Loss Analysis Of High-Frequency Magnetic Components And Study On Measuring Equipment Of Inductor Temperature-rise Current

Magnetic components are the key components in switching power supplies, andimproving switching frequency can reduce the volume of magnetic components, but itcan lead to high-frequency effects such as core losses and winding losses increasingobviously and can also lower the machine efficiency. So it is necessary to analyse thelosses of magnetic components in high-frequency working conditions. This paperdiscusses the magnetic components and analyses the source and generatingmechanism of its core losses and winding losses. Meanwhile, this paper analyses thecore losses and winding losses of high-frequency magnetic components in quantity.This paper analyses the influence of different high-frequency motivational waveformsto the core losses and summarizes the calculation models about core losses andwinding losses, and finally analyses the relationship between losses of high-frequencycomponents and its temperature-rise.The temperature-rise of inductor is the performance of calorification of theinductor, and the calorification of the inductor is from the the dc losses of winding,the ac losses of winding and the ac losses of core. In many applications of DC-DCconverter, the working current is composed of one large dc current component andone small ac current component generally, and the dc losses account for a largeproportion. Therefore, dc loss and ac loss are the important parts in the loss of theinductor. But inductor’s ac loss is directly bound up with the type, amplitude andfrequency of the motivational waveforms, and it is extremely complex to calculate thelosses. So it is usual to use the method of adding dc power to the inductor to measurethe relationship between the inductor losses and the inductor temperature-rise. At last,based on above developing a set of measuring equipment of inductor temperature-risecurrent.The measuring equipment of inductor temperature-rise current based on the PICmicrocontroller can overcome the disadvantages of the current measuring equipmentin industry such as unconvenient and measurement results easily to be disturbed bythe circuit wiring and position of instruments because the current measurement equipment consists of discrete instruments. The equipment consists of dc controllableconstant-current source, sampling unit, display unit, serial communication unit, loopfeedback control unit and inductor test platform. The current, temperature and voltagebetween the two ends of inductor sampled by the sampling unit are sent into SCM forprocessing, and then the temperature detected of the inductor will be compared withthe rated temperature-rise by the microcontroller. And by internal variable-stepadjustment, and the temperature loop feedback control unit, output current of theconstant-current source is changed, as well as the temperature of inductor, and finallytemperature of the inductor stabilizes in a rated temperature. Read the current in thistime namely rated temperature-rise current value.The paper finally processes and analyses the experimental data, and draws curvesincluding measurement of temperature and temperature-rise current with time, changeof temperature with temperature-rise current, relationship between the inductor lossesand temperature-rise, and change of the dc resistance of inductor with temperature-rise current, and analyses the resolution and measurement error of various parts of thisequipment.