Hello everyone,
I’m working on a 15kV power supply for an ion thruster. It converts 28V input to 15kV output through two stages (28V → 800V, then 800V → 15kV). Control is done by an Arduino Nano generating PWM signals, which drive power MOSFETs via TLP250 drivers.
Current issue
To measure the output voltage, I initially used a high-voltage resistor divider (100MΩ / 10kΩ) to scale 15kV down to 0-5V readable by the Arduino ADC, with a feedback loop adjusting the PWM duty cycle.
However, I’m concerned about:
- The risk of HV reaching the Arduino if there’s a fault
- Possibly insufficient isolation between HV and low-voltage sections
- Long-term stability and reliability of the HV resistor divider
New approach I’m considering
Instead of scaling the HV directly to 0-5V, I want to use a dedicated industrial HV probe with proper isolation to measure the voltage externally (away from the Arduino). Then, I would adjust the PWM duty cycle based on this external measurement to maintain stable output voltage.
Questions:
- Do you think this method is safer and more reliable?
- Are TLP250 drivers sufficient for isolating the PWM signals to the MOSFETs at high voltage, or should I consider other isolation methods (optocouplers, isolation transformers, etc.)?
- Any recommendations to improve overall system safety without redesigning everything?
Thanks a lot for your insights and advice!
