## 7 Impact of Control Strategies on OEWM-DTLI Performance  
As previously mentioned, the OEWM system is powered by a DTLI, and its modeling is similar to that of a conventional AC machine. In terms of control, two complementary levels of strategies can be identified in the literature: high-level control techniques, which focus on the regulation of machine variables (such as scalar control, vector control, and direct torque control (DTC)), and low-level control techniques, which deal directly with the generation of the modulation and carrier signals, typically based on PWM. Given our focus on voltage quality and energy efficiency, we concentrate on the PWM control of both inverters. Thus, the performance of the OEWM largely depends on how these two inverters are modulated to produce the appropriate output signals. To provide an overview of the existing literature, Table 6 presents a summary of the three types of configurations studied, highlighting their key contributions and their significant effects on OEWM performance. These contributions are particularly notable for their substantial improvements in critical performance parameters, including overcharging of the capacity, CMV, ZSV, THD, and the efficiency of the DTLI system. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**DCB Type**} & \multirow{2}{*}{**REF**} & \multirow{2}{*}{**Proposed Control Strategy**} & \multicolumn{6}{c}{**Improved Performances**} \\ \cline{3-8}  & & & **ZSV** & **CMV** & **Overcharging** & **THD** & **Efficiency** \\ \hline \multirow{8}{*}{[72]} & Proposes the PWM7 strategy, which is based on the combination of switching vectors from & ✓ & ✓ & ✗ & ✓ & ✓ \\  & groups (3216/3456). & & & & & & & \\ \cline{1-1} \cline{2-8}  & Proposes the PWM9 strategy, primarily relying on the combination of switching vectors from & ✓ & ✓ & ✗ & ✗ & ✗ \\  & the (3216/4451) groups. & & & & & & & \\ \cline{1-1} \cline{2-8}  & Introduces the PWM15 strategy, which relies mainly on the combination of switching vectors from & ✗ & ✓ & ✗ & ✓ & ✗ \\  & groups (4211/4451). & & & & & & & \\ \hline \multirow{8}{*}{[171]} & Proposes the use of Zero Sequence Current hysteresis control based on Space Vector Modulation to improve the suppression of parasitic currents and enhance overall system performance. & ✓ & ✗ & ✓ & ✓ & ✗ \\ \cline{1-1} \cline{2-8}  & Proposes a carrier-based SVPWM strategy, where the switching duty cycles are calculated using both the measured and reference voltages to improve modulation accuracy and system stability. & ✓ & ✓ & ✓ & ✓ & ✗ \\ \cline{1-1} \cline{2-8} Type 1 & Proposes a modified SVPWM technique that relies on the application of neighboring vectors, excluding the use of zero vectors, to enhance performance and reduce harmonic distortion. & ✓ & ✓ & ✓ & ✓ & ✓ \\ \cline{1-1} \cline{2-8}  & Proposes a generalized discontinuous PWM strategy, which aims to optimize the modulation process by introducing discontinuous patterns to improve the efficiency of the system. & ✗ & ✓ & ✗ & ✓ \\ \hline \multirow{8}{*}{[172]} & Proposes a strategy that decomposes the Zero Sequence Current into two orthogonal continuous signals using orthogonal integral-gate detection technology. & ✓ & ✗ & ✓ & ✓ & ✗ \\ \cline{1-1} \cline{2-8}  & Proposes a discontinuous PWM strategy optimized using a genetic algorithm, aiming to enhance the performance and efficiency of the system. & ✓ & ✓ & ✓ & ✓ & ✓ \\ \hline \multirow{8}{*}{[80]} & Proposes a Fault-Tolerant Control (FTC) method that uses two-phase current sensors when the one-phase current sensor fails while simultaneously suppressing the Zero Sequence Current (ZSC) during post-fault operation to maintain system reliability and performance. & ✓ & ✗ & ✓ & ✗ & ✗ \\ \cline{1-1} \cline{2-8}  & Proposes a Fault-Tolerant Control (FTC) method that uses two-phase current sensors when the one-phase current sensor fails while simultaneously suppressing the Zero Sequence Current (ZSC) during post-fault operation to maintain system reliability and performance.