Manufacturing-sensitive control of high rotor pole switched reluctance motors

A method for controlling a switched reluctance machine (SRM) comprising the steps of:

• providing an SRM control system having a commutation module;
• providing an initial rotor position for the SRM utilizing an initialization mechanism;
• defining a pinned point on a phase current waveform of a pulse during an initial current rise phase of the current waveform, the current waveform starting to rise in correspondence of an inductance rise (Θon) of a phase of the SRM, wherein the pinned point is defined at a point corresponding to a magnitude between 50% and 100% of the steady state current on the initial current rise;
• determining a slope of the current rise as the current waveform reaches the pinned point, the slope being fed to the commutation module;
• calculating an error signal of the pulse based on the slope of the current rise and providing the error signal as an input to a control loop in the SRM control system;
• and
• determining, using the error signal, an optimum time to fire a next pulse;
• whereby the SRM control system enables adaptive pulse positioning over a wide range of speeds and loads.

A method for controlling an SRM comprising the steps of:

• providing an SRM control system having a commutation module;
• providing an initial rotor position for the SRM utilizing an initialization mechanism;
• defining a pinned point on a phase current waveform of a pulse during an initial current rise phase of the current waveform, the current waveform starting to rise in correspondence of an inductance rise (Θon) of a phase of the SRM, wherein the pinned point is defined at a point corresponding to a magnitude between 50% and 100% of the steady state current on the initial current rise, the pinned point being static with respect to an underlying inductance value of the SRM;
• determining a slope of the current rise as the current waveform reaches the pinned point, the slope being fed to the commutation module;
• providing a frequency input signal to the commutation module to obtain a digital estimate for shaft speed;
• calculating a current speed utilizing the slope of the current rise and frequency input signal;
• generating a commanded current by a regulator unit utilizing a reference speed and the current speed;
• comparing the commanded current with a measured current by an inner current loop in the SRM control system to determine an optimum time signal to fire a next pulse;
• and
• utilizing the optimum time signal to fire the next pulse, generating pulse width modulation (PWM) signals to create a plurality of commutation angles for turning a plurality of switches of the SRM to on and off states;
• whereby the SRM control system enables adaptive pulse positioning over a wide range of speeds and loads.