An active rectification circuit and power supply system
Patent Information
- Application Number
- CN202522570245.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-03
- Publication Date
- 2026-11-03
- Estimated Expiration
- 2035-12-03
AI Technical Summary
Traditional active rectifier circuits are complex in structure, have low integration, high hardware cost, and are difficult and time-consuming to debug.
An H-bridge rectifier circuit, an AC current sampling circuit, and a controller are used. Overcurrent protection is achieved by controlling the protection switch through the controller, and the controller with multiplexed active switching transistors is used for current and voltage sampling.
It simplifies the circuit structure, increases integration, reduces hardware costs, simplifies the debugging process, and improves the reliability and safety of the circuit.
Smart Images
Figure CN224935355U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of power electronics technology, specifically to an active rectifier circuit and a power supply system. Background Technology
[0002] Traditional active rectifier circuits mostly use analog circuits for circuit protection. For example, parameters such as voltage and current can be sampled using pure hardware circuits, combined with comparators, operational amplifiers, and switching devices to achieve circuit protection. This makes the active rectifier circuit structure relatively complex, with low integration, and high hardware costs. Moreover, the hardware sampling circuit is difficult to debug and has a long debugging cycle. Utility Model Content
[0003] In view of this, this application provides an active rectifier circuit and power supply system that can reuse the controller of the active switching transistor to realize overcurrent protection of the active rectifier circuit.
[0004] To solve the above problems, the technical solution provided in this application is as follows:
[0005] In a first aspect of this application, an active rectifier circuit is provided, comprising: an H-bridge rectifier circuit, an AC current sampling circuit, a protection switch, and a controller;
[0006] The H-bridge rectifier circuit includes four active switching transistors;
[0007] An AC current sampling circuit is used to detect the current in the H-bridge rectifier circuit and send the detected current to the controller; a protection switch is connected in series between the output of the H-bridge rectifier circuit and the load.
[0008] The controller is used to control the protection switch to open when the current is greater than the current threshold, and to turn the protection switch back on after a first preset time. If the current is greater than the current threshold again, the controller will control the protection switch to open again. The controller is also used to send drive signals to the active switching transistor.
[0009] In one possible implementation, the controller is also configured to acquire the number of times the current exceeds a current threshold, and when the number of times the current exceeds the current threshold reaches a first threshold, control the protection switch to remain off.
[0010] In one possible implementation, the controller is also used to control the active switch and the protection switch to turn off when the direction of the current is opposite to the preset current direction, and after a second preset time, to turn on the active switch and the protection switch. If the direction of the current is again opposite to the preset current direction, the controller will then control the active switch and the protection switch to turn off again.
[0011] In one possible implementation, the controller is also configured to acquire the number of times the current direction is opposite to a preset current direction, and when the number of times the current direction is opposite to the preset current direction reaches a second threshold, control the active switch and the protection switch to remain off.
[0012] In one possible implementation, the controller is also used to acquire the input voltage and output voltage of the H-bridge rectifier circuit, and to turn on the active switch and protection switch when the input voltage is higher than the output voltage.
[0013] In one possible implementation, the protective switch includes a relay, and the controller is further configured to control the relay to turn off when the direction of the current is opposite to a preset current direction, and to turn the relay on after a second preset time, and to control the relay to turn off again when the direction of the current is opposite to the preset current direction again.
[0014] In one possible implementation, the controller is further configured to acquire the number of times the current direction is opposite to a preset current direction, and when the number of times the current direction is opposite to the preset current direction reaches a second threshold, control the relay to remain off.
[0015] In one possible implementation, the controller is also used to acquire the input voltage and the output voltage of the H-bridge rectifier circuit, and to turn on the relay when the input voltage is higher than the output voltage.
[0016] In one possible implementation, the four active switching transistors include a first switching transistor, a second switching transistor, a third switching transistor, and a fourth switching transistor;
[0017] The controller is also used to send drive signals to the active switching transistors, including: when the input voltage of the H-bridge rectifier circuit is positive, the controller controls the first and fourth switching transistors to turn on and the second and third switching transistors to turn off; when the input voltage of the H-bridge rectifier circuit is negative, the controller controls the second and third switching transistors to turn on and the first and fourth switching transistors to turn off.
[0018] In a second aspect of this application, a power supply system is provided, including the above-mentioned active rectifier circuit, and further including an AC power supply and a load;
[0019] The AC power supply is connected to the input terminal of the active rectifier circuit, and the load is connected to the output terminal of the active rectifier circuit.
[0020] The active rectifier circuit provided in this application controls the protection switch to open when the current flowing through the H-bridge rectifier circuit is large, thereby protecting the active switching transistor and subsequent circuits and reducing overcurrent damage. The controller turns the protection switch back on after a first preset time since the protection switch opened, automatically restoring the function of the active rectifier circuit after the momentary overcurrent fault ends, reducing human intervention. The active rectifier circuit achieves overcurrent protection by using a controller that reuses the active switching transistor, saving the need for dedicated analog circuitry for protection functions, resulting in high integration, simple structure, and reduced hardware costs. Furthermore, the use of a controller for current and voltage sampling simplifies debugging. Attached Figure Description
[0021] Figure 1 A schematic diagram of an active rectifier circuit provided in an embodiment of this application;
[0022] Figure 2 A schematic diagram of another active rectifier circuit provided in an embodiment of this application;
[0023] Figure 3 A schematic diagram illustrating a protective switch connection method provided in an embodiment of this application;
[0024] Figure 4 A schematic diagram of another active rectifier circuit provided in an embodiment of this application;
[0025] Figure 5 A schematic diagram of another active rectifier circuit provided in an embodiment of this application;
[0026] Figure 6 A schematic diagram of another active rectifier circuit provided in an embodiment of this application;
[0027] Figure 7 This is a schematic diagram of another active rectifier circuit provided in an embodiment of this application. Detailed Implementation
[0028] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the embodiments of this application will be further described in detail below with reference to the accompanying drawings and specific implementation methods.
[0029] See Figure 1 The figure is a schematic diagram of an active rectifier circuit provided in an embodiment of this application.
[0030] The active rectifier circuit provided in this application includes an H-bridge rectifier circuit 10, an AC current sampling circuit 20, a protection switch 30, and a controller 40.
[0031] The H-bridge rectifier circuit 10 includes four active switching transistors.
[0032] The AC current sampling circuit 20 is used to detect the current of the H-bridge rectifier circuit 10 and send the detected current to the controller 40; the protection switch 30 is connected in series between the output terminal of the H-bridge rectifier circuit 10 and the load.
[0033] The controller 40 is used to control the protection switch 30 to open when the current exceeds the current threshold, and to turn the protection switch 30 back on after a first preset time; if the current exceeds the current threshold again, the controller 40 will control the protection switch 30 to open again. The controller 40 is also used to send drive signals to the four active switching transistors.
[0034] When the current flowing through the H-bridge rectifier circuit 10 is large, or when a surge occurs on the AC side, it may cause overcurrent damage to the active switching transistors and downstream loads in the H-bridge rectifier circuit 10. When the current exceeds the current threshold, the controller 40 controls the protection switch 30 to open, which can promptly cut off the large current, realize overcurrent protection for the active rectifier circuit, protect the active switching transistors and downstream loads, and reduce the risk of overcurrent damage to the devices.
[0035] After the protection switch 30 is opened for a first preset time, the controller 40 turns on the protection switch 30, which can automatically restore the function of the active rectifier circuit after the instantaneous overcurrent ends, thereby reducing manual intervention. When the current exceeds the current threshold again, the controller 40 controls the protection switch 30 to open again, thus allowing the active rectifier circuit to achieve multiple shutdowns and restarts. The control method is simple and highly reliable.
[0036] The active rectifier circuit provided in this application embodiment controls the protection switch to open when the current flowing through the H-bridge rectifier circuit is large, thereby protecting the active switching transistor and subsequent circuits and reducing overcurrent damage. After the protection switch has been open for a first preset time, the controller re-opens the protection switch, automatically restoring the function of the active rectifier circuit after the momentary overcurrent fault ends, reducing human intervention. The active rectifier circuit achieves overcurrent protection by using a controller that reuses the active switching transistor, saving the need for dedicated analog circuits for protection functions, resulting in high circuit integration, simple structure, and reduced hardware costs. Furthermore, the use of a controller for current and voltage sampling simplifies debugging.
[0037] In one possible implementation, the controller is also used to acquire the number of times the current exceeds a current threshold. When the number of times the current exceeds the current threshold reaches a first threshold, the controller controls the protection switch to remain off.
[0038] See also Figure 1 When the number of times the current exceeds the current threshold reaches the first threshold, it indicates that the active rectifier circuit may have a non-instantaneous, continuous overcurrent fault. At this time, the controller 40 controls the protection switch 30 to remain off, which helps to improve the reliability of the active rectifier circuit.
[0039] The active rectifier circuit provided in this application embodiment can improve the reliability of circuit protection and reduce the number of times the current exceeds the current threshold. When the number of times the current exceeds the current threshold reaches a first threshold, the controller controls the protection switch to remain off. This reduces the cumulative damage to the active switching transistor and the load.
[0040] In one possible implementation, the controller is also used to control the active switch and the protection switch to turn off when the current direction is opposite to the preset current direction, and to turn on the active switch and the protection switch after a second preset time. If the current direction is opposite to the preset current direction again, the controller will then control the active switch and the protection switch to turn off.
[0041] See also Figure 1 When the current direction is opposite to the preset current direction, it indicates that an unwanted current backflow has occurred in the active rectifier circuit. When the current direction is opposite to the preset current direction, the controller 40 controls the protection switch 30 and the active switching transistor of the H-bridge rectifier circuit 10 to disconnect, which can achieve the effect of timely cutting off the current backflow.
[0042] After the active switch and protection switch 30 of the H-bridge rectifier circuit 10 are turned off for a second preset time, the controller 40 turns on the active switch and protection switch 30 of the H-bridge rectifier circuit 10. This allows the active rectifier circuit to automatically restore its function after a momentary backflow of current, thus reducing manual intervention. When the current direction is again opposite to the preset current direction, the controller 40 then controls the active switch and protection switch 30 of the H-bridge rectifier circuit 10 to turn off again, allowing the active rectifier circuit to achieve multiple shutdowns and restarts. The control method is simple and highly reliable.
[0043] The active rectifier circuit provided in this application embodiment has a controller that disconnects the active switching transistors and protection switches in the H-bridge rectifier circuit when the current direction is opposite to the preset current direction, thereby promptly cutting off the reverse current flow. After the active switching transistors and protection switches in the H-bridge rectifier circuit have been disconnected for a second preset time, the controller turns on the active switching transistors and protection switches in the H-bridge rectifier circuit, which can automatically restore the function of the active rectifier circuit after the instantaneous reverse current flow ends, reducing human intervention.
[0044] See also Figure 1 In one possible implementation, the controller 40 is also used to obtain the number of times the current direction is opposite to the preset current direction, and when the number of times the current direction is opposite to the preset current direction reaches a second threshold, control the active switch and the protection switch 30 in the H-bridge rectifier circuit 10 to remain off.
[0045] When the number of times the current direction is opposite to the preset current direction reaches the second threshold, it indicates that the active rectifier circuit may have experienced a non-instantaneous, continuous current backflow. At this time, the controller controls the active switching transistor and protection switch 30 in the H-bridge rectifier circuit 10 to remain off, which helps to improve the reliability of the active rectifier circuit.
[0046] The active rectifier circuit provided in this application embodiment can improve the reliability of circuit protection and reduce the number of times the protection switch is repeatedly activated when the number of times the current direction is opposite to the preset current direction reaches a second threshold.
[0047] The embodiments of this application do not specifically limit the values of the first threshold and the second threshold, nor do they specifically limit the values of the first preset time and the second preset time. The first threshold, the second threshold, the first preset time, and the second preset time can be selected according to the actual working conditions.
[0048] In one possible implementation, the controller is also used to acquire the input voltage and output voltage of the H-bridge rectifier circuit, and when the input voltage is higher than the output voltage, to turn on the active switching transistor and protection switch in the H-bridge rectifier circuit.
[0049] See Figure 2 The figure is a schematic diagram of another active rectifier circuit provided in an embodiment of this application.
[0050] Figure 2 In this circuit, the controller 40 is also used to acquire the input voltage Vin and the output voltage Vout of the H-bridge rectifier circuit 10. When the input voltage Vin of the H-bridge rectifier circuit 10 is higher than the output voltage Vout, it indicates that current can flow from the input to the output of the H-bridge rectifier circuit 10. The controller 40 determines that there will be no reverse current flow and turns on the active switch and the protection switch 30 in the H-bridge rectifier circuit 10. This allows the active rectifier circuit to resume its function without reverse current flow, resulting in high reliability.
[0051] This application does not specifically limit the type of protection switch. One possible implementation is that the protection switch may include a fully controllable switching transistor, capable of both controlling the protection switch's on and off states. For example, the protection switch may include an Insulated Gate Bipolar Transistor (IGBT), a Power Metal-Oxide-Semiconductor Field-Effect Transistor (PowerMOSFET), or a Gate Turn-Off Thyristor (GTO). Another possible implementation is that the protection switch may also include a relay.
[0052] In one possible implementation, when using a MOSFET as a protection switch, the body diode of the protection switch needs to be connected top-to-top with the body diode of the active switch in the H-bridge rectifier circuit. That is, a path cannot be formed between the body diode of the protection switch and the body diode of the active switch in the H-bridge rectifier circuit. This prevents current from still supplying power to the load through the body diode of the protection switch and the body diode of the active switch in the H-bridge rectifier circuit when the protection switch is turned off.
[0053] See Figure 3 The figure is a schematic diagram of a protective switch connection method provided in an embodiment of this application.
[0054] In one possible implementation, the protective switch includes a relay, and the controller is further configured to control the relay to turn off when the direction of the current is opposite to a preset current direction, and to turn the relay on after a second preset time, and to control the relay to turn off again when the direction of the current is opposite to the preset current direction again.
[0055] See Figure 4 This figure is a schematic diagram of another active rectifier circuit provided in an embodiment of this application.
[0056] Figure 4 and Figure 1 The difference is that, Figure 4 The protective switch 30 includes a relay S. In this case, the controller 40 does not need to control the active switching transistor in the H-bridge rectifier circuit 10. It can cut off the current path by turning off the relay S, thereby achieving the effect of timely cutting off the reverse current.
[0057] In one possible implementation, the controller is further configured to acquire the number of times the current direction is opposite to a preset current direction, and when the number of times the current direction is opposite to the preset current direction reaches a second threshold, control the relay to remain off.
[0058] In one possible implementation, the controller is also used to acquire the input voltage and the output voltage of the H-bridge rectifier circuit, and to turn on the relay when the input voltage is higher than the output voltage.
[0059] The active rectifier circuit provided in this application embodiment indicates that when the input voltage of the H-bridge rectifier circuit is higher than the output voltage, it means that the current can flow from the input terminal to the output terminal of the H-bridge rectifier circuit. The controller determines that there will be no current backflow at this time, and turns on the relay. The function of the active rectifier circuit can be restored without current backflow in the circuit. The control method is simple and highly reliable.
[0060] This application does not specifically limit the location of the AC current sampling circuit. The AC current sampling circuit can be connected in series at the input terminal of the H-bridge rectifier circuit or at the output terminal of the H-bridge rectifier circuit. Figure 1 The following explanation uses the example of the AC current sampling circuit 20 being connected to the negative output terminal of the H-bridge rectifier circuit 10. Other connection methods of the AC current sampling circuit will be explained below with reference to the accompanying drawings.
[0061] See Figure 5 The figure is a schematic diagram of another rectifier circuit provided in an embodiment of this application.
[0062] Figure 5 and Figure 1 The difference is that, Figure 5 In the circuit, the AC current sampling circuit 20 is connected to the negative input terminal of the H-bridge rectifier circuit 10.
[0063] This application does not specifically limit the structure of the AC sampling circuit. The AC current sampling circuit may include a Hall sensor, a current transformer, or a sampling resistor, etc. It should be noted that, for circuit safety, when the AC current sampling circuit is connected to the input or positive output of an H-bridge rectifier circuit, AC current sampling needs to be performed using isolated sampling. In this case, the AC current sampling circuit may include a Hall sensor, a current transformer, a sampling resistor, and an isolation amplifier, etc.
[0064] This application does not specifically limit the relative positions of the AC current sampling circuit and the protection switch. The AC current sampling circuit and the protection switch can be located on the same side of the output terminal of the H-bridge rectifier circuit, or they can be located on opposite sides of the output terminal of the H-bridge rectifier circuit. In one possible implementation, so that the controller can still obtain the sampling result of the AC current sampling circuit after the protection switch is opened, when the AC current sampling circuit and the protection switch are located on the same side of the output terminal of the H-bridge rectifier circuit, the AC current sampling circuit can be connected in series between the first output terminal of the H-bridge rectifier circuit and the protection switch.
[0065] See Figure 6This figure is a schematic diagram of another active rectifier circuit provided in an embodiment of this application.
[0066] Figure 6 and Figure 1 The difference is that, Figure 1 The AC current sampling circuit 20 and the protection switch 30 are located on opposite output terminals of the H-bridge rectifier circuit 10. Figure 6 The AC current sampling circuit 20 and the protection switch 30 are located on the same output side of the H-bridge rectifier circuit 10. Specifically, Figure 6 The AC current sampling circuit 20 is connected in series between the negative output terminal of the H-bridge rectifier circuit 10 and the protection switch 30.
[0067] See Figure 7 This figure is a schematic diagram of another active rectifier circuit provided in an embodiment of this application.
[0068] In one possible implementation, the four active switching transistors of the H-bridge rectifier circuit 10 include a first switching transistor T1, a second switching transistor T2, a third switching transistor T3, and a fourth switching transistor T4.
[0069] The controller 40 is also used to send drive signals to the four active switching transistors, including: when the input voltage of the H-bridge rectifier circuit 10 is positive, the controller 40 controls the first switching transistor T1 and the fourth switching transistor T4 to turn on and the second switching transistor T2 and the third switching transistor T3 to turn off; when the input voltage of the H-bridge rectifier circuit 10 is negative, it controls the second switching transistor T2 and the third switching transistor T3 to turn on and the first switching transistor T1 and the fourth switching transistor T4 to turn off.
[0070] Based on the active rectifier circuit provided in the above embodiments, this application also provides a power supply system. The power supply system provided in this application includes the active rectifier circuit provided in the above embodiments, and also includes an AC power supply and a load.
[0071] The AC power supply is connected to the input terminal of the active rectifier circuit, and the load is connected to the output terminal of the active rectifier circuit.
[0072] In one possible implementation, the power supply system provided in this application embodiment may further include a step-down circuit. The output voltage of the active rectifier circuit is stepped down by the step-down circuit to supply power to loads with lower voltage levels. For example, the power supply system provided in this application embodiment can supply power to a controller.
[0073] This application does not specifically limit the type of controller, and can be flexibly selected according to the actual application scenario. The controller can realize functions such as analog / digital signal conversion, numerical magnitude judgment, port level control, and pulse width modulation wave transmission. For example, the controller can be a microcontroller unit (MCU), a field-programmable gate array (FPGA), or a digital signal processor (DSP), or a central processing unit (CPU) or other control unit with data processing and logic control capabilities.
[0074] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.
[0075] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. An active rectifier circuit, characterized in that, include: H-bridge rectifier circuit, AC current sampling circuit, protection switch and controller; The H-bridge rectifier circuit includes four active switching transistors; The AC current sampling circuit is used to detect the current of the H-bridge rectifier circuit and send the detected current to the controller; the protection switch is connected in series between the output terminal of the H-bridge rectifier circuit and the load. The controller is configured to open the protection switch when the current is greater than the current threshold, and turn the protection switch on after a first preset time. If the current is greater than the current threshold again, the controller will then open the protection switch again. The controller is also used to send drive signals to the active switching transistor.
2. The active rectifier circuit according to claim 1, characterized in that, The controller is also configured to acquire the number of times the current exceeds the current threshold, and when the number of times the current exceeds the current threshold reaches a first threshold, control the protection switch to remain off.
3. The active rectifier circuit according to claim 2, characterized in that, The controller is also configured to control the active switch and the protection switch to turn off when the direction of the current is opposite to the preset current direction, and to turn on the active switch and the protection switch after a second preset time. If the direction of the current is again opposite to the preset current direction, the controller will then control the active switch and the protection switch to turn off again.
4. The active rectifier circuit according to claim 3, characterized in that, The controller is also configured to acquire the number of times the current direction is opposite to the preset current direction, and when the number of times the current direction is opposite to the preset current direction reaches a second threshold, control the active switch and the protection switch to remain off.
5. The active rectifier circuit according to claim 4, characterized in that, The controller is also used to acquire the input voltage and the output voltage of the H-bridge rectifier circuit, and when the input voltage is higher than the output voltage, to turn on the active switch and the protection switch.
6. The active rectifier circuit according to claim 2, characterized in that, The protective switch includes a relay, and the controller is further configured to control the relay to turn off when the direction of the current is opposite to the preset current direction, and to turn the relay on after a second preset time, and to control the relay to turn off again when the direction of the current is opposite to the preset current direction again.
7. The active rectifier circuit according to claim 6, characterized in that, The controller is also configured to acquire the number of times the current direction is opposite to the preset current direction, and when the number of times the current direction is opposite to the preset current direction reaches a second threshold, control the relay to remain off.
8. The active rectifier circuit according to claim 7, characterized in that, The controller is also used to acquire the input voltage and the output voltage of the H-bridge rectifier circuit, and to turn on the relay when the input voltage is higher than the output voltage.
9. The active rectifier circuit according to claim 1, characterized in that, The four active switching transistors include a first switching transistor, a second switching transistor, a third switching transistor, and a fourth switching transistor; The controller is further configured to send drive signals to the active switching transistors, including: when the input voltage of the H-bridge rectifier circuit is positive, the controller controls the first and fourth switching transistors to turn on and the second and third switching transistors to turn off; when the input voltage of the H-bridge rectifier circuit is negative, the controller controls the second and third switching transistors to turn on and the first and fourth switching transistors to turn off.
10. A power supply system, characterized in that, The circuit includes the active rectifier circuit according to any one of claims 1 to 9, and further includes an AC power supply and a load; The AC power supply is connected to the input terminal of the active rectifier circuit, and the load is connected to the output terminal of the active rectifier circuit.