MCF523X Datasheet, PDF (21/44 Pages) Freescale Semiconductor, Inc – DC Motor with Speed and Current Closed Loops, Driven by eTPU on

Channel 3 - Hall decoder (HD) - Phase C
Channel 5 - speed controller (SC)
Channel 6 - current controller (CC)
Channel 7 - PWM master for DC motors (PWMMDC)
Channel 8 - PWM full range (PWMF) - Phase A - base channel
Channel 10 - PWM full range (PWMF) - Phase B - base channel
Channel 14 - analog sensing for DC motors (ASDC)
Software Design
These eTPU channels are initialized by the fs_etpu_app_dcmhscl1_init eTPU
application API function (see 4.3). The application settings are as follows:
— PWM phases-type is full range complementary pairs
— PWM frequency 20kHz
— PWM dead-time 1µs
— Motor speed range 1 400 RPM
— Motor speed minimum 50 RPM
— DC-bus voltage 9V
— Number of motor pole pairs 8
— Motor speed calculated using HD revolution period
— Speed controller update frequency 1250 Hz
— Speed controller PI parameters:
P-gain is 0.256 (0x0020C4 * 2^-15), and
I-gain is 0.005127 (0x0000A8 * 2^-15).
The controller parameters were experimentally tuned.
— Ramp parameters:
0.3s to ramp up from zero to the maximum speed,
0.3s to ramp down from the maximum speed to zero.
— Current controller PI parameters:
P-gain is 25.6 (0x0CCCCC * 2^-15), and
I-gain is 0 (0x000000 * 2^-15).
The controller parameters were experimentally tuned.
— DC-bus current measurement range is 14.55A
— ASDC function triggers A/D converter on high-low edge
— DC-bus current measurement time including A/D conversion time and DMA transfer time is
11us
— p_ASDC_result_queue pointer contains the address of the measured sample of DC-bus
current
— Measured sample of DC-bus current is shifted left by 10 bits
— DC-bus current sample offset within ASDC_result_queue is 0
— ASDC EWMA filter time constant is 200 us
DC Motor with Speed and Current Closed Loops, Driven by eTPU on MCF523x, Rev. 0
Freescale Semiconductor
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