Electrical Engineer

  DC systems also produce magnetic fields in components like inductors, motors, and electromagnets. However, reactive power is a concept specific to AC (alternating current) systems , and here's why DC systems don't have reactive power in the same sense: 1. DC vs. AC Behavior : In AC systems , the current and voltage alternate sinusoidally. As the current and voltage continuously change, inductors and capacitors store and release energy, creating a constant exchange of energy between the source and the reactive components. This exchange is what defines reactive power (Q) in an AC system. In DC systems , the current is constant (steady-state), meaning it doesn't alternate. Once a magnetic field is established in an inductor (like in a DC motor or electromagnet), the field remains constant, and there is no continuous exchange of energy between the source and the inductor, as there is in AC. Therefore, reactive power does not exist in DC . 2. Energy Storage in DC : Wh

  What is a Smart Grid? A  smart grid  is a digitally enabled electrical grid that collects, distributes and works on the information about the behaviour of all suppliers and consumers in order to improve the efficiency, reliability and sustainability of electricity service. Smart Grid = Information Technology + Electrical Grid The smart grid uses a two-way digital communication of technologies and computer processing which enables electricity industry to better manage energy delivery and transmission. It is capable of providing real time information and enable the nearby quick balancing of supply and demand. How does a Smart Grid Work? In addition to the traditional grid’s generating facilities and transmission network the smart grid consists of three new components Smart control and measuring devices Digital communication systems Computer software programs The smart devices include computer controlled generators and other power sources as well as meters, monitors and intelligent elec

  Difference between Inverters VSI vs CSI VSI (Voltage Source Inverter) CSI (Current Source Inverter) 1. In voltage source inverter input voltage is kept constant. 1. In current source inverter input current is kept constant. 2. VSI is fed from a DC voltage source having small or negligible impedance. 2. CSI is fed with adjustable current source from a DC voltage source of high impedance. 3. DC source in parallel with large capacitor. 3. VSI can be converted into CSI, By connecting large series inductance. 4.Input voltage is maintained constant. 4. The input current is constant but adjustable. 5. An output voltage is independent of load. 5. An output current is independent of load 6. The waveform of the load current as well as its magnitude depends upon the nature of load impedance. 6. The magnitude of output voltage and its waveform depends upon the nature of the load impedance. 7. VSI has slow response than CSI.  7. CSI has fast response than VSI. 8. VSI requires feedback diodes 8. T

  8051 microcontroller is designed by Intel in 1981. It is an 8-bit microcontroller. It is built with 40 pins DIP (dual inline package), 4kb of ROM storage and 128 bytes of RAM storage, 2 16-bit timers. It consists of are four parallel 8-bit ports, which are programmable as well as addressable as per the requirement. An on-chip crystal oscillator is integrated in the microcontroller having crystal frequency of 12 MHz. Let us now discuss the architecture of 8051 Microcontroller. In the following diagram, the system bus connects all the support devices to the CPU. The system bus consists of an 8-bit data bus, a 16-bit address bus and bus control signals. All other devices like program memory, ports, data memory, serial interface, interrupt control, timers, and the CPU are all interfaced together through the system bus.

  Using MOSFET Body Diodes to Charge Battery in Inverters In this post we try to understand how the internal body diodes of MOSFETs could be exploited for enabling the charging of battery through the same transformer which is being used as the inverter transformer. In this article we will investigate a full bridge inverter concept and learn how the in-built diodes of its 4 MOSFETs could be applied for charging an attached battery. What is a Full Bridge or H-Bridge Inverter In few of my earlier posts we have discussed  full bridge inverter circuits  and regarding their working principle. As shown in the above image, basically, in a full-bridge inverter we have a set of 4 MOSFETs connected to the output load. The diagonally connected MOSFET pairs are alternately switched through an external  oscillator , causing the input DC from the battery to transform into an alternating current or AC for the load. The load is normally in the form of a  transformer , whose low voltage primary is conne

  Nowadays, SCRs are available of ratings up to 10 KV and 3 KA. But sometimes we face demand, more than these ratings. In this case combination of more than one SCRs is used. Series connection of SCRs meets high voltage demand and parallel connection of SCRs meets high current demand. These series and parallel connection of SCR or Thyristor will work efficiently if all SCRs are fully utilized. Although all SCRs in a string are of same rating, their V-I characteristics differ from one another. This leads to unequal voltage or current division among them. Hence every SCR is not fully utilized. So the efficiency of string is always less than 100% according to the given expression With increase in the numbers of SCRs in a string voltage or current handled by each SCR is minimized. This phenomenon increases the reliability of the string, but reduces the utilization of each SCR. Thus string efficiency decreases. Reliability of string is measured by derating factor (DRF) which is given b