This paper presents a new circuit configuration of single-phase multilevel current-source inverter (CSI). In this new topology, a basic H-bridge CSI working as a main inverter generates a multilevel current waveform in cooperation with inductor cells connected in parallel as auxiliary circuits. Each inductor cell is composed by four unidirectional power switches with an inductor across the cell circuit. The inductor cells work by generating the intermediate level of the multilevel current waveform with no additional external dc-power sources. A simple proportionalintegral controller is applied to control the intermediate-level currents of the multilevel output waveform. A five-level and a ninelevel pulsewidth-modulation inverter configuration, with chopperbased dc-current sources, are verified through computer simulations. Furthermore, an experimental prototype of a five-level CSIis set up and is tested. The results show that the test circuit works properly to generate the multilevel output-current waveform with low output harmonics by using small size of inductors without any additional external dc-power sources, which proves feasibility of the proposed strategy.Index Terms-Current-source inverter (CSI), H-bridge, inductor cell, multilevel.

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Abstract, This study aimed to test whether there is a relationship  of self-efficacy and social support with students adjustment in  learning. Subjects were 123 students of class VII students consisting of 62 men and 61 women taken at random in SMP Negeri 1 Larangan kabupaten Pamekasan. The results of multiple regression analysis obtained for R = 0.759 ; F = 81.600 , p = 0.000 ( p < 0.01 ) . The results of the analysis of this data show self-efficacy and social support of parents jointly associated with the adjustment of students in learning , at 56.9 % . Results of correlation analysis of self-efficacy with self-adjustment of students in the learning acquired partial r = 0.430 ; t = 5.222 and p = 0.000 ( p < 0.01 ) . These data show there is a positive correlation between self-efficacy with self-adjustment of students in learning , with effective contribution of 24.22% . The results of correlation analysis of parent social support with students adjustment in learning obtained partial r = 0.580 ; t = 7.799 and p = 0.000 ( p < 0.01 ) . These data show there is a positive correlation between social support of parents with students adjustment in learning, the effective contribution of 32.68%.Keyword : Adjustment, self efficacy, social support of parents.

Tujuan penelitian ini untuk mengetahui perbedaan efektifitas penggunaan model discovey learning dan model problem based learning terhadap hasil belajar IPA kelas 3 SD Gugus Mawar Suruh Kabupaten Semarang. Jenis penelitian yang digunakan adalah penelitian eksperimen semu. Persyaratan untuk melakukan Uji T telah dilakukan. Hasil yang diperoleh menunjukkan bahwa data berdistribusi normal dan homogen. Hasil penelitian Uji T diperoleh t hitung 2,067 > t tabel 2,011, dengan signifikansi sebesar 0,044 < 0,05 maka Hₐ diterima. Artinya terdapat perbedaan efektifitas penggunaan model discovery learning dan model problem based learning terhadap hasil belajar IPA. Sebelum dilakukan perlakuan, tidak terdapat perbedaan efektifitas hasil belajar IPA. Tetapi setelah dilakukan pelakuan, terdapat perbedaan efektifitas hasil belajar IPA siswa kelas 3 SD Gugus Mawar Suruh

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This paper presents a circuit configuration of five-level PWM voltage-source inverter developed from the three-level H-bridge inverter using only a single DC input power source. In the proposed five-level inverter, an auxiliary circuits working as the voltage balancing circuits of the inverter's DC capacitors is presented. The auxiliary circuits work to keep stable DC capacitor voltages of the inverter, and also to reduce the capacitor size of the inverter. The unique point of the proposed balancing circuits is that it needs only a single voltage sensor to control the voltages of the two capacitors in the inverter. Moreover, a minimum number the inverter's switching devices is also an important feature of the proposed inverter topology. A simple proportional integral controller is applied to control the voltage of the DC capacitors. The proposed topology is tested through computer simulation using PSIM software. Laboratory experimental tests were also conducted to verify the proposed inverter circuits. The computer simulation and experimental test results showed that the proposed balancing circuits works properly keeping stable voltages across the two DC capacitors of the inverter using only a single voltage sensor. The inverter also works well to synthesize a five-level PWM voltage waveform with sinusoidal load current.

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<p>A simplified circuit topology of the five-level pulse width modulation (PWM) inverter for DC-AC power conversion with no-isolated DC voltage sources and reduced switching device number is presented in this paper. The inverter circuit is based on the three-level H-bridge inverter configuration. The developed five-level inverter needs only five controlled power switches and four isolated gate drive circuits. Furthermore, the proposed topology does not require bidirectional power semiconductor controlled switches, hence a conventional discrete power MOSFETs or IGBTs can be used to build the inverter circuits. To obtain a better quality output voltage waveform, the level-phase-shifted carriers based sinusoidal pulse width modulation control was applied to produce a five-level PWM voltage waveform. The proposed inverter circuit was examined by using computer simulation with Power PSIM software. The basic principle operation of the inverter circuit was verified experimentally in laboratory using two non-isolated DC voltage sources as the inputs of the inverter’s prototype circuit. Some analysis of inverter’s output waveforms are provided and discussed. <em></em></p>