48V Bidirectional Motor Generator (BMG) Operating Manual

Understanding the Core Technology of the BMG Asymmetric dual three-phase stator design that gives redundancy and high power Two separate three-phase windings in the same stator in an Asymmetric arrangement: Windings are shifted by 30° electrical (not the symmetric 60°). Creates a 12-pulse system when rectified to DC.

12-pulse rectification : Dramatically reduces output ripple Harmonic cancellation : 5th, 7th harmonics eliminated Redundancy : Can operate on one winding if other fails 50% power available during single-winding fault Fault isolation : Windings magnetically coupled but electrically separate Continued operation : Critical for mission- critical applications Distributed losses : Heat spread across more conductors

30-40% better heat dissipation than single winding Lower hot-spot temperatures: Extended insulation life Independent cooling paths : Better coolant flow options • Reduced torque ripple : 3.4% • Lower vibration : Smoother operation, less mechanical stress • Reduced bearing loads : More uniform force distribution • Quieter operation : Less acoustic noise

Hybrid Excitation Technology that gives precise control and high power at idle. Offer unique advantages when operated as DC generators, combining the benefits of both permanent magnet (PM) and wound-field excitation.

Wide voltage regulation range : voltage from 50% to 150% of nominal Precise voltage control : ±0.5% regulation Load-independent regulation : Maintains stable voltage across varying loads Higher efficiency at partial loads : Field weakening reduces iron losses when full voltage isn't needed Extended speed range : Effective operation from 20% to 200% of rated speed

Low-speed performance : Strong power generation even at low RPM Overload capability : Can boost field for short-term 150-200% overload Lower ripple voltage : Hybrid excitation provides smoother field distribution Controlled shutdown : Can reduce field to zero for safe maintenance Redundant excitation : Can operate on PMs alone if field winding fails Short-circuit limiting : Field control provides inherent current limiting

Hairpin Windings that significant increase power density • Excellent slot fill despite dual windings • Superior thermal coupling to cooling system • Precise manufacturing enables tight tolerances • Lower resistance maximizes efficiency gains • •

Reliability: MTBF increased 3-5X Cost: 20-30% higher initial cost

Ripple frequency: 12 × fundamental vs. 6 × Ripple amplitude: 75% reduction

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Voltage regulation: ±0.5% vs. ±2% Efficiency gain: 2-4% improvement

EMI: Significantly reduced DC filter size: 60-80% smaller

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Power density: 10-15% reduction (due to extra windings)

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