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PMSM field oriented control
Considering closed loop feedback control of a plant model as in Equation and Equation , using stanard
PI controllers, then the controller proportional and integral gains can be derived, using a pole-placement
method, as follows:
Equation 7
Equation 8
where ω0 represents the system natural frequency [rad/sec] and ξ is the Damping factor [-] of the current
control loop.
3.4 Output voltage actuation
3.5 Phase current measurement
The 3-phase voltage source inverter shown in Figure 4 uses two shunt resistors (R68 and R48) placed in
each of the inverter leg as phase current sensors. Stator phase current which flows through the shunt
resistor produces a voltage drop which is interfaced to the AD converter of microcontroller through
conditional circuitry (refer to MC9S12ZVML128 Evaluation Board User Manual available at
freescale.com).
Figure 4. 3-phase DC/AC inverter with shunt resistors for current measurement
3-phase Sensorless PMSM Motor Control Kit with MagniV MC9S12ZVM Application Note Rev. 0 05/2015
Freescale Semiconductor, Inc.
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