Control Scheme Of PTC Electric Heater 2
1.Control mode:
CAN communication
2.Control function：
2.1Soft start function: PWM soft start
PWM uses 30 seconds from 0% to 100%. This function is used to protect the high inrush current and sudden changes on the high voltage bus. Each channel is gradually soft-started, and there is ripple current during the soft-start process, and the inrush current is small (<1.3 times of the rated current).
2.2Restricted function
2.2.1Temperature limit
①When the temperature of the water outlet reaches 80℃, the power will be gradually reduced to keep the temperature of the water outlet relatively constant
② When the temperature of any one of the IGBTs reaches 85°C, it will take the initiative to gradually reduce the power or shut down, and resume operation when it is lower than 80°C so that the IGBT temperature does not exceed the limit
2.2.2Power limit
Soft start power limit: The power of each channel is limited to 3800W during soft start
2.3Protection function
2.3.1High-voltage over-voltage protection
The operating voltage range can be set according to customer requirements. The heaters that are not within the range will not start or shut down, and will be soft-started to the current set value after returning to the range.
2.3.2IGBT drive voltage overvoltage protection
When the IGBT drive voltage is not within the set working range, the heating will be all shut down, and the soft start will be restarted to the current set value after recovery.
2.3.3Low voltage reverse connection protection Low voltage reverse connection does not work.
2.3.4Outlet water temperature over-temperature protection
When the water outlet temperature exceeds 105℃ for 3 seconds, all heating will be turned off immediately
2.3.5Short circuit protection
If any PTC circuit is short-circuited, the circuit will be closed immediately, and the test will be repeated 5 times, but the circuit is still short-circuited, and the circuit will not be heated until it is powered on again.
2.3.6Overcurrent protection
If the circuit exceeds 2 times the rated current for 5s during heating operation, it is considered as overloaded and the circuit is will be shut down and restarted.
Warning: High voltage does not have the ability to prevent reverse connection. High voltage reverse connection will cause direct heating to be uncontrolled. High voltage reverse connection may cause PTC damage, may cause the vehicle to fail to be precharged and fail to start, and may cause the precharge resistor to burn!
