Texas Instruments TMS320C6745 DSP - 14.3.5 Controlling Multiple Half H-Bridge (HHB) Converters; Pwm2 = N × F; Pwm1 )

CTR=0
CTR=CMPB
X
En
SyncOut
Phase reg
Ext SyncIn
(optional)
EPWM1A
EPWM1B
SyncOut
Phase reg
CTR=CMPB
CTR=0
X
En
EPWM2B
EPWM2A
Slave
Master
V
out1
EPWM1A
SyncIn
SyncIn
V
DC_bus
EPWM1B
EPWM2B
EPWM2A
V
DC_bus
V
out2
Φ=0°
Φ=0°
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SPRUH91D–March 2013–Revised September 2016
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Enhanced High-Resolution Pulse-Width Modulator (eHRPWM)
14.3.5 Controlling Multiple Half H-Bridge (HHB) Converters
Topologies that require control of multiple switching elements can also be addressed with these same
ePWM modules. It is possible to control a Half-H bridge stage with a single ePWM module. This control
can be extended to multiple stages. Figure 14-55 shows control of two synchronized Half-H bridge stages
where stage 2 can operate at integer multiple (N) frequencies of stage 1. Figure 14-56 shows the
waveforms generated by the configuration shown in Figure 14-55.
Module 2 (slave) is configured for Sync flow-through; if required, this configuration allows for a third Half-H
bridge to be controlled by PWM module 3 and also, most importantly, to remain in synchronization with
master module 1.
Figure 14-55. Control of Two Half-H Bridge Stages (F
PWM2
= N × F
PWM1
)