Multilevel inverters (MLI) consist of a wide range of power converters. They have many designs and have been introduced with different circuit topologies such as neutral point clamped, diode clamped, cascaded H-bridges, and flying capacitors. Some of these MLIs have disadvantages, including design complexity, size, and losses due to the large number of switching devices required when they produce many output voltage levels. They are also bulky in size and may require several DC power sources. This paper presents a review of the various topologies of single-phase T-Type MLIs (T-MLIs). These MLIs are used to convert DC power from renewable energy sources (RES)” into AC with a near-sine waveform and low total harmonic distortion (THD). Simple and complex MLI designs are discussed. The major types of modulation techniques are discussed, including sinusoidal pulse width modulation (SPWM), selective harmonic elimination (SHE), and preprogrammed PWM. Various methods of output voltage control are taken into consideration as well. The aim of this comprehensive survey is to identify T-MLIs for researchers and those interested in the power conversion field, as well as to discuss the many topologies, identifying designs with superior characteristics that can be efficiently implemented with RESs to obtain better AC voltage with enhanced power quality.

Brushless DC (BLDC) motors provide many benefits over normal DC motors. They have high efficiency, stability, low noise, longer lifetime than other motor kinds, high torque to weight ratio, and most importantly, no commentator sparks. With the other advantages, BLDC motors are widely used in electric vehicle applications. But in most cases, their rotational speed has to be regulated. This paper presents a comparative study of BLDC motor speed control by three types of Sliding Mode Control (SMC) techniques, which are 1 st order, 2 nd order, and Integral SMC. The motor ratings are 1 kW, 3000 r.p.m, at 3 N.m load torque. The aim is to use the BLDC for electric vehicle applications. This research found that the integral SMC is superior to the 1 st-order and 2 nd-order SMC techniques. Also, the lowest BLDC performance is obtained using the 2 nd-order SMC technique. At rated speed and full load conditions, it was found that steady-state errors for each controller are (2.4, 9.5, and 4.9) r.p.m for each integral SMC, 2 nd order SMC, and 1 st order SMC, respectively. The entire system is simulated successfully by MATLAB SIMULINK. The motor ratings are suitable for e-bike and tricycle applications.