Control system and control method for PTC heater of electric vehicle

Abstract

The invention discloses a control system and method for a PTC heater of an electric automobile, and belongs to the technical field of electric automobiles. The method comprises the steps that the initial duty ratio of a pulse width modulation (PWM) signal is configured through a control module; the man-machine interaction module triggers an instruction of needing the PTC heater for heating; the control module controls the duty ratio of a pulse width modulation (PWM) signal to be increased from an initial duty ratio to a target duty ratio according to a preset speed; the control module judges the size relation between the temperature of the PTC heater and the first preset temperature and the size relation between the temperature of the PTC heater and the second preset temperature, if the control module judges that the temperature of the PTC heater is larger than the first preset temperature, the control module controls the PTC heater to be closed, and if the control module judges that the temperature of the PTC heater is larger than the second preset temperature and not larger than the first preset temperature, the control module controls the PTC heater to be closed. And the control module controls to reduce the duty ratio of a pulse width modulation (PWM) signal. According to the invention, the power battery can be prevented from being damaged by impact current when the PTC heater is started.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric vehicles, and in particular, relates to a control system and a control method for a PTC heater of an electric vehicle. Background Art

[0002] Traditional fuel vehicles use the engine to provide heat for heating the interior of the vehicle. Electric vehicles, especially pure electric vehicles, are driven by drive motors, but it is difficult for drive motors to heat the entire vehicle by their own heat like engines do. Therefore, external heating components are required to generate heat for heating the entire vehicle. In the cold winter climate, in order to ensure the power and endurance of the entire vehicle, low-temperature charging heating and charging insulation of power batteries have also become an indispensable function of electric vehicles. Usually electric vehicles, especially pure electric vehicles, use heaters to heat the entire vehicle. The heater is generally composed of several PTCs (PTC1, PTC2, ·······) with different heating output powers. Each PTC is controlled on and off by an insulated gate bipolar transistor (IGBT). The heating demand and heating gear are sent to the PTC controller through the vehicle bus. The PTC controller controls the operation of different PTCs according to the demand instructions and the current status. Multiple heating gears are synthesized by requesting different PTCs or requesting multiple PTCs to work simultaneously. The gear request of the PTC uses a pulse width modulation (PWM) signal as the input signal of the insulated gate bipolar transistor (IGBT) drive circuit. The heater is controlled to operate in different gears by changing the duty cycle of the pulse width modulation (PWM) signal.

[0003] However, due to the parasitic capacitance of the PTC heater itself, there will be a large impact current when the switch tube is turned on. Therefore, the gear control strategy used by PTC heaters on the market will generate a large impact current every time the gear is changed. The discharge capacity of the power battery will weaken at low temperatures. The large impact current generated by the gear shift will cause the instantaneous output power of the PTC heater to increase. When the increased instantaneous output power exceeds the maximum discharge output power of the power battery, there will be a risk of over-discharge of the power battery. The more frequent the gear shift, the more impact currents will be generated, and the greater the damage to the power battery.

[0004] Patent CN112248754A discloses a control system and method for a pure electric vehicle water-heating PTC heater, including a control module and a water-heating system electrically connected to the control module, wherein the control module includes a microcontroller unit, a temperature acquisition module and a power supply module electrically connected to the microcontroller unit, the water-heating system includes a water pump, a water-heating PTC heater and a heater core circulating through a water pipe, a plurality of three-way valves are arranged on the water pipe, and an expansion kettle connected in parallel with the water pipe is connected between all the three-way valves, and the microcontroller unit is electrically connected to the water-heating PTC heater through an IGBT module.

[0005] However, the technology disclosed in the above patent cannot prevent the impact current from damaging the power battery when starting the PTC heater. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a control system and a control method for a PTC heater of an electric vehicle in view of the deficiencies in the prior art, so as to achieve the purpose of avoiding damage to the power battery caused by the impact current when starting the PTC heater.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] The invention provides a control system for a PTC heater of an electric vehicle, comprising a power module, a human-machine interaction module, a control module, an insulated gate bipolar transistor (IGBT) module and a PTC heater; the output end of the power module is respectively connected to the input end of the human-machine interaction module, the input end of the control module, the input end of the insulated gate bipolar transistor (IGBT) module and the input end of the PTC heater; the output end of the human-machine interaction module is connected to the input end of the control module; the output end of the control module is connected to the input end of the insulated gate bipolar transistor (IGBT) module; the output end of the insulated gate bipolar transistor (IGBT) module is connected to the input end of the PTC heater.

[0009] Furthermore, the system also includes a temperature detection module, the output end of the power module is connected to the input end of the temperature detection module; the output end of the temperature detection module is connected to the input end of the control module.

[0010] Furthermore, the control module configures an initial duty cycle of a pulse width modulation (PWM) signal, and controls the duty cycle of the pulse width modulation (PWM) signal to increase from the initial duty cycle to a target duty cycle at a preset speed.

[0011] Furthermore, the temperature detection module detects the temperature of the PTC heater and sends the detected temperature information of the PTC heater to the control module.

[0012] Furthermore, the control module determines the magnitude relationship between the temperature of the PTC heater and the first preset temperature and the second preset temperature.

[0013] Further, when the control module determines that the temperature of the PTC heater is greater than the first preset temperature, the control module controls to turn off the PTC heater.

[0014] Further, when the control module determines that the temperature of the PTC heater is greater than the second preset temperature and not greater than the first preset temperature, the control module controls to reduce the duty cycle of the pulse width modulation (PWM) signal.

[0015] Further, the initial duty cycle of the pulse width modulation (PWM) signal is 10%.

[0016] Further, the preset speed is to increase the duty cycle of the pulse width modulation (PWM) signal by 5% every 500 milliseconds.

[0017] The present invention also provides a control method for an electric vehicle PTC heater, the method comprising the following steps:

[0018] S1: configure the initial duty cycle of the pulse width modulation (PWM) signal through the control module;

[0019] S2: triggering the instruction requiring the PTC heater to perform heating through the human-computer interaction module;

[0020] S3: The control module controls the PTC heater to turn on through the insulated gate bipolar transistor (IGBT) module;

[0021] S4: The control module controls the duty cycle of the pulse width modulation (PWM) signal to increase from the initial duty cycle to the target duty cycle according to a preset speed;

[0022] S5: The temperature detection module detects the temperature of the PTC heater and sends the detected temperature information of the PTC heater to the control module;

[0023] S6: The control module determines the relationship between the temperature of the PTC heater and the first preset temperature and the second preset temperature. If the control module determines that the temperature of the PTC heater is greater than the first preset temperature, the process proceeds to S7. If the control module determines that the temperature of the PTC heater is greater than the second preset temperature and not greater than the first preset temperature, the process proceeds to S8.

[0024] S7: The control module controls to turn off the PTC heater and enters S9;

[0025] S8: The control module controls to reduce the duty cycle of the pulse width modulation (PWM) signal;

[0026] S9: End.

[0027] The control system and control method of the electric vehicle PTC heater of the present invention have the following advantages:

[0028] (1) The control system and control method of the electric vehicle PTC heater of the present invention can prevent the impact current from damaging the power battery when the PTC heater is started, further avoid the risk of over-discharging the power battery, and extend the service life of the power battery.

[0029] (2) Through the control system and control method of the electric vehicle PTC heater of the present invention, the low-temperature charging heating and charging insulation functions of the power battery can also be realized.

[0030] (3) After the low-temperature charging heating and charging insulation functions of the power battery are realized through the control system and control method of the electric vehicle PTC heater of the present invention, the power and endurance of the whole vehicle can be further improved.

[0031] (4) In the present invention, the temperature of the PTC heater is collected by a temperature detection module, and the control module determines the relationship between the temperature of the PTC heater collected by the temperature detection module and the first preset temperature and the second preset temperature. The judgment result is used to control whether to turn off the PTC heater or to control the reduction of the duty cycle of the pulse width modulation (PWM) signal to prevent the PTC heater from overheating.

[0032] (5) In the present invention, the output power of the PTC heater is regulated by controlling the duty cycle of the pulse width modulation (PWM) signal. When the PTC heater is just turned on, the initial duty cycle of the pulse width modulation (PWM) signal is used to control the PTC heater to operate at a low output power. Subsequently, the control module controls the duty cycle of the pulse width modulation (PWM) signal to increase from the initial duty cycle to the target duty cycle at a preset speed, thereby gradually increasing the output power of the PTC heater. In this way, damage to the power battery and the circuit caused by the impact current when starting the PTC heater can be effectively avoided, thereby extending the service life of the power battery.

[0033] (6) In the present invention, uniform heating can be ensured and excessive noise can be avoided by selecting the frequency of the pulse width modulation (PWM) signal for the PTC heater 5 .

[0034] (7) In the present invention, the damage to the power battery caused by the impact current when the PTC heater is turned on can be avoided by controlling the initial duty cycle of the pulse width modulation (PWM) signal, and the output power of the PTC heater can be gradually increased by controlling the speed of increasing the duty cycle of the pulse width modulation (PWM) signal. Combined with the mechanism of the temperature detection module detecting and feeding back the temperature information, the control module can turn off the PTC heater or reduce the duty cycle of the pulse width modulation (PWM) signal at any time according to the temperature information, which can prevent the PTC heater from overheating, thereby improving the stability, reliability and safety of the system of the present invention.

[0035] (8) In the present invention, the output power of the PTC heater can be precisely controlled and adjusted by controlling and adjusting the pulse width modulation (PWM) signal, which has the characteristics of rapid response. The output power of the PTC heater can also be adjusted at any time according to actual conditions, and the target temperature can be kept stable by combining the temperature feedback mechanism.

[0036] (9) In the present invention, the output power of the PTC heater can be precisely controlled and adjusted by controlling and adjusting the pulse width modulation (PWM) signal, which can achieve effective utilization of electrical energy, reduce unnecessary energy waste, and improve the overall performance of the system of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] This specification includes the following drawings, which show the following contents:

[0038] Figure 1 It is a logical structure block diagram of a control system of an electric vehicle PTC heater of the present invention;

[0039] Figure 2 The present invention is a flowchart of a control method for a PTC heater of an electric vehicle.

[0040] Explanation of the accompanying drawings: 1. Power module; 2. Human-computer interaction module; 3. Control module; 4. Insulated gate bipolar transistor (IGBT) module; 5. PTC heater; 6. Temperature detection module. DETAILED DESCRIPTION

[0041] The specific implementation methods of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention and facilitating their implementation.

[0042] Figure 1 It is a logical structure block diagram of a control system of an electric vehicle PTC heater 5 of the present invention, including a power module 1, a human-machine interaction module 2, a control module 3, an insulated gate bipolar transistor (IGBT) module 4 and a PTC heater 5; wherein the output end of the power module 1 is respectively connected to the input end of the human-machine interaction module 2, the input end of the control module 3, the input end of the insulated gate bipolar transistor (IGBT) module 4 and the input end of the PTC heater 5; the output end of the human-machine interaction module 2 is connected to the input end of the control module 3; the output end of the control module 3 is connected to the input end of the insulated gate bipolar transistor (IGBT) module 4; the output end of the insulated gate bipolar transistor (IGBT) module 4 is connected to the input end of the PTC heater 5. In addition, the system also includes a temperature detection module 6, the output end of the power module 1 is connected to the input end of the temperature detection module 6; the output end of the temperature detection module 6 is connected to the input end of the control module 3.

[0043] In this specific embodiment, the power supply module 1 is used to supply power to the human-machine interaction module 2, the control module 3, the insulated gate bipolar transistor (IGBT) module 4, the PTC heater 5 and the temperature detection module 6; the human-machine interaction module 2 refers to the central control screen of the car; the control module 3 can adopt a microcontroller (MCU), such as the STM32 series; the insulated gate bipolar transistor (IGBT) module 4 adopts an insulated gate bipolar transistor (IGBT), and when there are multiple PTC heaters 5 in the system, the insulated gate bipolar transistor (IGBT) module 4 can adopt multiple insulated gate bipolar transistors (IGBT) to control the opening and closing of different PTC heaters 5 respectively; the temperature detection module 6 can adopt a temperature sensor, and the temperature sensor is installed on the PTC heater 5.

[0044] Combine the following Figure 1 The working principle of the control system of the electric vehicle PTC heater 5 of the present invention is as follows:

[0045] First, the initial duty cycle of the pulse width modulation (PWM) signal needs to be configured through the control module 3, and the duty cycle of the pulse width modulation (PWM) signal needs to be increased from the initial duty cycle to the target duty cycle at a preset speed. Specifically, the initial duty cycle of the pulse width modulation (PWM) signal is configured and the pulse width modulation (PWM) signal is generated through the control module 3. After the PTC heater 5 is turned on, the duty cycle of the pulse width modulation (PWM) signal is increased from the initial duty cycle to the target duty cycle at a preset speed through the control module 3. The output power of the PTC heater 5 is controlled and adjusted by controlling the duty cycle of the pulse width modulation (PWM) signal through the control module 3. When the PTC heater is just turned on, the PTC heater is controlled to work at a small output power through the initial duty cycle of the pulse width modulation (PWM) signal, and then The control module 3 controls the duty cycle of the pulse width modulation (PWM) signal to increase from the initial duty cycle to the target duty cycle at a preset speed to gradually increase the output power of the PTC heater 5. In this way, the damage to the power battery and the circuit caused by the impact current when the PTC heater 5 is started can be effectively avoided, thereby extending the service life of the power battery, that is, the impact current can be avoided from damaging the power battery when the PTC heater 5 is started, and the risk of over-discharge of the power battery can be further avoided. At the same time, the low-temperature charging heating and charging insulation functions of the power battery can be realized, further improving the power and endurance of the vehicle. Among them, the frequency of the pulse width modulation (PWM) signal for the PTC heater 5 can be 30HZ, but the frequency is not limited to 30HZ, but can be selected between 10HZ and 100HZ, so as to ensure uniform heating and avoid excessive noise. In addition, during the operation of the system of the present invention, the temperature of the PTC heater 5 is detected by the temperature detection module 6, and the temperature information of the detected PTC heater 5 is sent to the control module 3. After receiving the temperature information of the PTC heater 5 sent by the temperature detection module 6, the control module 3 determines the relationship between the temperature of the PTC heater 5 and the first preset temperature and the second preset temperature. When the control module 3 determines that the temperature of the PTC heater 5 is greater than the first preset temperature, the control module 3 controls to turn off the PTC heater 5, that is, the control module 3 controls to turn off the PTC heater 5 by controlling the insulated gate bipolar transistor (IGBT) module 4, thereby preventing the PTC heater from having an over-temperature fault. When the control module 3 determines that the temperature of the PTC heater 5 is greater than the second preset temperature and not greater than the first preset temperature, the control module 3 controls to reduce the duty cycle of the pulse width modulation (PWM) signal, thereby reducing the output power of the PTC heater 5, thereby preventing the PTC heater from having an over-temperature fault.

[0046] Figure 21 is a flow chart of a control method of a PTC heater 5 of an electric vehicle according to the present invention, the method comprising the following steps:

[0047] S1: Configure the initial duty cycle of the pulse width modulation (PWM) signal through the control module 3; that is, corresponding to Figure 2 Specifically, the initial duty cycle of the pulse width modulation (PWM) signal needs to be configured by the control module 3 first.

[0048] S2: triggering the instruction requiring the PTC heater 5 to perform heating through the human-computer interaction module 2; that is, corresponding to Figure 2 Specifically, when the user has a heating demand, the human-computer interaction module 2 triggers a command requiring the PTC heater 5 to perform heating, and the human-computer interaction module 2 inputs the command information requiring the PTC heater 5 to perform heating to the control module 3 through the CAN bus.

[0049] S3: The control module 3 controls the PTC heater 5 to turn on through the insulated gate bipolar transistor (IGBT) module 4; Figure 2 Specifically, after the control module 3 controls the PTC heater 5 to be turned on through the insulated gate bipolar transistor (IGBT) module 4, the output power of the PTC heater 5 just after being turned on is controlled through the initial duty cycle of the pulse width modulation (PWM) signal.

[0050] S4: The control module 3 controls the duty cycle of the pulse width modulation (PWM) signal to increase from the initial duty cycle to the target duty cycle according to the preset speed; that is, the corresponding Figure 2 Specifically, the control module 3 controls the duty cycle of the pulse width modulation (PWM) signal to increase from the initial duty cycle to the target duty cycle at a preset speed, thereby gradually increasing the output power of the PTC heater 5.

[0051] S5: The temperature detection module 6 detects the temperature of the PTC heater 5 and sends the detected temperature information of the PTC heater 5 to the control module 3; that is, the corresponding Figure 2 Specifically, during the operation of the system of the present invention, the temperature of the PTC heater 5 is detected by the temperature detection module 6 , and the detected temperature information of the PTC heater 5 is sent to the control module 3 .

[0052] S6: The control module 3 determines the relationship between the temperature of the PTC heater 5 and the first preset temperature and the second preset temperature. If the control module 3 determines that the temperature of the PTC heater 5 is greater than the first preset temperature, the process proceeds to S7. If the control module 3 determines that the temperature of the PTC heater 5 is greater than the second preset temperature and not greater than the first preset temperature, the process proceeds to S8. Figure 2Specifically, after receiving the temperature information of the PTC heater 5 sent by the temperature detection module 6, the control module 3 determines the relationship between the temperature of the PTC heater 5 and the first preset temperature and the second preset temperature. When the control module 3 determines that the temperature of the PTC heater 5 is greater than the first preset temperature, it enters S7. When the control module 3 determines that the temperature of the PTC heater 5 is greater than the second preset temperature and not greater than the first preset temperature, it enters S8.

[0053] S7: The control module 3 controls to turn off the PTC heater 5 and enters S9; Figure 2 Specifically, the control module 3 controls the insulated gate bipolar transistor (IGBT) module 4 to control the PTC heater 5 to be turned off.

[0054] S8: The control module 3 controls to reduce the duty cycle of the pulse width modulation (PWM) signal; that is, the corresponding Figure 2 Specifically, the control module 3 controls to reduce the duty cycle of the pulse width modulation (PWM) signal, thereby reducing the output power of the PTC heater 5.

[0055] S9: End; corresponding Figure 2 S9 in.

[0056] In this specific embodiment, the initial duty cycle of the pulse width modulation (PWM) signal is 10%, but the initial duty cycle of the pulse width modulation (PWM) signal is not limited to 10%, but can be adjusted according to specific circumstances; the target duty cycle is 100%, but the target duty cycle is not limited to 100%, but can be adjusted according to specific circumstances; the preset speed is to increase the duty cycle of the pulse width modulation (PWM) signal by 5% every 500 milliseconds, but the preset speed is not limited to increasing the duty cycle of the pulse width modulation (PWM) signal by 5% every 500 milliseconds, but can be adjusted according to specific circumstances; the first preset temperature is 80°C, and the second preset temperature is 65°C, but the first preset temperature and the second preset temperature are not limited to 80°C and 65°C respectively, but can be adjusted according to specific circumstances.

[0057] The preset speed in this specific implementation is to increase the duty cycle of the pulse width modulation (PWM) signal by 5% every 500 milliseconds, which is a method of linearly increasing the duty cycle of the pulse width modulation (PWM) signal. In addition, an exponential increase method can also be used to control and adjust the duty cycle of the pulse width modulation (PWM) signal.

[0058] Functions and Effects of the Embodiments

[0059] The initial duty cycle of the pulse width modulation (PWM) signal is configured and controlled to generate the pulse width modulation (PWM) signal through the control module 3. After the PTC heater 5 is turned on, the duty cycle of the pulse width modulation (PWM) signal is increased from the initial duty cycle to the target duty cycle according to the preset speed through the control module 3. The output power of the PTC heater 5 is controlled and adjusted by the control module 3. When the PTC heater is just turned on, the PTC heater is controlled to work at a small output power through the initial duty cycle of the pulse width modulation (PWM) signal, and then the PTC heater is turned on and turned off. The control module 3 controls the duty cycle of the pulse width modulation (PWM) signal to increase from the initial duty cycle to the target duty cycle at a preset speed to gradually increase the output power of the PTC heater 5. In this way, the damage to the power battery and the circuit caused by the impact current when the PTC heater 5 is started can be effectively avoided, thereby extending the service life of the power battery, that is, the impact current can be avoided when the PTC heater 5 is started. The risk of over-discharge of the power battery is further avoided. At the same time, the low-temperature charging heating and charging insulation functions of the power battery can be realized, further improving the power and endurance of the vehicle. Among them, the frequency of the pulse width modulation (PWM) signal used for the PTC heater 5 can be 30HZ, but the frequency is not limited to 30HZ, but can be selected between 10HZ and 100HZ, so as to ensure uniform heating and avoid excessive noise. In addition, during the operation of the system of the present invention, the temperature of the PTC heater 5 is detected by the temperature detection module 6, and the temperature information of the detected PTC heater 5 is sent to the control module 3. After receiving the temperature information of the PTC heater 5 sent by the temperature detection module 6, the control module 3 determines the relationship between the temperature of the PTC heater 5 and the first preset temperature and the second preset temperature. When the control module 3 determines that the temperature of the PTC heater 5 is greater than the first preset temperature, the control module 3 controls to turn off the PTC heater 5, that is, the control module 3 controls to turn off the PTC heater 5 by controlling the insulated gate bipolar transistor (IGBT) module 4, thereby preventing the PTC heater from having an over-temperature fault. When the control module 3 determines that the temperature of the PTC heater 5 is greater than the second preset temperature and not greater than the first preset temperature, the control module 3 controls to reduce the duty cycle of the pulse width modulation (PWM) signal, thereby reducing the output power of the PTC heater 5, thereby preventing the PTC heater from having an over-temperature fault.

[0060] In the present invention, by controlling the initial duty cycle of the pulse width modulation (PWM) signal, the damage to the power battery caused by the impact current when the PTC heater is turned on can be avoided, and by controlling the speed of increasing the duty cycle of the pulse width modulation (PWM) signal, the output power of the PTC heater can be gradually increased. Combined with the mechanism of the temperature detection module detecting and feeding back temperature information, the control module can turn off the PTC heater or reduce the duty cycle of the pulse width modulation (PWM) signal at any time according to the temperature information, thereby preventing the PTC heater from over-temperature failure, thereby improving the stability, reliability and safety of the system of the present invention.

[0061] In the present invention, the output power of the PTC heater can be accurately controlled and adjusted by controlling and adjusting the pulse width modulation (PWM) signal. It has the characteristics of rapid response and can also adjust the output power of the PTC heater at any time according to actual conditions. Combined with the temperature feedback mechanism, the target temperature can be kept stable. It can also achieve effective use of electrical energy, reduce unnecessary energy waste, and improve the overall performance of the system of the present invention.

[0062] The present invention is described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A control system for a PTC heater of an electric vehicle, characterized in that: It includes a power module, a human-machine interaction module, a control module, an insulated gate bipolar transistor (IGBT) module and a PTC heater; the output end of the power module is respectively connected to the input end of the human-machine interaction module, the input end of the control module, the input end of the insulated gate bipolar transistor (IGBT) module and the input end of the PTC heater; the output end of the human-machine interaction module is connected to the input end of the control module; the output end of the control module is connected to the input end of the insulated gate bipolar transistor (IGBT) module; the output end of the insulated gate bipolar transistor (IGBT) module is connected to the input end of the PTC heater.

2. A control system for a PTC heater of an electric vehicle as claimed in claim 1, characterized in that: The system further comprises a temperature detection module, the output end of the power module is connected to the input end of the temperature detection module; the output end of the temperature detection module is connected to the input end of the control module.

3. A control system for a PTC heater of an electric vehicle as claimed in claim 2, characterized in that: The control module configures an initial duty cycle of a pulse width modulation (PWM) signal, and controls the duty cycle of the pulse width modulation (PWM) signal to increase from the initial duty cycle to a target duty cycle according to a preset speed.

4. A control system for a PTC heater of an electric vehicle as claimed in claim 3, characterized in that: The temperature detection module detects the temperature of the PTC heater and sends the detected temperature information of the PTC heater to the control module.

5. A control system for a PTC heater of an electric vehicle as claimed in claim 4, characterized in that: The control module determines the magnitude relationship between the temperature of the PTC heater and the first preset temperature and the second preset temperature.

6. A control system for a PTC heater of an electric vehicle as claimed in claim 5, characterized in that: When the control module determines that the temperature of the PTC heater is greater than a first preset temperature, the control module controls to turn off the PTC heater.

7. A control system for a PTC heater of an electric vehicle as claimed in claim 5, characterized in that: When the control module determines that the temperature of the PTC heater is greater than the second preset temperature and not greater than the first preset temperature, the control module controls to reduce the duty cycle of a pulse width modulation (PWM) signal.

8. A control system for a PTC heater of an electric vehicle as claimed in any one of claims 3 to 7, characterized in that: The initial duty cycle of the pulse width modulation (PWM) signal is 10%.

9. A control system for a PTC heater of an electric vehicle as claimed in any one of claims 3 to 7, characterized in that: The preset speed is to increase the duty cycle of the pulse width modulation (PWM) signal by 5% every 500 milliseconds.

10. A control method for a PTC heater of an electric vehicle according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: S1: configure the initial duty cycle of the pulse width modulation (PWM) signal through the control module; S2: triggering the instruction requiring the PTC heater to perform heating through the human-computer interaction module; S3: The control module controls the PTC heater to turn on through the insulated gate bipolar transistor (IGBT) module; S4: The control module controls the duty cycle of the pulse width modulation (PWM) signal to increase from the initial duty cycle to the target duty cycle according to a preset speed; S5: The temperature detection module detects the temperature of the PTC heater and sends the detected temperature information of the PTC heater to the control module; S6: The control module determines the relationship between the temperature of the PTC heater and the first preset temperature and the second preset temperature. If the control module determines that the temperature of the PTC heater is greater than the first preset temperature, the process proceeds to S7. If the control module determines that the temperature of the PTC heater is greater than the second preset temperature and not greater than the first preset temperature, the process proceeds to S8. S7: The control module controls to turn off the PTC heater and enters S9; S8: The control module controls to reduce the duty cycle of the pulse width modulation (PWM) signal; S9: End.

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