Motor control programming problem

Question

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

PV_Renesas · Answer

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

PV_Renesas · Answer

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