SWITCHED MODE POWER SUPPLY (SMPS) ANALYSIS FOR ENERGY-EFFICIENT INVERTERS, RECTIFIERS, VOLTAGE CONVERTERS, AND PHASE CONVERTERS
Our lifestyle is surrounded by a variety of power electronic products including inverter air conditioners, inverter fluorescent lamps, refrigerators, motors, amplifiers, and UPSs. The power control boards for these products contain microcomputers that gauge load conditions to allow optimum control. For example, the microcomputers in air conditioners estimate the current load to perform a precise noise and temperature control. This is accomplished by changing the rotary speed of the motor and without any restrictions to the motor inverter. Similarly, the inverter control panel in fluorescent lamps inhibit the flickering with continuous highfrequency lighting.
Switching power supplies are power supplies with in-built power control panels that perform complex (precise and intelligent) and high-speed control for electrical equipment and products. Switching power supplies are embedded in a variety of power electronic products and are applied in many areas.
To evaluate a SMPS, the following techniques are recommended (see PDF for details):
Observing circuit-internal waveforms, checking operating status, and confirming the safety of, and loss in, the devices used.
(1) Observing Waveforms and Measuring Parameters
Observation of I/O waveforms, control signals, waveforms during excessive operations, and various types of waveforms that occur during abnormalities and in other situations, and measurement of parameters.
(2) Measuring Switching Loss
Power measurement using integrals of voltage and current of the switching device. Has loss error correction function.
(3) Confirming the Safety Operation Area (SOA)
The operating status/margin of the voltage, current, and power values of the switching device
(4) Harmonic Analysis
Distortion in the input current waveform. EMC support.
