App Notes
High Voltage Safety Requirements 101
We often talk about power losses, efficiency and temperature, but we hardly mention isolation. Depending on the voltages that the windings experience, isolation can be the number 1 design parameter.
To evaluate the impact of the harmonics, a transformer was built and tested at Frenetic's Laboratories. Table 1 summarizes the constructive characteristics of the transformer under test (TUT) and Figure 1 shows the waveforms captured with the oscilloscope. Two cases were considered: Case 1 with a clean trapezoidal waveform and Case 2 with a distorted triangular waveform. To have a fair comparison, the same RMS current and therefore same energy content was applied in both cases. It should be noted that although there are some differences in the voltages applied, the core area and number of turns were selected to ensure negligible core losses. Figure 2 and Table 2 show the amplitude of the harmonics measured and the theoretical power losses calculated and Figure 3 shows the temperature measured during the test (thermocouple placed between windings).
The same transformer was redesigned optimizing the strand diameter for the 300-700 kHz harmonics. For a fair comparison, the conduction area was kept the same as in cases 1 and 2. The winding losses were reduced down to 1.39W, reaching thus a better performance than both previous cases.
Harmonics have a significant impact on magnetic components' performance. This paper has presented a simple example of three cases where the same transformer operates differently under the same input specifications. The objective of this paper is not to think of Litz wire optimization but rather on how the complete system can be optimized by considering the harmonics at the design stage.
We often talk about power losses, efficiency and temperature, but we hardly mention isolation. Depending on the voltages that the windings experience, isolation can be the number 1 design parameter.
We often talk about power losses, efficiency and temperature, but we hardly mention isolation. Depending on the voltages that the windings experience, isolation can be the number 1 design parameter.
Optimizing transformer design for Dual Active Bridge converters with a focus on leakage inductance, core choice, and Frenetic’s simulation tool.
Optimizing transformer design for Dual Active Bridge converters with a focus on leakage inductance, core choice, and Frenetic’s simulation tool.
The topic of Magnetics is becoming one of the most important tasks of every power electronics engineer. Therefore, at Frenetic, we are working on different technologies, experiments, research focused on the Magnetic components. This article talks about EMI in Flyback circuits.
The topic of Magnetics is becoming one of the most important tasks of every power electronics engineer. Therefore, at Frenetic, we are working on different technologies, experiments, research focused on the Magnetic components. This article talks about EMI in Flyback circuits.
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