Nitai Pal

Computation of inductance and AC resistance of a twisted litz-wire for high frequency induction cooker

A modeling method for computing the inductance and AC resistance of litz-wire for a household purpose induction cooker is presented. Litz wire construction controls the skin effect and proximity effect of conductor operating at high frequency. Both inductance and AC resistance of the twisted litz wires are calculated by varying the number of strands and layer construction. An attempt is also made to test the impact of twisting in the wire. To test the suitability at different operating frequency, inductance and resistances are also computed. Obtained results are found to be feasible for real implementation in high frequency inverter fed induction cooker. It has also been noticed that AC resistance reduces exponentially with the increase of number of twist in the wire, which in-turn reduces the skin effect loss of the cooker.

Review of induction cooking - a health hazards free tool to improve energy efficiency as compared to microwave oven

This article describes a health hazards free induction cooking which improves energy efficiency as compared to microwave cooking. Microwaves are very short waves of electromagnetic energy that travel at the speed of light. Microwave ovens contain a magnetron, a tube in which electrons are affected by magnetic and electric fields in such a way so as to produce micro wavelength radiation at about 2.45 GHz. This microwave radiation interacts with the molecules in food. A microwave oven decays and changes the molecular structure of the food by the process of radiation. On the other hand, only the heat radiation comes from an induction cooker. The heat produced in the base of an induction cooker is transferred to the food via conduction. The other advantages are good compactness, high reliability, quick response, absence of combustion waste and absence of shock hazard in the induction cookers. Above all, the cost of induction cooker is cheaper than that of microwave oven.

Energy efficient solar CFL lighting system using MOSFET based high frequency inverter for remote areas

The use of Compact Fluorescent Lamp increases for photovoltaic lighting systems due to their high luminous efficacy and ability to provide adequate lumen output for a given lighting application. The luminous efficacy increases with switching frequency while providing eye comfort to user. The low electrical consumption makes the CFL an ideal choice for solar photovoltaic power system for lighting application. However, the CFLs electrical requirements are not easily met by hard-switched inverters due to their higher switching losses at higher frequencies. The difficulty in meeting the complex electrical requirements such as preheat and ignition voltage of CFL resulting in lower efficiency. In order to make a successful photovoltaic lighting system, the first step is to select a well-suited high-frequency inverter and a series interrupting type charge controller for producing light at remote areas while maintaining reliability.

TRIAC-DIAC based DC series motor speed controller for mud pumps of drill-rig equipment

The present investigations relate to the development of TRIAC-DIAC based DC series motor speed controller for mud pumps of industrial drill-rig equipment. This paper deals with mud pumps on drilling rigs provide the means for supplying flow and pressure of the chemical mud fluid through the drill pipe, drill bit and return to the surface via the annulus of drill pipe. In this process, the mud maintains down-hole pressure, cools the drill bit and removes the cuttings from the well bore. Since flow is proportional to motor speed and pressure is proportional to motor current, flow and pressure signals can be obtained from the speed calculator card and from the field current of the DC series motor. The speed control of a dc series motor using a TRIAC together with a bridge rectifier is developed. The TRIACs of today are well suited to the requirements of switching inductive loads. TRIAC control circuits must be particularly well tuned to be both economical and applicable to inductive loads.

Selection of Power Semiconductor Switches - a Tool to Reduce Switching & Conduction Losses of High Frequency Hybrid Resonant Inverter fed Induction Cooker

An exhaustive method for the selection of different power semiconductor switches for high frequency hybrid resonant inverter fed induction heater is presented here. Heating coil of the induction heater is made of litz wire which minimizes the skin effect and proximity effect at high operating frequency. With the calculated optimum values of inductance and resistance of heating coil at a particular operating frequency, high frequency hybrid resonant inverter topology has been simulated using PSPICE software as well as constructing the experimental model of same rating. Obtained the voltage waveforms across heating coil and current waveforms through it, have been taken for further analysis. From this analysis, selection of suitable power semiconductor switches like IGBT, GTO and MOSFET are made. Waveforms have been shown to justify the feasibility for real implementation of high frequency hybrid resonant inverter fed induction heater in domestic applications.

A New Heat Treatment Topology for Reheating of Blood Tissues After Open Heart Surgery

This paper presents the human blood reheating technique for the blood tissues after surgery as 37–51 °C temperature is required during surgery with high frequency induction heating system. The surgeon opens the chest by dividing the breastbone (sternum) and connects with the heart-lung machine to operate on the heart. This machine allows the surgeon to operate directly on the heart by performing the functions of the heart and lungs. The length of the operation will depend on the type of surgery that is required for patient. Most surgeries take at least 4–5 h. The preparation for surgery, which requires approximately 45–60 min included in this time. After this operation the patients has required high temperature blood for the continuation of blood flow to the heart as the human body temperature is decreases after operation. Here high frequency converter technique can give better topology for reheating the blood after open heart surgery by taking least time than conventional system.

Selection of Switching Frequency for H. F. Mirror Inverter Employed in Industrial Induction Heating

Abstract —An exhaustive method for verifying & optimizing of switching frequency for the performance of high frequency mirror inverter for induction heater is presented. Litz-wire is used for heating coil of the induction heater which controls the skin effect and proximity effect of conductor operating at high frequency. With the calculated optimum values of inductance and resistance at a particular operating frequency, HF mirror inverter topology has been simulated using P-SIM. Optimum results are obtained by changing the switching frequency. Obtained results are then compared using different power semi-conductor switches like IGBT, BJT, MOSFET and GTO. Afterwards waveforms have been shown & we can see that at a particular switching frequency output is highly quality & can justify the feasibility for real implementation of high frequency mirror inverter fed induction heater in industrial appliances Index Terms —Induction heating, mirror inverter, P-SIM, semi-conductor switches, ZCS and ZVS

Performance of H.F. mirror inverter with different semiconductor switches for induction heating

An exhaustive method for verifying & optimizing the performance of high frequency mirror inverter for induction heater is presented here. Heating coil of the induction heater is made of litz wire which controls the skin effect and proximity effect of conductor operating at high frequency. With the calculated optimum values of inductance and resistance at a particular operating frequency, HF mirror inverter topology has been simulated using P-SIM. Obtained results are then compared using different power semi-conductor switches like IGBT, GTO and MOSFET. Afterwards waveforms have been shown to justify the feasibility for real implementation of high frequency mirror inverter fed induction heater in industrial appliances.

Optimum Construction of Heating Coil for Domestic Induction Cooker

The design and optimization of the parameters of heating coil is very important for the analytical analysis of high frequency inverter fed induction cooker. Moreover, accurate prediction of high frequency winding loss (i.e., losses due to skin and proximity effects) is necessary as the induction cooker used in power electronics applications. At high frequency current penetration in the induction coil circuit is very difficult for conducting wire due to skin‐effect. To eradicate the skin effect heating coil is made up of bundle conductor i.e., litz wire. In this paper inductances and AC resistances of a litz‐wire are calculated and optimized by considering the input parameters like wire type, shape, number of strand, number of spiral turn, number of twist per feet of heating coil and operating frequency. A high frequency half bridge series resonant mirror inverter circuit is used in this paper and taking the optimum values of inductance and ac resistance the circuit is simulated through PSPICE simulations....

Closed loop controlled boost converter using a pid controller for solar wind power system installation

Deployment of renewable energy resources on distributed energy system has reduced the reliance and transmission losses from the utility grid. It also helps to improve the system stability near the load center. Solar and wind are the two highly utilized green energy resources in present scenario. However, the fluctuations of solar irradiation, temperature, wind velocity are the preeminent issue for this type of systems which affects the efficiency of the solar and wind energy system. It requires the interfacing unit to stabilize the output voltage. The proposed work deals with the close loop boost converter with PID controller, which is used to attain a stabilized voltage despite of parameter changes and load disturbances. Designed system will help to analyze the better stable output voltage with efficient system having minimum fluctuation.