A heater driving circuit and a control method thereof, a heating device, and a vehicle

Abstract

The application provides a kind of heater driving circuit and its control method, heating device and vehicle field, belong to power electronics technical field, this heater driving circuit includes control circuit, first switch tube, second switch tube.The first controlled end of first switch tube is connected with power supply, and the second controlled end of first switch tube is connected with the first end of heater;The first controlled end of second switch tube is connected with the second end of heater, and the second controlled end of second switch tube is grounded;Control circuit is connected with the control end of first switch tube and the control end of second switch tube respectively, and control circuit responds to the power-on of heater driving circuit, and carries out short-circuit fault diagnosis to first switch tube and second switch tube;In response to the short-circuit fault of first switch tube and second switch tube, control second switch tube to continue conduction;Control first switch tube periodic conduction based on received heating demand instruction.The technical scheme of the application can improve the robustness of heater driving circuit operation.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, specifically to a heater drive circuit and its control method, a heating device, and a vehicle. Background Technology

[0002] In the fields of electronic power and heating control, positive temperature coefficient (PTC) heaters are widely used in new energy vehicle air conditioning, industrial temperature control systems, and other fields due to their advantages such as automatic temperature control and safety and reliability. The drive circuit of these heaters typically uses solid-state switches (e.g., insulated-gate bipolar transistors, IGBTs) to control the power supply.

[0003] However, when using IGBTs for high-frequency on / off control of the power supply, the nonlinear resistive characteristics of IGBTs can cause voltage coupling oscillations in the drive circuit, which can lead to short-circuit failure of the IGBT due to negative voltage impacts, resulting in insufficient robustness of the drive circuit. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this application is to provide a heater drive circuit and its control method, a heating device and a vehicle, which aims to improve the stability of the drive circuit operation.

[0005] In a first aspect, embodiments of this application provide a heater driving circuit. The heater driving circuit includes a control circuit, a first switching transistor, and a second switching transistor. A first controlled terminal of the first switching transistor is connected to a power supply, and a second controlled terminal is connected to a first end of the heater; the first controlled terminal of the second switching transistor is connected to a second end of the heater, and the second controlled terminal is grounded. The control circuit is connected to the control terminals of both the first and second switching transistors, and is configured to: in response to power-on of the heater driving circuit, perform short-circuit fault diagnosis on the first and second switching transistors; in response to the absence of a short-circuit fault in the first and second switching transistors, control the second switching transistor to remain continuously on, while simultaneously controlling the first switching transistor to periodically turn on based on received heating demand commands.

[0006] In this embodiment, the control circuit can diagnose the states of the first and second switching transistors. In the absence of a short circuit, the second switching transistor is continuously turned on. Simultaneously, based on the received heating demand command, the first switching transistor is periodically turned on, thus controllably meeting the power required for heating. Continuously turning on the second switching transistor avoids irreversible damage to it caused by voltage coupling oscillations in the heater drive circuit, reduces the risk of short-circuit failure due to negative voltage surges, and improves the stability of the drive circuit operation.

[0007] In one possible embodiment, the control circuit is further configured to: in response to a short-circuit fault in the first switching transistor, confirm the number of short circuits in the first switching transistor. If the number of short circuits in the first switching transistor does not exceed a preset short-circuit threshold, control the second switching transistor to periodically turn on based on the received heating demand command. This ensures that even when a short-circuit fault occurs in the first switching transistor, the heater drive circuit can still drive the heater to operate for a period of time to continue meeting the heating demand, allowing users time for maintenance and improving the user experience.

[0008] In one possible embodiment, the control circuit is further configured to: control the second switch to disconnect when it is confirmed that the number of short circuits of the first switch exceeds a preset short circuit threshold. This protects the second switch from short circuits, preventing the short circuit fault from worsening and causing the heater to become uncontrollable, thereby further improving the stability of the drive circuit operation.

[0009] In one possible embodiment, the control circuit is further configured to: in response to a short-circuit fault in the second switching transistor, confirm the number of short circuits in the second switching transistor. If the number of short circuits in the second switching transistor does not exceed a preset short-circuit threshold, control the first switching transistor to periodically turn on based on the received heating demand command. This ensures that even when a short-circuit fault occurs in the second switching transistor, the heater drive circuit can still drive the heater to operate for a period of time to continue meeting the heating demand, allowing users time for maintenance and improving the user experience.

[0010] In one possible embodiment, the control circuit is further configured to: control the first switch to disconnect when it is confirmed that the number of short circuits of the second switch exceeds a preset short circuit threshold. This protects the first switch from short circuits, preventing the short circuit fault from worsening and causing the heater to become uncontrollable, thereby further improving the stability of the drive circuit operation.

[0011] In one possible embodiment, the control circuit is also configured to output a fault code in the event of a short-circuit fault in the first or second switching transistor, in order to improve fault repair efficiency.

[0012] Secondly, embodiments of this application provide a control method for a heater driving circuit. This control method is applied to the heater driving circuit, which includes a control circuit, a first switching transistor, and a second switching transistor. The control method includes: the control circuit, in response to power-on of the heater driving circuit, performing short-circuit fault diagnosis on the first and second switching transistors. Specifically, a first controlled terminal of the first switching transistor is connected to a power supply, and a second controlled terminal of the first switching transistor is connected to a first terminal of the heater; the first controlled terminal of the second switching transistor is connected to a second terminal of the heater, and the second controlled terminal of the second switching transistor is grounded. When there is no short-circuit fault in the first and second switching transistors, the control circuit controls the second switching transistor to remain continuously on, and controls the first switching transistor to periodically turn on based on received heating demand commands.

[0013] In one possible embodiment, the control method further includes: in response to a short-circuit fault in the first switch, confirming the number of short circuits in the first switch. If the number of short circuits in the first switch does not exceed a preset short-circuit count threshold, controlling the second switch to periodically conduct based on a heating demand command.

[0014] In one possible implementation, the control method further includes: controlling the second switch to disconnect when the number of short circuits of the first switch exceeds a preset short circuit number threshold.

[0015] In one possible implementation, the control method further includes: in response to a short-circuit fault in the second switch, confirming the number of short circuits in the second switch. If the number of short circuits in the second switch does not exceed a preset short-circuit count threshold, controlling the first switch to periodically conduct based on a heating demand command.

[0016] In one possible implementation, the control method further includes: controlling the first switch to disconnect when the number of short circuits of the second switch exceeds a preset short circuit number threshold.

[0017] In one possible implementation, the control method further includes: outputting a fault code in response to a short-circuit fault in the first switch or a short-circuit fault in the second switch.

[0018] Thirdly, embodiments of this application provide a heating device, which includes a heater and the heater drive circuit described in the first aspect above. The heater is connected to the heater drive circuit, and the heater drive circuit is configured to control the heater.

[0019] Fourthly, embodiments of this application provide a vehicle that includes a battery and the heating device described in the third aspect above, wherein the battery and the heating device are connected.

[0020] It should be understood that the technical effects of the methods in the second to fourth aspects can be referred to the first aspect, and the implementation methods of this application will not be described again here. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the background art, the accompanying drawings used in the embodiments of this application will be described below.

[0022] Figure 1 This is a schematic diagram of the structure of a heater driving circuit disclosed in an embodiment of this application; Figure 2 This is a schematic diagram of a heater driving circuit with a freewheeling diode disclosed in an embodiment of this application; Figure 3 This is a schematic flowchart of a control method for a heater drive circuit disclosed in an embodiment of this application; Figure 4 This is a schematic diagram of a process in response to a heating demand command, as disclosed in an embodiment of this application. Figure 5 This is a schematic diagram of the structure of a heating device disclosed in an embodiment of this application; Figure 6 This is a schematic diagram of the structure of a vehicle disclosed in an embodiment of this application.

[0023] Explanation of reference numerals in the attached drawings: 100, heater drive circuit; 110, first switching transistor; 120, second switching transistor; 130, control circuit; 131, controller; 132, current detection circuit; 140, freewheeling diode; 200, heating device; 210, heater; 300, vehicle; 310, battery. Detailed Implementation

[0024] The terms “first,” “second,” etc., are used for descriptive purposes only and have no sequential or technical meaning, nor should they be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0025] The terms "exemplary" or "for example" used in the embodiments of this application are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0026] In the description of the embodiments of this application, unless otherwise expressly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0027] The term "electrical connection" refers to the ability of current or signal to flow from one conductor to another. An electrical connection between A and B means that current or signal can flow from A to B, and vice versa. This includes direct electrical connections and indirect electrical connections between A and B. A direct electrical connection between A and B means that A and B are physically connected.

[0028] In the air conditioning system of new energy vehicles, the vehicle's heating function is mainly achieved using a PTC heater, which is controlled by a heater drive circuit. In some implementations, the heater drive circuit typically uses a solid-state switch (e.g., IGBT) to control the power supply switching. However, when using IGBTs for high-frequency power supply switching control, the nonlinear resistive characteristics of the IGBT can cause voltage coupling oscillations in the heater drive circuit. There is a certain probability that the IGBT will short-circuit and fail due to a negative voltage surge, resulting in the vehicle having no heating function or an uncontrollable heating function.

[0029] Therefore, this application provides a heater drive circuit, which aims to reduce the risk of short-circuit failure of switching devices due to negative voltage surges, protect the integrity of the switching device functions and the robustness of the heater drive circuit operation.

[0030] like Figure 1 As shown, the heater drive circuit 100 includes a control circuit 130, a first switching transistor 110, and a second switching transistor 120; in some examples, both the first switching transistor 110 and the second switching transistor 120 can be IGBTs. The first controlled terminal of the first switching transistor 110 is connected to a power supply, and the second controlled terminal of the first switching transistor 110 is connected to the first terminal of the heater 210; the first controlled terminal of the second switching transistor 120 is connected to the second terminal of the heater 210, and the second controlled terminal of the second switching transistor 120 is grounded. For example, when the heater drive circuit 100 is applied in a new energy vehicle air conditioning system, the first controlled terminal of the first switching transistor 110 can be connected to the positive terminal of the new energy vehicle's power battery, and the second controlled terminal of the second switching transistor 120 can be connected to the negative terminal of the new energy vehicle's power battery.

[0031] Although not shown in the accompanying drawings, those skilled in the art will understand that the heater drive circuit 100 is not limited to... Figure 1 The first switch 110 and the second switch 120 shown may have multiple other switches connected in parallel with the second switch 120.

[0032] Please continue to refer to Figure 1The control circuit 130 includes a controller 131 and a current detection circuit 132. The current detection circuit 132 is connected in series in the power supply path of the heater 210 to detect the current in the power supply path of the heater 210. In some examples, the current detection circuit 132 can be located between the second controlled terminal of the second switching transistor 120 and the negative terminal of the new energy vehicle power battery 310. In some examples, the current detection circuit 132 can be implemented by connecting a current-sensing resistor in series.

[0033] The controller 131 includes one input terminal and two output terminals, which can be referred to as the first output terminal and the second output terminal, respectively. The input terminal is electrically connected to the current detection circuit 132, the first output terminal is electrically connected to the control terminal of the first switching transistor 110, and the second output terminal is electrically connected to the control terminal of the second switching transistor 120.

[0034] The control circuit 130 can perform short-circuit fault diagnosis on the first switch 110 and the second switch 120. For example, the input terminal of the controller 131 can continuously acquire the current detection results from the current detection circuit 132. When diagnosing a short-circuit fault on the first switch 110, the controller 131 can apply a first electrical signal to the control terminal of the first switch 110 through its first output terminal to control the first switch 110 to turn off, and apply a second electrical signal to the control terminal of the second switch 120 through its second output terminal to control the second switch 120 to turn on. At this time, if the current detection result indicates that there is current in the power supply path of the heater 210, it can be determined that the first switch 110 has a short-circuit fault; if the current detection result indicates that there is no current in the power supply path of the heater 210, it can be determined that the first switch 110 has not a short-circuit fault.

[0035] The process of diagnosing short-circuit faults in the second switch 120 can refer to the process of diagnosing short-circuit faults in the first switch 110 described above. For the sake of brevity, this application will not repeat the process here.

[0036] In this embodiment of the application, when neither the first switch 110 nor the second switch 120 has a short-circuit fault, the controller 131 directly controls the second switch 120 to remain continuously on, while simultaneously controlling the first switch 110 to periodically turn on based on the received heating demand command, so as to controllably meet the power required for heating. Continuously turning on the second switch 120 can avoid irreversible damage to the second switch 120 caused by voltage coupling oscillations in the heater drive circuit 100, reduce the risk of the second switch 120 short-circuiting due to negative voltage impact, and improve the stability of the drive circuit operation.

[0037] like Figure 2As shown, in some embodiments, the heater drive circuit 100 may further include a freewheeling diode 140, which is connected in reverse parallel with the first switching transistor 110. That is, the cathode of the freewheeling diode 140 is electrically connected to the first controlled terminal of the first switching transistor 110, and the anode of the freewheeling diode 140 is electrically connected to the second controlled terminal of the first switching transistor 110. When a negative voltage surge occurs, the freewheeling diode 140 can provide a freewheeling path for the first switching transistor 110, thereby preventing the first switching transistor 110 from failing due to the negative voltage surge and improving the stability of the drive circuit operation.

[0038] This application also provides a control method for a heater drive circuit 100, which may include a control circuit 130, a first switching transistor 110, and a second switching transistor 120. The control circuit 130 can execute this control method to optimize the insufficient robustness of the heater drive circuit 100. Specifically, as... Figure 3 As shown, the control method may include S110-S150, as follows: S110, the drive circuit is powered on and the system checks whether there is a short circuit fault in the first and second switching transistors.

[0039] For example, the control circuit 130 can control the actual switching state of the first switch 110 to be closed and the actual switching state of the second switch 120 to be open. If the current detection circuit 132 detects that there is no current in the heater drive circuit 100, then the second switch 120 in the heater drive circuit 100 is identified as being in normal working condition; if the current detection circuit 132 detects that there is current in the heater drive circuit 100, then the second switch 120 in the heater drive circuit 100 is identified as being short-circuited. Alternatively, the control circuit 130 can control the actual switching state of the first switch 110 to be open and the actual switching state of the second switch 120 to be closed. If the current detection circuit 132 detects that there is no current in the heater drive circuit 100, then the first switch 110 in the heater drive circuit 100 is identified as being in normal working condition; if the current detection circuit 132 detects that there is current in the heater drive circuit 100, then the first switch 110 in the heater drive circuit 100 is identified as being short-circuited.

[0040] S120: In the absence of a short circuit fault in the first and second switching transistors, the second switching transistor is kept on continuously, and the pulse width modulation (PWM) control of the first switching transistor is turned on or off according to the received heating demand command.

[0041] like Figure 4As shown, in some examples, the heating demand command includes an on heating demand command and a off heating demand command. In S120, when the control circuit 130 controls the second switch 120 to remain on, if it receives an on heating demand command, the control circuit 130 can activate the PWM control of the first switch 110 according to the received heating demand command to control the heating power. For example, the on heating demand command may include heating power information. The control circuit 130 can parse the heating power information. The greater the heating power represented by the heating power information, the greater the duty cycle of the first switch 110 controlled by the control circuit 130. If the control circuit 130 then receives a off heating demand command, it can turn off the PWM control of the first switch 110.

[0042] S130. In the event of a short circuit fault in the first or second switching transistor, output a fault code and determine whether the number of fault outputs exceeds a preset short circuit number threshold.

[0043] In some examples, the preset short circuit threshold of the heater drive circuit 100 can be 30 times, and the control circuit 130 performs S140-S150 control on the first switch tube 110 and the second switch tube 120 according to whether the number of output fault codes exceeds 30 times.

[0044] S140. If the number of fault reports does not exceed the preset short-circuit count threshold, the PWM control of the unshort-circuited switching transistor is turned on or off according to the received heating demand command.

[0045] In some examples, if the first switch 110 of the heater drive circuit 100 has a short circuit fault and the number of fault outputs does not exceed 30, the control circuit 130 can turn on the PWM control of the non-short-circuited second switch 120 according to the received heating demand command to realize the control of heating power; or, turn off the PWM control of the non-short-circuited second switch 120 according to the received heating demand command to turn off.

[0046] In some examples, if the second switch 120 of the heater drive circuit 100 has a short circuit fault and the number of fault outputs does not exceed 30, the control circuit 130 can turn on the PWM control of the non-short-circuited first switch 110 according to the received heating demand command to realize the control of heating power; or, turn off the PWM control of the non-short-circuited first switch 110 according to the received heating demand command to turn off.

[0047] S150. If the number of fault reports exceeds the preset short circuit count threshold, disconnect the non-short circuit switch and turn off the heater heating function.

[0048] In some examples, if the first switch 110 has a short-circuit fault and the fault output count exceeds 30 times, to protect the integrity of the function of the second switch 120, the control circuit 130 controls the non-short-circuited second switch 120 to open, thus turning off the heating function of the heater 210. In other examples, if the second switch 120 has a short-circuit fault and the fault output count exceeds 30 times, to protect the integrity of the function of the first switch 110, the control circuit 130 controls the non-short-circuited first switch 110 to open, thus turning off the heating function of the heater 210.

[0049] The control method of the heater drive circuit 100 provided in this application can still respond to heating demand commands for a period of time when the switching transistor is short-circuited. At the same time, it can control the duty cycle of another non-short-circuited switching transistor to meet the heating power required by the user according to the heating demand command, thereby improving the robustness of the heater drive circuit 100.

[0050] This application also provides a computer-readable storage medium storing computer program instructions, which, when executed by a processor, can perform the following functions: Figure 3 The control method is illustrated. Exemplary examples show that the computer-readable storage media described above may include, but are not limited to: magnetic storage devices (e.g., hard disks, floppy disks, or magnetic tapes), optical discs (e.g., compact disks (CDs), digital versatile disks (DVDs), etc.), smart cards, and flash memory devices (e.g., erasable programmable read-only memory (EPROMs), cards, sticks, or key drives, etc.).

[0051] like Figure 5 As shown, this application also provides a heating device 200, which includes a heater 210 and a heater drive circuit 100. The heater 210 is electrically connected to the heater drive circuit 100, and the heater drive circuit 100 is used to control the heater 210. For example, the heater drive circuit 100 can control the heating power of the heater 210 according to the received heating demand command to achieve the temperature required by the heating demand command.

[0052] like Figure 6As shown, this application also provides a vehicle 300, which can be, but is not limited to, a pure electric vehicle (PEV / BEV), a hybrid electric vehicle (HEV), a range-extended electric vehicle (REEV), and a plug-in hybrid electric vehicle (PHEV). The vehicle 300 includes a battery 310 and a heating device 200, which are electrically connected to provide power for the operation of the heating device 200.

[0053] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the descriptions of each embodiment in the above embodiments have different focuses. For parts not described in detail in a certain embodiment, refer to the corresponding processes in the foregoing device embodiments, which will not be repeated here.

[0054] It should be understood that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims. Those skilled in the art can understand that implementing all or part of the processes of the above embodiments and making equivalent changes according to the claims of this application still fall within the scope of this application.

Claims

1. A heater driving circuit, characterized in that, The heater drive circuit (100) includes a control circuit (130), a first switching transistor (110), and a second switching transistor (120); wherein, The first controlled terminal of the first switching transistor (110) is used to connect to the power supply, and the second controlled terminal of the first switching transistor (110) is used to connect to the first terminal of the heater (210); the first controlled terminal of the second switching transistor (120) is used to connect to the second terminal of the heater (210), and the second controlled terminal of the second switching transistor (120) is grounded. The control circuit (130) is connected to the control terminal of the first switching transistor (110) and the control terminal of the second switching transistor (120), respectively. The control circuit (130) is configured as follows: In response to the power-on of the heater drive circuit (100), short-circuit fault diagnosis is performed on the first switch (110) and the second switch (120); In response to the absence of a short circuit fault in the first switch (110) and the second switch (120), the second switch (120) is controlled to remain on continuously; and the first switch (110) is controlled to periodically turn on based on the received heating demand command.

2. The heater driving circuit according to claim 1, characterized in that, The control circuit (130) is also configured to: In response to a short circuit fault in the first switch (110), the number of short circuits in the first switch (110) is confirmed; If the number of short circuits of the first switch (110) does not exceed the preset short circuit number threshold, the second switch (120) is periodically turned on based on the heating demand command.

3. The heater driving circuit according to claim 2, characterized in that, The control circuit (130) is also configured to: If the number of short circuits of the first switch (110) exceeds the preset short circuit number threshold, the second switch (120) is controlled to disconnect.

4. The heater drive circuit according to any one of claims 2-3, characterized in that, The control circuit (130) is also configured to: In response to a short circuit fault in the first switch (110), a fault code is output.

5. A control method for a heater drive circuit, characterized in that, The control method includes: In response to the power-on of the heater drive circuit (100), short-circuit fault diagnosis is performed on the first switch (110) and the second switch (120); the first controlled terminal of the first switch (110) is used to connect to the power supply, and the second controlled terminal of the first switch (110) is used to connect to the first terminal of the heater (210); the first controlled terminal of the second switch (120) is used to connect to the second terminal of the heater (210), and the second controlled terminal of the second switch (120) is grounded; In response to the absence of a short circuit fault in the first switch (110) and the second switch (120), the second switch (120) is controlled to remain on continuously; and the first switch (110) is controlled to periodically turn on based on the received heating demand command.

6. The control method according to claim 5, characterized in that, The control method further includes: In response to a short circuit fault in the first switch (110), the number of short circuits in the first switch (110) is confirmed; If the number of short circuits of the first switch (110) does not exceed the preset short circuit number threshold, the second switch (120) is periodically turned on based on the heating demand command.

7. The control method according to claim 6, characterized in that, The control method further includes: If the number of short circuits of the first switch (110) exceeds the preset short circuit number threshold, the second switch (120) is controlled to disconnect.

8. The control method according to any one of claims 6-7, characterized in that, The control method further includes: In response to a short circuit fault in the first switch (110), a fault code is output.

9. A heating device, characterized in that, The heating device (200) includes a heater (210) and a heater drive circuit (100) according to any one of claims 1-4, wherein the heater (210) is connected to the heater drive circuit (100) and the heater drive circuit (100) is configured to control the heater (210).

10. A vehicle, characterized in that, The vehicle (300) includes a battery (310) and a heating device (200) as claimed in claim 9, wherein the battery (310) and the heating device (200) are connected.

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