Abstract
Modular multilevel converter (MMC) has become a promising technology Handling of Electric vehicles (EV) power source by using different techniques and algorithm. Where the battery cells are series connected to enhance the output voltage. In this topology, individual batteries are connected together and became a dc link of the converter subsystem, to allowing the highest flexibility for the discharge and recharge by estimating the State of charge. The battery power has kept in balance by sorting algorithm and the controlling the submodules by PS –PWM techniques. Interactive power management at EVs will make effective utilization of battery power and switching of semiconductor can operate motor into regenerative mode. Simulation study has been done in MATLAB/SIMULINK platform and it is observed the output voltage, THD % values and State-of-Charge (SOC) of batteries are well maintained
Description
Multilevel Converter have been used extensively in the last few decades starting from high-voltage direct current transmission to injection of renewable energy into the grid. In electric vehicle, higher voltage may be required which cannot be supplied by a single battery. Mostly PD-PWM, POD-PWM, APOD-PWM & PS PWM are implemented to control and balance the dc link voltages of submodules. The voltage balancing is addressed based on the high-frequency component in arm current. An improved PS-PWM method is implemented in for balancing the submodule voltages by alternatively distributing the gating pulses among the submodules within several carrier periods. This effectively increases the time for balancing the DC voltages.
The topology actively equalizes the cells therefore improving the battery life. Arm and cell balancing controllers have been implemented for regulating the dc link voltages of the submodules. A reduced switching-frequency voltage balancing algorithm is introduced in to balance the dc link voltages. Control of medium-voltage AC motor drive using MMC is presented for wide speed range region of operation. State-of-Health balancing control mechanism is reported for the battery energy storage system connected with MMC. One of the main drawbacks of MMCs for low-voltage applications is the increased conduction losses, if compared with traditional inverters due to the high number of devices conducting in series. In a battery-powered electric vehicle, regenerative braking is the conversion of the vehicle’s kinetic energy into chemical/ electro static energy stored in the battery, where it can be used later to drive the vehicle. It is braking because it also serves to slow the vehicle. It is regenerative because the energy is recaptured in the battery where it can be used again. The kinetic energy stored in a moving vehicle is related to the mass and speed of the vehicle by the equation E = ½mv². All else being equal, if your car is twice as heavy it has twice the kinetic energy and if it is moving twice as fast it has four times the kinetic energy. Any time your car slows down the kinetic energy stored in the vehicle has to go somewhere. Let’s take a look at where this energy goes. There is always some kinetic energy consumed by the rolling resistance, mechanical friction, and aerodynamics of your car. These bits of energy go into heating the road, the surrounding air, and various spinning parts in your car. But the vast majority of the kinetic energy is converted into heat by your brake pads when you stomp on the brakes. Regenerative braking recovers some energy that would otherwise have been wasted in the brakes.
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