|
Torque at Stall
(i.e. Zero speed, locked rotor)
Shown below is an oscillogram showing
the step torque response at stall, with the rotor locked.
In this test the torque is stepped from -100% of rated motor
torque to +100% of rated motor torque. The time to slew between both
extremes is approximately 0.3 milliseconds.
This embodiment utilized CogniSim operating with 50 microsecond time-frame
(algorithm update rate).
The motor used was a 575V, 10HP 1774 rpm induction motor.
The hardware implemented utilizes 1µs A/D conversion time with
15-bit
plus sign resolution A/D converters.
The average switching frequency for this motor is targeted to
approximately 2.2KHz.
The outstanding ability for torque at stall, and rotating
restart in relatively simple hardware allows opportunity for CogniSim sensorless
motor control to replace and render volts/hertz drives obsolete, as well as
all other forms of sensorless vector control.
|
