CN118487492B - Current sampling circuit used in bidirectional converter, bidirectional converter - Google Patents
Current sampling circuit used in bidirectional converter, bidirectional converter Download PDFInfo
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- CN118487492B CN118487492B CN202410941422.2A CN202410941422A CN118487492B CN 118487492 B CN118487492 B CN 118487492B CN 202410941422 A CN202410941422 A CN 202410941422A CN 118487492 B CN118487492 B CN 118487492B
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- 238000005070 sampling Methods 0.000 title claims abstract description 158
- 230000002457 bidirectional effect Effects 0.000 title claims abstract description 43
- 239000003990 capacitor Substances 0.000 claims description 15
- 230000000087 stabilizing effect Effects 0.000 claims description 5
- 238000010586 diagram Methods 0.000 description 19
- 238000004590 computer program Methods 0.000 description 7
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/14—Indicating direction of current; Indicating polarity of voltage
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0009—Devices or circuits for detecting current in a converter
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of DC power input into DC power output
- H02M3/02—Conversion of DC power input into DC power output without intermediate conversion into AC
- H02M3/04—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters
- H02M3/10—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/158—Conversion of DC power input into DC power output without intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
- H02M3/1582—Buck-boost converters
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Abstract
本发明提供运用于双向变换器的电流采样电路、双向变换器，采样电路包括正向半波整流电路、负向半波整流电路以及采样通道切换控制电路；正向半波整流电路的输入端、负向半波整流电路的输入端和采样通道切换控制电路的第一输入端分别与差分电压输出端连接；正向半波整流电路的正向通道输出端和负向半波整流电路的负向通道输出端分别与采样通道切换控制电路的第二输入端连接；当输入电流为正时，选择正向半波整流电路的正向通道输出端作为输出；当输入电流为负时，选择负向半波整流电路的负向通道输出端作为输出。由此可靠地实现全负载段的精准采样。
The present invention provides a current sampling circuit and a bidirectional converter for use in a bidirectional converter, wherein the sampling circuit comprises a positive half-wave rectifier circuit, a negative half-wave rectifier circuit and a sampling channel switching control circuit; the input end of the positive half-wave rectifier circuit, the input end of the negative half-wave rectifier circuit and the first input end of the sampling channel switching control circuit are respectively connected to the differential voltage output end; the positive channel output end of the positive half-wave rectifier circuit and the negative channel output end of the negative half-wave rectifier circuit are respectively connected to the second input end of the sampling channel switching control circuit; when the input current is positive, the positive channel output end of the positive half-wave rectifier circuit is selected as the output; when the input current is negative, the negative channel output end of the negative half-wave rectifier circuit is selected as the output. Thus, accurate sampling of the full load section can be reliably achieved.
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. The inductance current in the BUCK/BOOST circuit in FIG. 1 is assumed to be positive to the right and negative to the left, the peak value of the inductance current is 100A, the positive value is 0A-100A, the negative value is-100A-0A, the inductance current range is-100A, and compared with the unidirectional operation, the inductance current range needs 2 times of the current range, 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 current of-100A-0A corresponds to the voltage of the AD port to be 0-1.65V, and the current of 0A-100A corresponds to the voltage of the AD port to be 1.65V-3.3V. That is, the voltage of 0-3.3V of the AD port corresponds to a measuring range of 200A, and a bias voltage of 3.3V/2 is required due to positive and negative current sampling, which leads to an increase in the measuring range, and the increase in the measuring range directly affects the accuracy of 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 threshold, a wide-range current sampling circuit channel V_IDC_AD1 is used, and when the current is less than a certain threshold, 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), and then the sampling channel V_IDC_AD1 or V_IDC_AD2 is selected by software.
In the improved bidirectional current sampling circuit shown in fig. 3, since each AD port corresponds to 100A range from 0 v to 3.3v, the sampling accuracy is improved in comparison with the conventional scheme shown in fig. 2, but the bidirectional current sampling circuit has the fatal disadvantage that when the bidirectional current sampling circuit works in a working condition of a large-range frequent fluctuation of load for a long time, two current sampling channels with large and small ranges need to be frequently switched, so that the current sampling accuracy 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 not only can reliably realize full-load segment sampling, but also can effectively improve the precision of full-load segment sampling.
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.
In order to achieve the above purpose, an embodiment of a first aspect of the present invention provides a current sampling circuit for a bidirectional converter, including a positive half-wave rectifying circuit, a negative half-wave rectifying circuit, and a sampling channel switching control circuit, where an input end of the positive half-wave rectifying circuit, an input end of the negative half-wave rectifying circuit, and a first input end of the sampling channel switching control circuit are respectively connected with a differential voltage output end;
The sampling channel switching control circuit is configured to select the positive channel output end of the positive half-wave rectification circuit as output when the output current of the differential voltage output end is positive, and select the negative channel output end of the negative half-wave rectification circuit as output when the output current of the differential voltage output end is negative.
According to the current sampling circuit applied to the bidirectional converter, independent sampling is carried out on positive and negative currents respectively, the range of the sampling circuit is optimized, 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 analog to control is matched to realize the output according to the positive and negative currents and automatically switch the sampling channels, 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:
The sampling channel switching control circuit comprises a comparator U5, a gating chip U6, a gating chip U7, an electric interlocking circuit and a sampling output end, wherein the positive electrode input end of the comparator U5 is connected with a differential voltage output end, the negative electrode input end of the comparator U5 is grounded, the output end of the comparator U is connected with the electric interlocking circuit, the first input end of the gating chip U6 is connected with the positive channel output end, the second input end of the gating chip U6 is connected with the electric interlocking circuit, the output 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, the output end of the gating chip U7 is connected with the sampling output end, the first input end of the sampling channel switching control circuit is the positive electrode input end of the comparator U5, and the second input end of the sampling channel switching control circuit comprises the first input end of the gating chip U6 and the first input end of the gating chip U7;
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 and lock the gating chip U7 in an off state when the judgment result of the comparator U5 is positive current, and control the gating chip U7 to be conducted and lock the gating chip U6 in the off state when the judgment result of the comparator U5 is negative current.
Optionally, the electrical interlock circuit includes a triode Q1 and a triode Q2, where a base electrode of the triode Q1 is connected with an output end and a ground end of the comparator U5, an emitter electrode is connected with the ground end, a collector electrode is connected with a second input end of the gating chip U7, a power supply VCC and a base electrode of the triode Q2, a base electrode of the triode Q2 is connected with a collector electrode of the triode Q1, an emitter electrode is connected with the power supply VCC, and a collector electrode is connected with a second input end of the gating chip U6 and the ground end.
Optionally, the sampling channel switching control circuit further comprises a resistor R1, wherein the resistor R1 is connected in parallel between the positive input end and the output end of the comparator U5.
Optionally, the sampling channel switching control circuit further comprises a diode D5 and a voltage stabilizing tube ZD1, wherein the cathode of the diode D5 is connected with the output end of the comparator U5, the anode is connected with the ground, and the output end of the comparator U5 is connected with the electrical interlocking circuit again through the voltage stabilizing tube ZD 1.
The positive half-wave rectifier circuit comprises an operational amplifier U2, an operational amplifier U3, a diode D1 and a diode D2, wherein the negative input end of the operational amplifier U2 is connected with a differential voltage output end, the positive input end of the operational amplifier U2 is connected with a grounding end, the output end of the operational amplifier is connected with the cathode of the diode D2, the anode of the diode D2 is respectively connected with the grounding end through a first resistor and the negative input end of the operational amplifier U3 through a second resistor, the positive input end of the operational amplifier U3 is connected with the grounding end through a third resistor, the negative input end of the operational amplifier U3 is connected with the output end of the operational amplifier U3 through a fourth resistor, the output end of the operational amplifier U3 serves as a positive channel output end, the anode of the diode D1 is connected with the output end of the operational amplifier U2, and the cathode of the diode D1 is connected with the negative input end of the operational amplifier U2.
Optionally, the negative half-wave rectification circuit comprises an operational amplifier U4, a diode D3 and a diode D4, wherein 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 ground end, the output end is connected with the anode of the diode D4, the cathode of the diode D4 is connected with the ground 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, the device further comprises a differential circuit, wherein 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.
The differential circuit comprises an input end V_IDC+, an input end V_IDC-, an operational amplifier U1, a capacitor C2, a resistor R4, a resistor R2 and a resistor R3, wherein 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 and the resistor R4 are connected in parallel and then grounded, the other end of the capacitor C1 and the resistor R4 are connected with the positive electrode input end of the operational amplifier U1, one end of the capacitor C2 and one end of the resistor R2 are connected with the negative electrode input end of the operational amplifier U1 in parallel, the other end of the capacitor C2 and the output end of the operational amplifier U1 are connected 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 can reliably realize full-load section sampling, and can effectively improve the precision of full-load section sampling. 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, the embodiment of the invention provides a current sampling circuit 100 applied to a bidirectional converter, which comprises a positive half-wave rectifying circuit 101, a negative half-wave rectifying circuit 102 and a sampling channel switching control circuit 103, wherein the input end of the positive half-wave rectifying circuit 101, the input end of the negative half-wave rectifying 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 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 positive channel output end of the positive half-wave rectification circuit as output when the output current of the differential voltage output end is positive, and select the negative channel output end of the negative half-wave rectification circuit as output when the output current of the differential voltage output end is negative.
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 and the voltage V_A of the point A is larger than 0, the negative half-wave rectifying circuit is cut off and does not work, the positive half-wave rectifying circuit is conducted and works to filter negative half waves of the input current and output positive half waves, the voltage V_C of the point C of the positive channel output end is multiplied by V_A, and the sampling channel switching control circuit selects the positive channel output end of the positive half-wave rectifying circuit as output, namely V_I_DC_AD=V_C+V_D=K multiplied by 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 and the voltage V_A of the point A is smaller than 0, the positive half-wave rectifying circuit is cut off and does not work, the negative half-wave rectifying circuit is conducted and works, the input current is filtered to remove positive half waves and turn over negative half waves to be positive half waves and then output, the voltage V_C= -KXV_A of the point D of the negative channel is output, and the sampling channel switching control circuit selects the negative channel output end of the negative half-wave rectifying circuit as output, namely V_I_DC_AD=V_C+V_D= -KXV_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 at 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, the current sampling precision in a full-load range is effectively improved on the premise of not sacrificing the load measuring range, and a gating mode adopting pure analog control is further 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 current sampling circuit is simple, reliable and practical.
The positive half-wave rectification circuit is a positive precise half-wave rectification circuit, and the negative half-wave rectification circuit is a negative 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 embodiments of the present embodiment, as shown in fig. 7, the sampling channel switching control circuit 103 includes a comparator U5, a gating chip U6, a gating chip U7, an electrical interlock circuit 31, and a sampling output terminal v_i_dc_ad, where an anode input terminal of the comparator U5 is connected to a differential voltage output terminal, a cathode input terminal is grounded, an output terminal is connected to the electrical interlock circuit 31, a first input terminal of the gating chip U6 is connected to the forward channel output terminal, a second input terminal is connected to the electrical interlock circuit 31, an output terminal is connected to the sampling output terminal, a first input terminal of the gating chip U7 is connected to the negative channel output terminal, a second input terminal is connected to the electrical interlock circuit 31, and an output terminal is connected to the sampling output terminal 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 and lock the gating chip U7 in an off state when the judgment result of the comparator U5 is positive current, and control the gating chip U7 to be conducted and lock the gating chip U6 in the off state when the judgment result of the comparator U5 is negative current. 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 mainly includes a triode Q1 and a triode Q2, wherein a base electrode of the triode Q1 is connected with an output end and a ground end of the comparator U5 respectively, an emitter electrode of the triode is connected with the ground end, a collector electrode of the triode is connected with a second input end of the gating chip U7, a power supply VCC and a base electrode of the triode Q2 respectively, a base electrode of the triode Q2 is connected with a collector electrode of the triode Q1, an emitter electrode of the triode is connected with the power supply VCC, and a collector electrode of the triode is connected with a second input end of the gating chip U6 and the ground end respectively.
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 corresponding A point sampling voltage 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, the gating chip U7 is turned off, meanwhile, the triode Q2 is conducted, the second input end CS_EN_1 of the gating chip U6 is high, the gating chip U6 is turned on, and the point C voltage of the output end C of the forward half-wave rectifying circuit is the final output voltage, namely V_IDC_AD=V_C.
(2) When the output current of the differential voltage output end is negative current, the corresponding A point sampling voltage 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, the gating chip U7 is on, meanwhile, the triode Q2 is cut off, the second input end CS_EN_1 of the gating chip U6 is low, the gating chip U6 is off, and the D point voltage of the negative half-wave rectification circuit is the final output voltage, namely 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 R1, the resistor R1 being connected in parallel between the positive input terminal and the output terminal of the comparator U5.
Here, the resistor R1 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 yet another specific example, as shown in fig. 7, the sampling channel switching control circuit further includes a diode D5 and a voltage regulator ZD1, wherein a cathode of the diode D5 is connected to an output terminal of the comparator U5, an anode of the diode D5 is connected to a ground terminal, and an output terminal of the comparator U5 is further connected to the electrical interlock circuit via the voltage regulator ZD 1.
The diode D5 is used for clamping to ensure that the output of the comparator U5 is greater than or equal to the GND level, and the voltage stabilizing tube ZD1 is used for limiting the anti-interference processing of the output voltage and avoiding misleading of the triode Q1.
In some embodiments of the present disclosure, as shown in fig. 7, the forward half-wave rectifier 101 includes an operational amplifier U2, an operational amplifier U3, a diode D1, and a diode D2, where a negative input terminal of the operational amplifier U2 is connected to a differential voltage output terminal, a positive input terminal is connected to a ground terminal, an output terminal is connected to a cathode of the diode D2, an anode of the diode D2 is connected to the ground terminal through a first resistor and to a negative input terminal of the operational amplifier U3 through a second resistor, a positive input terminal of the operational amplifier U3 is connected to the ground terminal through a third resistor, a negative input terminal of the operational amplifier U3 is connected to an output terminal thereof through a fourth resistor, an output terminal of the operational amplifier U3 is used as a forward channel output terminal, an anode of the diode D1 is connected to an output terminal of the operational amplifier U2, and a cathode of the diode D2 is connected to a negative input terminal 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 positive, the sampling voltage V_A of the corresponding point A is larger than 0, the diode D1 is cut off, the diode D2 is conducted, the operational amplifier U2 is equivalent to an inverting proportion operational amplifier circuit, and the point B voltage V_B= -KXV_A is processed by the inverting proportion operational amplifier U3;
(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 voltage at the point B is clamped to be 0, namely V_B=0;
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 some embodiments of the present disclosure, as shown in fig. 7, the negative half-wave rectifier 102 includes an operational amplifier U4, a diode D3, and a diode D4, where the negative input terminal of the operational amplifier U4 is connected to the differential voltage output terminal, the positive input terminal is connected to the ground terminal, the output terminal is connected to the anode of the diode D4, the cathode of the diode D4 is connected to the ground terminal and is also used as a negative channel output terminal, and the anode of the diode D3 is connected to the negative input terminal of the operational amplifier U4, and the cathode is connected to the output terminal 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, the voltage V_D= -K multiplied by V_A at the point D, and the negative voltage is turned to be 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 specific embodiments, the current sampling circuit for a bidirectional converter provided in this embodiment, as shown in fig. 7, further includes a differential circuit 104, where an input end of the differential circuit 104 is connected to an output end of the hall current sensor HCT or an output end of the current transformer CT, and an output end of the differential circuit is used as the differential voltage output end and is connected to the positive half-wave rectifier circuit 101, the negative half-wave rectifier circuit 102, and the sampling channel switching control circuit 103, respectively.
The inputs of the differential circuit here comprise v_idc+ and v_idc-. The v_idc+ and v_idc-can be either direct outputs from the Hall (HCT) as shown in fig. 8 or outputs from the 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, and when the current is negative, the sampling voltage corresponding to the point A is negative.
As a specific example, the differential circuit comprises an input end V_IDC+, an input end V_IDC-, an operational amplifier U1, a capacitor C2, a resistor R4, a resistor R2 and a resistor R3, wherein the input end V_IDC+ is connected with the positive input end of the operational amplifier U1, the input end V_IDC-is connected with the negative input end of the operational amplifier U1, one end of the capacitor C1 and the resistor R4 are connected in parallel and then grounded, the other end of the capacitor C1 and the resistor R4 are connected with the positive input end of the operational amplifier U1, one end of the capacitor C2 and one end of the resistor R2 are connected with the negative input end of the operational amplifier U1 in parallel, the other end of the capacitor C2 and the output end of the operational amplifier U1 are connected 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, and U6 and U7 are strobe chips multiplexed by two.
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.
According to the working principle of the current sampling circuit provided by the embodiment, V_I_DC_AD=V_C+V_D= | -K×V_A|, and a 100kHz alternating sine wave is fed into an AD port after passing through two independent precise half-wave rectification sampling circuits to obtain a 200kHz positive half-wave, so that 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 circuits according to the positive/negative phases of the input current, and can effectively reduce the respective measuring range to improve the sampling precision due to creatively integrating the two precise half-wave rectifying circuits, and further realize the automatic switching of the sampling channels according to the positive/negative currents for output by combining the sampling channel switching control circuit of analog control, thereby realizing the reliable realization of the full-load section sampling, and simultaneously effectively improving the sampling precision of the full-load section.
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, mechanically connected, electrically connected, directly connected, indirectly connected via an intervening medium, or in communication between two elements or in an interaction relationship between 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 (9)
1. The current sampling circuit applied to the bidirectional converter is characterized by comprising a positive half-wave rectifying circuit, a negative half-wave rectifying circuit and a sampling channel switching control circuit, wherein the input end of the positive half-wave rectifying circuit, the input end of the negative half-wave rectifying circuit and the first input end of the sampling channel switching control circuit are respectively connected with a differential voltage output end;
The sampling channel switching control circuit is configured to select the positive channel output end of the positive half-wave rectification circuit as output when the output current of the differential voltage output end is positive, and select the negative channel output end of the negative half-wave rectification circuit as output when the output current of the differential voltage output end is negative;
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, wherein the positive electrode input end of the comparator U5 is connected with a differential voltage output end, the negative electrode input end of the comparator U5 is grounded, the output end of the comparator U5 is connected with the electrical interlocking circuit, the first input end of the gating chip U6 is connected with the positive channel output end, the second input end of the gating chip U6 is connected with the electrical interlocking circuit, the output 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 electrical interlocking circuit, the output end of the gating chip U7 is connected with the sampling output end, the first input end of the sampling channel switching control circuit is the positive electrode input end of the comparator U5, and the second input end of the sampling channel switching control circuit comprises the first input end of the gating chip U6 and the first input end of the gating chip U7;
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 and lock the gating chip U7 in an off state when the judgment result of the comparator U5 is positive current, and control the gating chip U7 to be conducted and lock the gating chip U6 in the off state when the judgment result of the comparator U5 is negative current.
2. The current sampling circuit for a bidirectional converter according to claim 1, wherein the electrical interlock circuit comprises a triode Q1 and a triode Q2, wherein a base electrode of the triode Q1 is respectively connected with an output end and a grounding end of the comparator U5, an emitter electrode is connected with the grounding end, a collector electrode is respectively connected with a second input end of the gating chip U7, a power supply VCC and a base electrode of the triode Q2, a base electrode of the triode Q2 is connected with a collector electrode of the triode Q1, an emitter electrode is connected with the power supply VCC, and a collector electrode is respectively connected with a second input end of the gating chip U6 and the grounding end.
3. The current sampling circuit for a bi-directional converter of claim 1 wherein said sampling channel switching control circuit further comprises a resistor R1, said resistor R1 being connected in parallel between the positive input and the output of said comparator U5.
4. The current sampling circuit for a bidirectional converter according to claim 1, wherein the sampling channel switching control circuit further comprises a diode D5 and a voltage stabilizing tube ZD1, wherein a cathode of the diode D5 is connected with an output end of the comparator U5, an anode of the diode D5 is connected with a ground end, and an output end of the comparator U5 is connected with the electrical interlocking circuit again through the voltage stabilizing tube ZD 1.
5. The current sampling circuit for a bidirectional converter according to claim 1, wherein the forward half-wave rectifying circuit comprises an operational amplifier U2, an operational amplifier U3, a diode D1 and a diode D2, wherein a negative input end of the operational amplifier U2 is connected with a differential voltage output end, a positive input end is connected with a grounding end, an output end is connected with a cathode of the diode D2, an anode of the diode D2 is connected with the grounding end through a first resistor and a negative input end of the operational amplifier U3 through a second resistor respectively, a positive input end of the operational amplifier U3 is connected with the grounding end through a third resistor, a negative input end of the operational amplifier U3 is connected with an output end of the operational amplifier U3 through a fourth resistor, an output end of the operational amplifier U3 serves as a forward channel output end, an anode of the diode D1 is connected with an output end of the operational amplifier U2, and a cathode of the diode D1 is connected with a negative input end of the operational amplifier U2.
6. The current sampling circuit for a bidirectional converter according to claim 1, wherein the negative half-wave rectifier circuit comprises an operational amplifier U4, a diode D3 and a diode D4, wherein the negative input end of the operational amplifier U4 is connected with a differential voltage output end, the positive input end is connected with a ground end, the output end is connected with the anode of the diode D4, the cathode of the diode D4 is connected with the ground end and serves 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.
7. The current sampling circuit for a bi-directional converter according to claim 1, further comprising a differential circuit, wherein an input terminal of the differential circuit is connected to an output terminal of the hall current sensor HCT or an output terminal of the current transformer CT, and an output terminal of the differential circuit is used as the differential voltage output terminal.
8. The current sampling circuit for a bidirectional converter according to claim 7, wherein the differential circuit comprises an input terminal v_idc+, an input terminal v_idc-, an operational amplifier U1, a capacitor C2, a resistor R4, a resistor R2 and a resistor R3, wherein the input terminal v_idc+ is connected to the positive input terminal of the operational amplifier U1, the input terminal v_idc-is connected to the negative input terminal of the operational amplifier U1, one end of the capacitor C1 and the resistor R4 are connected in parallel and then grounded, the other end of the capacitor C1 and the resistor R4 are connected to the positive input terminal of the operational amplifier U1, one end of the capacitor C2 and one end of the resistor R2 are connected in parallel and then connected to the negative input terminal of the operational amplifier U1, the other end of the capacitor C2 is connected to the output terminal of the operational amplifier U1, and the output terminal of the operational amplifier U1 is used as the differential voltage output terminal.
9. A bi-directional converter comprising a current sampling circuit as claimed in any one of claims 1 to 8 for use in a bi-directional converter.
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| 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 | A kind of precision 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 |
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| JP2006078184A (en) * | 2004-09-07 | 2006-03-23 | Hioki Ee Corp | Current integrating method and apparatus |
| CN205544368U (en) * | 2016-01-21 | 2016-08-31 | 易事特集团股份有限公司 | An uninterruptible power supply with bidirectional current detection circuit |
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|---|---|---|---|---|
| US5461305A (en) * | 1992-06-10 | 1995-10-24 | Samsung Electronics Co., Ltd. | Preprocessing circuit for measuring signal envelope flatness degree in a reproducer |
| 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 | A kind of precision 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 |
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