Working circuit of PTC heater based on CAN communication

Abstract

The utility model provides a working circuit of a PTC heater based on CAN communication. The working circuit is used for reducing power loss of a control side of the PTC heater. The working circuit comprises a low-voltage-side electrical area and a high-voltage-side electrical area, and the low-voltage-side electrical area and the high-voltage-side electrical area are connected through a digital isolation chip. The working circuit comprises three DCDC circuits, two circuits for converting DCDC into 5V adopt a BUCK topological structure and have very high conversion efficiency compared with an LDO (Low Dropout Regulator) circuit adopted in the traditional controller design, and the other DCDC flyback topological circuit adopts a flyback power supply control chip with an enabling function, so that when the PTC heater works normally, the PTC heater can be switched to 5V, and the conversion efficiency is very high. If the control command is not received for a long time, the MCU of the PTC heater forbids the enabling function of the flyback power supply control chip, so that the high-voltage side power supply is disconnected to achieve the purpose of reducing the working power consumption; in addition, the voltage reduction function is achieved on the high-voltage side and the low-voltage side through the DCDC circuit, so that the use efficiency of the power supply is greatly improved, and the purpose of reducing the power consumption of the PTC heater control area is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of PTC heaters for electric vehicles, in particular to a working circuit of a PTC heater based on CAN communication. Background Art

[0002] In recent years, new energy vehicles have played an increasingly important role in the global automobile market. The background mainly includes the demand for environmental protection and sustainable development and the replacement of traditional fuel vehicles. As the issue of climate change becomes increasingly prominent, reducing greenhouse gas emissions has become a global consensus, and new energy vehicles are widely recognized as a clean energy means of transportation.

[0003] Power consumption control of new energy vehicles is one of the key issues to achieve efficient energy utilization and extend driving range. However, there are also some problems with power consumption control of new energy vehicles, and the improvement of energy consumption utilization has gradually received attention. The cost of controller dormancy for electronic control equipment with CAN communication is high, which is generally solved by specific frame wake-up of Aotusar architecture, which can control the dormancy current below 0.1mA. However, most CAN communication models currently do not use specific frame wake-up method, causing unnecessary power loss. Utility Model Content

[0004] The purpose of this utility model is to provide a working circuit of a PTC heater based on CAN communication to solve the high power consumption problem caused by the existing LDO voltage conversion in vehicles that do not have a specific frame wake-up of the Aotusar architecture. At present, in the field of PTC heaters, the static working current of the controller is mostly around 100mA. This utility model can control the static working current of the controller to less than 50mA, and the efficiency is more than doubled. The specific technical solution is as follows:

[0005] A working circuit of a PTC heater based on CAN communication, comprising a high-voltage side region, a low-voltage side region and a digital isolation chip between the high-voltage side region and the low-voltage side region;

[0006] The low-voltage side area includes a power supply module, a first DCDC conversion circuit module and a second DCDC flyback circuit module connected to the output end of the power supply module, a low-voltage side MCU circuit module connected to the output end of the first DCDC conversion circuit module, and a CAN communication circuit module interconnected with the low-voltage side MCU circuit module, and the low-voltage side MCU circuit module is also connected to the second DCDC flyback circuit module;

[0007] The high-voltage side region includes a third DCDC conversion circuit module and a high-voltage side MCU circuit module connected to the output end of the third DCDC conversion circuit module;

[0008] The second DCDC flyback circuit module is connected to the third DCDC conversion circuit module.

[0009] Furthermore, the low-voltage side MCU circuit module and the high-voltage side MCU circuit module are connected to each other through the digital isolation chip.

[0010] Furthermore, the high-voltage side region also includes a collection circuit module and a drive circuit module connected to the high-voltage side MCU circuit module.

[0011] Furthermore, the power supply voltage of the power supply module is 12V.

[0012] Furthermore, the second DCDC flyback circuit module includes an input capacitor, a flyback power supply control chip, a transformer, and an output capacitor. The flyback power supply control chip is an enable flyback control chip, and the enable pin of the MCU chip of the low-voltage side MCU circuit module is connected to the enable pin of the flyback power supply control chip.

[0013] Furthermore, the second DCDC flyback circuit module can convert a 12V voltage into a 15V voltage, and the conversion efficiency of the second DCDC flyback circuit module is greater than 90%.

[0014] Furthermore, the first DCDC conversion circuit module includes an input capacitor, a BUCK circuit control chip, an inductor, and an output capacitor. The first DCDC conversion circuit module can convert a 12V voltage into 5V. The conversion efficiency of the first DCDC conversion circuit module is greater than 90%.

[0015] Furthermore, the third DCDC conversion circuit module includes an input capacitor, a BUCK circuit control chip, an inductor, and an output capacitor. The third DCDC conversion circuit module converts a 15V voltage into 5V. The conversion efficiency of the third DCDC conversion circuit module is greater than 90%.

[0016] The utility model provides a working circuit of a PTC heater based on CAN communication, which has the following beneficial effects:

[0017] The utility model provides a working circuit of a PTC heater based on CAN communication, including two electrical areas of a low-voltage side and a high-voltage side, and a total of three DCDC circuits: two DCDC-to-5V circuits adopt a BUCK topology structure, and compared with the LDO circuit adopted in the traditional controller design, the conversion efficiency thereof is very high, about 90%, and the conversion efficiency of the LDO is determined by the input and output voltages, such as the conversion efficiency of the 15V-to-5V LDO circuit is about 33%; another DCDC flyback topology circuit, the flyback power supply control chip used in the flyback power supply control chip has an enable function, when the PTC heater is not needed or when no heating request of the PTC heater is received, an instruction can be sent to stop the conversion of 12V to 15V, thereby reducing the static power consumption of the PTC heater. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The utility model provides a connection diagram of a working circuit of a PTC heater based on CAN communication. DETAILED DESCRIPTION

[0019] The following will be combined with the accompanying drawings provided by the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. According to the following description, the advantages and features of the utility model will be clearer. It should be noted that the drawings are all in a very simplified form and are not in precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the utility model.

[0020] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connection" and "connected" should be interpreted in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0021] In the description of the present invention, terms such as "upper", "lower", "left", "right", "front", "back", "center", "horizontal", "vertical", "top", "bottom", "inside" and "outside" and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of description and simplification of operation, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0022] Embodiment: This embodiment provides a working circuit of a PTC heater based on CAN communication, see Figure 1As shown, the heater includes a high-voltage side area, a low-voltage side area and a digital isolation chip 6 between the high-voltage side area and the low-voltage side area, wherein the low-voltage side area includes a power supply module 1, a DCDC conversion circuit module 2, a CAN communication circuit module 3, a low-voltage side MCU circuit module 4, and a DCDC flyback circuit module 5; the high-voltage side area includes a high-voltage side MCU circuit module 7 and a DCDC conversion circuit module 8, and also includes an acquisition circuit module and a drive circuit module.

[0023] As a specific implementation method of the low-voltage side area, the output end of the power supply module 1 is connected to the DCDC conversion circuit module 2 and the DCDC flyback circuit module 5, the output end of the DCDC conversion circuit module 2 is connected to the low-voltage side MCU circuit module 4, the low-voltage side MCU circuit module 4 and the CAN communication circuit module 3 are interconnected, and information is exchanged with the whole vehicle or other CAN communication equipment through the CAN communication circuit module 3, and at the same time, the low-voltage side MCU circuit module 4 is connected to the DCDC flyback circuit module 5.

[0024] As a specific implementation of the high-voltage side region, the DCDC conversion circuit module 8 is connected to the DCDC flyback circuit module 5 in the low-voltage side region, and the output end of the DCDC conversion circuit module 8 is connected to the high-voltage side MCU circuit module 7, and the high-voltage side MCU circuit module 7 is connected to the low-voltage side MCU circuit module 4 through a digital isolation chip, and the digital isolation chip acts as a carrier for information transmission between the high-voltage side region and the low-voltage side region and realizes the function of electrical isolation. At the same time, the high-voltage side MCU circuit module 7 is also connected to the acquisition circuit module and the drive circuit module.

[0025] Optionally, the power supply voltage of the power supply module 1 is 12V.

[0026] Optionally, the DCDC conversion circuit module 2 includes an input capacitor, a BUCK circuit control chip, an inductor, and an output capacitor. The DCDC conversion circuit module 2 can convert a 12V voltage into 5V, and the conversion efficiency can reach more than 90%.

[0027] Optionally, the DCDC flyback circuit module 5 includes an input capacitor, a flyback power supply control chip, a transformer, and an output capacitor. The DCDC flyback circuit module 5 can convert a 12V voltage into a 15V voltage, and the conversion efficiency can reach more than 90%; the DCDC flyback circuit module 5 can realize electrical isolation between the high-voltage side area and the low-voltage side, wherein the flyback power supply control chip is a flyback control chip with an enable function, and the enable pin of the MCU chip of the low-voltage side MCU circuit module 4 is connected to the enable pin of the flyback power supply control chip of the DCDC flyback circuit module 5. When the PTC heater is not needed or when no heating request from the PTC heater is received, the low-voltage side MCU circuit module 4 can send an instruction to stop the DCDC flyback circuit module 5 from converting 12V into 15V, and the high-voltage side area will be powered off, thereby reducing the static power consumption of the PTC heater.

[0028] Optionally, the DCDC conversion circuit module 8 has the same circuit structure and function as the DCDC conversion circuit module 2. The DCDC conversion circuit module 8 also includes an input capacitor, a BUCK circuit control chip, an inductor, and an output capacitor. The DCDC conversion circuit module 8 can convert a 15V voltage into 5V, and the conversion efficiency can reach more than 90%.

[0029] The working process and principle of the above-mentioned low-power CAN communication PTC heater circuit are described in detail below: the power supply module 1 in the low-voltage side area supplies power, and the supply voltage is 12V. The high-efficiency DCDC conversion circuit module 2 converts 12V into 5V, and supplies power to the low-voltage side MCU circuit module 4 and the CAN communication circuit module 3. The low-voltage side MCU circuit module 4 controls the entire low-voltage side area circuit, and can communicate information with the vehicle or other CAN communication equipment through the CAN communication circuit module 3. At the same time, the DCDC flyback circuit module 5 converts the supply voltage 12V to 15V. The principle is to transfer energy to the high-voltage side through electromagnetic transformation, and the transformer acts as a carrier of energy conversion and electrical isolation. The conversion circuit module 8 in the high-voltage side area converts the 15V voltage into 5V, and the 5V voltage supplies power to the high-voltage side MCU circuit module 7. The high-voltage side MCU circuit module 7 controls the entire high-voltage side area circuit, obtains the information of the acquisition circuit module, and transmits the operation information to the drive circuit module. The high-voltage side MCU circuit module 7 communicates information with the low-voltage side MCU circuit module 4 through the digital isolation chip, and the digital isolation chip acts as a carrier of information transmission and electrical isolation.

[0030] The PTC heater circuit uses three DCDC conversion circuits to improve the conversion efficiency of the power supply, wherein the DCDC conversion circuit module 2 for converting 12V to 5V and the DCDC conversion circuit module 8 for converting 15V to 5V are two BUCK topology circuits, which do not need to be electrically isolated, and only need to achieve high-efficiency power conversion. Another DCDC flyback circuit module 5 for converting 12V to 15V not only needs to achieve the function of boosting, but also needs to be electrically isolated. The topology of the flyback power supply just meets this feature, and the conversion efficiency can also exceed 90%. If the signal for the PTC heater to work is not received, the enable of the flyback power supply control chip is turned off, which will greatly reduce the static power consumption of the PTC heater.

[0031] Those skilled in the art should understand that the present invention can be implemented in many other specific forms without departing from the spirit and scope of the present invention. Based on the embodiments of the present invention, any changes and modifications made by ordinary technicians in the field of the present invention according to the above disclosure are within the scope of protection of the claims.

Claims

1. A working circuit of a PTC heater based on CAN communication, characterized in that: It includes a high-voltage side region, a low-voltage side region, and a digital isolation chip between the high-voltage side region and the low-voltage side region; The low-voltage side area includes a power supply module, a first DCDC conversion circuit module and a second DCDC flyback circuit module connected to the output end of the power supply module, a low-voltage side MCU circuit module connected to the output end of the first DCDC conversion circuit module, and a CAN communication circuit module interconnected with the low-voltage side MCU circuit module, and the low-voltage side MCU circuit module is also connected to the second DCDC flyback circuit module; The high-voltage side region includes a third DCDC conversion circuit module and a high-voltage side MCU circuit module connected to the output end of the third DCDC conversion circuit module; The second DCDC flyback circuit module is connected to the third DCDC conversion circuit module.

2. The working circuit of the PTC heater based on CAN communication according to claim 1 is characterized in that: The low-voltage side MCU circuit module and the high-voltage side MCU circuit module are connected to each other through the digital isolation chip.

3. The working circuit of the PTC heater based on CAN communication according to claim 2 is characterized in that: The high-voltage side region further includes a collection circuit module and a drive circuit module connected to the high-voltage side MCU circuit module.

4. The working circuit of the PTC heater based on CAN communication according to claim 3 is characterized in that: The power supply voltage of the power supply module is 12V.

5. The working circuit of the PTC heater based on CAN communication according to any one of claims 1 to 4, characterized in that: The second DCDC flyback circuit module includes an input capacitor, a flyback power supply control chip, a transformer, and an output capacitor. The flyback power supply control chip is an enable flyback control chip, and the enable pin of the MCU chip of the low-voltage side MCU circuit module is connected to the enable pin of the flyback power supply control chip.

6. The working circuit of the PTC heater based on CAN communication according to claim 5 is characterized in that: The second DCDC flyback circuit module can convert a 12V voltage into a 15V voltage, and the conversion efficiency of the second DCDC flyback circuit module is greater than 90%.

7. The working circuit of the PTC heater based on CAN communication according to any one of claims 1 to 4, characterized in that: The first DCDC conversion circuit module includes an input capacitor, a BUCK circuit control chip, an inductor, and an output capacitor. The first DCDC conversion circuit module can convert a 12V voltage into 5V. The conversion efficiency of the first DCDC conversion circuit module is greater than 90%.

8. The working circuit of the PTC heater based on CAN communication according to any one of claims 1 to 4, characterized in that: The third DCDC conversion circuit module includes an input capacitor, a BUCK circuit control chip, an inductor, and an output capacitor. The third DCDC conversion circuit module converts a 15V voltage into 5V. The conversion efficiency of the third DCDC conversion circuit module is greater than 90%.

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