UM0324 datasheet(29/105 Pages) STMICROELECTRONICS

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UM0324

Running the demo program

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3.2

Closed loop

Figure 14 shows a summary of the LCD menus and settings (blinking items are shown

underlined).

Figure 14.

LCD menus in closed loop

Switching from open to closed loop operation and vice versa is done by moving the joystick

up or down while the first menu shown in the above figure is displayed and motor is stopped.

In closed loop operation, you can vary the target speed by moving the joystick up or down

while the PID motor speed target selection menu is displayed. The demo program also

allows real-time tuning of the speed PID regulator coefficients.

Finally, although you cannot act directly on torque and flux references, you can also observe

both the target and measured flux and torque stator current component. In fact, in closed

loop, both flux and torque references are the outputs of speed PID regulator and field

weakening blocks.

As in open loop, pressing the joystick or the KEY button will start the motor.

The closed loop ramp-up strategy is shown in Figure 15. Basically, a linear torque ramp is

applied to the motor until it reaches speed TACHO_SPEED_VAL (if a tacho speed sensor is

used) or ENCODER_CL_ENABLE (if an encoder is used). Then, the speed PID regulator is

enabled and takes control of the torque reference.

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