Grid Tech

The inverter is an electronic device or circuitry that changes direct current (DC) to alternating current (AC). In short, the Inverter is a DC-AC converter. It can be seen as an application for DC chopper. We can classify inverters into single-phase inverters and 3-phase inverters. We will see some inverter circuits and how they act. 1. Single Phase Inverter: Half Bridge, Full Bridge Half Bridge 1-1. Half-bridge inverter circuit 1-2 Half-bridge inverter graph  In figure 1-1, we can see the Half-bridge circuit. In this circuit, there are two rules of triggering: First, because of KVL, T1 and T2 can not be on at the same time. Second, KCL is satisfied by D1 and D2.  A pair of a diode and a transistor acts like a switch. So In figure 1-2, if SW1 (T1 and D1) is on for the time duration 0<t<T/2, then V_o is V_s/2. On the other hand,  if SW2 (T2 and D2) is on for the time duration T/2<t<T, then V_o is V_s/2. Assuming that it's a highly indu...

 A voltage converter is an electric power converter that changes the voltage of an electrical power source. On this page, I am going to talk about the DC-DC converter. In the DC-DC converter, there are 3 types. 1. Step-down(Buck) converter: Where the output voltage of the converter is lower than the input voltage. In a buck converter, there are two types of modes. Continuous conduction mode(CCM) and Discontinuous conduction mode(DCM). During CCM(Mode 1), while switch S is on, the voltage of the load is conducted as V_s. During DCM(Mode 2), while switch S is off, any current doesn't flow.  V_a=F(t_on, f_s) is a linear function. t_on is the on pulse width. Controlling t_on is known as PWM control. f_s is the switching frequency.  Low current ripple(by adding inductor) This is a buck converter which provides a low current ripple by adding an inductor on load.  Low voltage ripple(by adding capacitor) This is a buck converter which provides lo...

EV means "Electric Vehicles", which use one or more electric motors or traction motors for propulsion. In this poster, there will be a description about the history of electric vehicles and their current infrastructure. History of Electric Vehicle   Electric car built by  Thomas Parker , photo from 1895    In 1827, Hungarian priest, Ányos Jedlik, started electric power. After that year, he used an electric motive motor to power his small car. It had been developed and upgraded more and more.  Finally, in America, in the early 1900s, the first mass-produced electric vehicles appeared. But It had more disadvantages than advantages compared to a combustion engine vehicle which appeared later. The high cost, low speed, and short-range battery problem were the main problems of EV in comparison to a combustion engine vehicle.  But, in the 21st century, demand for alternative fuel instead of oil has been increasing. By the help of the trend, the import...