A Novel Inductor for Stabilizing the DC Link of Adjustable Speed Drive

The DC-link filter which includes a magnetic inductor and a storage capacitor is one of the key parts of adjustable speed drives in the market. It significantly affects the stability, reliability, and power density of the motor-drive system. This paper proposes a novel, variable active inductor to improve the performance of DC links in terms of stability, reliability, size, and cost. In contrast to conventional DC-link magnetic inductors, the variable active inductor is made of power electronic circuits, including active switches, passive filters, and smart controllers, which no longer rely on magnetic material. The demonstration shows that the inductor can emulate the electrical characteristics of the magnetic inductor for filtering harmonics and stabilizing the DC link, meanwhile representing a smaller size, lighter weight, and lower cost compared with a conventional one. Furthermore, this paper proposes a variable inductance control method which is able to adaptively tune the inductance value with the operating conditions of the drive system. The DC link can be stabilized, and high performance can be maintained in both balanced and unbalanced grid voltage conditions. A case study of the proposed variable inductor in a motor drive with a three-phase diode-bridge rectifier as the front end is discussed. Experimental results are given to verify the functionality and effectiveness of the proposed variable inductor.

A New Era: Large Subsea Multiphase Compressor - Driven by Subsea Adjustable Speed Drive

The use of subsea processing equipment, which maintains, increases, and accelerates oil and gas production, is now more and more widespread in offshore subsea field developments. Furthermore, there is a strong drive for electrification of offshore fields, both subsea and topside, to lower emissions. To meet the technical challenges, a significant effort is put into research and technology development by academia and the industry. ABB, a specialist in electrical equipment and control systems, and OneSubsea, a specialist in subsea processing, have executed large development programs organized as Joint Industry Projects (JIPs) together with oil and gas operators. In this paper, we discuss how ABB and OneSubsea joined forces in testing and validating their respective subsea technologies as a full subsea system for subsea multiphase gas compression. This paper presents the world's first full-scale, combined subsea adjustable speed drive (ASD) and multiphase compressor (WGC6000) string test. In spring of 2020, both the ASD, and the WGC6000 reached Technology Readiness Level 4. The string test, with both units concurrently submerged, completed its witness test program in June 2020, with mapping of the WGC6000 speed and power envelope and a subsequent 24 h thermal stability run. The flawless test result confirms the strategic development road map for all the involved partners. The technologies presented in this paper are now fully qualified and available for commercial use enabling a paradigm shift in subsea oil and gas production.

Mixed-Mode Effect on Motor Common Mode Current

This paper presents the mixed-mode effect on motor common mode current (CMC) in an adjustable speed drive (ASD). It is expected that the motor CMC is lower than inverter output CMC. However, the measurement result of the ASD shows that the AC motor input CMC is higher than the inverter output CMC in a frequency range. By using a mixed-mode (MM) 6-port networks, it is proven that the AC motor input CMC is higher due to an MM CMC which is generated from differential mode current.

Comparative Case Study on Oscillatory Behavior in Power Systems of Marine Vessels With High Power Converters

The chief aim of the proposed paper is to compare the behavior of supply voltage registered onboard three vessels equipped with high power converters during normal operation. The vessels considered are a chemical tanker with shaft generator working via power converter, a research-training ship with bow thruster, and a research vessel with dynamic positioning (DP) and electrical propulsion. In the case of the two latter ships, power electronic loads are present, which include a bow thruster adjustable speed drive equipped with the six pulse uncontrolled rectifier and the adjustable speed drive with an active front end (AFE) for propulsion system. For each ship, instantaneous frequency is determined and subsequently fluctuations of fundamental components and chosen harmonics are calculated using zoom-DFT. The characteristics of these irregular fluctuations are compared and commented on. Next, phase portraits and Poincare map of the registered voltages are calculated and compared. Moreover, the impact of ship rolling and pitching on the oscillatory behavior is assessed for the DP ship. The final conclusions identify reasons for oscillatory behavior in electric power systems of marine vessels containing high power converters on the source side and load side. The feasibility of using voltage trajectories as well as Poincare maps for oscillatory behavior detection is assessed.

ANALISA PEMODELAN ARUS TRANSIEN SAAT SWITCHING KAPASITOR BANK PADA RUMAH SAKIT ISLAM SULTAN AGUNG SEMARANG

Transien yaitu peralihan gelombang tegangan atau arus dalam waktu yang sangat singkat. Transien biasanya disebabkan oleh saklar yang terbuka dan menutup. Salah satunya adalah switching kapasitor bank. Rumah Sakit Islam Sultan Agung Semarang memiliki daya sebesar 1.7 KVA dengan beban yang selalu berubah – ubah pada setiap waktunya. Terdapatnya beban induktif seperti motor listrik pada Rumah Sakit Islam Sultan Agung Semarang menyebabkan faktor daya mengalami penurunan , dan hal tersebut akan mengakitbatkan kerugian terhadap Rumah Sakit Islam Sultan Agung Semarang dan juga penyedia daya yaitu PLN, sehingga dipasang kapasitor bank untuk mengatasi faktor daya yang rendah akibat beban induktif tersebut. Sistem jaringan kapasitor bank pada Rumah Sakit Islam Sultan Agung Semarang bekerja secara otomatis setiap waktunya dengan menyesuaikan beban yang bekerja, sehingga kapasitor bank bekerja secara terus menurus. Saat switching kapasitor bank mengakibatkan gejala transien yang dapat membahayakan sistem tenaga listrik yang terdapat pada Rumah Sakit Islam Sultan Agung Semarang jika terjadi secara terus menerus. Salah satunya adalah menimbulkan trip pada sistem tenaga listrik. Riset ini bertujuan untuk mengetahui dan menganalisi besarnya arus maksimum transien saat terjadi switching kapasitor bank pada Rumah Sakit Islam Sultan Agung Semarang melalui metode pemodelan dan simulasi sistem switching kapasitor bank dengan menggunakan software simulink matlab, berdasarkan data – data parameter arus, tegangan, faktor daya, dan daya yang diperoleh dari hasil pengukuran pada lokasi dan solusi yang ditawarkan melalui instaslasi reaktor induktor untuk mengurangi arus maksimum transien yang terjadi.Berdasarkan hasil Simulasi memperlihatkan bahwa sebelum switching kapasitor bank daya aktif rata - rata 71.93 kW , daya reaktif rata-rata 78.41 kVAR dan faktor daya rata- rata 0.6. Setelah dilakukan Switching kapasitor bank daya aktif rata-rata menjadi 66.46 kW , daya reaktif rata-rata 21.81 kVAR , faktor daya rata-rata 0.95 dan menghasilkan arus maksimum transien yang tinggi yaitu 918.75 A. Untuk mereduksi arus transien tersebut digunakan reactor inductor yang mampu mengurangi arus maksimum transien menjadi 558.25 A atau terjadi penurunan sebesar 39.24%Fenomena tegangan transien yang sering terjadi pada sistem distribusi daya listrik adalah switching capasitor bank yang digunakan untuk perbaikan faktor daya oleh konsumen listrik. Tegangan transien akan menimbulkan arus transien yaitu perubahan arus dari keadaan normal yang secara mendadak melonjak tinggi sekali dan setelah itu berangsur – angsur turun dan kembali menuju keadaan normalnya. Arus maksimum saat terjadi arus transien tersebut dikenal sebagai arus inrush. Jika arus inrush terlalu tinggi, maka dapat menimbulkan permasalahan seperti kerusakan sistem kontrol, trip pada adjustable speed drive, dan kerusakan peralatan elektronik. Penelitian ini bertujuan untuk mengetahui besarnya arus inrush saat terjadi switching capasitor bank di Rumah Sakit Islam Sultan Agung Semarang dan mereduksi arus inrush tersebut melalui penggunaan induktor seri pada kapasitor bank. Metode penelitian dilakukan dengan simulasi melalui pemodelan switching kapasitor bank menggunakan software SimulinkMatlab. Berdasarkan hasil pengukuran dan perhitungan terlihat kebutuhan daya aktif rata-rata 71.93 kW, daya reaktif rata-rata 78.41 kVAR dengan faktor daya rata-rata 0.673. Hasil penelitian memperlihatkan bahwa melalui pemasangan kapasitor bank terjadi perbaikan faktor daya menjadi 0.95 sehingga kebutuhan daya reaktif turun secara signifikan menjadi 21.7 kVAR dan daya aktif menjadi 66.47 kW. Dampak pemasangan kapasitor bank tersebut ternyata menimbulkan arus transien saat terjadi switching dengan arus inrush mencapai antara 7 - 10 kali arus rmsbeban. Pengurangan arus inrush dilakukan dengan penggunakan induktor seri pada kapasitor bank dengan nilai dipilih 2.8 mH agar faktor daya tetap konstan sekitar 0.95. Hasilnya memperlihatkan adanya penurunan arus inrush menjadi antara 4 - 6 kali arus rms beban. Sebagai contoh saat terjadi switching capasitor bank arus inrush mencapai 918.75 Ampere sedangkan saat digunakan induktor seri turun menjadi 558.25 Ampere atau mengalami penuruanan arus inrush sebesar 39.24 %.[OBP1] [OBP1]Abstrak lebih dari 200 kata