Electromechanical Motor Control 석 사 2기 최 우 영 Systems & control Lab.

3.5 Laboratory 1:5, Voltage/Frequency and speed control of IM Lab 1:5: Phase B Lab 1:5: Phase C Lab 1:5: Phase C+ 목차

Lab 1-5: Dual PM/PM drive 3 / 7 Phase B : Testing and implementation of the controller We combine two drive control modules of lab's 1-3 to produce : - PM sensored FOC on converter 1 - PM sensored FOC converter 2 - Dual drive operating with PM 2 under torque control and PM 1 under speed control - Combine motor and generating modes - DCBUS must be tied together in 'real' drive !

4 / 7 Lab 1-5: Dual PM/PM drive Phase B : Testing and implementation of the controller Vector plots steady-state operation:  PM-1 operating under torque control and with a negative quadrature current (generator mode) - d-axis vector (green) - current (red) - voltage (blue) - PM flux in direction of d-axis  PM-2 control with speed loop operating in motor mode - d-axis vector (green) - current (red) - voltage (blue) - PM flux in direction of d-axis Note: when running simulation rotational speed of vectors is the same.

5 / 7 Lab 1-5: Dual PM/PM drive Phase C-C+ : Testing and implementation of the controller We combine two lab's 1-3 setups to produce: -PM sensored FOC on DRV PM sensored FOC converter DRV Dual drive operating with PM 1 under torque control and PM 2 under speed control -Combine motor and generating modes -DCBUS must be tied together in 'real' drive ! Note: new LaunchXL-069 with two Boost packs: can be used to control two machines directly.

3.5 Laboratory 1:5, Voltage/Frequency and speed control of IM 6 / 7

7 / 7 The quadrature reference current follows from the torque expression 3.5 Laboratory 1:5, Voltage/Frequency and speed control of IM

3.5.1 Lab 1:5: Phase B 8 / 7 - Description: V/f and Speed control of a IM motor - Equipment/Software: VisSim simulation program - Outcomes: Show the various waveforms that occur in the drive when using a fixed point representation of the controller when operating under Voltage/frequency control.

3.5.1 Lab 1:5: Phase B 9 / 7 - The ’operational Variables’ dialog box is used to assign full scale values for the voltage, current, frequency and (in this case) stator flux. - Dialog box entries for the maximum allowable rate of change for flux and frequency are also provided, together with a speed controller limit value speedcontroller_limit(A). - This value is the maximum (absolute) quadrature current value, which the speed controller is set to provide.

3.5.1 Lab 1:5: Phase B 10 / 7 - The sampling time Ts as defined in the program pull-down menu is set to 66.67μs, i.e a 15kHz ADC sampling frequency is used the discrete controller model.

3.5.2 Lab 1:5: Phase C 11 / 7 - A phase C development stage, cannot be used to run a drive, but its primary task is to assemble all the modules needed for drive operation with a given controller configuration. - The drive setup as given in figure 3.58, shows the ’Open loop V/f IM Controller’ module, which must be compiled to generate an out-file.

3.5.2 Lab 1:5: Phase C 12 / 7 - Moving one level down into the Controller module leads to the set of modules/dialog boxes shown in figure The dialog boxes shown in this diagram have already been discussed in phase B (see figure 3.56). - A ’Diagnostic tool’ module is again used to buffer two variables, which are subsequently displayed in a graph when operating in phase C+. A ’two channel’ multiplexer is used to allow the user to either display variables Test1,Test2 or Test3, Test4 by using a button connected to chan_sel input of the module. - A ’100Hz’ module acts as a ’heart beat’ and flashes an ‘red’ LED on the LAUNCHXL-F28069M module. - A ‘blue’ LED remains ’on’ if a current trip condition occurs. In addition, all the drive background tasks are undertaken by this unit.

3.5.2 Lab 1:5: Phase C 13 / 7 - The ’V/f and Speed Controller’ was introduced in phase B. - The ’ADC-PWM’ unit shown, is identical to the one used in the previous laboratory given that the same drive setup is in use.

3.5.2 Lab 1:5: Phase C 14 / 7 - Inputs to the speed controller are the reference electrical frequency freq_n and actual electrical shaft frequency (from the shaft encoder) fshn. - Output of this module is the per unit quadrature reference current iqn. - The reference shaft speed signal is connected to the ref input of the Speed controller module via a frequency rate limiter module ’F-RAMP’ and switch (with input con_act2) which ensures that said variable is held at zero when the converter is disabled.

3.5.2 Lab 1:5: Phase C 15 / 7 - The V/f controller module, is hatched ‘green’ because, like the speed module, it is executed at 1/15 of the ADC sampling frequency, i.e at 1kHz in this case. - The basic structure of the fixed point controller as shown in figure 3.62 reflects the control structure of the floating point version (see figure 3.54). - The difference being that the reverse Park module and integrator were also incorporated in the floating point module. - The outputs of the fixed point module are given in terms of the modulation index.

3.5.3 Lab 1:5: Phase C+ 16 / 7 - Note that the rotational direction of the induction machine, should be the same as the encoder, i.e a positive reference speed of the controller, should show a positive encoder generated shaft speed. This is ensured by using the motor wiring sequence shown in figure 3.63.

3.5.3 Lab 1:5: Phase C+ 17 / 7 Prior to activating the drive the following ’Pre-Drive’ check list should be executed:

3.5.3 Lab 1:5: Phase C+ 18 / 7 - Additional experimental evidence of drive operation is provided by the oscilloscope plot given in figure 3.64, which shows the phase current as measured with a DC current probe. - The frequency and amplitude of the measured current are in agreement with the scope results given in figure 3.63.

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