In a power plant such as micro-hydropower (MHP), an induction generator (IG) is usually employed to produce electrical power. Therefore, an inverter is needed to deliver it with high efficiency. Z-source inverter (ZSI) has been introduced as a topology with many advantages over conventional inverters. This research aims to investigate the performance of ZSI based simple boost control (SBC) in laboratory-scale MHP systems using a rewinding induction generator. This research has been conducted both from simulations and experiments. Based on the result, the waveform characteristic and value of ZSI are close to the desired design. A shoot-through duty ratio of 17% can reach 60 Vrms output voltage, and this condition has a conversion ratio of about 2.05 times. Also, SBC can significantly reduce the Total Harmonic Distortion (THD). ZSI efficiency has a value of 84.78% at 50% of rating load 100 W and an average value of 80%. Compared to the previous study, the proposed design has more economical with the same component for the higher rating power. Moreover, it has a smoother and entire output waveform of the voltage.

The development of wave energy converters (WEC) is increasing over time with various designs. The need for a WEC design that emphasizes the level of simplicity, portability, and closeness of its implementation to the nearshore is quite interesting to discuss. One of the WECs that can meet these criteria is oscillating buoy based on a direct mechanical drive system. This research proposes the concept of oscillating buoy WEC based on a direct mechanical drive system, which is designed with a unidirectional gear system to be able to generate energy both in the upward and downward wave phases. The WEC is also making to produce high rotation on the output side from the small motion of the buoy, especially in the heave direction. Predicting the power generated by this concept is very interesting because up to now, there has not been sufficient analytical model to estimate the power generated by oscillating buoys WEC based on a direct mechanical drive system, especially under irregular waves. In this work, an analytical method is conducting to describe the interaction between the model and irregular waves from the JONSWAP model. Model interaction is simulating numerically using the MATLAB program. The buoy translational motion of the model in the heave direction, which is converting to electric power by increasing the rotation of the gearbox and the energy stored in the flywheel, can produce significant output power. In the future, the proposed model can be used to develop more feasible and efficient models of wave energy converters.

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Perairan barat Provinsi Lampung merupakan salah satu lokasi yang diperkirakan memiliki potensi energi gelombang yang cukup besar. Namun, minimnya informasi tentang titik potensial energi gelombang laut yang lebih rinci membuat kawasan ini belum dapat dieksplorasi dengan baik. Penelitian ini bertujuan untuk mendapatkan tinggi gelombang signifikan (Hs) yang merupakan salah satu variabel utama dalam menentukan energi gelombang laut di perairan barat Provinsi Lampung. Studi ini dilakukan melalui pemodelan numerik menggunakan model SWAN pada software Delft3D-WAVE dengan input model gelombang yang bersumber dari data ECMWF-Era 5 di laut lepas. Hasil pemodelan numerik menunjukkan gelombang signifikan terbesar terjadi pada musim barat dengan nilai 1,25-2,975 m. Sedangkan tinggi gelombang signifikan terkecil terjadi pada musim timur dengan nilai 0,941-2,079 m. Verifikasi hasil tersebut terhadap data AVISO menghasilkan nilai MAPE sebesar 16,355%, koefisien korelasi sebesar 0,8691, RMSE berkisar 0,277 m yang menunjukkan validasi yang baik dan memuaskan.

Pembangunan Dermaga C sebagai fasilitas baru di PT Petrokimia Gresik bertujuan untuk meningkatkan produktivitas perusahaan. Produktivitas ini terwujud dalam bentuk aktivitas percepatan bongkar muat barang yang diangkut dari kapal ke daratan atau sebaliknya. Namun, aktivitas ini akan terkendala di masa depan jika sedimentasi tidak diatasi dengan baik. Untuk mengatasi fenomena sedimentasi di suatu dermaga, perlu dilakukan analisis laju sedimentasi secara dini dengan mempertimbangkan faktor-faktor seperti karakteristik pasang surut, pola arus, dan profil gelombang. Beberapa cara dapat dilakukan untuk meminimalisir laju sedimentasi, salah satunya dengan memodifikasi layout dermaga dengan tujuan untuk mengurangi frekuensi pengerukan. Penelitian ini bertujuan untuk menganalisis laju sedimentasi di sekitar Dermaga C dan menghitung perkiraan volumenya. Dua layout alternatif dari Dermaga C eksisting diusulkan untuk meminimalisir bed level thickness yang dapat terjadi di dermaga. Penelitian ini menerapkan pemodelan numerik berbasis software MIKE 21. Hasilnya, layout alternatif 1 dan 2 untuk periode yang sama mampu mengurangi volume sedimentasi terhadap layout eksisting masing-masing sebesar 9348.12 m3 dan 13215.48 m3 atau memiliki persentase penurunan sebesar 45.3% dan 64.1%. Di antara layout alternatif 1 (LA1) dan 2 (LA2), layout kedua adalah rekomendasi yang paling optimal. Oleh karena itu, dapat disimpulkan bahwa modifikasi layout terbukti dapat menurunkan laju sedimentasi di Dermaga C. Construction of Port C as a new facility at PT Petrokimia Gresik aims to increase the company's productivity. This productivity is manifested in accelerating the loading and unloading of materials transported from ships to land or vice versa. However, this activity will be hampered in the future if the sedimentation is not handled correctly. Hence, the sedimentation phenomenon in a port needs to be overcome. It is essential to investigate the sedimentation rate by considering tidal characteristics, current patterns, and wave profiles. Various ways can be conducted to decrease the sedimentation rate, one of which is by modifying the port layout to minimize the intensity of dredging. This research aims to analyze the sedimentation rate around Port C and calculate the estimated volume. Two alternative layouts are proposed to minimize the bed level thickness on the Port C. This research applies numerical modeling based on MIKE 21 software. As a result, alternative layouts 1 and 2 for the same period can reduce the sedimentation volume to the existing layout by 9348.12 m3 and 13215.48 m3, respectively, or have a decreasing percentage of 45.3% and 64.1. %. The last layout is the most significant among alternative layouts 1 (LA1) and 2 (LA2). It can be emphasized that the layout modification is proven to decrease the sedimentation rate at Port C.