wave rectifying circuit 102 and the sampling channel switching control circuit 103.
The inputs of the differential circuit here comprise v_idc+ and v_idc-. The v_idc+ and v_idc-i.e. direct outputs from Hall (HCT) as shown in fig. 8; or from the output of a Current Transformer (CT), as shown in fig. 9. The output of the Hall (HCT) is a voltage signal, and the current transformer CT is finally converted into a voltage signal through a sampling resistor. The voltage signals are the voltage differences between the input terminals v_idc+ and v_idc-of the differential circuit.
The input terminals v_idc+ and v_idc-of the differential circuit will first go through a first differential ratio to obtain the voltage at point a. The current is positive and negative, and the voltage at the point A is also positive and negative. When the current is positive, the sampling voltage corresponding to the point A is positive; when the current is negative, the sampling voltage corresponding to the point A is negative.
As a specific example, the differential circuit includes an input terminal v_idc+, an input terminal v_idc-, an operational amplifier U1, a capacitor C2, a resistor R1, a resistor R2, and a resistor R3; the input end V_IDC+ is connected with the positive electrode input end of the operational amplifier U1; the input end V_IDC-is connected with the negative electrode input end of the operational amplifier U1; one end of the capacitor C1 is grounded after the capacitor C1 and the capacitor R1 are connected in parallel, and the other end of the capacitor C1 is connected with the positive input end of the operational amplifier U1; one end of the capacitor C2 and one end of the capacitor R2 are connected in parallel, and then the other end of the capacitor C2 is connected with the negative input end of the operational amplifier U1, and the other end of the capacitor C2 is connected with the output end of the operational amplifier U1; the output end of the operational amplifier U1 is used as the differential voltage output end.
Further, in the present embodiment, it is preferable that U1 to U5 are operational amplifiers supplied with dual power supplies; u6 and U7 are strobe chips multiplexed in two ways.
Referring to fig. 10, fig. 10 is a diagram illustrating sampling of voltages at A, C points and D points when an alternating AC current is sampled by a current sampling circuit according to an embodiment of the present invention.
The invention is further developed based on the embodiment, and is applied to sampling alternating AC current.
An LLC resonant cavity AC current, 100kHz alternating sine wave, is exemplified below.
The working principle of the current sampling circuit provided according to the above embodiment is as follows: V_I_DC/u ad=v_c+v d= | -K x v_a|; the 100kHz alternating sine wave passes through two independent precise half-wave rectification sampling circuits to obtain 200kHz positive half-wave, the positive half-wave is sent to the AD port, and the DSP/MCU can accurately realize sampling. In the present embodiment, examples of sampling of the point a voltage, the point C voltage, and the point D voltage are shown in fig. 10.
The embodiment of the invention also provides a bidirectional converter based on the embodiment, which comprises the current sampling circuit applied to the bidirectional converter. The specific structure of the current sampling circuit is not repeated here, and reference is made to the description of the above embodiments for details.
In summary, the current sampling circuit applied to the bidirectional converter and the bidirectional converter provided by the invention can be used for independently sampling by matching the corresponding positive/negative half-wave rectifying circuit according to the positive/negative phases of the input current, and the two precise half-wave rectifying circuits are innovatively integrated, so that the respective measuring ranges can be effectively reduced to improve the sampling precision; the sampling channel switching control circuit which is further combined with analog control realizes automatic switching of the sampling channels for output according to positive and negative currents, thereby realizing reliable full-load section sampling; and meanwhile, the sampling precision of the full-load section is effectively improved.
It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
It should be noted that in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The use of the words first, second, third, etc. do not denote any order. These words may be interpreted as names.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
In the description of the present invention, it should be understood that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.
In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms should not be understood as necessarily being directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.
Claims (10)
1. A current sampling circuit for a bi-directional converter, comprising: the sampling channel switching control circuit comprises a positive half-wave rectification circuit, a negative half-wave rectification circuit and a sampling channel switching control circuit; the input end of the positive half-wave rectification circuit, the input end of the negative half-wave rectification circuit and the first input end of the sampling channel switching control circuit are respectively connected with a differential voltage output end; the positive channel output end of the positive half-wave rectification circuit and the negative channel output end of the negative half-wave rectification circuit are respectively connected with the second input end of the sampling channel switching control circuit;
The sampling channel switching control circuit is configured to select the forward channel output end of the forward half-wave rectification circuit as output when the output current of the differential voltage output end is positive; and when the output current of the differential voltage output end is negative, selecting the negative channel output end of the negative half-wave rectification circuit as output.
2. The current sampling circuit for a bi-directional converter according to claim 1, wherein said sampling channel switching control circuit comprises a comparator U5, a strobe chip U6, a strobe chip U7, an electrical interlock circuit and a sampling output terminal; the positive electrode input end of the comparator U5 is connected with the differential voltage output end, the negative electrode input end is grounded, and the output end is connected with the electrical interlocking circuit; the first input end of the gating chip U6 is connected with the output end of the forward channel, the second input end of the gating chip U6 is connected with the electrical interlocking circuit, and the output end of the gating chip U6 is connected with the sampling output end; the first input end of the gating chip U7 is connected with the negative channel output end, the second input end of the gating chip U7 is connected with the electric interlocking circuit, and the output end of the gating chip U7 is connected with the sampling output end;
The comparator U5 is configured to judge whether the output current of the differential voltage output end is positive current or negative current;
The electrical interlocking circuit is configured to control the gating chip U6 to be conducted when the judgment result of the comparator U5 is forward current, and lock the gating chip U7 in a cut-off state; when the judgment result of the comparator U5 is negative current, the gating chip U7 is controlled to be conducted, and meanwhile the gating chip U6 is locked in a cut-off state.
3. A current sampling circuit for a bi-directional converter according to claim 2, wherein said electrical interlock circuit comprises a transistor Q1 and a transistor Q2; the base electrode of the triode Q1 is respectively connected with the output end and the grounding end of the comparator U5, the emitter electrode is connected with the grounding end, and the collector electrode is respectively connected with the second input end of the gating chip U7, the power supply VCC and the base electrode of the triode Q2; the base electrode of the triode Q2 is connected with the collector electrode of the triode Q1, the emitter electrode is connected with the power supply VCC, and the collector electrode is respectively connected with the second input end and the grounding end of the gating chip U6.
4. A current sampling circuit for a bi-directional converter according to claim 2, wherein said sampling channel switching control circuit further comprises a resistor R3; the resistor R3 is connected in parallel between the positive input and the output of the comparator U5.
5. A current sampling circuit for a bi-directional converter according to claim 2, wherein said sampling channel switching control circuit further comprises a diode D5 and a regulator tube ZD1; the cathode of the diode D5 is connected with the output end of the comparator U5, and the cathode is connected with the grounding end; the output end of the comparator U5 is connected with the electric interlocking circuit through the voltage stabilizing tube ZD 1.
6. The current sampling circuit for a bi-directional converter according to claim 1, wherein said forward half-wave rectifier circuit comprises an operational amplifier U2, an operational amplifier U3, a diode D1 and a diode D2; the negative input end of the operational amplifier U2 is connected with the differential voltage output end, the positive input end is connected with the grounding end, and the output end is connected with the cathode of the diode D2; the anode of the diode D2 is respectively connected with the grounding end, the negative electrode input end and the positive electrode input end of the operational amplifier U3; the output end of the operational amplifier U3 is used as a forward channel output end; the anode of the diode D1 is connected with the output end of the operational amplifier U2, and the cathode is connected with the negative input end of the operational amplifier U2.
7. The current sampling circuit for a bi-directional converter according to claim 1, wherein said negative half-wave rectifier circuit comprises an operational amplifier U4, a diode D3 and a diode D4; the negative input end of the operational amplifier U4 is connected with the differential voltage output end, the positive input end is connected with the grounding end, and the output end is connected with the anode of the diode D4; the cathode of the diode D4 is connected with the grounding end and is used as a negative channel output end; the anode of the diode D3 is connected with the negative input end of the operational amplifier U4, and the cathode is connected with the output end of the operational amplifier U4.
8. The current sampling circuit for a bi-directional converter of claim 1 further comprising a differential circuit; the input end of the differential circuit is connected with the output end of the Hall current sensor HCT or the output end of the current transformer CT, and the output end is used as the differential voltage output end.
9. The current sampling circuit for a bi-directional converter according to claim 8, wherein said differential circuit comprises an input v_idc+, an input v_idc-, an operational amplifier U1, a capacitor C2, a resistor R1, a resistor R2, and a resistor R3; the input end V_IDC+ is connected with the positive electrode input end of the operational amplifier U1; the input end V_IDC-is connected with the negative electrode input end of the operational amplifier U1; one end of the capacitor C1 is grounded after the capacitor C1 and the capacitor R1 are connected in parallel, and the other end of the capacitor C1 is connected with the positive input end of the operational amplifier U1; one end of the capacitor C2 and one end of the capacitor R2 are connected in parallel, and then the other end of the capacitor C2 is connected with the negative input end of the operational amplifier U1, and the other end of the capacitor C2 is connected with the output end of the operational amplifier U1; the output end of the operational amplifier U1 is used as the differential voltage output end.
10. A bi-directional converter comprising a current sampling circuit as claimed in any one of claims 1 to 9 for use in a bi-directional converter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410941422.2A CN118487492A (en) | 2024-07-15 | 2024-07-15 | Current sampling circuit applied to bidirectional converter and bidirectional converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202410941422.2A CN118487492A (en) | 2024-07-15 | 2024-07-15 | Current sampling circuit applied to bidirectional converter and bidirectional converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN118487492A true CN118487492A (en) | 2024-08-13 |
Family
ID=92198279
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202410941422.2A Pending CN118487492A (en) | 2024-07-15 | 2024-07-15 | Current sampling circuit applied to bidirectional converter and bidirectional converter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN118487492A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5461305A (en) * | 1992-06-10 | 1995-10-24 | Samsung Electronics Co., Ltd. | Preprocessing circuit for measuring signal envelope flatness degree in a reproducer |
| JP2006078184A (en) * | 2004-09-07 | 2006-03-23 | Hioki Ee Corp | Current integration method and its system |
| WO2008028948A1 (en) * | 2006-09-08 | 2008-03-13 | Continental Automotive Gmbh | Circuit arrangement und method for converting a signal |
| CN111614230A (en) * | 2020-06-05 | 2020-09-01 | 深圳市艾博尔电源技术有限公司 | Precise voltage sampling circuit and sampling method |
| CN220933379U (en) * | 2023-10-31 | 2024-05-10 | 先勒动力控制技术(上海)有限公司 | Interlocking circuit and forklift control system |
-
2024
- 2024-07-15 CN CN202410941422.2A patent/CN118487492A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5461305A (en) * | 1992-06-10 | 1995-10-24 | Samsung Electronics Co., Ltd. | Preprocessing circuit for measuring signal envelope flatness degree in a reproducer |
| JP2006078184A (en) * | 2004-09-07 | 2006-03-23 | Hioki Ee Corp | Current integration method and its system |
| WO2008028948A1 (en) * | 2006-09-08 | 2008-03-13 | Continental Automotive Gmbh | Circuit arrangement und method for converting a signal |
| CN111614230A (en) * | 2020-06-05 | 2020-09-01 | 深圳市艾博尔电源技术有限公司 | Precise voltage sampling circuit and sampling method |
| CN220933379U (en) * | 2023-10-31 | 2024-05-10 | 先勒动力控制技术(上海)有限公司 | Interlocking circuit and forklift control system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103152946B (en) | A kind of high efficiency LED drive circuit | |
| US8773879B2 (en) | Bridgeless PFC circuit system having current sensing circuit and controlling method thereof | |
| CN205753986U (en) | PFC segmentation booster circuit and Switching Power Supply | |
| CN103108470A (en) | Dynamic linear control light emitting diode (LED) driver circuit | |
| CN103516188A (en) | Active bleeder, active bleeding method, and power supply device where the active bleeder is applied | |
| US9997994B1 (en) | Totem-pole power factor corrector and current-sampling unit thereof | |
| CN209419485U (en) | Booster system response speed translation circuit based on PFM control | |
| CN109617412A (en) | Booster system response speed translation circuit and its control method based on PFM control | |
| CN111327186A (en) | Inductive current zero-crossing detection method of bridgeless power factor correction circuit | |
| US20230089905A1 (en) | Bridgeless power factor correction pfc circuit | |
| CN109496016B (en) | Low-frequency ripple suppression method for high-power-factor LED driving power supply | |
| CN203072226U (en) | Dynamic-linear-control LED driving circuit | |
| CN111405708B (en) | Bleeder control system, silicon controlled rectifier dimming phase angle detection circuit and method | |
| CN103036457A (en) | Alternating-current/direct-current converter | |
| CN108271285B (en) | LED dimming driving circuit with closed loop architecture and switching power supply | |
| CN118487492A (en) | Current sampling circuit applied to bidirectional converter and bidirectional converter | |
| CN112217390A (en) | Fast dynamic response CRM boost PFC converter based on controllable current source | |
| CN116155116A (en) | Bidirectional DC-DC converter with wide-range output | |
| CN100491921C (en) | Voltage sense circuit and method therefor | |
| CN108271286B (en) | LED dimming driving circuit and switching power supply | |
| CN100517927C (en) | Three-phase power supply parallel feedforward compensation power factor correction circuit | |
| CN103560662A (en) | PFC control method and control device | |
| CN103513104A (en) | Dimming angle sensing circuit, dimming angle sensing method, and power supply device comprising the dimming angle sensing circuit | |
| CN216216530U (en) | Transistor-based switching power supply | |
| CN1086615A (en) | Be applicable to the module parallel power factor correcting method and the device of arbitrary load |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |