I am using STPM34 for measuring RMS voltages. When I measure grid voltages it's fine. But I read the inverter output voltage, the value is oscillating from 0 to 500v. Please help me to resolve this.

[THANGAMUTHU]

..

[Peter BENSCH]

What is the inverter output voltage: AC or DC?
When AC: what frequency?
How did you connect the STPM34 to this voltage?
Regards
/Peter

[THANGAMUTHU]

Inverter Output voltage : 200 - 270V AC

Frequency : 50Hz

 

[Javier1]

we need to see te code aswell, did you probed the inverter output with an oscilloscope?

Maybe is much much noisier and spikey than you expect. (specially with no load attached)

[THANGAMUTHU]

V factor = VREF * (1 + (R1 / R2)) / (AU * CALIB_V * DPOW)

        = (1.18 * (1+ (810000/470))) / ( 2 * 0,875) = 116274,11

I factor = VREF / (AI * CALIB_I * DPOW * KSI * KINT )

        = 1.18 / (2 * 0,875 * 0,00260 * 1) = 25934,06

By using the above formula we calculated Voltage and Current. For Grid Voltage STPM34 is reading Correctly, we are facing the issue when reading inverter output AC voltage. I have attached waveforms across the VIP1 pin. I have changed the Capacitor across VIP1 pin 10nF to 100nF but also facing the issue same.

[Javier1]

that looks like a very noisy signal.....

What about triggering the ADC reading only when the pwm event?

[THANGAMUTHU]

Kindly Suggest proceeding further?

1. Grid Input
2. Inverter Input