User guide
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V 1.0.1
2021-01-27
REF-AIRCON-C302A-IM564 user guide
Air conditioner application reference design kits
System and functional description
9.
Double click the “VF Diagnostic” function in Motor1 page, and monitor the motor current with oscilloscope.
If the motor current is not sinusoidal, change the target speed and Vd_Ext in VF Diagnostic sub-function,
then double-click “VF Diagnostic” until oscilloscope shows a steady sinusoidal current, with an amplitude of
30~50% motor rate current.
Double-click “Iu & Iv_Slow” in System page > Monitor Definitions; the motor current feedback should be
very clean and sinusoidal, as shown in Figure 8, otherwise please tune “Gating Propagation Delay & Phase
Shift Window Size” in MCEWizard. The sampled motor current amplitude should be over 300 cts ~500 cts
(corresponding to 30%~50% motor rate current); otherwise, the motor-current sample related hardware
and setup need tuning.
“VF Diagnostic” sub function can verify:
•
If motor is correctly connected
•
If MOS & gate driver work as expected
•
If current sensing related parameters are correctly configured
•
If PCB layout and DC bus decoupling have been done correctly
After “VF Diagnostic” is done, click STOP button (the red traffic light button) to stop PWM.
Figure 8
Trace waveform for Iu & Iv open loop diagnostic
10.
Start the motor by clicking the green traffic light button in the control bar (or double-click Start Motor sub
function in Motor1 page, group of User Application Function Definitions); motor runs if above step goes well.
11.
Check motor spin direction, adjust UVW connection order or set negative target speed in MCEDesigner if
direction is wrong.
12.
Set target speed to about 50% of MAX speed, start “Iu & Flx_M” trace with “Auto Repeat on Level”. As Figure
9. Flx_M is better within the range of 2000~2500 cts (rated value is 2048), and MUST be steady and DC-like.
Some key tips for better motor-performance tuning:
•
If Flx_M is not steady (swinging or oscillating), double-check motor parameters, speed loop PI gain, flux Estimator
time constant and PLL PI bandwidth (parameters PLLKp & PLLKi) related setup.
•
If Flx_M is very noisy, double-check current feedback and Vdc-related hardware and parameters.
•
If Flx_M is far from 2048, “Motor Back EMF Constant (Ke)” needs to be adjusted in MCEWizard.
