AN2528 Datasheet, PDF (4/28 Pages) Freescale Semiconductor, Inc – Standard Space Vector Modulation TPU Function Set (svmStd)

AN2528/D
Freescale Semiconductor, Inc.
NOTE:
3. Initializes function parameters. The parameters T, prescaler, DT, MPW,
SQRT3 and sync_presc_addr must be set before initialization. If an
svmStd_sync channel or an svmStd_res channel is used, then also its
parameters must be set before initialization.
4. Issues an HSR (Host Service Request) type %10 to one of the
svmStd_bottom channels to initialize all PWM channels. Issues an HSR
type %10 to the svmStd_sync channels, svmStd_res channels and
svmStd_fault channel, if used.
5. Enables servicing by assigning high, middle or low priority to the channel
priority bits. All PWM channels must be assigned the same priority to
ensure correct operation. The CPU must ensure that the svmStd_sync
or svmStd_res channels are initialized after the initialization of PWM
channels:
– assign a priority to the PWM channels to enable their initialization
– if a Synchronization Signal or a Resolver Reference Signal channel
is used, wait until the HSR bits are cleared to indicate that
initialization of the PWM channels has completed and
– assign a priority to the svmStd_sync or svmStd_res channels to
enable their initialization
A CPU routine that configures the TPU can be generated automatically using
the MPC500_Quick_Start Graphical Configuration Tool.
Detailed Function Description
Standard Space
Vector Modulation –
Top (svmStd_top)
and Standard Space
Vector Modulation –
Bottom
(svmStd_bottom)
The svmStd_top and svmStd_bottom TPU functions work together to generate
a 6-channel, 3-phase PWM signal, with dead-time between the top and bottom
channels. In order to charge the bootstrap transistors, the PWM signals start to
run 1.6ms after their initialization (at 20MHz TCR1 clock). The functions
generate signals corresponding to Reference Voltage Vector Amplitude of 0
(50% duty-cycle) until the first reload values are processed.
The CPU controls the PWM output by setting the TPU parameters. The Stator
Reference Voltage Vector components u_á and u_â have to be adjusted during
run time. The PWM period T and the prescaler – the number of PWM periods
per reload of new values – are also read at each reload, so these parameters
can be changed during run time. Conversely, dead-time (DT) and minimum
pulse width (MPW) are not supposed to be changed during run time. The CPU
notifies the TPU that the new reload values are prepared by setting the LD_OK
parameter. The TPU notifies the CPU that the reload values have been read
and new values can be written by clearing the LD_OK parameter.
The TPU writes the parameter Sector, which indicates the current Stator
Reference Voltage Vector position in sector 1 to 6.
4
Standard Space Vector Modulation TPU Function Set (svmStd)
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