Bidirectional power supply and bidirectional power supply control method

Abstract

The present application discloses a bidirectional power supply and a control method for a bidirectional power supply, and belongs to the field of power electronics technology. The bidirectional power supply includes a bidirectional AC / DC conversion circuit, a bidirectional transformer circuit, and a control circuit, wherein: the bidirectional AC / DC conversion circuit is connected to an AC source and a bidirectional transformer circuit respectively; the bidirectional transformer circuit is connected to a voltage bus of a target device; the control circuit is connected to the bidirectional transformer circuit, and is used to obtain electrical parameters at the connection between the bidirectional transformer circuit and the voltage bus, and control the electrical transmission direction of the bidirectional transformer circuit based on the electrical parameters. The bidirectional power supply provided by the present application can transmit the electrical energy generated by the target device in the power generation working state to the AC source, and there is no need to configure a discharge resistor, a cooling fan, etc. for the target device, which can reduce the production cost of the target device, reduce the volume of the target device, etc.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a bidirectional power supply and a control method for a bidirectional power supply. Background Art

[0002] In industrial production, some equipment uses motors to drive actuators, enabling automated production. However, in certain situations, the actuators may reverse motion due to external forces such as gravity, driving the motors and causing them to generate electricity.

[0003] For example, a SCARA (Selective Compliance Assembly Robot Arm) robot may frequently lift and lower heavy objects during operation. When a SCARA robot lifts a heavy object using its arm, it uses a motor to drive the arm. When the SCARA robot lowers the object using its arm, gravity may cause the arm to move downward, driving the motor, which then generates electricity and outputs it.

[0004] In related technologies, a large discharge resistor is installed in the device to consume the electrical energy generated by the motor during power generation. Because the discharge resistor converts electrical energy into heat, a cooling fan is also required to dissipate the heat. Alternatively, a battery can be installed to store the electrical energy generated by the motor during power generation. However, whether the device is equipped with a discharge resistor and a cooling fan, or a battery, it undoubtedly increases the production cost and size of the device. Summary of the Invention

[0005] This application provides a bidirectional power supply and a bidirectional power supply control method, which can reduce the production cost of the device and reduce the size of the device. The corresponding technical solutions are as follows:

[0006] In one aspect, a bidirectional power supply is provided, comprising a bidirectional AC / DC conversion circuit, a bidirectional voltage transformation circuit, and a control circuit, wherein:

[0007] The bidirectional AC / DC conversion circuit is connected to the AC source and the bidirectional voltage conversion circuit respectively;

[0008] The bidirectional voltage transformation circuit is connected to the voltage bus of the target device;

[0009] The control circuit is connected to the bidirectional transformer circuit and is used to obtain electrical parameters at the connection point between the bidirectional transformer circuit and the voltage bus, and control the electrical transmission direction of the bidirectional transformer circuit based on the electrical parameters.

[0010] Optionally, the electrical parameter is a voltage value;

[0011] The control circuit is used to:

[0012] When the electrical transmission direction of the bidirectional transformer circuit is from a first electrical transmission interface to a second electrical transmission interface, if a voltage value of the second electrical transmission interface is greater than or equal to a first voltage threshold, switching the electrical transmission direction of the bidirectional transformer circuit to from the second electrical transmission interface to the first electrical transmission interface, wherein the first electrical transmission interface is an interface in the bidirectional transformer circuit connected to the bidirectional AC / DC conversion circuit, and the second electrical transmission interface is an interface in the bidirectional transformer circuit connected to a voltage bus of the target device;

[0013] When the electrical transmission direction of the bidirectional transformer circuit is from the second electrical transmission interface to the first electrical transmission interface, if the voltage value of the second electrical transmission interface is less than or equal to a second voltage threshold, the electrical transmission direction of the bidirectional transformer circuit is switched to from the first electrical transmission interface to the second electrical transmission interface, wherein the first voltage threshold is greater than the second voltage threshold.

[0014] Optionally, the second voltage threshold is an operating voltage of the target device.

[0015] Optionally, the electrical parameter is current direction;

[0016] The control circuit is used to:

[0017] When the power transmission direction of the bidirectional transformer circuit is from a first power transmission interface to a second power transmission interface, if the current direction of the second power transmission interface is opposite to a preset current direction, switching the power transmission direction from the second power transmission interface to the first power transmission interface, wherein the first power transmission interface is an interface in the bidirectional transformer circuit connected to the bidirectional AC / DC conversion circuit, and the second power transmission interface is an interface in the bidirectional transformer circuit connected to a voltage bus of the target device;

[0018] When the electrical transmission direction of the bidirectional transformer circuit is from the second electrical transmission interface to the first electrical transmission interface, if the current direction of the second electrical transmission interface is the same as the preset current direction, the electrical transmission direction is switched from the first electrical transmission interface to the second electrical transmission interface.

[0019] Optionally, the control circuit includes a detector and a processor;

[0020] The detector is used to detect electrical parameters at the connection between the bidirectional transformer circuit and the voltage bus;

[0021] The processor is used to obtain the electrical parameters detected by the detector, and control the electrical transmission direction of the bidirectional transformer circuit based on the electrical parameters.

[0022] Optionally, the target device is configured with a robotic arm driven by a motor.

[0023] Optionally, the bidirectional AC-DC conversion circuit is a bidirectional power factor correction (PFC) circuit.

[0024] Optionally, the bidirectional transformer circuit is a bidirectional dual active bridge DAB circuit.

[0025] On the other hand, a control method for a bidirectional power supply is provided, wherein the bidirectional power supply includes a bidirectional AC / DC conversion circuit, a bidirectional voltage transformation circuit, and a control circuit;

[0026] The bidirectional AC / DC conversion circuit is connected to the AC source and the bidirectional voltage transformation circuit respectively, the bidirectional voltage transformation circuit is connected to the voltage bus of the target device, and the control circuit is connected to the bidirectional voltage transformation circuit;

[0027] The method includes: the control circuit acquiring electrical parameters at a connection point between the bidirectional transformer circuit and the voltage bus, and controlling the electrical transmission direction of the bidirectional transformer circuit based on the electrical parameters.

[0028] Optionally, the electrical parameter is a voltage value;

[0029] The controlling the electrical transmission direction of the bidirectional transformer circuit based on the electrical parameter includes:

[0030] When the electrical transmission direction of the bidirectional transformer circuit is from a first electrical transmission interface to a second electrical transmission interface, if the control circuit determines that a voltage value of the second electrical transmission interface is greater than or equal to a first voltage threshold, the electrical transmission direction of the bidirectional transformer circuit is switched from the second electrical transmission interface to the first electrical transmission interface, wherein the first electrical transmission interface is an interface in the bidirectional transformer circuit connected to the bidirectional AC / DC conversion circuit, and the second electrical transmission interface is an interface in the bidirectional transformer circuit connected to a voltage bus of the target device;

[0031] When the electrical transmission direction of the bidirectional transformer circuit is from the second electrical transmission interface to the first electrical transmission interface, if the control circuit determines that the voltage value of the second electrical transmission interface is less than or equal to a second voltage threshold, the electrical transmission direction of the bidirectional transformer circuit is switched to from the first electrical transmission interface to the second electrical transmission interface, wherein the first voltage threshold is greater than the second voltage threshold.

[0032] Optionally, the second voltage threshold is an operating voltage of the target device.

[0033] Optionally, the electrical parameter is current direction;

[0034] The controlling the electrical transmission direction of the bidirectional transformer circuit based on the electrical parameter includes:

[0035] When the power transmission direction of the bidirectional transformer circuit is from the first power transmission interface to the second power transmission interface, if the control circuit determines that the current direction of the second power transmission interface is opposite to a preset current direction, the power transmission direction is switched from the second power transmission interface to the first power transmission interface, wherein the first power transmission interface is an interface in the bidirectional transformer circuit connected to the bidirectional AC / DC conversion circuit, and the second power transmission interface is an interface in the bidirectional transformer circuit connected to the voltage bus of the target device;

[0036] When the electrical transmission direction of the bidirectional transformer circuit is from the second electrical transmission interface to the first electrical transmission interface, if the control circuit determines that the current direction of the second electrical transmission interface is the same as the preset current direction, the electrical transmission direction is switched from the first electrical transmission interface to the second electrical transmission interface.

[0037] Optionally, the control circuit includes a detector and a processor;

[0038] The obtaining of electrical parameters at a connection point between the bidirectional transformer circuit and the voltage busbar includes:

[0039] The detector detects electrical parameters at the connection between the bidirectional transformer circuit and the voltage bus;

[0040] The controlling the electrical transmission direction of the bidirectional transformer circuit based on the electrical parameter includes:

[0041] The processor obtains the electrical parameters detected by the detector, and controls the electrical transmission direction of the bidirectional transformer circuit based on the electrical parameters.

[0042] The beneficial effects of the technical solution provided by the embodiments of the present application are:

[0043] The bidirectional power supply provided in the embodiment of the present application includes a bidirectional AC / DC conversion circuit, a bidirectional transformer circuit and a control circuit. The control circuit can control the electrical transmission direction of the bidirectional transformer circuit according to the electrical parameters at the connection point between the bidirectional transformer circuit and the voltage bus of the target device. Since the electrical parameters at the connection point are directly related to the working state of the motor of the target device, the electrical transmission direction of the bidirectional transformer circuit can be controlled by detecting the electrical parameters. When the motor of the target device is in the power generation working state, the DC power generated by the motor can be transmitted to the bidirectional AC / DC conversion circuit through the bidirectional transformer circuit, and then the bidirectional AC / DC conversion circuit converts the incoming DC power into AC power and transmits it to the AC source. In this way, the present application no longer needs to configure a discharge resistor, a cooling fan, etc. for the target device, which can reduce the production cost of the target device, reduce the volume of the target device, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0045] Figure 1 is a schematic diagram of a bidirectional power supply provided in an embodiment of the present application;

[0046] Figure 2 is a schematic diagram of a bidirectional power supply provided in an embodiment of the present application;

[0047] Figure 3 This is a circuit diagram of a bidirectional power supply provided in an embodiment of the present application.

[0048] Illustration

[0049] 1. Bidirectional AC / DC conversion circuit; 2. Bidirectional voltage transformation circuit; 3. Control circuit;

[0050] 11. DC interface; 12. AC interface;

[0051] 21. First electrical transmission interface; 22. Second electrical transmission interface; 23. Control interface. DETAILED DESCRIPTION

[0052] In order to make the objectives, technical solutions and advantages of this application clearer, the implementation methods of this application will be further described in detail below with reference to the accompanying drawings.

[0053] In industrial production, some equipment uses motors to drive actuators, thereby achieving automated production. However, in certain situations, the actuators may reverse motion due to external forces such as gravity, driving the motor to rotate and causing it to enter a power generation mode. This results in the motor having two operating states: power consumption and power generation. In related technologies, technicians can configure the equipment with a large discharge resistor to consume the electricity generated by the motor in the power generation mode. However, since the discharge resistor converts electrical energy into heat, a cooling fan is also required to dissipate the heat from the discharge resistor. This not only adds a discharge resistor but also a cooling fan to the equipment, increasing its production and operating costs, its size, and other factors, while also preventing the full utilization of the electricity generated by the motor. Alternatively, technicians can configure the equipment with a battery to store the electricity generated by the motor in the power generation mode, but this also increases the production and operating costs of the equipment and its size.

[0054] The present application provides a bidirectional power supply, which can be connected to an AC source (such as a power grid) and can supply power to a target device. The motor in the target device has a power-consuming working state and a power-generating working state. When the motor of the target device is in the power-consuming working state, the bidirectional power supply can convert the AC power in the power grid into DC power to supply power to the motor. When the motor of the target device is in the power-generating working state, the bidirectional power supply can convert the DC power generated by the motor into AC power and transmit it to the AC source connected to the bidirectional power supply. The use of this application can reduce the cost of producing and using the target device, improve energy utilization, etc.

[0055] The following is an introduction to the bidirectional power supply provided by this application:

[0056] Figure 1 A bidirectional power supply is provided in an embodiment of the present application. The bidirectional power supply includes:

[0057] Bidirectional AC / DC conversion circuit 1, bidirectional transformer circuit 2, and control circuit 3, wherein: bidirectional AC / DC conversion circuit 1 is connected to an AC source and bidirectional transformer circuit 2, respectively; bidirectional transformer circuit 2 is connected to a voltage busbar of a target device; and control circuit 3 is connected to bidirectional transformer circuit 2 to obtain electrical parameters at the connection between bidirectional transformer circuit 2 and the voltage busbar and, based on these electrical parameters, control the electrical transmission direction of bidirectional transformer circuit 2. The electrical parameters are voltage values ​​or current directions.

[0058] like Figure 1 As shown, the bidirectional power supply can be composed of a bidirectional AC / DC conversion circuit 1, a bidirectional voltage transformation circuit 2 and a control circuit 3.

[0059] The bidirectional AC / DC conversion circuit 1 may include a DC interface 11 and an AC interface 12. Under the control of the control circuit 3, the bidirectional AC / DC conversion circuit 1 may convert AC power connected to the AC interface 12 into DC power and output it through the DC interface 11, or convert DC power connected to the DC interface 11 into AC power and output it through the AC interface 12. The AC source connected to the AC interface 12 may be a power grid.

[0060] The bidirectional voltage conversion circuit 2 may include a first electrical transmission interface 21 and a second electrical transmission interface 22. Under the control of the control circuit 3, the bidirectional voltage conversion circuit 2 may convert the current input from the first electrical transmission interface 21 and transmit it to the second electrical transmission interface 22, or convert the current input from the second electrical transmission interface 22 and transmit it to the first electrical transmission interface 21. The first electrical transmission interface 21 of the bidirectional voltage conversion circuit 2 may be connected to the DC interface 11 in the bidirectional AC / DC conversion circuit 1, and the second electrical transmission interface 22 of the bidirectional voltage conversion circuit 2 may be connected to the voltage bus of the target device. Thus, when the motor of the target device is in an electrical working state, the bidirectional voltage conversion circuit 2 may be controlled to reduce the voltage of the DC power input from the DC interface 11 (to the normal operating voltage of the target device) and transmit it to the voltage bus of the target device through the second electrical transmission interface 22 to drive the motor of the target device to rotate. On the contrary, when the motor of the target device is in the power generation working state, the bidirectional transformer circuit 2 can be controlled to boost the DC power transmitted from the voltage bus of the target device, and transmit it to the DC interface of the bidirectional AC / DC conversion circuit 1 through the first electrical transmission interface 21, and then the bidirectional AC / DC conversion circuit 1 converts the input DC power into AC power, and transmits it into the power grid through the AC interface 12.

[0061] The control circuit 3 can be connected to the control interface 13 of the bidirectional AC / DC conversion circuit 1 ( Figure 1 ), and is connected to the control interface 23 of the bidirectional transformer circuit 2, for realizing control of the bidirectional AC / DC conversion circuit 1 and the bidirectional transformer circuit 2.

[0062] The control circuit 3 can detect the working state of the motor of the target device to control the electrical transmission direction of the bidirectional power supply. When the motor of the target device is in the power-using working state, the bidirectional power supply needs to power the target device, and the voltage value at the connection point between the bidirectional transformer circuit 2 and the voltage bus of the target device (i.e., the second electrical transmission interface 22) is the normal operating voltage of the target device. When the target device is in the power generation working state, the current generated by the motor flows back to the second electrical transmission interface 22 of the bidirectional transformer circuit 2 through the voltage bus of the target device. In this way, the current direction at the second electrical transmission interface 22 is opposite to the current direction when the target device is in the power-using working state, and the voltage value at the second electrical transmission interface 22 is raised. Therefore, the control circuit 3 can determine the working state of the target device by obtaining the electrical parameters (voltage value or current direction) at the second electrical transmission interface 22. Then, the bidirectional AC / DC conversion circuit 1 and the bidirectional transformer circuit 2 can be controlled according to the working state of the target device.

[0063] It should be noted that the electrical working state of the motor may include the rotational state after the motor is powered on, and may also include the standby state of the motor. When the actuator of the target device drives the motor to rotate, the motor can generate electricity, and the motor is in the power generation working state. The target device is equipped with a robotic arm, which can be driven by a motor. For example, the target device can be a SCARA robot, the corresponding actuator can be the robotic arm of the SCARA robot, and the motor that determines the robotic arm of the SCARA robot can be a servo motor.

[0064] It should be noted that a robotic arm of the target device may be equipped with multiple motors. Multiple motors can constitute a motor system. In the motor system, there may be motors in the power-consuming state and motors in the power-generating state at the same time. Therefore, the motor system may be equipped with an energy distribution device, which can provide the electric energy generated by the motors in the power-generating state to the motors in the power-consuming state. When the motor system is consuming electricity as a whole, that is, when the electric energy generated by the motors in the power-generating state in the motor system is less than the electric energy required to be consumed by the motors in the power-consuming state, the motor system can be considered to be in the power-consuming state. When the motor system is generating electricity as a whole, that is, when the electric energy generated by the motors in the power-generating state in the motor system is greater than the electric energy required to be consumed by the motors in the power-consuming state, the motor system can be considered to be in the power-generating state. When the target device has multiple motors, the motors of the target device mentioned above being in the power-consuming state or in the power-generating state can also be considered to be in the power-consuming state or in the power-generating state.

[0065] As can be seen, the bidirectional power supply provided in this application can power the target device when the target device's motor is in an electrical working state, and can switch the power transmission direction of the bidirectional power supply when the target device's motor is in a generating working state, transmitting the power generated by the motor into the power grid. This eliminates the need to configure a discharge resistor for the target device, and even more so, eliminates the need to configure a cooling fan for the discharge resistor. This can, to a certain extent, reduce the production and use costs of the target device, reduce the size of the target device, and improve energy utilization.

[0066] In one possible implementation, when the control circuit 3 determines the operating state of the motor and controls the power transmission direction of the bidirectional transformer circuit 2 based on the voltage value at the connection point between the bidirectional transformer circuit 2 and the voltage bus of the target device, further processing is as follows:

[0067] When the electrical transmission direction of the bidirectional transformer circuit 2 is from the first electrical transmission interface 21 to the second electrical transmission interface 22, if the voltage value of the second electrical transmission interface 22 is greater than or equal to a first voltage threshold, the electrical transmission direction of the bidirectional transformer circuit 2 is switched from the second electrical transmission interface 22 to the first electrical transmission interface 21. When the electrical transmission direction of the bidirectional transformer circuit 2 is from the second electrical transmission interface 22 to the first electrical transmission interface 21, if the voltage value of the second electrical transmission interface 22 is less than or equal to a second voltage threshold, the electrical transmission direction of the bidirectional transformer circuit 2 is switched from the first electrical transmission interface 21 to the second electrical transmission interface 22, wherein the first voltage threshold is greater than the second voltage threshold. The second voltage threshold may be the operating voltage of the target device.

[0068] In practice, when the target device's motor is in the power-consuming state, the power transmission direction of the bidirectional transformer circuit 2 is from the first power transmission interface 21 to the second power transmission interface 22, and the voltage value of the second power transmission interface 22 should be the target device's normal operating voltage. If the target device's motor switches from the power-consuming state to the power-generating state, because the power transmission direction of the bidirectional transformer circuit 2 cannot change instantaneously, when the motor just switches to the power-generating state, the power transmission direction of the bidirectional transformer circuit 2 remains from the first power transmission interface 21 to the second power transmission interface 22, and the voltage value of the second power transmission interface 22 remains the target device's operating voltage. However, while the motor is in the power-generating state, the power generated by the motor is transmitted to the second power transmission interface 22 via the voltage bus, causing the voltage of the second power transmission interface 22 (i.e., the voltage at the connection between the second power transmission interface 22 and the voltage bus) to increase. Therefore, when the motor of the target device is in the power-consuming state, the control circuit 3 can periodically detect the voltage value of the second power transmission interface 22. If the voltage value of the second power transmission interface 22 is greater than or equal to the first voltage threshold (the first voltage threshold is greater than the operating voltage of the target motor), it means that the motor of the target device is in the power generation state. Therefore, the power transmission direction of the bidirectional voltage conversion circuit 2 can be switched from the second power transmission interface 22 to the first power transmission interface 21, thereby transmitting the power generated by the motor of the target device back to the power grid. At the same time, the control circuit 3 can change the motor from the power-consuming state to the power generation state.

[0069] When the target device's motor is in the power generation state, the power transmission direction of the bidirectional transformer circuit 2 is from the second power transmission interface 22 to the first power transmission interface 21. Since the target device transmits power outward, the voltage of the second power transmission interface 22 increases. At this time, the voltage of the second power transmission interface 22 should be greater than the target device's normal operating voltage. If the target device's motor stops generating power, the voltage of the second power transmission interface 22 will gradually decrease. Therefore, when the target device's motor is in the power generation state, the control circuit 3 can periodically detect the voltage value of the second power transmission interface 22. If the voltage value of the second power transmission interface 22 is less than or equal to the second voltage threshold (the second voltage threshold is less than the first voltage threshold), it indicates that the target device's motor has stopped generating power. Therefore, the power transmission direction of the bidirectional transformer circuit 2 can be switched from the first power transmission interface 21 to the second power transmission interface 22. After that, power can be supplied to the target device's motor through the second power transmission interface 22. At the same time, the control circuit 3 can change the motor's power consumption state to the power consumption state.

[0070] Among them, the first voltage threshold and the second voltage threshold can be set by the technician according to the operating voltage of the target device. The second voltage threshold is greater than the first voltage threshold, and the first voltage threshold can be the normal operating voltage of the target device. Here, by setting two voltage thresholds, the switching of the electrical transmission direction of the bidirectional transformer circuit 2 due to the voltage jitter of the second electrical transmission interface 22 can be avoided. For example, the operating voltage of the target device and the first voltage threshold are 48V, and the second voltage threshold is 52V. When the motor of the target device is in an electrical working state, the voltage of the second electrical transmission interface 22 may jitter around 48V. In this way, even if the voltage of the second electrical transmission interface 22 jitters to 50V, the electrical transmission direction of the bidirectional transformer circuit 2 will not be switched, and the normal operation of the motor can be guaranteed.

[0071] In one possible implementation, when the control circuit 3 determines the operating state of the motor and controls the power transmission direction of the bidirectional transformer circuit 2 based on the current direction at the connection between the bidirectional transformer circuit 2 and the voltage bus of the target device, further processing is as follows:

[0072] When the electrical transmission direction of the bidirectional transformer circuit 2 is from the first electrical transmission interface 21 to the second electrical transmission interface 22, if the current direction of the second electrical transmission interface 22 is opposite to the preset current direction, the electrical transmission direction is switched from the second electrical transmission interface 22 to the first electrical transmission interface 21; when the electrical transmission direction of the bidirectional transformer circuit 2 is from the second electrical transmission interface 22 to the first electrical transmission interface 21, if the current direction of the second electrical transmission interface 22 is the same as the preset current direction, the electrical transmission direction can be switched from the first electrical transmission interface 21 to the second electrical transmission interface 22.

[0073] The preset current direction may be the current direction at the second electrical transmission interface 22 when the target device is in an electrical working state.

[0074] In practice, when the motor of the target device is in the power-using working state, the power transmission direction of the bidirectional transformer circuit 2 is from the first power transmission interface 21 to the second power transmission interface 2, and the bidirectional power supply provides power to the target device through the second power transmission interface 22. The current direction at the second power transmission interface 22 should be the same as the preset current direction. If the motor of the target device is converted from the power-using working state to the power-generating working state, the DC power generated by the motor of the target device can be transmitted to the second power transmission interface 22 through the voltage bus of the target device, and the energy storage device (such as a capacitor) in the bidirectional transformer circuit 2 is charged through the second power transmission interface 22. Therefore, the current direction at the second power transmission interface 22 at this time is opposite to the current direction when the motor of the target device is in the power-using working state. Therefore, when the motor of the target device is in the power-consuming state, the control circuit 3 can periodically detect the current direction of the second power transmission interface 22. If the current direction detected at the second power transmission interface 22 is opposite to the preset current direction, it indicates that the motor of the target device is in the power generation state. Therefore, the power transmission direction of the bidirectional voltage conversion circuit 2 can be switched from the second power transmission interface 22 to the first power transmission interface 21, thereby transmitting the power generated by the motor of the target device back to the power grid. At the same time, the control circuit 3 can change the motor from the power-consuming state to the power generation state. It should be noted that the power-consuming state of the motor can include the motor being powered on and rotating, and can also include the motor being in the standby state.

[0075] When the target device is in the power generation state, the power transmission direction of the bidirectional transformer circuit 2 is from the second power transmission interface 22 to the first power transmission interface 21. Since the current output by the target device causes the current direction at the second power transmission interface 22 to be opposite to the preset current direction. If the motor of the target device switches from the power generation state to the power consumption state, although the power transmission direction of the bidirectional transformer circuit 2 does not change instantaneously, the energy stored in the energy storage device (such as a capacitor) included in the bidirectional transformer circuit 2 will be transmitted to the target device, so the current direction at the second power transmission interface 22 will be the same as the preset current direction. Therefore, when the motor of the target device is in the power generation state, the control circuit 3 can periodically detect the current direction of the second power transmission interface 22. If the control circuit 3 detects that the current direction at the second power transmission interface 22 is the same as the preset current direction, it means that the motor of the target device has stopped generating power, and the power transmission direction of the bidirectional transformer circuit 2 can be switched from the first power transmission interface 21 to the second power transmission interface 22. After that, the target device can be powered through the second power transmission interface 22. At the same time, the control circuit 3 can change the motor from a power generation working state to a power consumption working state.

[0076] In one possible implementation, the control circuit 3 includes a detector 31 and a processor 32. The detector 31 is configured to detect electrical parameters at the connection between the bidirectional transformer circuit 2 and the voltage bus of the target device, and the processor 32 is configured to obtain the electrical parameters detected by the detector 31 and control the electrical transmission direction of the bidirectional transformer circuit 2 based on the electrical parameters.

[0077] like Figure 2 As shown, the control circuit 3 may include a detector 31 and a processor 32 .

[0078] The detector 31 can be used to detect voltage or current values ​​in the circuit, and the direction of the current can be indicated by the positive or negative sign of the current value. For example, the detector 31 can be a voltage detector or a current detector, or a detector including a voltage detection component and a current detection component. The detector 31 can establish a connection with the bidirectional transformer circuit 2 based on the detection function it implements to detect the voltage value or current direction at the connection between the bidirectional transformer circuit 2 and the voltage bus of the target device. The detector 31 can establish a connection with the processor 32, and the detector 31 can send the detected voltage value, current value, or current direction to the processor 32.

[0079] The processor 32 can be any processing chip that can determine the operating state of the target device based on the voltage value or current direction sent by the detector 31, and control the power transmission direction of the bidirectional transformer circuit 2 based on the operating state of the target device. In other words, when it is determined that the motor of the target device is in the power-consuming state, the power transmission direction of the bidirectional transformer circuit 2 can be set from the first power transmission interface 21 to the second power transmission interface 22, thereby providing power to the target device. When it is determined that the motor of the target device is in the power-generating state, the power transmission direction of the bidirectional transformer circuit 2 can be set from the second power transmission interface 22 to the first power transmission interface 21, thereby reversely transmitting the current generated by the motor into the power grid.

[0080] In a possible implementation, the bidirectional AC-DC conversion circuit 1 is a bidirectional PFC (Power Factor Correction) circuit, and the bidirectional transformer circuit 2 is a bidirectional DAB (Dual Active Bridge) circuit.

[0081] like Figure 3As shown, the bidirectional AC / DC conversion circuit 1 is a bidirectional PFC circuit. The bidirectional PFC circuit can be composed of an H-bridge, an inductor L1, and a capacitor C1. The H-bridge includes four independently controlled switching devices Q1-Q4. The AC interface 12 of the bidirectional PFC circuit can be connected to the power grid, and the DC interface 11 of the bidirectional PFC circuit is connected to the first power transmission interface 21 of the bidirectional DAB circuit. The switching devices can be metal-oxide-semiconductor field-effect transistors (MOSFETs). The switching devices Q1-Q4 can be considered as control terminals 13 of the bidirectional PFC circuit. The control circuit 3 can convert the AC power flowing into the AC interface 12 into DC power by controlling the closing of the switching devices Q1-Q4, and output it through the DC interface 11. Alternatively, the control circuit 3 can convert the DC power flowing into the DC interface 11 into AC power and output it through the AC interface 12.

[0082] The bidirectional transformer circuit 2 is a bidirectional DAB circuit, which can be composed of two H-bridges, capacitors C2 and C3, a transformer T1, and an inductor L2. The two H-bridges are electrically isolated by transformer T1. Each H-bridge includes eight switching devices S1-S8, and inductor L2 can be located in the middle arm of either H-bridge. The eight switching devices S1-S8 can be considered the control terminal 23 of the bidirectional DAB circuit. The control circuit 3 controls the power transmission direction of the bidirectional DAB circuit by controlling the closing of the switching devices S1-S8. For example, when the power transmission direction of the bidirectional DAB circuit needs to be controlled from the first power transmission interface 21 to the second power transmission interface 22, the switching devices in the first H-bridge near the first power transmission interface 21 can be controlled to be turned on, thereby transmitting the DC power input from the first power transmission interface 21 to the transformer T1. Then, the switching devices in the second H-bridge near the second power transmission interface 22 can be controlled to be turned on, thereby transmitting the DC power in the first H-bridge to the second H-bridge through the transformer. Similarly, when controlling the power transmission direction of the bidirectional DAB circuit from the second power transmission interface 22 to the first power transmission interface 21, the switching devices in the second H-bridge can be controlled to be turned on first to transmit the DC power input from the second power transmission interface 22 to the transformer T1. The switching devices in the first H-bridge can then be controlled to be turned on to transmit the DC power from the second H-bridge to the first H-bridge via the transformer. The control method of the control circuit 3 for controlling the different switching devices in the first and second H-bridges is conventional and will not be described in detail here.

[0083] The first electrical transmission interface 21 of the bidirectional DAB circuit is connected to the DC interface of the bidirectional PFC circuit, and the second electrical transmission interface 22 of the bidirectional DAB circuit is connected to the voltage bus of the target device.

[0084] When the target device's motor is in a power-consuming state, the bidirectional DAB circuit transmits power from the first power transmission interface 21 to the second power transmission interface 22. The voltage across capacitor C3, i.e., the second power transmission interface 22, is the target device's normal operating voltage, for example, 48V. If the target device switches to a power-generating state, the target device's motor transmits current to the second power transmission interface 22 via the voltage bus, causing the voltage across the second power transmission interface 22 to increase and the current direction through the second power transmission interface 22 to be opposite to the preset current direction. The control circuit 3 can then switch the control mode of the switching devices S1-S8 to shift the power transmission direction of the bidirectional DAB circuit from the second power transmission interface 22 to the first power transmission interface 21. This allows the DC power generated by the target device's motor to be transmitted to the bidirectional DAB circuit, where the DC power is boosted and transmitted to the bidirectional PFC circuit. The bidirectional PFC circuit then converts the DC power to AC power for transmission to the power grid.

[0085] When the target device's motor is in a power generation mode, the bidirectional DAB circuit's power transmission direction is from the second power transmission interface 22 to the first power transmission interface 21. The voltage across capacitor C3 is greater than the target device's normal operating voltage, meaning that the second power transmission interface 22 is greater than the target device's normal operating voltage, for example, 52V. If the target device switches to a power consumption mode, the voltage across capacitor C3 returns to the target device's operating voltage, and the current direction through the second power transmission interface 22 becomes the same as the preset current direction. The control circuit 3 can then switch the control mode for switching devices S1-S8, switching the power transmission direction of the bidirectional DAB circuit from the first power transmission interface 21 to the second power transmission interface 22. Thus, when the target device's motor requires power, the bidirectional PFC circuit can convert AC power from the power grid into DC power and transmit it to the bidirectional DAB circuit. The bidirectional DAB circuit can then step down the DC power transmitted from the bidirectional PFC circuit to the target device's normal operating voltage, thereby driving the target device's motor.

[0086] It can be seen that the bidirectional power supply provided by this application can transmit the electric energy generated by the motor to the AC source when the motor of the target device is in the power generation working state, and can power the motor when the motor of the target device is in the power consumption working state. It can also automatically identify the working state of the motor in the target device and automatically switch the power transmission direction of the bidirectional power supply according to the working state, which can cope with the situation where the motor frequently switches its working state. In this way, there is no need to configure the target device with a discharge resistor, a cooling fan, etc., which can reduce the production cost of the target device, reduce the size of the target device, and further improve energy utilization.

[0087] The present application also provides a control method for a bidirectional power supply, wherein the bidirectional power supply includes a bidirectional AC / DC conversion circuit 1, a bidirectional transformer circuit 2 and a control circuit 3; the bidirectional AC / DC conversion circuit 1 is connected to an AC source and a bidirectional transformer circuit 2 respectively, the bidirectional transformer circuit 2 is connected to a voltage bus of a target device, and the control circuit 3 is connected to the bidirectional transformer circuit 2; the control method for the bidirectional power supply includes: the control circuit 3 obtains electrical parameters at the connection between the bidirectional transformer circuit 2 and the voltage bus, and controls the electrical transmission direction of the bidirectional transformer circuit 2 based on the electrical parameters.

[0088] In a possible implementation, the electrical parameter may be a voltage value. The process of controlling the electrical transmission direction of the bidirectional voltage conversion circuit 2 based on the electrical parameter is as follows:

[0089] When the electrical transmission direction of the bidirectional transformer circuit 2 is from the first electrical transmission interface 21 to the second electrical transmission interface 22, if the control circuit 3 determines that the voltage value of the second electrical transmission interface 22 is greater than or equal to the first voltage threshold, the electrical transmission direction of the bidirectional transformer circuit 2 is switched from the second electrical transmission interface 22 to the first electrical transmission interface 21, wherein the first electrical transmission interface 21 is the interface of the bidirectional transformer circuit 2 connected to the bidirectional AC / DC conversion circuit 1, and the second electrical transmission interface 22 is the interface of the bidirectional transformer circuit 2 connected to the voltage bus of the target device;

[0090] When the electrical transmission direction of the bidirectional transformer circuit 2 is from the second electrical transmission interface 22 to the first electrical transmission interface 21, if the control circuit 3 determines that the voltage value of the second electrical transmission interface 22 is less than or equal to the second voltage threshold, the electrical transmission direction of the bidirectional transformer circuit 2 is switched from the first electrical transmission interface 21 to the second electrical transmission interface 22, wherein the first voltage threshold is greater than the second voltage threshold.

[0091] In a possible implementation, the second voltage threshold is a normal operating voltage of the target device.

[0092] In a possible implementation, the electrical parameter may be a current direction. The process of controlling the electrical transmission direction of the bidirectional transformer circuit 2 based on the electrical parameter is as follows:

[0093] When the power transmission direction of the bidirectional transformer circuit 2 is from the first power transmission interface 21 to the second power transmission interface 22, if the control circuit 3 determines that the current direction of the second power transmission interface 22 is opposite to the preset current direction, the power transmission direction is switched from the second power transmission interface 22 to the first power transmission interface 21, wherein the first power transmission interface 21 is the interface of the bidirectional transformer circuit 2 connected to the bidirectional AC / DC conversion circuit 1, and the second power transmission interface 22 is the interface of the bidirectional transformer circuit 2 connected to the voltage bus of the target device;

[0094] When the power transmission direction of the bidirectional transformer circuit 2 is from the second power transmission interface 22 to the first power transmission interface 21, if the control circuit 3 determines that the current direction of the second power transmission interface 22 is the same as the preset current direction, the power transmission direction is switched from the first power transmission interface 21 to the second power transmission interface 22.

[0095] In one possible implementation, the control circuit 3 includes a detector 31 and a processor 32; obtaining electrical parameters at a connection between the bidirectional transformer circuit 2 and the voltage bus includes:

[0096] The detector 31 detects the electrical parameters at the connection between the bidirectional transformer circuit 2 and the voltage bus;

[0097] Controlling the electrical transmission direction of the bidirectional transformer circuit 2 based on the electrical parameters includes:

[0098] The processor 32 obtains the electrical parameters detected by the detector 31 and controls the electrical transmission direction of the bidirectional transformer circuit 2 based on the electrical parameters.

[0099] The bidirectional power supply provided in the embodiment of the present application includes a bidirectional AC / DC conversion circuit, a bidirectional transformer circuit and a control circuit. The control circuit can control the electrical transmission direction of the bidirectional transformer circuit according to the electrical parameters at the connection point between the bidirectional transformer circuit and the voltage bus of the target device. Since the electrical parameters at the connection point are directly related to the working state of the motor of the target device, the electrical transmission direction of the bidirectional transformer circuit can be controlled by detecting the electrical parameters. When the motor of the target device is in the power generation working state, the DC power generated by the motor can be transmitted to the bidirectional AC / DC conversion circuit through the bidirectional transformer circuit, and then the bidirectional AC / DC conversion circuit converts the incoming DC power into AC power and transmits it to the AC source. In this way, the present application no longer needs to configure a discharge resistor, a cooling fan, etc. for the target device, which can reduce the production cost of the target device, reduce the volume of the target device, etc.

[0100] Among them, the control method of a bidirectional power supply in this embodiment has the same concept as the embodiment corresponding to the above-mentioned bidirectional power supply. The specific implementation process is detailed in the embodiment corresponding to the bidirectional power supply and will not be repeated here.

[0101] In this application, the terms "first" and "second" are used to distinguish between identical or similar items with substantially the same role and function. It should be understood that there is no logical or temporal dependency between "first" and "second," nor does it limit the quantity or order of execution. The term "plurality" in this application means two or more.

[0102] The above description is only a specific implementation method of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A bidirectional power supply, characterized in that: The bidirectional power supply supplies power to a motor in a target device, and includes a bidirectional AC / DC conversion circuit (1), a bidirectional voltage transformation circuit (2), and a control circuit (3). The target device is a selective compliance assembly robot arm SCARA robot. The SCARA robot is equipped with a robot arm, and the robot arm is driven by a plurality of motors. The plurality of motors constitute a motor system. The motor system further includes an electric energy distribution device, and the electric energy distribution device is used to supply electric energy generated by the motor in a power generation working state to the motor in a power consumption working state, wherein: The bidirectional AC / DC conversion circuit (1) is connected to an AC source and the bidirectional voltage conversion circuit (2) respectively, and the AC source is a power grid; The bidirectional voltage transformation circuit (2) is connected to a voltage busbar of a target device; The control circuit (3) is connected to the bidirectional voltage transformation circuit (2) and is used to: Obtaining a voltage value at a connection point between the bidirectional voltage transformation circuit (2) and the voltage bus; When the electric transmission direction of the bidirectional transformer circuit (2) is from the first electric transmission interface (21) to the second electric transmission interface (22), if the voltage value of the second electric transmission interface (22) is greater than or equal to a first voltage threshold, the electric transmission direction of the bidirectional transformer circuit (2) is switched to from the second electric transmission interface (22) to the first electric transmission interface (21), so as to transmit the current generated by the motor in the power generation working state to the power grid through the bidirectional AC / DC conversion circuit (1), wherein the first electric transmission interface (21) is an interface in the bidirectional transformer circuit (2) connected to the bidirectional AC / DC conversion circuit (1), and the second electric transmission interface (22) is an interface connecting the bidirectional transformer circuit (2) to the voltage bus of the target device; When the electric transmission direction of the bidirectional voltage conversion circuit (2) is from the second electric transmission interface (22) to the first electric transmission interface (21), if the voltage value of the second electric transmission interface (22) is less than or equal to a second voltage threshold, the electric transmission direction of the bidirectional voltage conversion circuit (2) is switched to from the first electric transmission interface (21) to the second electric transmission interface (22) to supply power to the motor in an electric working state, wherein the first voltage threshold is greater than the second voltage threshold, and the second voltage threshold is the operating voltage of the target device.

2. The bidirectional power supply according to claim 1, wherein: The control circuit (3) includes a detector (31) and a processor (32); The detector (31) is used to detect the voltage value at the connection point between the bidirectional voltage transformation circuit (2) and the voltage bus; The processor (32) is used to obtain the voltage value detected by the detector (31), and when the electric transmission direction of the bidirectional transformer circuit (2) is from the first electric transmission interface (21) to the second electric transmission interface (22), if the voltage value of the second electric transmission interface (22) is greater than or equal to a first voltage threshold, the electric transmission direction of the bidirectional transformer circuit (2) is switched to from the second electric transmission interface (22) to the first electric transmission interface (21), so as to transmit the current generated by the motor in the power generation working state to the power grid through the bidirectional AC / DC conversion circuit (1), wherein the first electric transmission interface (21) is a portion of the bidirectional transformer circuit (2) connected to the bidirectional AC / DC conversion circuit (1). The invention relates to an interface for connecting the bidirectional transformer circuit (2) to the voltage bus of the target device, wherein the second electrical transmission interface (22) is an interface for connecting the bidirectional transformer circuit (2) to the voltage bus of the target device; when the electrical transmission direction of the bidirectional transformer circuit (2) is from the second electrical transmission interface (22) to the first electrical transmission interface (21), if the voltage value of the second electrical transmission interface (22) is less than or equal to a second voltage threshold, the electrical transmission direction of the bidirectional transformer circuit (2) is switched to from the first electrical transmission interface (21) to the second electrical transmission interface (22) to supply power to the motor in an electrical working state, wherein the first voltage threshold is greater than the second voltage threshold, and the second voltage threshold is the working voltage of the target device.

3. The bidirectional power supply according to claim 1 or 2, characterized in that: The bidirectional AC / DC conversion circuit (1) is a bidirectional power factor correction (PFC) circuit.

4. The bidirectional power supply according to any one of claims 1 or 2, characterized in that: The bidirectional voltage conversion circuit (2) is a bidirectional dual active bridge DAB circuit.

5. A method for controlling a bidirectional power supply, characterized in that: The bidirectional power supply supplies power to a motor in a target device, and includes a bidirectional AC / DC conversion circuit (1), a bidirectional voltage transformation circuit (2), and a control circuit (3). The target device is a selective compliance assembly robot arm SCARA robot. The SCARA robot is equipped with a robot arm, and the robot arm is driven by a plurality of motors. The plurality of motors constitute a motor system. The motor system further includes an electric energy distribution device, and the electric energy distribution device is used to supply electric energy generated by the motor in a power generation working state to the motor in a power consumption working state. The bidirectional AC / DC conversion circuit (1) is connected to an AC source and the bidirectional voltage transformation circuit (2) respectively, the bidirectional voltage transformation circuit (2) is connected to a voltage bus of a target device, the control circuit (3) is connected to the bidirectional voltage transformation circuit (2), and the AC source is a power grid; The method comprises: the control circuit (3) acquires the voltage value at the connection point between the bidirectional voltage transformation circuit (2) and the voltage bus; When the electric transmission direction of the bidirectional transformer circuit (2) is from the first electric transmission interface (21) to the second electric transmission interface (22), if the control circuit (3) determines that the voltage value of the second electric transmission interface (22) is greater than or equal to the first voltage threshold, the electric transmission direction of the bidirectional transformer circuit (2) is switched to from the second electric transmission interface (22) to the first electric transmission interface (21), so as to transmit the current generated by the motor in the power generation working state to the power grid through the bidirectional AC / DC conversion circuit (1), wherein the first electric transmission interface (21) is an interface in the bidirectional transformer circuit (2) connected to the bidirectional AC / DC conversion circuit (1), and the second electric transmission interface (22) is an interface connecting the bidirectional transformer circuit (2) to the voltage bus of the target device; When the electric transmission direction of the bidirectional voltage conversion circuit (2) is from the second electric transmission interface (22) to the first electric transmission interface (21), if the control circuit (3) determines that the voltage value of the second electric transmission interface (22) is less than or equal to a second voltage threshold, the electric transmission direction of the bidirectional voltage conversion circuit (2) is switched to from the first electric transmission interface (21) to the second electric transmission interface (22) to supply power to the motor in an electric working state, wherein the first voltage threshold is greater than the second voltage threshold, and the second voltage threshold is the operating voltage of the target device.

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