A PTC multiple over-temperature protection system for electric vehicles

Abstract

The present invention provides an electric vehicle PTC multiple over-temperature protection system, comprising a PTC heating core and a vehicle controller, the vehicle controller comprising an AC control signal input terminal, a PTC control signal input terminal, an AC control signal output terminal, and a PTC control signal output terminal; a low-voltage power supply is electrically connected to the PTC control signal input terminal via a blower switch and a PTC request switch, and the PTC control signal output terminal is electrically connected to a first high-voltage relay; the low-voltage power supply is electrically connected to the AC control signal input terminal via a blower switch and a compressor control switch, and the AC control signal output terminal is electrically connected to a second high-voltage relay; the high-voltage power supply supplies power to the PTC heating core via the first high-voltage relay, and the high-voltage power supply supplies power to an electric compressor via a second high-voltage relay.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicles, and in particular to a PTC multiple over-temperature protection system for electric vehicles. Background Art

[0002] At present, the heating system of electric vehicles all adopts electric PTC core heating. PTC core heating is divided into water-heating PTC and air-heating PTC according to the different heat transfer media. As for air-heating PTC, because it is based on traditional fuel vehicles, the changes to the heating system are relatively small. It only needs to directly replace the water heating core of fuel vehicles with PTC core to meet the system use requirements. It is currently widely used in the field of electric vehicles. However, PTC has the risk of overheating compared with water heating core. The temperature of PTC core may exceed the tolerance limit of HVAC shell, causing damage to HVAC shell, and even the risk of vehicle fire. Therefore, air-heating PTC adopts temperature control switch for overheating protection. The temperature control switch may be damaged, resulting in protection failure, which poses certain safety risks to the vehicle. Summary of the invention

[0003] The purpose of the present invention is to provide an electric vehicle PTC multiple over-temperature protection system to address the defects of the prior art, thereby reducing the overheating risk of the PTC core and ensuring the safety of vehicle use.

[0004] The present invention provides an electric vehicle PTC multiple over-temperature protection system, which is characterized by comprising a PTC heating core and a vehicle controller, wherein the vehicle controller comprises an AC control signal input end, a PTC control signal input end, an AC control signal output end, and a PTC control signal output end; a low-voltage power supply is electrically connected to the PTC control signal input end via a blower switch and a PTC request switch, and the PTC control signal output end is electrically connected to a first high-voltage relay; the low-voltage power supply is electrically connected to the AC control signal input end via a blower switch and a compressor control switch, and the AC control signal output end is electrically connected to a second high-voltage relay; the high-voltage power supply supplies power to the PTC heating core through the first high-voltage relay, and the high-voltage power supply supplies power to the electric compressor through the second high-voltage relay; when the AC control signal input end receives an input signal, the AC control signal output end outputs an electrical signal, and the PTC control signal output end does not output an electrical signal; when the PTC control signal input end receives an input signal and the AC control signal input end does not receive an input signal, the PTC control signal output end outputs an electrical signal, and the AC control signal output end does not output an electrical signal.

[0005] A first PTC thermostat is connected in series between the blower switch and the PTC request switch.

[0006] A second PTC thermostat is connected in series between the blower switch and the PTC request switch, and the first PTC thermostat and the second PTC thermostat are connected in series.

[0007] The above technical solution also includes that the resistance end of the third relay is electrically connected to the pull-in feedback end of the second high-voltage relay, one end of the switch end of the third relay is electrically connected to the speed start / stop signal input end of the electric compressor, and the other end of the switch end of the third relay is electrically connected to the low-voltage power supply via the temperature control module, the compressor control switch and the blower switch.

[0008] In the above technical solution, a fourth relay is connected in series between the compressor control switch and the AC control signal input terminal.

[0009] In the above technical solution, a pressure switch is connected in series between one end of the switch terminal of the third relay and the speed start / stop signal input terminal of the electric compressor.

[0010] In the above technical solution, the AC control output terminal is electrically connected to the resistance terminal of the second high-voltage relay, and the high-voltage power supply is electrically connected to the high-voltage input terminal of the electric compressor via the switch terminal of the second high-voltage relay.

[0011] In the above technical solution, the low-voltage power supply supplies power to the blower via the blower switch, a plurality of resistors are connected in series between the blower and the blower switch, the blower switch includes a plurality of gear ends, and one end of the plurality of resistors is electrically connected to the corresponding gear ends respectively.

[0012] In the above technical solution, the temperature control module is provided with a resistance sensor for controlling the temperature of the air conditioner evaporator not to drop to the freezing point.

[0013] In the above technical solution, the PTC heating core includes a PTC heating sheet and a heat sink; the first PTC thermostat and the second PTC thermostat are arranged on the PTC heating core.

[0014] The present invention realizes triple protection of PTC overheating through a PTC request switch, two PTC thermostats, and a blower switch connected in series at the signal input end of the vehicle controller. The present invention adds a thermostat as the control source of PTC operation to avoid the risk of PTC overheating caused by damage to a single thermostat; at the same time, a blower switch is added as the control source of PTC operation. The system requires that the PTC can only be turned on after the blower is turned on to avoid PTC dry burning. Even if the thermostat is damaged, the PTC will not overheat if there is airflow cooling. In addition, the vehicle controller simultaneously receives the PTC opening request signal and the cooling opening request signal, and the PTC control output state is judged by combining the two signal states to prevent PTC from dry burning, which serves as the fourth protection against PTC overheating. In the cooling mode, because the air door in the cold and warm mode closes the airflow to the PTC core, the VCU adds whether the cooling is turned on as the judgment condition of whether the PTC is turned on. When the cooling is turned on, the PTC request switch is mistakenly turned on, and the PTC does not work, preventing the PTC from dry burning. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a circuit diagram of the present invention DETAILED DESCRIPTION

[0016] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments to facilitate a clear understanding of the present invention, but they do not constitute a limitation on the present invention.

[0017] like Figure 1 As shown, the present invention provides an electric vehicle PTC multiple over-temperature protection system, which is characterized by comprising a PTC heating core and a vehicle controller, the vehicle controller comprising an AC control signal input terminal, a PTC control signal input terminal, an AC control signal output terminal, and a PTC control signal output terminal; a low-voltage power supply is electrically connected to the PTC control signal input terminal via a blower switch and a PTC request switch, and the PTC control signal output terminal is electrically connected to a first high-voltage relay; the low-voltage power supply is electrically connected to the AC control signal input terminal via a blower switch and a compressor control switch, and the AC control signal output terminal is electrically connected to a second high-voltage relay; the high-voltage power supply supplies power to the PTC heating core through the first high-voltage relay, and the high-voltage power supply supplies power to the electric compressor through the second high-voltage relay; when the AC control signal input terminal receives an input signal, the AC control signal output terminal outputs an electrical signal, and the PTC control signal output terminal does not output an electrical signal; when the PTC control signal input terminal receives an input signal and the AC control signal input terminal does not receive an input signal, the PTC control signal output terminal outputs an electrical signal, and the AC control signal output terminal does not output an electrical signal.

[0018] A first PTC thermostat is connected in series between the blower switch and the PTC request switch. A second PTC thermostat is connected in series between the blower switch and the PTC request switch. The first PTC thermostat and the second PTC thermostat are connected in series to avoid the risk of PTC overheating caused by damage to a single thermostat.

[0019] The above technical solution also includes that the resistance end of the third relay is electrically connected to the pull-in feedback end of the second high-voltage relay, one end of the switch end of the third relay is electrically connected to the speed start-stop signal input end of the electric compressor, and the other end of the switch end of the third relay is electrically connected to the low-voltage power supply via the temperature control module, the compressor control switch and the blower switch. A fourth relay is connected in series between the compressor control switch and the AC control signal input end. A pressure switch is connected in series between one end of the switch end of the third relay and the speed start-stop signal input end of the electric compressor. The AC control output end is electrically connected to the resistance end of the second high-voltage relay, and the high-voltage power supply is electrically connected to the high-voltage input end of the electric compressor via the switch end of the second high-voltage relay.

[0020] The workflow of the present invention is as follows:

[0021] After the vehicle is powered on with high voltage, if there is a need for heating and defrosting, turn on the PTC request switch;

[0022] Turn on the blower switch, and the low-voltage power supply output current passes through the blower switch, two thermostats and the PTC request switch to the PTC control input terminal; the vehicle controller receives the PTC control input high effective signal;

[0023] If the compressor control switch is off at this time and there is no signal input to the AC control input terminal, the PTC control output terminal outputs a (high effective) voltage, the first high-voltage relay is energized and turned on, and the PTC works normally, otherwise the PTC heating core does not work;

[0024] During the PTC operation, if the temperature detected by the first PTC thermostat 1 and the second PTC thermostat 2 is lower than the set temperature, they are turned on and the PTC heating core works normally, otherwise the PTC heating core stops working;

[0025] During the PTC working process, if one of the two PTC temperature controllers is damaged and is in the on state, the other PTC temperature controller will be turned on when the detected temperature is lower than the set temperature, and the PTC heating core will work normally, otherwise the PTC heating core will stop working.

[0026] If the compressor control switch is in the closed state at this time, the low-voltage power supply outputs current through the blower switch and the compressor control switch to the AC control input terminal; the vehicle controller receives a low-valid signal from the AC control input, and the PTC control output terminal does not output voltage, the first high-voltage relay is in the disconnected state, and the PTC heating core does not work. The AC control output terminal outputs an electrical signal to turn on the second high-voltage relay, so that the high-voltage power supply supplies power to the electric compressor, and the strong ground end of the electric compressor is grounded. The pull-in feedback end of the second high-voltage relay outputs an electrical signal to the third relay, and the conduction of the third relay realizes the electrical connection between the temperature control module and the electric compressor speed start and stop signal input. The low-voltage power supply is electrically connected to the electric compressor via the blower switch, the compressor control switch, the temperature control module, the pressure switch, and the electric compressor, and the weak ground end of the electric compressor is grounded.

[0027] In the above technical solution, the low-voltage power supply supplies power to the blower through the blower switch, a plurality of resistors are connected in series between the blowers, the blower switch includes a plurality of gear ends, one end of the plurality of resistors is electrically connected to the corresponding gear ends respectively. The blower switch is turned to different gears to switch the wind speed.

[0028] In the above technical solution, the temperature control module is provided with a resistance sensor, which is used to control the temperature of the air conditioner evaporator not to drop to the freezing point. When the temperature control module detects that the real-time temperature in the car is lower than the set value, it automatically disconnects, that is, stops outputting electrical signals to the speed start-stop signal input terminal of the electric compressor, thereby stopping the electric compressor; when the temperature control module detects that the real-time temperature in the car is higher than the set value, it automatically turns on, that is, outputs electrical signals to the speed start-stop signal input terminal of the electric compressor, thereby causing the electric compressor to rotate. The pressure switch is used to prevent the refrigeration system pipeline from being too high or too low. Too high or too low will control the compressor to stop.

[0029] In the above technical solution, the PTC heating core includes a PTC heating sheet and a heat sink; the first PTC thermostat and the second PTC thermostat are arranged on the PTC heating core to realize real-time monitoring of the PTC heating core.

[0030] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. An electric vehicle PTC multiple over-temperature protection system, characterized in that It includes a PTC heating core and a vehicle controller, and the vehicle controller includes an AC control signal input terminal, a PTC control signal input terminal, an AC control signal output terminal, and a PTC control signal output terminal; a low-voltage power supply is electrically connected to the PTC control signal input terminal via a blower switch and a PTC request switch, and the PTC control signal output terminal is electrically connected to a first high-voltage relay; the low-voltage power supply is electrically connected to the AC control signal input terminal via a blower switch and a compressor control switch, and the AC control signal output terminal is electrically connected to a second high-voltage relay; the high-voltage power supply supplies power to the PTC heating core through the first high-voltage relay, and the high-voltage power supply supplies power to the electric compressor through the second high-voltage relay; when the AC control signal input terminal receives an input signal, the AC control signal output terminal outputs an electrical signal, and the PTC control signal output terminal does not output an electrical signal; when the PTC control signal input terminal receives an input signal and the AC control signal input terminal does not receive an input signal, the PTC control signal output terminal outputs an electrical signal, and the AC control signal output terminal does not output an electrical signal; A first PTC thermostat is connected in series between the blower switch and the PTC request switch; A second PTC thermostat is connected in series between the blower switch and the PTC request switch, and the first PTC thermostat and the second PTC thermostat are connected in series; The resistance end of the third relay is electrically connected to the pull-in feedback end of the second high-voltage relay, one end of the switch end of the third relay is electrically connected to the speed start / stop signal input end of the electric compressor, and the other end of the switch end of the third relay is electrically connected to the low-voltage power supply via the temperature control module, the compressor control switch and the blower switch; A fourth relay is connected in series between the compressor control switch and the AC control signal input terminal; A pressure switch is connected in series between one end of the switch terminal of the third relay and the speed start / stop signal input end of the electric compressor.

2. According to claim 1, the electric vehicle PTC multiple over-temperature protection system is characterized in that The AC control output terminal is electrically connected to the resistance terminal of the second high-voltage relay, and the high-voltage power supply is electrically connected to the high-voltage input terminal of the electric compressor via the switch terminal of the second high-voltage relay.

3. According to claim 1, the electric vehicle PTC multiple over-temperature protection system is characterized in that The low-voltage power supply supplies power to the blower via the blower switch. A plurality of resistors are connected in series between the blower and the blower switch. The blower switch includes a plurality of gear ends. One end of the plurality of resistors is electrically connected to the corresponding gear ends respectively.

4. The electric vehicle PTC multiple over-temperature protection system according to claim 1 is characterized in that The temperature control module is provided with a resistance sensor.

5. The electric vehicle PTC multiple over-temperature protection system according to claim 1 is characterized in that The PTC heating core comprises a PTC heating sheet and a heat sink; the first PTC thermostat and the second PTC thermostat are arranged on the PTC heating core.

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