Product Control Scheme Of High Voltage Coolant Heater 2
PTC water heater can provide heat for the cockpit of new energy vehicles and meet the standard of safe defrosting and defogging. It also provides heat to other parts of the vehicle that require temperature regulation, such as the battery.
Control Function
1. Soft start function:PWM soft start
PWM uses 30s from 0% to 100%。This function is used to protect high inrush currents and sudden changes on the high voltage bus. Each channel is gradually soft-started, there is ripple current in the soft-start process, and the inrush current is small (<1.3 times the rated current).
2. Restricted function：
2.1 Temperature limit
①When the outlet temperature reaches 80°C, it will actively reduce the power gradually to keep the water temperature at the outlet relatively constant.
② When the temperature of any IGBT reaches 85°C, it will actively reduce the power gradually or turn it off. When it is lower than 80°C, it will resume work, so that the IGBT temperature does not exceed the limit.
2.2 Power limit
Soft start power limit: each power is limited to 2850W during soft start.
3. Protection function：
3.1 High voltage overvoltage and undervoltage protection
The working voltage range can be set according to customer requirements. The heater that is not within the range will not be started or turned off. If it returns to the range, it will restart softly to the current set value.
3.2 IGBT drive voltage overvoltage and undervoltage protection
When the IGBT drive voltage is not within the set working range, the heating will be completely turned off, and after recovery, it will restart softly to the current set value.
3.3 Low voltage anti-reverse connection protection
Low voltage reverse connection does not work.
3.4 Outlet water temperature over temperature protection
When the water temperature at the outlet exceeds 105°C for 3 seconds, all heating will be turned off immediately.
3.5 Short circuit protection
Any PTC circuit is short-circuited, the circuit will be turned off immediately, repeat the detection 5 times, and it is still short-circuited, the circuit will not be turned on for heating before powering on again.
3.6 Overcurrent protection
During the heating operation, if the circuit continues to exceed 2 times the rated current for 5s, it is considered to be overloaded, and the circuit will be shut down and restarted.
Warning: High voltage does not have the ability to prevent reverse connection. High voltage reverse connection will lead to uncontrolled direct heating. High voltage reverse connection may cause PTC damage, may cause the vehicle to fail to be precharged and cannot be started, and may cause the precharge resistor to be burned!
