Output current sampling circuit of bidirectional charging pile

Abstract

This utility model relates to an output current sampling circuit for a bidirectional charging pile, comprising a current sampling circuit, a forward sampling current differential amplifier circuit, a reverse sampling current differential amplifier circuit, and a regulated output circuit. The current sampling circuit samples the current value between the bidirectional charging pile and the charging battery. The forward and reverse sampling current differential amplifier circuits identify the direction of the sampled current and transmit the forward charging current and reverse inverter current to the analog-to-digital converter (ADC) module for analog-to-digital conversion. The output current sampling circuit in this technical solution can achieve current sampling whether the bidirectional charging pile is operating in forward charging or reverse inverter mode. During charging pile operation, the output current sampling error is small, minimizing the error between the calculated sampled value and the actual current value to achieve high-precision sampling performance. When an overcurrent occurs in the charging pile, the output fuse can quickly blow to provide protection.

Description

Technical Field

[0001] This utility model relates to the field of bidirectional charging pile circuit technology, specifically to an output current sampling circuit for a bidirectional charging pile. Background Technology

[0002] Zero emissions give electric vehicles (EVs) excellent environmental performance, leading to their increasing adoption in people's lives. As the number of EVs increases, so does the demand for charging. To address the difficulties and high costs of charging for EV owners, installing bidirectional charging stations in locations such as supermarkets, residential areas, stadiums, and hotels can effectively alleviate these problems.

[0003] Bidirectional charging stations can not only replenish the energy of vehicles, but also feed the energy from electric vehicle batteries back into the power grid. This allows them to take advantage of electricity price differences, charging during off-peak hours and discharging during peak hours, thus saving on electricity bills. Unlike unidirectional DC charging stations, the output port network of a bidirectional charging station can serve as both a forward output port and an inverter input port, whereas the output current sampling circuit of a typical DC charging station cannot meet the requirement of sampling the bidirectional current value of the port. Utility Model Content

[0004] Therefore, it is necessary to provide an output current sampling circuit for a bidirectional charging pile that can achieve bidirectional current value sampling of input and output and has a simple circuit structure.

[0005] A current sampling circuit for a bidirectional charging pile is disclosed, used for sampling the bidirectional current value at the charging pile port. The circuit includes a current sampling circuit, a forward sampling current differential amplifier circuit, a reverse sampling current differential amplifier circuit, and a voltage regulated output circuit.

[0006] The current sampling circuit is connected between the charging pile port AGND_S and the negative terminal BAT- of the charging battery. The current sampling circuit is used to sample the current value between the charging pile and the charging battery. The current sampling circuit has an output terminal IOUT+.

[0007] The forward sampling current differential amplifier circuit is used to identify and output the forward charging current between the charging pile port AGND_S and the negative terminal BAT- of the charging battery;

[0008] The reverse sampling current differential amplifier circuit is used to identify and output the reverse inverter current between the negative terminal BAT- of the charging battery and the port AGND_S of the charging pile.

[0009] The input terminals of the forward sampling current differential amplifier circuit and the reverse sampling current differential amplifier circuit are respectively connected to the charging pile port AGND_S and the output terminal IOUT+ of the current sampling circuit;

[0010] The regulated output circuit is used to provide a reference voltage for the forward sampling current differential amplifier circuit and the reverse sampling current differential amplifier circuit, and the regulated output circuit has a reference voltage output terminal.

[0011] Preferably, the current sampling circuit includes a high-precision sampling resistor group, a common-mode inductor L9, and a fuse group connected in series. The high-precision sampling resistor group includes five milliohm-level high-precision sampling resistors RS1, RS2, RS3, RS4, and RS5 connected in parallel. The fuse group includes five fuses F1, F2, F3, F4, and F5 connected in parallel. A first RC filter circuit is connected in parallel to the high-precision sampling resistor group. The first RC filter circuit includes a seventy-eighth capacitor C78 and a three hundred and eighty-seventh resistor R378 connected in series. The output terminal IOUT+ of the current sampling circuit is located at the connection point of the seventy-eighth capacitor C78 and the three hundred and eighty-seventh resistor R378. An eighty-fifth capacitor C85 is provided between the high-precision sampling resistor group and the common-mode inductor L9, and the free end of the eighty-fifth capacitor C85 is grounded.

[0012] Preferably, the voltage regulation output circuit includes a three-terminal voltage regulator U46. The cathode of the three-terminal voltage regulator U46 is connected to a 5V reference voltage source through a current-limiting resistor R583. The anode of the three-terminal voltage regulator U46 is connected to the charging pile port AGND_S. The reference terminal of the three-terminal voltage regulator U46 is the reference voltage output terminal, and the output reference voltage value is 2.5VREF. A filter capacitor C519 is provided between the anode and the reference terminal of the three-terminal voltage regulator U46.

[0013] Preferably, the forward sampling current differential amplifier circuit includes a first differential amplifier U15-A, the positive input terminal of the first differential amplifier U15-A is connected to the output terminal IOUT+ of the current sampling circuit through a series connection of the forty-third inductor L43 and the five hundred and seventy-seventh resistor R577; the inverting input terminal of the first differential amplifier U15-A is connected to the charging pile port AGND_S through a series connection of the forty-fourth inductor L44 and the five hundred and seventy-eighth resistor R578.

[0014] The output terminal of the first differential amplifier U15-A is connected to the inverting input terminal of the first differential amplifier U15-A through the parallel connection of the 580th resistor R580 and the 518th capacitor C518; the output terminal of the first differential amplifier U15-A is connected to the output terminal IO_CTRP of the forward sampling current differential amplifier circuit through the series connection of the 56th resistor R56 and the 581st resistor R581.

[0015] Preferably, the positive input terminal of the first differential amplifier U15-A is connected to the charging pile port AGND_S through the parallel connection of the 579th resistor R579 and the 514th capacitor C514, and the positive input terminal of the first differential amplifier U15-A is connected to the reference voltage output terminal of the voltage regulator circuit through the 582nd resistor R582.

[0016] The positive input terminal of the first differential amplifier U15-A is also connected to a capacitor C517, which together with the resistor R577 forms a second RC filter circuit; the inverting input terminal of the first differential amplifier U15-A is also connected to a capacitor C513, which together with the resistor R578 forms a third RC filter circuit.

[0017] Preferably, the inverse sampling current differential amplifier circuit includes a second differential amplifier U15-B, the positive input terminal of the second differential amplifier U15-B is connected to the charging pile port AGND_S through a series connection of a forty-fifth inductor L45 and a fortyth resistor R40; the inverse input terminal of the second differential amplifier U15-B is connected to the output terminal IOUT+ of the current sampling circuit through a series connection of a forty-sixth inductor L46 and a forty-first resistor R41.

[0018] The output terminal of the second differential amplifier U15-B is connected to the inverting input terminal of the second differential amplifier U15-B through the parallel 42nd resistor R42 and the 226th capacitor C226; the output terminal of the second differential amplifier U15-B is connected to the output terminal IO_CTRN of the inverting sampling current differential amplifier circuit through the series 534th resistor R534 and the first resistor R1.

[0019] Preferably, the positive input terminal of the second differential amplifier U15-B is connected to the charging pile port AGND_S through the parallel 43rd resistor R43 and the 228th capacitor C228, and the positive input terminal of the second differential amplifier U15-B is connected to the reference voltage output terminal of the voltage regulator circuit through the 71st resistor R71.

[0020] The positive input terminal of the second differential amplifier U15-B is also connected to the second 224th capacitor C224, which together with the fortieth resistor R40 forms the fourth RC filter circuit; the inverting input terminal of the second differential amplifier U15-B is also connected to the second 225th capacitor C225, which together with the forty-first resistor R41 forms the fifth RC filter circuit.

[0021] In the aforementioned bidirectional charging pile's output current sampling circuit, the current sampling circuit is located between the bidirectional charging pile and the charging battery, used to sample the current value between the bidirectional charging pile and the charging battery. The forward sampling current differential amplifier circuit and the reverse sampling current differential amplifier circuit are used to identify the direction of the sampled current and transmit the forward charging current and reverse inverter current to the analog-to-digital converter (ADC) module for analog-to-digital conversion. The output current sampling circuit in this technical solution can achieve current sampling when the bidirectional charging pile is operating in either forward charging or reverse inverter mode. When the charging pile is operating, the output current sampling error is small, and the error between the calculated sample value and the actual current value is minimized to achieve high-precision sampling performance. When an overcurrent occurs in the charging pile, the output fuse can quickly blow to achieve protection. The circuit structure of this utility model is simple, easy to implement, low in cost, and easy to promote. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the current sampling circuit of the output current sampling circuit of the bidirectional charging pile according to an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of the circuit structure of the forward sampling current differential amplifier circuit of the output current sampling circuit of the bidirectional charging pile according to an embodiment of the present invention.

[0024] Figure 3 This is a schematic diagram of the circuit structure of the inverse sampling current differential amplifier circuit of the output current sampling circuit of the bidirectional charging pile according to an embodiment of the present invention.

[0025] Figure 4 This is a schematic diagram of the voltage regulation output circuit of the output current sampling circuit of the bidirectional charging pile according to an embodiment of the present invention. Detailed Implementation

[0026] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings.

[0027] Please see Figures 1 to 4 This paper illustrates an output current sampling circuit for a bidirectional charging pile, used for sampling the bidirectional current value at the charging pile port. The circuit includes a current sampling circuit, a forward sampling current differential amplifier circuit, a reverse sampling current differential amplifier circuit, and a voltage regulated output circuit.

[0028] The current sampling circuit is connected between the charging pile port AGND_S and the negative terminal BAT- of the charging battery. The current sampling circuit is used to sample the current value between the charging pile and the charging battery. The current sampling circuit has an output terminal IOUT+.

[0029] The forward sampling current differential amplifier circuit is used to identify and output the forward charging current between the charging pile port AGND_S and the negative terminal BAT- of the charging battery;

[0030] The reverse sampling current differential amplifier circuit is used to identify and output the reverse inverter current between the negative terminal BAT- of the charging battery and the port AGND_S of the charging pile.

[0031] The input terminals of the forward sampling current differential amplifier circuit and the reverse sampling current differential amplifier circuit are respectively connected to the charging pile port AGND_S and the output terminal IOUT+ of the current sampling circuit;

[0032] The regulated output circuit is used to provide a reference voltage for the forward sampling current differential amplifier circuit and the reverse sampling current differential amplifier circuit, and the regulated output circuit has a reference voltage output terminal.

[0033] Specifically, the reference voltage output terminal of the voltage regulator output circuit outputs 2.5VREF.

[0034] Preferably, please refer to Figure 1 The current sampling circuit includes a high-precision sampling resistor group, a common-mode inductor L9, and a fuse group connected in series. The high-precision sampling resistor group includes five milliohm-level high-precision sampling resistors RS1, RS2, RS3, RS4, and RS5 connected in parallel. The fuse group includes five fuses F1, F2, F3, F4, and F5 connected in parallel. A first RC filter circuit is connected in parallel to the high-precision sampling resistor group. The first RC filter circuit includes a seventy-eighth capacitor C78 and a three hundred and eighty-seventh resistor R378 connected in series. The output terminal IOUT+ of the current sampling circuit is located at the connection point of the seventy-eighth capacitor C78 and the three hundred and eighty-seventh resistor R378. An eighty-fifth capacitor C85 is provided between the high-precision sampling resistor group and the common-mode inductor L9, and the free end of the eighty-fifth capacitor C85 is grounded.

[0035] Specifically, the free end of the high-precision sampling resistor group is connected to the charging pile port AGND_S, and the free end of the fuse group is connected to the negative terminal BAT- of the charging battery; the common-mode inductor L9 is used to eliminate common-mode interference in the circuit; the eighty-fifth capacitor C85 is a Y capacitor and plays a filtering role; a seventy-first capacitor C71 is provided between the fuse group and the negative terminal BAT- of the charging battery, and the seventy-first capacitor C71 plays a filtering role.

[0036] Preferably, please refer to Figure 4The voltage regulation output circuit includes a three-terminal voltage regulator U46. The cathode of the three-terminal voltage regulator U46 is connected to a 5V reference voltage source through the 583rd current-limiting resistor R583. The anode of the three-terminal voltage regulator U46 is connected to the charging pile port AGND_S. The reference terminal of the three-terminal voltage regulator U46 is the reference voltage output terminal, and the output reference voltage value is 2.5VREF. A 519th filter capacitor C519 is provided between the anode and the reference terminal of the three-terminal voltage regulator U46.

[0037] Preferably, please refer to Figure 2 The forward sampling current differential amplifier circuit includes a first differential amplifier U15-A. The positive input terminal of the first differential amplifier U15-A is connected to the output terminal IOUT+ of the current sampling circuit through a series connection of the forty-third inductor L43 and the five-hundred-seventy-seventh resistor R577. The inverting input terminal of the first differential amplifier U15-A is connected to the charging pile port AGND_S through a series connection of the forty-fourth inductor L44 and the five-hundred-seventy-eighth resistor R578.

[0038] The output terminal of the first differential amplifier U15-A is connected to the inverting input terminal of the first differential amplifier U15-A through the parallel connection of the 580th resistor R580 and the 518th capacitor C518; the output terminal of the first differential amplifier U15-A is connected to the output terminal IO_CTRP of the forward sampling current differential amplifier circuit through the series connection of the 56th resistor R56 and the 581st resistor R581.

[0039] Specifically, the output terminal IO_CTRP of the forward sampling current differential amplifier circuit is connected to the analog-to-digital converter (ADC) module for analog-to-digital conversion to obtain the corresponding output current value.

[0040] Preferably, the positive input terminal of the first differential amplifier U15-A is connected to the charging pile port AGND_S through the parallel connection of resistor R579 (579) and capacitor C514 (514), and the positive input terminal of the first differential amplifier U15-A is connected to the reference voltage output terminal 2.5VREF of the voltage regulator output circuit through resistor R582 (582).

[0041] The positive input terminal of the first differential amplifier U15-A is also connected to a capacitor C517, which together with the resistor R577 forms a second RC filter circuit; the inverting input terminal of the first differential amplifier U15-A is also connected to a capacitor C513, which together with the resistor R578 forms a third RC filter circuit.

[0042] Specifically, the eighty-seventh capacitor C87 and the five hundred and sixteenth capacitor C516 are respectively provided at the two ends of the five hundred and eighty-first resistor R581; the five hundred and thirty-fifth capacitor C535 is provided between the connection point between the forty-third inductor L43 and the five hundred and seventy-seventh resistor R577 and the connection point between the forty-fourth inductor L44 and the five hundred and seventy-eighth resistor R578; the five hundred and fifteenth capacitor C515 is provided between the positive input terminal and the negative input terminal of the first differential amplifier U15-A; the eighty-seventh capacitor C87, the five hundred and sixteenth capacitor C516, the five hundred and thirty-fifth capacitor C535, the five hundred and fifteenth capacitor C515, the five hundred and eighteenth capacitor C518, and the five hundred and fourteenth capacitor C514 are used to filter interference signals in the circuit.

[0043] Preferably, please refer to Figure 3 The inverse sampling current differential amplifier circuit includes a second differential amplifier U15-B. The positive input terminal of the second differential amplifier U15-B is connected to the charging pile port AGND_S through a series connection of a forty-fifth inductor L45 and a fortyth resistor R40. The inverse input terminal of the second differential amplifier U15-B is connected to the output terminal IOUT+ of the current sampling circuit through a series connection of a forty-sixth inductor L46 and a forty-first resistor R41.

[0044] The output terminal of the second differential amplifier U15-B is connected to the inverting input terminal of the second differential amplifier U15-B through the parallel 42nd resistor R42 and the 226th capacitor C226; the output terminal of the second differential amplifier U15-B is connected to the output terminal IO_CTRN of the inverting sampling current differential amplifier circuit through the series 534th resistor R534 and the first resistor R1.

[0045] Specifically, the output terminal IO_CTRN of the reverse sampling current differential amplifier circuit is connected to the analog-to-digital converter (ADC) module for analog-to-digital conversion to obtain the corresponding output current value.

[0046] Preferably, the positive input terminal of the second differential amplifier U15-B is connected to the charging pile port AGND_S through the parallel 43rd resistor R43 and the 228th capacitor C228, and the positive input terminal of the second differential amplifier U15-B is connected to the reference voltage output terminal 2.5VREF of the voltage regulator output circuit through the 71st resistor R71.

[0047] The positive input terminal of the second differential amplifier U15-B is also connected to the second 224th capacitor C224, which together with the fortieth resistor R40 forms the fourth RC filter circuit; the inverting input terminal of the second differential amplifier U15-B is also connected to the second 225th capacitor C225, which together with the forty-first resistor R41 forms the fifth RC filter circuit.

[0048] Specifically, capacitors C188 (188th capacitor) and C106 (106th capacitor) are respectively provided at both ends of the first resistor R1; capacitor C536 (536th capacitor) is provided between the connection point between the forty-fifth inductor L45 and the fortieth resistor R40 and the connection point between the forty-sixth inductor L46 and the forty-first resistor R41; capacitor C105 (105th capacitor) is provided between the positive input terminal and the negative input terminal of the second differential amplifier U15-B; capacitors C188 (188th capacitor), C106 (106th capacitor), C536 (536th capacitor), C105 (105th capacitor), C226 (226th capacitor), and C228 (228th capacitor) are used to filter interference signals in the circuit.

[0049] Specifically, in this embodiment, the current flowing through the five parallel sampling resistors of the high-precision sampling resistor group generates a potential difference between the charging pile port AGND_S and the current sampling circuit output terminal IOUT+. This potential difference serves as the input signals Up and Un of the first differential amplifier U15-A or the second differential amplifier U15-B. Specifically, in the first differential amplifier U15-A, Up is IOUT+ and Un is AGND_S; in the second differential amplifier U15-B, Up is AGND_S and Un is IOUT+. For the first differential amplifier U15-A, based on the virtual open and virtual short characteristics of the operational amplifier, the following equation can be obtained:

[0050] (1);

[0051] (2);

[0052] (3).

[0053] In the voltage regulation output circuit, if a Vcc=5V voltage is provided to the three-terminal regulator U46, its reference voltage output terminal 2.5VREF will stably output a 2.5V voltage, so Vref is a stable 2.5V voltage.

[0054] Solving the above three equations together yields Uout. Then, through transmission resistors R56 and R581, the voltage value of Uout is transmitted to the ADC for digital-to-analog conversion, resulting in the corresponding output current value.

[0055] Similarly, the reverse sampling current differential amplifier circuit can perform the same calculations.

[0056] Specifically, when the bidirectional charging pile is working in the forward charging mode, the current flows from AGND_S to BAT- and out. At this time, for the first differential amplifier U15-A, Uout>0V, the first differential amplifier U15-A op-amp can output Uout normally. However, for the second differential amplifier U15-B, Uout<0V. Since the lowest level of the op-amp power supply is 0V, the second differential amplifier U15-B cannot output voltage normally and is in the cutoff state.

[0057] When the bidirectional charging pile is working in inverter mode, the current flows from BAT- to AGND_S. At this time, Uout>0V for the second differential amplifier U15-B, the second differential amplifier U15-B can output Uout normally, while Uout<0V for the first differential amplifier U15-A, so the first differential amplifier U15-A cannot output voltage normally and is in the cutoff state.

[0058] Because the output current sampling circuit of the bidirectional charging pile can both detect the output current of the charging pile in both working modes and achieve high-precision sampling performance.

[0059] In the aforementioned bidirectional charging pile's output current sampling circuit, the current sampling circuit is located between the bidirectional charging pile and the charging battery, used to sample the current value between the bidirectional charging pile and the charging battery. The forward sampling current differential amplifier circuit and the reverse sampling current differential amplifier circuit are used to identify the direction of the sampled current and transmit the forward charging current and reverse inverter current to the analog-to-digital converter (ADC) module for analog-to-digital conversion. The output current sampling circuit in this technical solution can achieve current sampling when the bidirectional charging pile is operating in either forward charging or reverse inverter mode. When the charging pile is operating, the output current sampling error is small, and the error between the calculated sample value and the actual current value is minimized to achieve high-precision sampling performance. When an overcurrent occurs in the charging pile, the output fuse can quickly blow to achieve protection. The circuit structure of this utility model is simple, easy to implement, low in cost, and easy to promote.

[0060] It should be noted that this utility model is not limited to the above-described embodiments. Based on the inventive spirit of this utility model, those skilled in the art can make other changes, and these changes made based on the inventive spirit of this utility model should be included within the scope of protection claimed by this utility model.

Claims

1. A bidirectional charging pile output current sampling circuit for sampling bidirectional current values of a bidirectional charging pile port, characterized in that, It includes a current sampling circuit, a forward sampling current differential amplifier circuit, a reverse sampling current differential amplifier circuit, and a regulated output circuit. The current sampling circuit is connected between the charging pile port AGND_S and the negative terminal BAT- of the charging battery. The current sampling circuit is used to sample the current value between the charging pile and the charging battery. The current sampling circuit has an output terminal IOUT+. The forward sampling current differential amplifier circuit is used to identify and output the forward charging current between the charging pile port AGND_S and the negative terminal BAT- of the charging battery; The reverse sampling current differential amplifier circuit is used to identify and output the reverse inverter current between the negative terminal BAT- of the charging battery and the port AGND_S of the charging pile. The input terminals of the forward sampling current differential amplifier circuit and the reverse sampling current differential amplifier circuit are respectively connected to the charging pile port AGND_S and the output terminal IOUT+ of the current sampling circuit; The regulated output circuit is used to provide a reference voltage for the forward sampling current differential amplifier circuit and the reverse sampling current differential amplifier circuit, and the regulated output circuit has a reference voltage output terminal.

2. The output current sampling circuit of the bidirectional charging pile according to claim 1, wherein, The current sampling circuit includes a high-precision sampling resistor group, a common-mode inductor L9, and a fuse group connected in series. The high-precision sampling resistor group includes five milliohm-level high-precision sampling resistors RS1, RS2, RS3, RS4, and RS5 connected in parallel. The fuse group includes five fuses F1, F2, F3, F4, and F5 connected in parallel. A first RC filter circuit is connected in parallel to the high-precision sampling resistor group. The first RC filter circuit includes a seventy-eighth capacitor C78 and a three hundred and eighty-seventh resistor R378 connected in series. The output terminal IOUT+ of the current sampling circuit is located at the connection point of the seventy-eighth capacitor C78 and the three hundred and eighty-seventh resistor R378. An eighty-fifth capacitor C85 is provided between the high-precision sampling resistor group and the common-mode inductor L9, and the free end of the eighty-fifth capacitor C85 is grounded.

3. The output current sampling circuit of the bidirectional charging pile according to claim 1, wherein, The voltage regulation output circuit includes a three-terminal voltage regulator U46. The cathode of the three-terminal voltage regulator U46 is connected to a 5V reference voltage source through the 583rd current-limiting resistor R583. The anode of the three-terminal voltage regulator U46 is connected to the charging pile port AGND_S. The reference terminal of the three-terminal voltage regulator U46 is the reference voltage output terminal, and the output reference voltage value is 2.5VREF. A 519th filter capacitor C519 is provided between the anode and the reference terminal of the three-terminal voltage regulator U46.

4. The output current sampling circuit of the bidirectional charging pile according to claim 1, wherein, The forward sampling current differential amplifier circuit includes a first differential amplifier U15-A. The positive input terminal of the first differential amplifier U15-A is connected to the output terminal IOUT+ of the current sampling circuit through a series connection of the forty-third inductor L43 and the five hundred and seventy-seventh resistor R577. The inverting input terminal of the first differential amplifier U15-A is connected to the charging pile port AGND_S through a series connection of the forty-fourth inductor L44 and the five hundred and seventy-eighth resistor R578. The output terminal of the first differential amplifier U15-A is connected to the inverting input terminal of the first differential amplifier U15-A through the parallel connection of the 580th resistor R580 and the 518th capacitor C518; the output terminal of the first differential amplifier U15-A is connected to the output terminal IO_CTRP of the forward sampling current differential amplifier circuit through the series connection of the 56th resistor R56 and the 581st resistor R581.

5. The output current sampling circuit of the bidirectional charging pile according to claim 4, wherein, The positive input terminal of the first differential amplifier U15-A is connected to the charging pile port AGND_S through the parallel 579 resistor R579 and 514 capacitor C514. The positive input terminal of the first differential amplifier U15-A is connected to the reference voltage output terminal of the voltage regulator circuit through the 582 resistor R582. The positive input terminal of the first differential amplifier U15-A is also connected to a capacitor C517, which together with the resistor R577 forms a second RC filter circuit; the inverting input terminal of the first differential amplifier U15-A is also connected to a capacitor C513, which together with the resistor R578 forms a third RC filter circuit.

6. The output current sampling circuit of the bidirectional charging pile according to claim 1, wherein, The reverse sampling current differential amplifier circuit includes a second differential amplifier U15-B. The positive input terminal of the second differential amplifier U15-B is connected to the charging pile port AGND_S through a series connection of the forty-fifth inductor L45 and the fortieth resistor R40. The inverting input terminal of the second differential amplifier U15-B is connected to the output terminal IOUT+ of the current sampling circuit through a series connection of the forty-sixth inductor L46 and the forty-first resistor R41. The output terminal of the second differential amplifier U15-B is connected to the inverting input terminal of the second differential amplifier U15-B through the parallel 42nd resistor R42 and the 226th capacitor C226; the output terminal of the second differential amplifier U15-B is connected to the output terminal IO_CTRN of the inverting sampling current differential amplifier circuit through the series 534th resistor R534 and the first resistor R1.

7. The output current sampling circuit of the bidirectional charging pile as described in claim 6, characterized in that, The positive input terminal of the second differential amplifier U15-B is connected to the charging pile port AGND_S through the parallel 43rd resistor R43 and the 228th capacitor C228. The positive input terminal of the second differential amplifier U15-B is connected to the reference voltage output terminal of the voltage regulator circuit through the 71st resistor R71. The positive input terminal of the second differential amplifier U15-B is also connected to the second 224th capacitor C224, which together with the fortieth resistor R40 forms the fourth RC filter circuit; the inverting input terminal of the second differential amplifier U15-B is also connected to the second 225th capacitor C225, which together with the forty-first resistor R41 forms the fifth RC filter circuit.

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