Control systems and methods for starting permanent magnet rotating machines
View Patent ↗Systems and methods for controlling a rotating electromagnetic machine. The rotating machine, such as a permanent magnet motor or hybrid switched reluctance motor, includes a stator having a plurality of phase windings and a rotor that rotates relative to the stator. A drive is connected to the phase windings for energizing the windings. A controller outputs a control signal to the drive in response to inputs of demanded torque, rotor position and/or speed. Control methods include calculating a scaled torque demand from the received torque demand to obtain substantially constant torque over a range of motor speeds, calculating an optimal dr-axis injection current using a cost function and a starting method that switches from speed control mode to torque control mode at a predetermined rotor speed or at predetermined start-up timing intervals.
1. A method of starting a sensorless permanent magnet rotating machine from standstill, the machine including a stator and a rotor situated to rotate relative to the stator, the stator having a plurality of energizable phase windings situated therein, the method comprising:
starting operation of the machine in an open loop speed control mode using a first predetermined rotor speed value;
determining whether an actual speed of the machine exceeds a second predetermined rotor speed value; and
switching operation of the machine from the open loop speed control mode to a torque control mode when the actual speed of the machine exceeds the second predetermined rotor speed value.
2. The method of claim 1 wherein the first predetermined rotor speed value is different than the second predetermined rotor speed value.
3. The method of claim 1 wherein the torque control mode is a closed loop mode.
4. The method of claim 1 further comprising receiving a rotor torque demand, and operating the machine in the torque control mode according to the rotor torque demand.
5. The method of claim 4 wherein receiving includes receiving the rotor torque demand via an input to a controller for the machine.
6. The method of claim 4 wherein receiving includes deriving the rotor torque demand from an input parameter provided to a controller for the machine.
7. The method of claim 1 further comprising determining the first predetermined rotor speed value according to characteristics of said machine.
8. A permanent magnet rotating machine and controller assembly configured to perform the method of claim 1 .
9. A climate control system comprising the assembly of claim 8 .
10. The climate control system of claim 9 wherein the system includes an air handler and wherein the air handler includes said assembly.