Hello everyone,
I'm using a control board (RTK0EMX870C00000BJ) with an RX66T chip.
I've burned the induction motor control program from the website (Vector Control of Three-Phase Induction Motor Used in Driving a Pump RX66T Implementation Rev.1.10 - Sample Code) onto it.
I'm inputting a 3-phase sinusoidal signal from a signal generator to pins P40, P41, and P42.
When I test to see if these three current signals are being received in Renesas Motor Workbench, I find that the positive half-cycle of the signals is being cut off.I'm wondering if this is related to the values of g_f4_offset_iu, g_f4_offset_iv, and g_f4_offset_iw in the program, or if there's another reason. Does anyone know what might be causing this?
Regards,
RR
Dear RR,Thank you for posting your question online.It's quite common measuring only the current of the bottom power switches (see illustration below), which explain your scope snapshot .Could you please let us know which inverter board do you use?Thank you,Panos
Hi PanosCurrently, I'm just trying to verify if the A/D function of this controller is working correctly. Therefore, the read current signal should be a sine wave without any clipping. It shouldn't be related to the inverter board. Could it be more related to the program that reads the current signal?
I'm using the T1102 inverter board.
Hello,Based on the inverter block diagram, the current measurements are made on the bottom IGBTs, as you may notice from the image below. So, the current output will be zero during the "positive" semi-period, since during this time, no current is flowing through the current sense resistors.Thank you,Panos
Hi,Regarding your response, the current measured by the inverter when driving a motor must have both positive and negative variations. It's impossible to measure only the negative half-cycle just because the current sensing resistor is located below the IGBT. So, you might have misunderstood my meaning.
Additionally, my current testing method only involves the controller, without using the inverter part. I'm simply testing the A/D converter of this controller. I'm inputting a voltage signal into the three pins used to receive the current signal, and using RMW to see if the signal is received. This is my current issue.