Voltage and Harmonic Control of Inverters: Voltage and Harmonic Control of Inverters – In applying Inverters for motor control both V and f (keeping V/f constant) need to be varied. Further, the inverters apply essentially nonsinusoidal ac voltage to the motor. External filter circuits cannot be employed due to the difficulty in operating inverters over […]
Voltage and Harmonic Control of Inverters Read More »
Induction Motor Speed Control Methods: The only way to control the speed of a synchronous motor is to control the input frequency and voltage such as to keep V/f constant. The Induction Motor Speed Control, on the other hand, can be controlled by the following means: Stator Voltage Control Frequency Control Slip Control 1. Stator
Induction Motor Speed Control Methods Read More »
Basic Principle of Chopper Circuit: A Basic Principle of Chopper Circuit is essentially a thyristor switch in series with the load as shown in Fig. 11.27(a). A shunting diode is provided across the load for free-wheeling the load current when the thyristor is off. The thyristor shown enclosed by a dotted square can be turned-on
Basic Principle of Chopper Circuit Read More »
Thyristor Control of Motors: Thyristor Control of Motors – A variety of thyristor control circuitry has been devised for use in motor control depending upon the type of supply (ac/dc) and the type and size of the motor. For dc motor control, controlled dc power from a constant voltage ac supply is obtained by means
Thyristor Control of Motors Read More »
Block Diagram of Electrical Drives | Advantages | Applications: Block Diagram of Electrical Drives – Invention of thyristor led to emergence of semiconductor drives in early sixties. The improvements in converters and development of new drive-control strategies, such as field oriented (or vector) control of ac drives, sliding-mode control, energy saving strategies, etc. brought about
Block Diagram of Electrical Drives Read More »
Recent Trends in Power Semiconductors: The recent trends in Power Semiconductors from application point of view show that MOSFETs and IGBTs are replacing BJTs almost completely while GTOs are currently being used for high V and power ratings (> 0.5 MVA), these are expected to be replaced by IGBTs and recently introduced IGCTs (integrated Gate
Recent Trends in Power Semiconductors Read More »
MOS Controlled Thyristor (MCT) | Symbol | Equivalent Circuit: An MOS Controlled Thyristor (MCT) is a thyristor-like trigger-into-conduction device that can be turned on or off by a short pulse on the MOS gate. It is a high power, high frequency, low conduction drop switching device and shows a tremendous promise for next generation power
MOS Controlled Thyristor (MCT) Read More »
Insulated Gate Bipolar Transistor (IGBT): An Insulated Gate Bipolar Transistor (IGBT) is basically a hybrid MOS-gated turn on/off bipolar transistor that combines the features of MOSFET (voltage control features), BJT (fast acting features and high power capability) and thyristor. The device is also known as MOSIGT, COMFET (conductively modulated FET), or GEMFET (gain modulated FET),
Insulated Gate Bipolar Transistor (IGBT) Read More »
What is Silicon Controlled Rectifier (SCR)? | Construction and Working of SCR: What is Silicon Controlled Rectifier (SCR)? – This semiconductor switching device is also known as a thyristor. It is a 4-layer, 3-junction, bistable (ON and OFF) semiconductor switch. The terminal to the outer p-layer is the anode, the terminal to the outer n-layer
What is Silicon Controlled Rectifier (SCR)? Read More »
Speed Control of Induction Motor: Stepless control of speed of induction motors cannot be carried out as efficiently and inexpensively as for dc motors. Various methods of Speed Control of Induction Motor can be visualized by consideration of the speed equation It is seen from this equation that there are two basic methods of speed
Speed Control of Induction Motor Read More »
