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Gangguan elektromagnetik berupa conducted emission noise yang ditimbulkan oleh inverter pada sistem photovoltaic (PV) off-grid telah berhasil dikarakterisasi. Noise yang merambat pada jalur konduksi dihasilkan dari fenomena switching inverter untuk proses konversi daya dari listrik searah (DC) menjadi arus bolak balik (AC). Standar IEC 62920:2017 dan CISPR 25:2016 digunakan untuk mengukur noise yang dihasilkan oleh inverter di sisi DC. Pengukuran conducted emission noise pada inverter dilakukan dalam tiga kondisi, yakni kondisi tanpa beban, terhubung dengan beban lampu pijar 60 W, dan terhubung dengan beban lampu pijar beserta dimmer untuk variasi daya. Pengukuran dilakukan pada lima buah inverter dengan kapasitas daya dan jenis keluaran (output) yang berbeda-beda, yaitu 200 W, 300 W, dan 700 W untuk tegangan keluaran modified sine wave serta 500 W dan 1.000 W untuk tegangan keluaran pure sine wave. Hasil pengukuran menunjukkan bahwa pada kondisi inverter terhubung dengan beban lampu pijar beserta dimmer, inverter model pure sine wave 500 W dan 1.000 W memiliki peak noise level yang cukup rendah dan berpotensi lebih sedikit untuk menimbulkan gangguan elektromagnetik di sisi DC.

LED lighting market share shows an ever increasing trend. This is driven by some of the LED advantages, such as higher efficiency, wide range of colors, and longer lifetime. LED is a DC device, and to power it from AC supply, like in household or street lightings, a driver is required to convert AC to DC supply. In addition, LED driver is preferred to operate in constant current mode in order to avoid LED thermal runaway. Also the driver has to have high efficiency, low THD (total harmonic distortion), and comply with electromagnetic emission limits. In this paper, a prototype of primary-side-regulated AC-DC flyback LED driver has been implemented. It has a constant output current of 0.990A 0.012A across the output voltage 15.59V – 42.80V. Measurement results show that the achieved efficiency is up to 88.55%, current harmonics comply with IEC 61000-3-2, and conducted emission levels comply with CISPR 15.

One of the key components in switching power supplies is the main switch, of which MOSFET is commonly used. High dv/dt and di/dt are inherent in MOSFET switching operation, and so it is a major source of electromagnetic emissions that may fail the standard limits. In this paper, effects of MOSFET gate driving on conducted emissions are examined. Measurements are made on a prototype of flyback LED driver. It is found that increasing gate resistance could suppress the drain turn-off oscillation voltage. By experiment, an external gate resistance necessary to reduce emission below limit lines is obtained. Anti-parallel diode speeds turn-off up but increases EMI level. It was confirmed that the noise upper 20MHz was originating from the drain voltage spike. Instead of anti-parallel, the diode can be also connected in parallel to the gate resistance. In this way, it can facilitate faster MOSFET turn-on transients, and therefore power efficiency had shown an improvement but without increasing EMI level.

Two important parts of wireless power transfer are transmitter circuit and receiver circuit. Previous research has been completed which use CMOS H-Bridge in transmitter and full wave rectifier in receiver. This paper presented simple design of transmitter circuit and optimization of receiver circuit in rectifier circuit with transient analysis and Fast Fourier Transform (FFT) from LT spice software. The simple transmitter circuit used an integrated circuit (IC) NE555 with push-pull as oscillator circuit and LC resonant, while the receiver circuit used LC resonant, rectifier circuit, CLC filter for smoothing direct current (DC) output and 500 Ohm as load. The circuit design had resonant frequency of 250 kHz on both of transmitter and receiver, which comply with Power Matters Alliance (PMA) standard. The optimization of rectifier circuit had been done by comparing output of power load when it used basic rectifier (full wave), voltage doubler (dickson circuit and Villard circuit) and voltage multiplier (cockcroft-walton circuit). The results showed the receiver with Dickson circuit as rectifier has the highest efficiency compared to other rectifier circuits with efficiency of 10.93 % when it used coupling coefficient of 0.99, because Dickson rectifier has resonant frequency that is closest to 250 kHz and the highest level power, compared to other rectifier circuits.

Electrocardiograph endurance test system ha s two work process es like defibrillator. Charg ing process produce s energy stored in capacitor (E S ) and discharges process produce defibrillation energy. Defibrillation energy without connect to electrocardiograph (E 2 ) at test system is influenced by the resistance values of inductor (R L ). In previous research, test system only produce s E 2 = 19,83 joule, this is caused by the inductor used with value R L = 72 Ω . The purpose of this research is to select inductor resistance value to get good and efficient value E 2 . Range value R L used in test system was 1–10 Ω , based on standar International Electrotechnical Commission (IEC) 60601-2-27 clause 201.8.5.5.2 . Voltage measured in point 100 Ω every time interval (∆t) 0,02 ms obtained from multisim software simulation. The result of simulation indicated if peak voltage increased, then value R L was used approach zero. In other side, measure d Voltage data was used as parameter to calculate total E 2 in every range of R L value, then result E 2 total was compared to E S value to get energy ratio value . Value R L = 1 Ω was the most effi cient because has ratio energy value 98,45% with E 2 = 393,80 joule, while energy ratio when R L = 10 Ω was not effi cient because only had energy ratio value 89,58% with E 2 = 358,33 joule .