Case Study - BLDC Motor Drive (Inverter)

The Customer

The Manufacturers of one of India’s widest range of air conditioning and commercial refrigeration products as well as a comprehensive range of air purifiers, water purifiers, air coolers, cold storages and specialty products.

THE PROBLEM

  • There was room for improvement of efficiency, and to reduce overall power consumption
  • Upon start, a high current was able to cause damage to other devices, and cause light flickering which had to be controlled
  • There was a long delay between start up and achievement of desired cooling

THE ANALYSIS

  • Better compressor technology had to be incorporated
  • Slower ramp up and ramp down of compressor was needed
  • Larger input voltage range had to be accommodated to counter the effect of inconsistent power input

THE SOLUTION

  • Incorporated a variable speed BLDC motor compressor
  • Drive converted to constant voltage, variable frequency
  • Allow compressor to run near peak rated speed
  • Incorporated an active Power Factor Correction (PFC) circuit at the mains input stage
  • BLDC Motor Driver with power & Control card (single card)
  • Firmware logic design for BLDC Motor drive as well as air conditioning application
  • EMS vendor identification for manufacturing of PCB assemblies

THE OUTCOME

  • Power consumption reduced by 30%
  • Starting surge current substantially reduced
  • Wide mains input voltage range supported
  • Lesser time to achieve desired cooling effect
  • This generic Inverter can be tailored for various applications

Technology Areas

  • BLDC Motor Control
  • Active PFC
  • Power Electronics

TECHNICAL DETAILS

Inverter

Hardware

  • Single board solution – double sided PTH
  • Schematics, BOM, Layout & Gerber: PADS from Mentor Graphics
  • Microcontroller: Renesas R5F524T8ADFM
  • PFC Driver: Infineon IRS44273L
  • IPM: Mitsubishi PSS20S92F6-AG-N
  • Bridge Rectifier: Vishay GBPC35
  • MOSFET: ST Microelectronics STGW30V60DF

Firmware

  • Code in C

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