Development and Performance Testing of a $V/f$ Control for Permanent Magnet Synchronous Motor Drives with Wavelet Modulated Power Electronic Converters

Volt-per-hertz (
$V/f$
) control is one the simplest control structures developed for operating electric motor drives, including permanent magnet synchronous motor (PMSM) drives. This paper presents the development and testing of a
$V/f$
control for PMSM drives that utilize a
$3\phi$
wavelet modulated (WM) dc-ac power electronic converter (PEC). The wavelet modulation technique is characterized by the maximum scale (
$J$
) and scale-time interval factor (
$\gamma$
). The output voltage of a
$3\phi$
WM dc-ac PEC has its magnitude directly dependent on
$J$
, while its frequency and phase are dependent to
$\gamma$
. These two parameters of the wavelet modulation technique can be used to implement a
$V/f$
control for PMSM drives. The proposed
$V/f$
control is featured with a stabilizing loop to correct the
$V/f$
ratio, and improve the stability of the controlled PMSM drive. The
$V/f$
control for a PMSM drive fed by a wavelet modulated dc-ac PEC, is implemented for performance testing using a laboratory 10
$-hp$
PMSM drive under different operating conditions. Performance results demonstrate stable, dynamic, and accurate responses, with minor sensitivities to the load torque and/or speed changes. Furthermore, test results demonstrate the ability to enhance the efficiency using the tested control for PMSM drives.