Overvoltage discharge circuit and electronic speed controller

Abstract

This application discloses an overvoltage relief circuit and an electronic speed controller. The overvoltage relief circuit includes a power supply module, a control circuit, and an energy relief module connected in sequence. The control circuit includes a loop on / off module, a bus voltage detection module, a voltage comparison module, and a drive control module. The loop on / off module is electrically connected to the positive bus terminals of the power supply module, the drive control module, and the electronic speed controller, respectively. The bus voltage detection module is electrically connected to the positive bus terminal of the power unit and the voltage comparison module, respectively. The voltage comparison module is electrically connected to the drive control module, and the drive control module is electrically connected to the energy relief module. The energy relief module is electrically connected between the positive and negative bus terminals of the electronic speed controller. This application can relieve energy at the bus terminals of the power unit, preventing excessively high bus terminal voltage from damaging components in the circuit and preventing backflow from damaging the power supply module. It can also employ different energy relief rates according to different bus voltage levels.

Description

Technical Field

[0001] This application relates to the field of power equipment technology, specifically to an overvoltage relief circuit and an electronic speed governor. Background Technology

[0002] An electronic speed controller is a power control device used in motor-driven equipment such as electric scooters, electric drones, model cars, and model boats. It drives the motor to rotate to achieve various operating actions of the equipment.

[0003] During deceleration or braking, the motor will generate a back electromotive force, which will cause the bus voltage to rise, potentially burning out components or even the power supply.

[0004] Therefore, there is an urgent need to provide an overvoltage relief circuit to protect the entire power system. Summary of the Invention

[0005] To solve the above-mentioned technical problems, this application provides an overvoltage discharge circuit and an electronic speed controller, which protects the device from being burned out by discharging the back electromotive force generated by the motor during deceleration or braking.

[0006] According to a first aspect of this application, an overvoltage relief circuit is provided, wherein the overvoltage relief circuit is connected in series between the positive terminal and the negative terminal of the busbar of the power unit, and the overvoltage relief circuit includes a power supply module, a control circuit and an energy discharge module connected in sequence. The control circuit includes a loop on / off module, a bus voltage detection module, a voltage comparison module, and a drive control module. The loop on / off module is electrically connected to the power supply module, the drive control module, and the positive bus terminal of the power unit. The bus voltage detection module is electrically connected to the positive bus terminal of the power unit and the voltage comparison module. The voltage comparison module is electrically connected to the drive control module. The drive control module is electrically connected to the energy discharge module. The energy discharge module is electrically connected between the positive and negative bus terminals of the power unit. The bus voltage detection module is used to compare and detect the bus voltage of the power unit. The voltage comparison module drives the drive control module, and the drive control module controls the energy discharge module to close, thereby discharging energy. The drive control module also controls the circuit switching module to open, thereby preventing power backflow into the power supply module.

[0007] Preferably, the circuit switching module includes a first MOS transistor and a second MOS transistor forming a back-to-back structure.

[0008] Preferably, the bus voltage detection module includes a first voltage divider sampling resistor and a second voltage divider sampling resistor; One end of the first voltage divider sampling resistor is electrically connected to the positive terminal of the bus of the power unit, and the other end is electrically connected to the voltage comparison module and the second voltage divider sampling resistor respectively. The other end of the second voltage divider sampling resistor is grounded.

[0009] Preferably, the voltage comparison module includes a first comparator; The non-inverting input of the first comparator is electrically connected to the common node of the first voltage divider sampling resistor and the second voltage divider sampling resistor, the inverting input is connected to the first reference voltage, and the output is electrically connected to the input of the drive control module.

[0010] Preferably, the energy discharge module includes a first energy consumption element and a third MOSFET; One end of the first energy-consuming element is electrically connected to the positive terminal of the bus of the power device, and the other end is electrically connected to the drain of the third MOS transistor. The source of the third MOS transistor is electrically connected to the negative terminal of the bus of the electronic speed controller, and the gate is electrically connected to the output terminal of the drive control module.

[0011] Preferably, the drive control module includes a gate driver, an inverter, a first isolated optocoupler gate driver, and a first isolated power supply; The input terminal of the gate driver is electrically connected to the output terminal of the voltage comparison module, and the output terminal of the gate driver is electrically connected to the gate of the third MOS transistor. The input terminal of the inverter is electrically connected to the output terminal of the voltage comparator module. The input terminal of the first isolation optocoupler gate driver is electrically connected to the output terminal of the inverter and the first isolation power supply, respectively. The output terminal of the first isolation optocoupler gate driver is electrically connected to the source and gate of the first MOS transistor and the second MOS transistor, respectively.

[0012] Preferably, the bus voltage detection module further includes a third voltage divider sampling resistor, a fourth voltage divider sampling resistor, and a multi-position switch; the voltage comparison module further includes a second comparator; and the drive control module further includes a selection unit. The third and fourth voltage-dividing sampling resistors are connected in series and in parallel with the second voltage-dividing sampling resistor to form different branches. The multi-position switch is used to select the connection between the first voltage-dividing sampling resistor and different branches to realize different levels of voltage detection. The non-inverting input of the second comparator is electrically connected to the common node of the third and fourth voltage-dividing sampling resistors, and the inverting input is connected to the second reference voltage. The selection unit includes a second energy-consuming element, which is used to control the operating state of the second energy-consuming element according to the comparison result of the second comparator, thereby controlling the energy discharge rate.

[0013] Preferably, the selection unit further includes a second isolated optocoupler gate driver, a second isolated power supply, and a fourth MOS transistor; The second energy-consuming element is connected in series between the first energy-consuming element and the third MOS transistor. The drain and source of the fourth MOS transistor are respectively connected to the two ends of the second energy-consuming element. The input terminal of the second isolation optocoupler gate driver is electrically connected to the output terminal of the second comparator and the second isolation power supply, respectively. The output terminal of the second isolation optocoupler gate driver is electrically connected to the gate of the fourth MOS transistor.

[0014] Preferably, the third voltage divider sampling resistor and the fourth voltage divider sampling resistor are configured with multiple sets of different resistance values ​​and form multiple branches, and the second comparator and the selection unit are correspondingly configured with multiple levels; The drive control module further includes an OR logic gate set in the i-th level selection unit, where i∈[2,n], and n is the level of the selection unit; The input of each OR logic gate is electrically connected to the output of the second comparator of the j-th stage, j∈[1,i], and the output of each OR logic gate is electrically connected to the input of the second isolated optocoupler gate driver of the current stage.

[0015] According to a second aspect of this application, an electronic speed controller is provided, including an overvoltage relief circuit as described above, the overvoltage relief circuit being connected in series between the positive and negative terminals of the electronic speed controller's bus.

[0016] This application proposes an overvoltage discharge circuit and an electronic speed controller. When an excessively high bus voltage is detected in the electronic speed controller, a first energy-consuming element dissipates energy to prevent damage to the element due to the excessively high bus voltage. Simultaneously, two back-to-back MOSFETs are shut down to prevent backflow and damage to the power supply module, achieving reverse electromotive force absorption. The power supply is temporarily replaced by an internal capacitor in the electronic speed controller. When the bus voltage of the electronic speed controller is detected to be within a safe range, the two back-to-back MOSFETs are turned on, and the power supply module provides normal power. Furthermore, by setting multiple sampling resistors and using a multi-position switch, different voltage level detection functions can be achieved. A second energy-consuming element can be selected for auxiliary energy discharge, controlling the energy discharge rate and preventing circuit instability caused by overheating of the energy-consuming element or excessive voltage drop. Attached Figure Description

[0017] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and, together with the description, serve to explain the principles of this application. Other embodiments and many anticipated advantages of these embodiments will be readily recognized as they become better understood through reference to the following detailed description. Elements in the drawings are not necessarily to scale. The same reference numerals refer to corresponding similar parts.

[0018] Figure 1 This is a schematic block diagram of an overvoltage discharge circuit according to an embodiment of this application; Figure 2 This is a schematic diagram of an overvoltage discharge circuit according to an embodiment of this application.

[0019] The meaning of each number in the diagram: 10. Overvoltage discharge circuit; 11. Power supply module; 12. Control Circuit; 121. Loop On / Off Module; 1211. First MOSFET; 1212. Second MOSFET; 122. Bus Voltage Detection Module; 1221. First Voltage Divider Sampling Resistor; 1222. Second Voltage Divider Sampling Resistor; 1223. Filter Capacitor; 1224. Third Voltage Divider Sampling Resistor; 1225. Fourth Voltage Divider Sampling Resistor; 1226. Multi-position Switch; 123. Voltage Comparison Module; 1231. First Comparator; 1232. Second Comparator; 124. Drive Control Module; 1241. Gate Driver; 1242. Inverter; 1243. First Isolation Optocoupler Gate Driver; 1244. First Isolation Power Supply; 1245. Second Energy Consumption Component; 1246. Second Isolation Optocoupler Gate Driver; 1247. Second Isolation Power Supply; 1248. Fourth MOSFET; 1249. OR Logic Gate; 13. Energy discharge module; 131. First energy consumption element; 132. Third MOSFET; 20. Power unit. Detailed Implementation

[0020] In the following detailed description, reference is made to the accompanying drawings, which form part of the detailed description and illustrate illustrative specific embodiments in which the present application may be practiced. In this regard, directional terms such as “top,” “bottom,” “left,” “right,” “up,” “down,” etc., are used with reference to the orientation of the described figures. Because components of the embodiments can be positioned in several different orientations, directional terms are used for illustrative purposes and are by no means limiting. It should be understood that other embodiments may be utilized or logical changes may be made without departing from the scope of the present application. Therefore, the following detailed description should not be taken in a limiting sense, and the scope of the present application is defined by the appended claims.

[0021] Furthermore, it should be understood that in the following description, "circuit" refers to a conductive loop consisting of at least one element or sub-circuit connected by electrical or electromagnetic connections. When an element or circuit is said to be "connected" to another element or "connected" between two nodes, it can be directly coupled or connected to another element, or there may be intermediate elements. The connection between elements can be physical, logical, or a combination thereof. Conversely, when an element is said to be "directly coupled to" or "directly connected" to another element, it means that there are no intermediate elements between them.

[0022] According to a first aspect of this application, an overvoltage discharge circuit is proposed. Figure 1 A schematic block diagram of an overvoltage discharge circuit according to an embodiment of this application is shown, such as... Figure 1 As shown, the overvoltage relief circuit 10 is connected in series between the positive and negative terminals of the busbar of the power unit 20. The overvoltage relief circuit 10 includes a power supply module 11, a control circuit 12, and an energy discharge module 13 connected in sequence. Specifically, the control circuit 12 includes a loop switching module 121, a bus voltage detection module 122, a voltage comparison module 123, and a drive control module 124. The loop switching module 121 is electrically connected to the power supply module 11, the drive control module 124, and the positive terminal of the busbar of the power unit 20. The bus voltage detection module 122 is electrically connected to the positive terminal of the busbar of the power unit 20 and the voltage comparison module 123. The voltage comparison module 123 is electrically connected to the drive control module 124. The drive control module 124 is electrically connected to the energy discharge module 13. The energy discharge module 13 is electrically connected between the positive and negative terminals of the busbar of the power unit 20.

[0023] The bus voltage detection module 122 is used to compare the bus voltage of the power unit 20 with the voltage of the power unit 20. The voltage comparison module 123 is used to compare the bus voltage of the power unit 20 with the safe voltage threshold. When the voltage comparison module 123 detects that the bus voltage of the power unit 20 is greater than the safe voltage threshold, the voltage comparison module 123 drives the drive control module 124, and uses the drive control module 124 to control the energy discharge module 13 to close, thereby discharging energy. The drive control module 124 also controls the circuit switching module 121 to open, thereby preventing power backflow to the power supply module 11. Conversely, when the voltage comparison module 123 detects that the bus voltage of the power unit 20 is less than the safe voltage threshold, the voltage comparison module 123 drives the drive control module 124, and the drive control module 124 controls the energy discharge module 13 to open and the circuit switching module 121 to close, so that the power supply module 11 supplies power normally.

[0024] In this embodiment, the power unit 20 is an electronic speed governor. It is understood that in other embodiments, the overvoltage relief circuit can also be applied to other powertrains with the same principle, and the power unit is not limited to an electronic speed governor.

[0025] To better understand this application, the working principle of the overvoltage discharge circuit of this application will be explained below with reference to specific embodiments.

[0026] Figure 2 A schematic diagram of an overvoltage discharge circuit according to an embodiment of this application is shown, such as... Figure 2 As shown, in some embodiments, the circuit switching module 121 includes a first MOSFET 1211 and a second MOSFET 1212 forming a back-to-back structure. The first MOSFET 1211 and the second MOSFET 1212 are connected in series between the power supply module 11 and the positive terminal of the bus of the power device 20. Since a single MOSFET has a body diode, it can only block current in one direction and cannot completely block reverse current. However, the two body diodes of the back-to-back structure MOSFET are in opposite directions, thus enabling bidirectional shutdown and preventing power backflow from damaging the power supply module.

[0027] In some embodiments, the bus voltage detection module 122 includes a first voltage divider sampling resistor 1221, a second voltage divider sampling resistor 1222, and a filter capacitor 1223. The second voltage divider sampling resistor 1222 and the filter capacitor 1223 constitute an RC filter circuit. Specifically, one end of the first voltage divider sampling resistor 1221 is electrically connected to the positive terminal of the bus of the power unit 20, and the other end is electrically connected to the voltage comparison module 123 and grounded through the RC filter circuit. The voltage at the positive terminal of the bus of the power unit 20 is sampled using the common node of the first voltage divider sampling resistor 1221 and the second voltage divider sampling resistor 1222 as the first sampling point and input to the voltage comparison module 123 for comparison. At the same time, the RC filter circuit can perform filtering.

[0028] It should be noted that in this embodiment, the voltage at the positive terminal of the busbar of the power unit 20 is detected by means of a sampling resistor. Those skilled in the art will readily understand that in other embodiments, voltage detection chips, current detection chips, or combined circuits with equivalent functions can also be used to detect the voltage at the positive terminal of the busbar of the power unit; this is not a limitation.

[0029] In some embodiments, the voltage comparison module 123 includes a first comparator 1231, the non-inverting input terminal of the first comparator 1231 being electrically connected to the common node of the first voltage divider sampling resistor 1221 and the second voltage divider sampling resistor 1222, and the inverting input terminal being connected to the first reference voltage V. REF1 The output terminal is electrically connected to the input terminal of the drive control module 124.

[0030] In this embodiment, the first reference voltage V REF1 This can be generated by a reference voltage circuit, which will not be elaborated here. Furthermore, the first reference voltage V... REF1It can be adjusted according to different set safety voltage thresholds.

[0031] In some embodiments, the energy discharge module 13 includes a first energy-consuming element 131 and a third MOSFET 132. One end of the first energy-consuming element 131 is electrically connected to the positive terminal of the bus of the power unit 20, and the other end is electrically connected to the drain of the third MOSFET 132. The source of the third MOSFET 132 is electrically connected to the negative terminal of the bus of the power unit 20, and the gate is electrically connected to the output terminal of the drive control module 124. By selecting the circuit of the first energy-consuming element 131 through the third MOSFET 132, part of the energy can be consumed by the first energy-consuming element 131, avoiding the failure or damage of the entire power system due to the generated overvoltage, thereby ensuring the safe operation of the entire power system.

[0032] In this embodiment, the first energy-consuming element 131 is a resistor. In other embodiments, the first energy-consuming element may also be a heating wire, a ceramic heating element, or other components with equivalent functions; no limitation is made here.

[0033] In some embodiments, the drive control module 124 includes a gate driver 1241, an inverter 1242, a first isolation optocoupler gate driver 1243, and a first isolation power supply 1244. The input terminal of the gate driver 1241 is electrically connected to the output terminal of the first comparator 1231, and the output terminal of the gate driver 1241 is electrically connected to the gate of the third MOSFET 132. The input terminal of the inverter 1242 is electrically connected to the output terminal of the first comparator 1231. The input terminal of the first isolation optocoupler gate driver 1243 is electrically connected to both the output terminal of the inverter 1242 and the first isolation power supply 1244. The output terminal of the first isolation optocoupler gate driver 1243 is simultaneously electrically connected to the source and gate of the first MOSFET 1211 and the second MOSFET 1212.

[0034] Therefore, the control logic of control circuit 12 is as follows: The bus voltage of the power unit 20 is sampled and detected using the first sampling point. When the bus terminal voltage of the power unit 20 is over-voltage, the first comparator 1231 compares the voltage V at the first sampling point. BUS Greater than the first reference voltage V REF1When the first comparator 1231 outputs a signal "1" (high level), the gate driver 1241 drives the third MOSFET 132 to close, dissipating energy through the first energy-consuming element 131, thus releasing energy. Simultaneously, the signal "1" output by the first comparator 1231 is inverted by the inverter 1242 to become "0" (low level), and the first isolation optocoupler gate driver 1243 drives the first MOSFET 1211 and the second MOSFET 1212 to disconnect, preventing backflow of power to the power supply module 11. At this time, the power unit 20 temporarily supplies power through its internal capacitor for a short period.

[0035] When the bus terminal voltage of the power unit 20 is at a safe value, the first comparator 1231 compares the voltage V at the first sampling point. BUS Less than the first reference voltage V REF1 When the first comparator 1231 outputs a signal "0", i.e., a low level, the gate driver 1241 drives the third MOSFET 132 to disconnect, and energy is no longer discharged. At the same time, the signal "0" output by the first comparator 1231 is inverted by the inverter 1242 and becomes "1", i.e., a high level. The first isolation optocoupler gate driver 1243 drives the first MOSFET 1211 and the second MOSFET 1212 to close, and the power supply module 11 resumes normal power supply.

[0036] It should be noted that in this embodiment, since the source of the back-to-back structure formed by the first MOSFET 1211 and the second MOSFET 1212 is floating, a "bootstrapping" is required. This application can replace the bootstrap circuit with the first isolated optocoupler gate driver 1243 and the first isolated power supply 1244 to directly drive the high-measurement Vgs, which is suitable for application scenarios where the MOSFET needs to be 100% on for a long time, ensuring the power supply stability of the power supply module 11. In contrast, the third MOSFET 132 in this embodiment is a "bottom-up bootstrap," so no bootstrap circuit is needed, and it can be driven directly by the gate driver 1241.

[0037] It should be noted that in this embodiment, the third MOSFET 132 is controlled by the gate driver 1241. Those skilled in the art will readily understand that in other embodiments, an MCU controller or other control circuits with equivalent functions can also be used to control the third MOSFET; this is not a limitation.

[0038] As a preferred solution, the positive terminal of the power unit 20 will generate different levels of voltage in different application scenarios. Therefore, the overvoltage discharge circuit 10 needs to be set with different reference safety threshold voltages and perform reference tests for different voltage levels.

[0039] Therefore, in some embodiments, the bus voltage detection module 122 further includes a third voltage divider sampling resistor 1224, a fourth voltage divider sampling resistor 1225 and a multi-position switch 1226, the voltage comparison module 123 further includes a second comparator 1232, and the drive control module 124 further includes a selection unit.

[0040] The third voltage divider sampling resistor 1224 and the fourth voltage divider sampling resistor 1225 are connected in series and in parallel with the second voltage divider sampling resistor 1222 to form different branches. The resistance value of the third voltage divider sampling resistor 1224 and the fourth voltage divider sampling resistor 1225 connected in series is different from the resistance value of the second voltage divider sampling resistor 1222. The multi-position switch 1226 is used to select the connection of the first voltage divider sampling resistor 1221 with different branches to realize different voltage detection levels.

[0041] In this embodiment, the multi-position switch 1226 is a DIP switch.

[0042] The non-inverting input of the second comparator 1232 is electrically connected to the common node of the third voltage divider sampling resistor 1224 and the fourth voltage divider sampling resistor 1225, and the inverting input is connected to the second reference voltage V. REF2 Among them, the second reference voltage V REF2 It is a positive voltage greater than 0, which can also be generated by the reference voltage circuit. The common node of the third voltage divider sampling resistor 1224 and the fourth voltage divider sampling resistor 1225 is used as the second sampling point. It is mainly used to determine which position the multi-position switch 1226 is set to and which branch to select for voltage sampling and detection.

[0043] The selection unit includes at least a second energy-consuming element 1245. The selection unit is used to control the operating state of the second energy-consuming element 1245 according to the comparison result of the second comparator 1232, thereby controlling the energy discharge rate.

[0044] In this embodiment, the second energy-consuming element 1245 is also a resistor. In other embodiments, the second energy-consuming element may also be a heating wire, a ceramic heating element, or other components with equivalent functions; no limitation is made here.

[0045] In some embodiments, the selection unit further includes a second isolation optocoupler gate driver 1246, a second isolation power supply 1247, and a fourth MOSFET 1248. The second energy-consuming element 1245 is connected in series between the first energy-consuming element 131 and the third MOSFET 132. The drain and source of the fourth MOSFET 1248 are respectively connected to the two ends of the second energy-consuming element 1245. The input terminal of the second isolation optocoupler gate driver 1246 is electrically connected to the output terminal of the second comparator 1232 and the second isolation power supply 1247. The output terminal of the second isolation optocoupler gate driver 1246 is electrically connected to the gate of the fourth MOSFET 1248.

[0046] Taking the example that the resistance of the third voltage divider sampling resistor 1224 and the fourth voltage divider sampling resistor 1225 connected in series is less than the resistance of the second voltage divider sampling resistor 1222, the control logic of the control circuit 12 is as follows: When a lower-level reference voltage test is required on the bus voltage of the power unit 20, the multi-position switch 1226 is switched to the branch containing the third voltage divider sampling resistor 1224 and the fourth voltage divider sampling resistor 1225; when the first sampling point detects an overvoltage at the bus terminal of the power unit 20, the gate driver 1241 controls the third MOS transistor 132 to close, at which point the second sampling point detects a voltage greater than the second reference voltage V. REF2 When the positive voltage is applied, the second comparator 1232 outputs a signal "1", the second isolation optocoupler gate driver 1246 drives the fourth MOS transistor 1248 to close, the second energy consumption element 1245 is short-circuited, and at this time energy is discharged only through the first energy consumption element 131.

[0047] When a higher level of reference voltage detection is required on the bus voltage of the power unit 20, the multi-position switch 1226 is switched to the branch where the second voltage divider sampling resistor 1222 is located; when the first sampling point detects an overvoltage at the bus terminal of the power unit 20, the gate driver 1241 controls the third MOSFET 132 to close. At this time, no voltage is detected at the second sampling point, i.e., the output is 0, which is less than the second reference voltage V. REF2 When the second comparator 1232 outputs a signal of "0", the second isolation optocoupler gate driver 1246 drives the fourth MOS transistor 1248 to disconnect and the second energy consumption element 1245 to turn on. At this time, energy is discharged simultaneously through the first energy consumption element 131 and the second energy consumption element 1245.

[0048] In this way, when different levels of bus voltage need to be detected, the operating state of the second energy-consuming element 1245 can be controlled by toggling the multi-position switch 1226, thereby controlling the energy discharge rate. Specifically, for low-level bus voltages, the second energy-consuming element 1245 is short-circuited and not working by the selection unit, while the first energy-consuming element 131 discharges energy alone, which can increase the energy discharge rate. For high-level bus voltages, the second energy-consuming element 1245 is operated by the selection unit, and both the first and second energy-consuming elements 131 discharge energy simultaneously, which can reduce the energy discharge rate, reduce the heat generation of the energy-consuming elements, and avoid circuit instability caused by excessively rapid voltage drops and overheating of the energy-consuming elements.

[0049] In some embodiments, the third voltage divider sampling resistor 1224 and the fourth voltage divider sampling resistor 1225 are configured with multiple sets of different resistance values ​​and form multiple branches, and the second comparator 1232 and the selection unit are correspondingly configured with multiple levels. Specifically, according to different levels of bus voltage detection, the resistance values ​​of the third voltage divider sampling resistor 1224 and the fourth voltage divider sampling resistor 1225 can be set step by step from low level to high level.

[0050] In some embodiments, the drive control module 124 further includes an OR logic gate 1249 disposed in the i-th level selection unit, where i ∈ [2, n] and n is the level of the selection unit. The input terminal of each OR logic gate 1249 is electrically connected to the output terminal of the second comparator 1232 of the j-th level, j ∈ [1, i], and the output terminal of each OR logic gate 1249 is electrically connected to the input terminal of the second isolated optocoupler gate driver 1246 of the current level.

[0051] Reference Figure 2 Based on the bus voltage detection from low to high levels, taking the third voltage divider sampling resistor 1224 and the fourth voltage divider sampling resistor 1225 as an example with 3 levels, the control logic of the control circuit 12 is as follows: For low-level bus voltage detection, the multi-position switch 1226 is set to position 1, the third-level second comparator 1232 outputs "1 0 0" respectively, the output logic of the third-level selection unit is finally "1 1 1", the third-level second energy consumption element 1245 is short-circuited at the same time, and the first energy consumption element 131 discharges energy separately.

[0052] For medium-level bus voltage detection, the multi-position switch 1226 is switched to position 2. The third-stage second comparator 1232 outputs "0 1 0" respectively. The output logic of the third-stage selection unit is finally "0 1 1". The second energy consumption element 1245 of the second and third stages is short-circuited, and the second energy consumption element 1245 of the first stage is activated.

[0053] For high-level bus voltage detection, the multi-position switch 1226 is switched to position 3, and the third-stage second comparator 1232 outputs "0 0 1" respectively. The output logic of the third-stage selection unit is finally "0 0 1". The second energy consumption element 1245 of the third stage is short-circuited, and the second energy consumption elements 1245 of the first and second stages are working.

[0054] For the highest level of bus voltage detection, the multi-position switch 1226 is switched to position 4, the third-level second comparator 1232 outputs "0 0 0" respectively, the output logic of the third-level selection unit is finally "0 0 0", and the third-level second energy consumption element 1245 works at the same time.

[0055] Based on the above logic, by toggling the multi-position switch 1226 according to different bus voltage levels, different combinations and resistance values ​​of energy-consuming components can be switched, thereby controlling the energy discharge rate and ensuring the safety and stability of the circuit.

[0056] In summary, the overvoltage discharge circuit 10 proposed in this application, when detecting that the bus terminal voltage of the power unit 20 is too high, utilizes the first energy-consuming element 131 to dissipate energy, preventing damage to the components due to the excessive bus terminal voltage. Simultaneously, it shuts down two back-to-back MOSFETs to prevent backflow and damage to the power supply module 11, achieving reverse electromotive force absorption, with the power supply temporarily replaced by the internal capacitor of the power unit 20. When the bus terminal voltage of the power unit 20 is detected to be at a safe value, the first energy-consuming element 131 is disconnected, and the two back-to-back MOSFETs are simultaneously turned on, allowing the power supply module 11 to supply power normally. Furthermore, by setting multiple sampling resistors and toggling the multi-position switch 1226, different voltage level detection functions can be achieved, and the second energy-consuming element 1245 can be selected accordingly for auxiliary energy discharge, controlling the energy discharge rate and preventing circuit instability caused by overheating of the energy-consuming elements or excessive voltage drops.

[0057] According to a second aspect of this application, an electronic speed controller is also proposed, including the overvoltage relief circuit of the first aspect described above, wherein the overvoltage relief circuit is connected in series between the positive terminal and the negative terminal of the busbar of the electronic speed controller.

[0058] It is obvious that those skilled in the art can make various modifications and alterations to the embodiments of this application without departing from the spirit and scope of this application. In this way, this application also aims to cover such modifications and alterations if they fall within the scope of the claims and their equivalents. The word "comprising" does not exclude the presence of other elements or steps not listed in the claims. The simple fact that certain measures are described in mutually different dependent claims does not indicate that a combination of these measures cannot be used for profit. Any reference numerals in the claims should not be considered limiting in scope.

Claims

1. An overvoltage discharge circuit, characterized in that, The overvoltage relief circuit is connected in series between the positive end and the negative end of the busbar of the power unit. The overvoltage relief circuit includes a power supply module, a control circuit and an energy relief module connected in sequence. The control circuit includes a loop on / off module, a bus voltage detection module, a voltage comparison module, and a drive control module. The loop on / off module is electrically connected to the power supply module, the drive control module, and the positive bus terminal of the power unit. The bus voltage detection module is electrically connected to the positive bus terminal of the power unit and the voltage comparison module. The voltage comparison module is electrically connected to the drive control module. The drive control module is electrically connected to the energy discharge module. The energy discharge module is electrically connected between the positive and negative bus terminals of the power unit. The bus voltage detection module is used to compare and detect the bus voltage of the power unit. The voltage comparison module drives the drive control module, and the drive control module controls the energy discharge module to close, thereby discharging energy. The drive control module also controls the circuit switching module to open, thereby preventing power backflow into the power supply module.

2. The overvoltage discharge circuit according to claim 1, characterized in that, The circuit switching module includes a first MOSFET and a second MOSFET that form a back-to-back structure.

3. The overvoltage discharge circuit according to claim 2, characterized in that, The bus voltage detection module includes a first voltage divider sampling resistor and a second voltage divider sampling resistor; One end of the first voltage divider sampling resistor is electrically connected to the positive terminal of the bus of the power unit, and the other end is electrically connected to the voltage comparison module and the second voltage divider sampling resistor respectively. The other end of the second voltage divider sampling resistor is grounded.

4. The overvoltage discharge circuit according to claim 3, characterized in that, The voltage comparison module includes a first comparator; The non-inverting input of the first comparator is electrically connected to the common node of the first voltage divider sampling resistor and the second voltage divider sampling resistor, the inverting input is connected to the first reference voltage, and the output is electrically connected to the input of the drive control module.

5. The overvoltage discharge circuit according to claim 3, characterized in that, The energy dissipation module includes a first energy consumption element and a third MOSFET; One end of the first energy-consuming element is electrically connected to the positive terminal of the bus of the power device, and the other end is electrically connected to the drain of the third MOS transistor. The source of the third MOS transistor is electrically connected to the negative terminal of the bus of the power device, and the gate is electrically connected to the output terminal of the drive control module.

6. The overvoltage discharge circuit according to claim 5, characterized in that, The drive control module includes a gate driver, an inverter, a first isolated optocoupler gate driver, and a first isolated power supply. The input terminal of the gate driver is electrically connected to the output terminal of the voltage comparison module, and the output terminal of the gate driver is electrically connected to the gate of the third MOS transistor. The input terminal of the inverter is electrically connected to the output terminal of the voltage comparator module. The input terminal of the first isolation optocoupler gate driver is electrically connected to the output terminal of the inverter and the first isolation power supply, respectively. The output terminal of the first isolation optocoupler gate driver is electrically connected to the source and gate of the first MOS transistor and the second MOS transistor, respectively.

7. The overvoltage discharge circuit according to claim 5, characterized in that, The bus voltage detection module further includes a third voltage divider sampling resistor, a fourth voltage divider sampling resistor, and a multi-position switch; the voltage comparison module further includes a second comparator; and the drive control module further includes a selection unit. The third and fourth voltage-dividing sampling resistors are connected in series and in parallel with the second voltage-dividing sampling resistor to form different branches. The multi-position switch is used to select the connection between the first voltage-dividing sampling resistor and different branches to realize different levels of voltage detection. The non-inverting input of the second comparator is electrically connected to the common node of the third and fourth voltage-dividing sampling resistors, and the inverting input is connected to the second reference voltage. The selection unit includes a second energy-consuming element, which is used to control the operating state of the second energy-consuming element according to the comparison result of the second comparator, thereby controlling the energy discharge rate.

8. The overvoltage discharge circuit according to claim 7, characterized in that, The selection unit further includes a second isolated optocoupler gate driver, a second isolated power supply, and a fourth MOS transistor; The second energy-consuming element is connected in series between the first energy-consuming element and the third MOS transistor. The drain and source of the fourth MOS transistor are respectively connected to the two ends of the second energy-consuming element. The input terminal of the second isolation optocoupler gate driver is electrically connected to the output terminal of the second comparator and the second isolation power supply, respectively. The output terminal of the second isolation optocoupler gate driver is electrically connected to the gate of the fourth MOS transistor.

9. The overvoltage discharge circuit according to claim 8, characterized in that, The third and fourth voltage divider sampling resistors are configured with multiple sets of different resistance values ​​and form multiple branches. The second comparator and the selection unit are correspondingly configured with multiple levels. The drive control module further includes an OR logic gate set in the i-th level selection unit, where i∈[2,n], and n is the level of the selection unit; The input of each OR logic gate is electrically connected to the output of the second comparator of the j-th stage, j∈[1,i], and the output of each OR logic gate is electrically connected to the input of the second isolated optocoupler gate driver of the current stage.

10. An electronic speed controller, characterized in that, Includes an overvoltage relief circuit as described in any one of claims 1-9, wherein the overvoltage relief circuit is connected in series between the positive and negative terminals of the busbar of the electronic speed controller.

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