###### Abstract  
An \(n/2\)-sensor-based and an \((m+1)/2\)-sensor-based phase current detection scheme are proposed for even-numbered switched reluctance motors (EMSRMs) with \(n\) phases and odd-numbered switched reluctance motors (OMSRMs) with \(m\) phases. For the EMSRMs, the phases are divided into \(n/2\) groups each of which includes two phases furthest from each other, and the lower dc bus is split into \(n/2+1\) buses such that the currents through the lower switches of a group flow through a bus whose current is detected by a sensor. For the OMSRMs, the phases are divided into \((m+1)/2\) groups and the currents through the lower switches of a group are detected by a multiplexed sensor without converter modification; the phase grouping is generalized as an optimization problem considering the volume and measuring range of the sensors. The schemes can detect the magnetization and freewheeling phase currents under multiphase excitation without pulse injection and voltage penalty. Compared to the existing schemes using cross-winding sensors, the proposed schemes can increase the motor torque by extending the phase conduction region. In addition, the proposed scheme for EMSRMs can combine the low-cost low-side shunt current sensing technique, and the proposed scheme for OMSRMs can increase the current sensing resolution. Simulations are carried out to validate the two proposed schemes. The proposed \((m+1)/2\)-sensor-based scheme is further verified experimentally. s +
Footnote †: journal: Applied Sciences  
_Applied_  
_sciences_  
_Article_  
_Torque-Enhanced Phase Current Detection Schemes for Multiphase Switched Reluctance Motors with Reduced Sensors._  
_S.S._, S.  
method using reduced sensors is firstly applied to the SRM drives. The lower dc bus of asymmetric half-bridge converter (AHBC) is split into two buses, such that a single current sensor is used to sense the sum of the currents through the commutating switches of all the motor phases. In the two-phase excitation region, the current samplings of the two phases are staggered in time, and the AHBC is temporarily forced into a \"sense state\" at each sampling instant. In the \"sense state\" of a phase, only the current of this phase can pass through the single sensor and thus be detected. The insertions of the \"sense states\" are implemented by adding some complex logic circuits. In [12], the insertions are achieved by injecting double phase-shifted PWM signals with the same frequency and duty cycle into the drive signals of the down switches of the two phases simultaneously excited, thus avoiding the additional circuits. Combined with the phase current reconstruction scheme in [12], a wavelet packet decomposition-based fault diagnosis scheme is developed in [13], and a sensorless rotor position estimation method is proposed in [14]. However, all the insertions above will lead to voltage penalty, additional current ripples, and additional switching losses. In [15], the voltage penalty and the additional current ripples are avoided based on the proposed power converter, which adds an excitation current path for each phase compared to the AHBC. However, the phase current reconstruction requires injecting four high-frequency pulses into the drive signals of four switches, which will result in more extra switching losses. Moreover, all the one-sensor-based methods above cannot detect the phase currents in demagnetization. In [16], a one-sensor-based method that can reconstruct the magnetization and also the demagnetization phase currents is proposed for three-phase SRMs based on a four-leg power converter. However, the problems of voltage penalty, additional current ripples, and additional switching losses still exist due to the pulse injection. Additionally, the freewheeling phase currents cannot be detected.