AN1910 Freescale Semiconductor / Motorola, AN1910 Datasheet - Page 17

• Manufacturer Part Number: AN1910
• Description: 3-Phase AC Motor Control with V/Hz Speed Closed Loop Using the DSP56F80X
• Manufacturer: Freescale Semiconductor / Motorola

6.1.7 Fault Control
Input process:
Output process:
Results calculated by mcgen3PhWaveSine3rdHIntp function are directly passed to the PWM value
registers using PWM driver.
This process is responsible for fault handling. The software accommodates five fault inputs:
overcurrent, overvoltage, undervoltage, overheating and wrong identified hardware.
Overcurrent: In case of overcurrent in DC-Bus link, the external hardware provides a rising edge on
the fault input pin FAULTA1 of the DSP. This signal immediately disables all motor control PWM’s
outputs (PWM1 - PWM6) and sets DC_Bus_OverCurrent bit of DriveFaultStatus variable.
Overvoltage: In case of overvoltage in DC-bus link, the external hardware provides a rising edge on
the fault input pin FAULTA0 of the DSP. This signal immediately disables all motor control PWM’s
outputs (PWM1 - PWM6) and sets DC_Bus_OverVoltage bit of DriveFaultStatus variable.
Undervoltage: The DC-bus voltage sensed by ADC is compared with the limit within the software. In
case of undervoltage after a period defined by UNDERVOLTAGE_COUNT all motor control PWM
outputs are disabled and DriveFaultStatus variable is set to DC_Bus_UnderVoltage.
Overheating: The temperature of power module sensed by ADC is compared with the limit within the
software. In case of overheating after a period defined by OVERHEATING_COUNT all motor control
PWM outputs are disabled and DriveFaultStatus variable is set to OverHeating.
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Figure 6-6. 3-ph Sine Waves with 3rd Harmonic Injection, Amplitude = 50%

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Amplitude - obtained from DC-bus ripple elimination process
Omega_required - obtained from acceleration/deceleration ramp process
3-Phase AC Motor Control with V/Hz Speech Closed Loop
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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Software Design
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