A Cross-Cycle Dead Zone Compensation Strategy for Phase Current Reconstruction in PMSM Drives

In single DC-link current sensor-based phase current reconstruction for permanent magnet synchronous motor (PMSM) drives, the current reconstruction dead zone caused by insufficient active voltage vector duration restricted by driver dead time, switching settling, and Analog to Digital Converter (ADC) latency degrades current sensing accuracy, particularly in low modulation and sector boundary regions. Conventional phase shift methods, while extending the sampling window through Pulse Width Modulation (PWM) pattern modification, inevitably introduce asymmetric switching sequences that generate additional phase current harmonics and may reduce the linear modulation range. This article analytically characterizes the dead zone formation mechanism across the space vector plane and proposes a cross-cycle compensation strategy based on vector approximation. The method replaces the reference voltage vector with the nearest measurable vector in the present switching cycle and compensates for the resulting voltage error in the subsequent cycle, thereby extending the sampling window while preserving precise volt-second balance without extra hardware. Experimental results demonstrate that the proposed method eliminates the current reconstruction dead zone, achieves high-fidelity phase current reconstruction, and ensures robust dynamic performance under various load conditions and transients. The feasibility and effectiveness of the single current sensor drive are thoroughly validated.