Medium Voltage Motor Drive – Universal Power Converter (UPC)

Voltage Motor Drive

Notes –

  • Projected, based on simulations BOM for 15 kW prototype, with or reverse blocking SGCTs, about 97.5 % with high voltage IGBTs and rectifier grade diodes
  • Allen-Bradley Medium Voltage Current Sourced Drive 7000A, also uses SGCTs, with isolation transformer to eliminate common mode on motor
  • Non-IPC drives cannot boost voltage, so output voltage drops to input voltage under input sag conditions. IPC-UPC can boost input voltage as needed for sag immunity
  • Link frequency of 1500 Hz for IPC-UPC drive gives power cycle frequency of 3000 Hz, with 100% inter-cycle current control, allowing current control bandwidth over 400 Hz, allowing high power servo applications.
  • AB MV-7000 data sheet states 97.5% for their PWM input drives, and assuming 1% loss for integral transformer
  • IPC-UPC needs no transformer to eliminate common mode voltages (CMV) on output, while the AB MV-7000 requires an input transformer to eliminate CMV.
  • TM-Drive GE, has 18 pulse transformer isolated, rectifier input, multi-level output (http://www.tmge.com/upload/library_docs/english/TM-MV-Flyer-06-1_1160739851.pdf)
  • Multi-step output waveform, so high dv/dt effects are somewhat mitigated

Observations –

  • ll drives have similar power quality on input, with the UPC drive having lower losses (higher efficiency), better sag immunity, and much higher current control bandwidth.
  • Other drives achieve no output common mode voltages by use of isolation transformers, with an accompanying much higher drive weight and higher losses.