A bidirectional ACDC power supply circuit

Abstract

The utility model provides a bidirectional ACDC power supply circuit, which belongs to the field of power supply circuits. The utility model bidirectional ACDC power supply circuit includes a rectifier inverter circuit, a bidirectional DC conversion circuit, and an MCU main control circuit, and is characterized in that: the MCU main control circuit includes an MCU and an AC current sampling module, an AC voltage sampling module, and a bus voltage sampling module respectively connected to the MCU input end, the input end of the AC current sampling module and the input end of the AC current sampling module are respectively connected to the AC voltage end of the rectifier inverter circuit, and are used to collect the AC voltage and AC current of the rectifier inverter circuit, the input end of the bus voltage sampling module is connected between the rectifier inverter circuit and the bidirectional DC conversion circuit, and is used to collect the bus DC voltage, and the bus voltage sampling module adopts an isolated optocoupler for isolated sampling. The utility model improves the safety of the MCU main control circuit in collecting various current and voltage signals.

Description

Technical Field

[0001] The utility model relates to the field of power supply circuits, in particular to a bidirectional ACDC power supply circuit. Background Art

[0002] With the development of energy storage technology, more and more energy storage application solutions are used in our real life. Bidirectional ACDC power supply has been widely used in household energy storage and portable outdoor energy storage. As the main component, the bidirectional ACDC power supply needs to rely on the relevant input and output voltage and current information parameters in the circuit to participate in the control to achieve stable and reliable output of the circuit. These related parameters must be sampled and isolated to convert the strong electric signal into a weak electric signal to the MCU to participate in the control, so as to ensure the safety of the MCU. However, most of the current solutions are implemented by high-resistance isolation. This method only weakens the strong electric signal and does not achieve complete electrical isolation. Therefore, the existing sampling circuit needs to be improved. Utility Model Content

[0003] In order to solve the problems in the prior art, the utility model provides a bidirectional ACDC power supply circuit.

[0004] The utility model discloses a bidirectional ACDC power supply circuit, comprising a rectifier inverter circuit, a bidirectional DC conversion circuit, and an MCU main control circuit. The MCU main control circuit comprises an MCU and an AC current sampling module, an AC voltage sampling module, and a bus voltage sampling module respectively connected to an input end of the MCU. The input end of the AC current sampling module and the input end of the AC current sampling module are respectively connected to an AC voltage end of the rectifier inverter circuit, and are used to collect the AC voltage and AC current of the rectifier inverter circuit. The input end of the bus voltage sampling module is connected between the rectifier inverter circuit and the bidirectional DC conversion circuit, and is used to collect the bus DC voltage. The bus voltage sampling module adopts an isolation optocoupler for isolation sampling.

[0005] Furthermore, it also includes a battery or a battery pack connected to the bidirectional DC conversion circuit, and the MCU main control circuit also includes a battery voltage sampling module and a battery current sampling module connected to the MCU input end. The battery voltage sampling module and the battery current sampling module are connected to the battery connection end of the bidirectional DC conversion circuit and are used to collect battery current and voltage respectively.

[0006] Furthermore, the bus voltage sampling module includes a voltage dividing sampling unit, an amplifying unit, a voltage-to-current unit, an isolation optocoupler and a current-to-voltage unit which are arranged in sequence according to the signal flow direction, and the current-to-voltage unit outputs a voltage signal to the bus voltage collection terminal of the MCU.

[0007] Furthermore, the voltage divider sampling unit is one or more resistors connected in series, and the amplification unit includes an operational amplifier U1A, a resistor R1, and a resistor R11, wherein the inverting input terminal of the operational amplifier U1A is respectively connected to one end of the resistor R1 and the resistor R11, the other end of the resistor R11 is connected to the negative electrode of the bus voltage, the other ground of the resistor R1 is connected to the output terminal of the operational amplifier U1A, the positive input terminal of the operational amplifier U1A is connected to the output terminal of the voltage divider sampling unit through a resistor, the negative electrode of the operational amplifier U1A is grounded, and the positive electrode is connected to a certain value of DC voltage.

[0008] Furthermore, the voltage-to-current unit includes an operational amplifier U1B, a capacitor C2, a resistor R7 and a capacitor C1, wherein the inverting input terminal of the operational amplifier U1B is respectively connected to the output terminal of the amplification unit, the capacitor C1, the capacitor C2 and one end of the resistor R7, the other ends of the capacitor C2 and the resistor R7 are respectively connected to a certain value of DC voltage, the other end of the capacitor C1 is connected to the output terminal of the operational amplifier U1B, and the positive input terminal of the operational amplifier U1B is connected to the negative electrode of the bus voltage.

[0009] Furthermore, the isolation optocoupler adopts a linear optocoupler U2, pin 1 of the linear optocoupler is connected to the output end of the voltage-to-current unit, pin 2 is connected to a certain value of DC voltage, pin 3 is connected between the amplification unit and the voltage-to-current unit, pin 4 is connected to the negative pole of the bus voltage, and pins 5 and 6 are connected to the input end of the current-to-voltage unit.

[0010] Furthermore, the current-to-voltage unit includes an operational amplifier U3A, a resistor R14, a resistor R10 and a capacitor C3, wherein the inverting input terminal of the operational amplifier U3A is connected to pin 6 of the linear optocoupler U2, the resistor R10, and one end of the capacitor C3, and the non-inverting input terminal is respectively connected to pin 5 of the linear optocoupler U2 and the grounding resistor R14, and the other ends of the resistor R10 and the capacitor C3 are connected to the output terminal of the operational amplifier U3A.

[0011] Furthermore, the AC current sampling module and the AC voltage sampling module respectively use transformer isolation sampling.

[0012] The AC voltage sampling module includes a voltage divider unit, a voltage transformer T1, a sampling unit and a differential amplifier unit, wherein the input end of the voltage divider unit is connected to the AC input end of the rectifier inverter circuit, the output end of the voltage divider unit is connected to the primary side of the voltage transformer T1, the secondary side of the voltage transformer T1 is connected to the input end of the sampling unit, the output end of the sampling unit is connected to the input end of the differential amplifier unit, and the output end of the differential amplifier unit is connected to the AC voltage sampling end of the MCU.

[0013] Furthermore, the voltage divider unit includes more than two voltage divider resistors, which are evenly arranged on the live wire and the neutral wire of the alternating current. The two input ends of the primary side of the voltage transformer T1 are respectively connected to the output ends of the voltage divider resistor, and the two output ends of the secondary side are respectively connected to the sampling unit. The sampling unit is a sampling resistor, and the two ends of the sampling resistor are connected in parallel to the two output ends of the secondary side of the voltage transformer T1.

[0014] Furthermore, the differential amplification unit includes a resistor R16, a resistor R25, a resistor R26, a resistor R15, a capacitor C11, a capacitor C8, and an operational amplifier U4A, wherein the inverting input terminal of the operational amplifier U4A is connected to one end of the sampling resistor R20 through the resistor R16, and is connected to the output terminal of the operational amplifier U4A through the parallel resistor R15 and the capacitor C8, the non-inverting input terminal of the operational amplifier U4A is connected to the other end of the sampling resistor R20 through the resistor R25, and is respectively connected to one end of the parallel resistor R26 and the capacitor C11, and the other ends of the resistor R26 and the capacitor C11 are respectively connected to the reference voltage VREF and grounded through the capacitor C13.

[0015] Compared with the prior art, the beneficial effects of the utility model are as follows: different isolation sampling structures are selected according to the characteristics of AC and high-voltage DC, the voltage and current sampling of the AC end are realized by mutual inductors, and the bus voltage sampling is realized by isolation optocouplers, ensuring that the safety requirements of the system are met, realizing the safe isolation of the MCU main control circuit, and the system is more stable and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is a structural diagram of the utility model;

[0018] Figure 2 This is a circuit schematic diagram of an embodiment of a bus voltage sampling module;

[0019] Figure 3 This is a circuit schematic diagram of an embodiment of an AC voltage sampling module. DETAILED DESCRIPTION

[0020] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by technicians in the technical field of the present invention; the terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of the present invention or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0021] Reference to "embodiments" in the present invention means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it mutually exclusive, independent, or alternative to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in the present invention may be combined with other embodiments.

[0022] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the accompanying drawings.

[0023] like Figure 1 As shown, the bidirectional ACDC power supply circuit of the utility model includes a rectifier inverter circuit, a bidirectional direct current (DCDC) conversion circuit, and an MCU main control circuit. The MCU main control circuit includes an MCU and an AC current sampling module, an AC voltage sampling module, and a bus voltage sampling module respectively connected to the MCU input end. The input end of the AC current sampling module and the input end of the AC current sampling module are respectively connected to the AC voltage end of the rectifier inverter circuit, and are used to collect the AC voltage and AC current of the rectifier inverter circuit. The input end of the bus voltage sampling module is connected between the rectifier inverter circuit and the bidirectional direct current conversion circuit, and is used to collect the bus DC voltage. The bus voltage sampling module adopts an isolated optocoupler for isolated sampling.

[0024] It also includes a battery or a battery pack connected to the bidirectional DC conversion circuit. The MCU main control circuit also includes a battery voltage sampling module and a battery current sampling module connected to the MCU input end. The battery voltage sampling module and the battery current sampling module are connected to the battery connection end of the bidirectional DC conversion circuit and are used to collect battery current and voltage respectively.

[0025] Preferably, the battery voltage sampling and battery current signal in this example are weak current signals, so they can be directly sampled by sampling resistors, while the bus voltage is a strong current signal, and is sampled by isolating optocouplers. The alternating current is also a strong current signal, and is isolated by mutual inductors and other isolation methods, and then the converted weak current signal is sampled. The utility model selects different sampling methods and sampling structures according to the characteristics of the strength of the AC and DC voltages, realizes the isolation of strong current signals and weak current signals, meets the safety requirements of the system, improves the safety of the MCU main control circuit, and makes the system more stable and reliable.

[0026] The rectifier / inverter circuit of this example adopts a PFC rectifier / inverter circuit, which is mainly composed of a power device IGBT, an inductor, and a capacitor. In the entire power supply circuit, a high-voltage DC bus voltage is established after the input AC power is rectified by PFC, or the high-voltage DC bus voltage is inverted and output as an AC voltage; the bidirectional DCDC conversion circuit is composed of a transformer, a resonant inductor, a resonant capacitor, a high-voltage MOS tube, a low-voltage MOS tube and a lamp device, and in the entire power supply circuit, the bus voltage is stepped down to a battery voltage to charge the battery, or the battery voltage is stepped up to a bus voltage; the MCU main control circuit realizes the sampling of AC voltage, AC current, bus voltage, battery voltage, and battery current, and controls the output of PWM waves by real-time detection of relevant parameters, thereby realizing the functions of the bidirectional ACDC power supply to charge the battery and invert the output.

[0027] This example works like this:

[0028] When the power is in AC charging state, the AC input port connection line is plugged into the mains socket, and the bidirectional ACDC power supply circuit converts the 220V mains voltage through PFC rectification and DCDC conversion to output the voltage to charge the battery pack. The MCU main control circuit adjusts the output of the ACDC module according to the current voltage of the battery pack to achieve intelligent charging and complete the charging of the battery pack.

[0029] When working in the inverter output state, the bidirectional ACDC power supply circuit boosts the voltage of the battery pack to the DC bus voltage through the bidirectional DCDC conversion circuit, and then inverts the bus voltage to an AC220V voltage to power the equipment.

[0030] When working in bypass state, the bidirectional ACDC power supply detects the presence of AC power input and directly supplies power to the device through bypass mode by closing the input and output relays.

[0031] When working in the state of charging and discharging at the same time, the bidirectional ACDC power supply circuit detects the presence of AC power input, closes the input and output relays, supplies power to the device while starting the PFC rectification and DCDC conversion to charge the battery.

[0032] like Figure 2 As shown, the AC current sampling module and the AC voltage sampling module in this example respectively use mutual inductor isolation sampling. Of course, it can also be implemented by using isolation methods such as Hall sensors.

[0033] The AC voltage sampling module of this example includes a voltage divider unit, a voltage transformer T1, a sampling unit and a differential amplifier unit, wherein the input end of the voltage divider unit is connected to the AC input end of the rectifier inverter circuit, the output end of the voltage divider unit is connected to the primary side of the voltage transformer T1, the secondary side of the voltage transformer T1 is connected to the input end of the sampling unit, the output end of the sampling unit is connected to the input end of the differential amplifier unit, and the output end of the differential amplifier unit is connected to the AC voltage sampling end of the MCU.

[0034] The voltage divider unit includes more than two voltage divider resistors, which are evenly arranged on the live wire and the neutral wire of the alternating current. The two input ends of the primary side of the transformer T1 are respectively connected to the output ends of the voltage divider resistor, and the two output ends of the secondary side are respectively connected to the sampling unit. The sampling unit is a sampling resistor, and the two ends of the sampling resistor are connected in parallel to the two output ends of the secondary side of the voltage transformer T1.

[0035] The differential amplifier unit includes a resistor R16, a resistor R25, a resistor R26, a resistor R15, a capacitor C11, a capacitor C8, and an operational amplifier U4A, wherein the inverting input terminal of the operational amplifier U4A is connected to one end of the sampling resistor R20 through the resistor R16, and is connected to the output terminal of the operational amplifier U4A through the parallel resistor R15 and the capacitor C8, the non-inverting input terminal of the operational amplifier U4A is connected to the other end of the sampling resistor R20 through the resistor R25, and is respectively connected to one end of the parallel resistor R26 and the capacitor C11, and the other ends of the resistor R26 and the capacitor C11 are respectively connected to the reference voltage VREF and grounded through the capacitor C13.

[0036] In this circuit, the AC input voltage is divided by multiple resistors and then isolated and output by the voltage transformer T1. The secondary side of the voltage transformer T1 is connected to a sampling resistor, and then differential amplification is achieved through an operational amplifier. The output of the operational amplifier is connected to the AD port of the MCU for real-time sampling of the AC input voltage.

[0037] The current sampling circuit in this example is also implemented using a transformer. Specifically, the current sampling in this example uses a current transformer to achieve isolated output, and then uses an operational amplifier to achieve differential amplification. The output of the operational amplifier is connected to the AD port of the MCU for real-time sampling of the AC input current. The secondary side of the current transformer can use the same circuit as the secondary side of the voltage transformer T1 in this example.

[0038] like Figure 3As shown, the bus voltage sampling module of this example includes a voltage dividing sampling unit, an amplifying unit, a voltage-to-current unit, an isolation optocoupler and a current-to-voltage unit arranged in sequence according to the signal flow direction, and the current-to-voltage unit outputs a voltage signal to the bus voltage collection terminal of the MCU.

[0039] The voltage-dividing sampling unit is one or more resistors connected in series, and the amplifying unit includes an operational amplifier U1A, a resistor R1, and a resistor R11, wherein the inverting input terminal of the operational amplifier U1A is respectively connected to one end of the resistor R1 and the resistor R11, the other end of the resistor R11 is connected to the negative electrode of the bus voltage, the other ground of the resistor R1 is connected to the output terminal of the operational amplifier U1A, the positive input terminal of the operational amplifier U1A is connected to the output terminal of the voltage-dividing sampling unit through a resistor, the negative electrode of the operational amplifier U1A is grounded, and the positive electrode is connected to a certain value of DC voltage.

[0040] The voltage-to-current unit includes an operational amplifier U1B, a capacitor C2, a resistor R7 and a capacitor C1, wherein the inverting input terminal of the operational amplifier U1B is respectively connected to the output terminal of the amplification unit, the capacitor C1, the capacitor C2 and one end of the resistor R7, the other ends of the capacitor C2 and the resistor R7 are respectively connected to a certain value of DC voltage, the other end of the capacitor C1 is connected to the output terminal of the operational amplifier U1B, and the positive input terminal of the operational amplifier U1B is connected to the negative electrode of the bus voltage.

[0041] The isolation optocoupler adopts a linear optocoupler U2, wherein pin 1 of the linear optocoupler is connected to the output end of the voltage-to-current unit, pin 2 is connected to a certain DC voltage, pin 3 is connected between the amplification unit and the voltage-to-current unit, pin 4 is connected to the negative pole of the bus voltage, and pins 5 and 6 are connected to the input end of the current-to-voltage unit.

[0042] The current-to-voltage unit includes an operational amplifier U3A, a resistor R14, a resistor R10 and a capacitor C3, wherein the inverting input terminal of the operational amplifier U3A is connected to pin 6 of the linear optocoupler U2, the resistor R10 and one end of the capacitor C3, the non-inverting input terminal is respectively connected to pin 5 of the linear optocoupler U2 and the grounding resistor R14, and the other ends of the resistor R10 and the capacitor C3 are connected to the output terminal of the operational amplifier U3A.

[0043] In this example, the bus voltage is sampled through multiple resistors, then amplified by op amp U1A, and then converted into a current signal by op amp U1B. The current signal is isolated and output through linear optocoupler U2. The isolated output signal is converted into a voltage signal by op amp U3A, and then the converted signal is connected to the AD port of MCU for real-time sampling of the bus voltage. Through multiple resistors, the voltage value of the bus voltage is effectively reduced, and the strong electric signal is weakened. By amplifying the sampled signal, the effective signal collection can be achieved. In addition, through the isolation conversion of linear optocoupler U2, the strong electric signal is further isolated, so that the voltage signal on the MCU side is safer, and the safety and stability of the MCU main control circuit are improved.

[0044] The specific implementation methods described above are preferred implementation methods of the present utility model, and are not intended to limit the specific implementation scope of the present utility model. The scope of the present utility model includes but is not limited to the specific implementation methods. All equivalent changes made in accordance with the present utility model are within the protection scope of the present utility model.

Claims

1. A bidirectional ACDC power supply circuit, comprising a rectifier inverter circuit, a bidirectional DC conversion circuit, and an MCU main control circuit, characterized in that: The MCU main control circuit includes an MCU and an AC current sampling module, an AC voltage sampling module, and a bus voltage sampling module respectively connected to the input end of the MCU. The input end of the AC current sampling module and the input end of the AC current sampling module are respectively connected to the AC voltage end of the rectifier inverter circuit, and are used to collect the AC voltage and AC current of the rectifier inverter circuit. The input end of the bus voltage sampling module is connected between the rectifier inverter circuit and the bidirectional DC conversion circuit, and is used to collect the bus DC voltage. The bus voltage sampling module adopts isolation optocoupler isolation sampling.

2. The bidirectional ACDC power supply circuit according to claim 1, characterized in that: It also includes a battery or a battery pack connected to the bidirectional DC conversion circuit. The MCU main control circuit also includes a battery voltage sampling module and a battery current sampling module connected to the MCU input end. The battery voltage sampling module and the battery current sampling module are connected to the battery connection end of the bidirectional DC conversion circuit and are used to collect battery current and voltage respectively.

3. The bidirectional ACDC power supply circuit according to claim 1 or 2, characterized in that: The bus voltage sampling module includes a voltage dividing sampling unit, an amplifying unit, a voltage-to-current unit, an isolation optocoupler and a current-to-voltage unit which are arranged in sequence according to the signal flow direction. The current-to-voltage unit outputs a voltage signal to the bus voltage collection terminal of the MCU.

4. The bidirectional ACDC power supply circuit according to claim 3, characterized in that: The voltage-dividing sampling unit is one or more resistors connected in series, and the amplifying unit includes an operational amplifier U1A, a resistor R1, and a resistor R11, wherein the inverting input terminal of the operational amplifier U1A is respectively connected to one end of the resistor R1 and the resistor R11, the other end of the resistor R11 is connected to the negative electrode of the bus voltage, the other ground of the resistor R1 is connected to the output terminal of the operational amplifier U1A, the positive input terminal of the operational amplifier U1A is connected to the output terminal of the voltage-dividing sampling unit through a resistor, the negative electrode of the operational amplifier U1A is grounded, and the positive electrode is connected to a certain value of DC voltage.

5. The bidirectional ACDC power supply circuit according to claim 3, characterized in that: The voltage-to-current unit includes an operational amplifier U1B, a capacitor C2, a resistor R7 and a capacitor C1, wherein the inverting input terminal of the operational amplifier U1B is respectively connected to the output terminal of the amplification unit, the capacitor C1, the capacitor C2 and one end of the resistor R7, the other ends of the capacitor C2 and the resistor R7 are respectively connected to a certain value of DC voltage, the other end of the capacitor C1 is connected to the output terminal of the operational amplifier U1B, and the positive input terminal of the operational amplifier U1B is connected to the negative electrode of the bus voltage.

6. The bidirectional ACDC power supply circuit according to claim 5, characterized in that: The isolation optocoupler adopts a linear optocoupler U2, wherein pin 1 of the linear optocoupler is connected to the output end of the voltage-to-current unit, pin 2 is connected to a certain DC voltage, pin 3 is connected between the amplification unit and the voltage-to-current unit, pin 4 is connected to the negative pole of the bus voltage, and pins 5 and 6 are connected to the input end of the current-to-voltage unit.

7. The bidirectional ACDC power supply circuit according to claim 6, characterized in that: The current-to-voltage unit includes an operational amplifier U3A, a resistor R14, a resistor R10 and a capacitor C3, wherein the inverting input terminal of the operational amplifier U3A is connected to pin 6 of the linear optocoupler U2, the resistor R10 and one end of the capacitor C3, the non-inverting input terminal is respectively connected to pin 5 of the linear optocoupler U2 and the grounding resistor R14, and the other ends of the resistor R10 and the capacitor C3 are connected to the output terminal of the operational amplifier U3A.

8. The bidirectional ACDC power supply circuit according to claim 1 or 2, characterized in that: The AC current sampling module and the AC voltage sampling module respectively use transformer isolation sampling. The AC voltage sampling module includes a voltage divider unit, a voltage transformer T1, a sampling unit and a differential amplifier unit, wherein the input end of the voltage divider unit is connected to the AC input end of the rectifier inverter circuit, the output end of the voltage divider unit is connected to the primary side of the voltage transformer T1, the secondary side of the voltage transformer T1 is connected to the input end of the sampling unit, the output end of the sampling unit is connected to the input end of the differential amplifier unit, and the output end of the differential amplifier unit is connected to the AC voltage sampling end of the MCU.

9. The bidirectional ACDC power supply circuit according to claim 8, characterized in that: The voltage divider unit includes more than two voltage divider resistors, which are evenly arranged on the live wire and the neutral wire of the alternating current. The two input ends of the primary side of the transformer T1 are respectively connected to the output ends of the voltage divider resistor, and the two output ends of the secondary side are respectively connected to the sampling unit. The sampling unit is a sampling resistor, and the two ends of the sampling resistor are connected in parallel to the two output ends of the secondary side of the voltage transformer T1.

10. The bidirectional ACDC power supply circuit according to claim 9, characterized in that: The differential amplifier unit includes a resistor R16, a resistor R25, a resistor R26, a resistor R15, a capacitor C11, a capacitor C8, and an operational amplifier U4A, wherein the inverting input terminal of the operational amplifier U4A is connected to one end of the sampling resistor R20 through the resistor R16, and is connected to the output terminal of the operational amplifier U4A through the parallel resistor R15 and the capacitor C8, the non-inverting input terminal of the operational amplifier U4A is connected to the other end of the sampling resistor R20 through the resistor R25, and is respectively connected to one end of the parallel resistor R26 and the capacitor C11, and the other ends of the resistor R26 and the capacitor C11 are respectively connected to the reference voltage VREF and grounded through the capacitor C13.

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