Abstract:
In an elevator operating, some electrical energy is produced when elevator motor perform as a generator. This energy cannot be used in the system and has to convert to heat power via a resistive load or dump load. However, it would be useful, if the energy loss can be managed and regenerated back to the grid system in order to reduce energy consumption from the elevator. There is a method called regenerative technique the will be used as an elevator energy regenerative unit which consists of 2 main parts as: the DC to AC converter and the grid connected system controller.
This thesis presents the grid connected model of the unstable source from the DC to AC converter in the elevator energy regenerative unit (EERU). The model employs power flow technique using current loop control with phase lock loop (PLL) technique to inject current back to the distribution system. MATLAB/Simulink program is applied for model simulation. Then the proposed system is implemented and tested the performance of power grid synchronization with industrial inverter.
From the experiment, the simulation result was compared to implementation result that performed to the rated motor of 7.5 kW. It is found that proposed EERU system was able to connect with the power grid. The system can be synchronized the power from elevator to the power grid system when the elevators motor is operated in generator mode with current flow control at 180 degree out of phase. As the result, the system can feed average power to the gird approximately 4 kW or around 53 percent of the rated motor.