Texas Instruments TMS320x28xx, 28xxx manual Controlling Multiple Half H-Bridge HHB Converters

Models: 28xxx TMS320x28xx

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3.5Controlling Multiple Half H-Bridge (HHB) Converters

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Controlling Multiple Half H-Bridge (HHB) Converters

3.5Controlling 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 3-7shows control of two synchronized Half-H bridge stages where stage 2 can operate at integer multiple (N) frequencies of stage 1. Figure 3-8shows the waveforms generated by the configuration shown in Figure 3-7.

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 3-7. Control of Two Half-H Bridge Stages (FPWM2 = N x FPWM1)

 

 

 

Ext SyncIn

VDC_bus

 

 

 

(optional)

 

Master

 

 

Phase reg

SyncIn

EPWM1A

 

 

 

 

 

En

 

 

 

 

EPWM1A

Φ

 

°

 

=0

 

 

 

 

CTR=zero

 

EPWM1B

 

 

 

CTR=CMPB

 

 

 

 

X

SyncOut

EPWM1B

 

 

 

 

 

 

 

Slave

 

 

 

Phase reg

SyncIn

 

 

 

 

VDC_bus

 

 

En

 

Φ=0°

 

EPWM2A

 

CTR=zero

 

EPWM2B

 

 

EPWM2A

CTR=CMPB

 

 

 

X

SyncOut

 

 

 

 

 

 

 

 

 

EPWM2B

Vout1

Vout2

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Applications to Power Topologies

SPRU791D–November 2004–Revised October 2007

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Texas Instruments TMS320x28xx, 28xxx manual Controlling Multiple Half H-Bridge HHB Converters