EMI and EMC Aspects of a Brushless Repulsion Motor/DrivePresented by DynaMotors, Inc.1 12004 SMMA2004 SMMAEMI and EMC Aspects of a Brushless Repulsion Motor/DriveBackgroundInverters that drive induction motors, brushless dc motors and switched reluctance motors can produce EMI and cause EMC problems. 2 22004 SMMA2004 SMMATypical PWM Motor Drive Inverter3 32004 SMMA2004 SMMAEMI and EMC Aspects of a Brushless Repulsion Motor/driveBackgroundInverters that drive induction motors, brushless dc motors and switched reluctance motors can produce EMI and cause EMC problems.Cabling between drive inverters and motors can conduct common-mode energy to the motor stator windings which might cause damaging bearing currents.4 42004 SMMA2004 SMMAHi-Frequency Common-Mode current paths 5 52004 SMMA2004 SMMAEMI and EMC Aspects of a Brushless Repulsion Motor/driveBackgroundInverters that drive induction motors, brushless dc motors and switched reluctance motors can produce EMI and cause EMC problems.Cabling between drive inverters and motors can conduct common-mode energy the motor stator windings which might cause damaging bearing currents.Long cables between the drive inverter and the motor may set up standing voltage waves that reduce the motor insulation life.6 62004 SMMA2004 SMMAEMI and EMC Aspects of a Brushless Repulsion Motor/driveBackgroundInverters that drive induction motors, brushless dc motors and switched reluctance motors can produce EMI and cause EMC problems.Cabling between drive inverters and motors can conduct common-mode energy the motor stator windings which might cause damaging bearing currents.Long cables between the drive inverter and the motor may set up standing voltage waves that reduce the motor insulation life.Filters added to drive inverters designed to reduce or eliminate the above problems must carry the motor rated current.7 72004 SMMA2004 SMMATypical filter add-ons used with drive inverters8 82004 SMMA2004 SMMAEMI and EMC Aspects of a Brushless Repulsion Motor/driveBackgroundInverters that drive induction motors, brushless dc motors and switched reluctance motors can produce EMI and cause EMC problems.Cabling between drive inverters and motors can conduct common-mode energy the motor stator windings which might cause damaging bearing currents.Long cables between the drive inverter and the motor may set up standing voltage waves that reduce the motor insulation life.Filters added to drive inverters to reduce the above problems must carry the motor rated current.Shielded cables are often needed to reduce EMI.9 92004 SMMA2004 SMMASolutions to the EMI and EMC problemWays to minimize the EMI and EMC problemUse only linear (sine-wave) drives for adjustable- speed motors10102004 SMMA2004 SMMASolutions to the EMI and EMC problemWays to minimize the EMI and EMC problemUse only linear (sine-wave) drives for adjustable- speed motorsAdd shielded cabling11112004 SMMA2004 SMMASolutions to the EMI and EMC problemWays to minimize the EMI and EMC problemUse only linear (sine-wave) drives for adjustable-speedAdd shielded cabling Use very high-frequency carrier PWM drives (100- 200kHz) with filtered outputs and perfectly shielded and grounded enclosures12122004 SMMA2004 SMMASolutions to the EMI and EMC problemWays to minimize the EMI and EMC problemUse only linear (sine-wave) drives for adjustable-speedAdd shielded cablingUse very high-frequency carrier PWM drives (100- 200kHz) with filtered outputs and perfectly shielded and grounded enclosuresBuild the drive into the motor still needs output and input filters to limit bearing currents but does help reduce EMI caused by drive to motor cables.13132004 SMMA2004 SMMASolutions to the EMI and EMC problemWays to minimize the EMI and EMC problemUse only linear (sine-wave) drives for adjustable-speedAdd shielded cablingUse very high-frequency carrier PWM drives (100- 200kHz) with filtered outputs and perfectly shielded and grounded enclosuresBuild the drive into the motor still needs output and input filters to limit bearing currents but does help reduce EMI caused by drive to motor cables.Use a brushless repulsion motor.14142004 SMMA2004 SMMA48 Frame 4-pole 1/2HP HVAC Brushless Repulsion Motor with Integrated Drive Control15152004 SMMA2004 SMMAConstruction of a Brushless Repulsion Motor16162004 SMMA2004 SMMASimplified image of a Brushless Repulsion MotornArmature coil is opennArmature coil is shorted17172004 SMMA2004 SMMAFlux pattern in 4-pole Brushless Repulsion Motor18182004 SMMA2004 SMMACoil Switch side of 48 Frame HVAC Motor PC Board (Mounted on armature shaft)19192004 SMMA2004 SMMAEMI and EMC Aspects of a Brushless Repulsion Motor/DriveRadiated and Conducted Noise Measurements on the 48 frame HVAC Motor nRadiated standards were FCC Class A 3m and CE standard EN55022 Class A 3mnBoth the horizontal and vertical planes were measured in the testsnConducted noise standard was EN55022 Class A202