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This study proposes a practical output current measurement system in a three-phase inverter with a single printed circuit board (PCB) Rogowski coil sensor inserted in the bus between the DC-link capacitor and the power semiconductor module. This system demonstrates its advantage over conventional output current sensors, such as the Hall effect current sensors, in terms of the size, weight, operation temperature and cost. The system can be applied to 6-in-1 power modules as it does not require sensors in the inverter phase legs. In our previous works, we have developed a method called “envelope tracking”, which is used in this system as well. This method traces the switching current instead of the output current to reproduce the output current signal in real-time. Envelope tracking successfully reproduced the output current waveform for single phase inverters under certain conditions. However, a large error is observed in the three-phase inverter demonstration under a high switching frequency (narrow pulse) or when the switching of different phases overlap each other. These errors must be completely suppressed to implement the system for feedback control in three-phase inverters. In this study, a new analog basis output current waveform reproduction system is introduced to suppress the above mentioned errors. This system is implemented in a three-phase insulated-gate bipolar transistor (IGBT) inverter and successfully reproduces the output current with a single PCB sensor inserted between a 6-in-1 IGBT power module and DC-link capacitor, operating under a switching frequency of 3.5–7.0 kHz and output current of 6 A with DC-link voltage of 150 V.
Жил ирэх тусам эрчим хүчний хэрэглээ өсөн нэмэгдэж байна. Эрчим хүчний үйлдвэрлэлийн дийлэнх хувийг шатамхай түлш бүхий үүсгүүр ашиглан гарган авч буй нь хязгаарлагдмал нөөцийн асуудлаас гадна байгаль орчинд хор хөнөөлтэй учир дэлхий дахин сэргээгдэх эрчим хүч буюу ногоон эрчим хүчийг ашиглаж эхлээд байна. Гэсэн хэдий ч бид ойрын жилүүдэд шатамхай түлш ашиглан эрчим хүч үйлдвэрлэх үүсгүүрийн технологийг бүрэн халах боломжгүй учраас эрчим хүчний системийг илүү үр ашиг сайтай, ашиглалтын хугацаа өндөр, хэрэгцээгүй зарцуулалтыг багасгах шаардлага тулгараад байгаа юм. Эдгээр асуудлуудыг чадлын электроникийн өндөр технологийг ашиглан шийдвэрлэх боломжтой. Чадлын электроникийн технологи нь эрчим хүчний системд шаардагдаж буй чадал, энергийг хангах зорилгоор өндөр хүчдэл, гүйдлийг боловсруулдаг цахилгааны инженерчлэлийн нэгэн салбар юм. Эрчим хүчний дамжуулах, түгээх сүлжээ, компьютерын сүлжээ, мэдээллийн технологи, томоохон үйлдвэрийн автоматжуулалт, сэргээгдэх эрчим хүчний систем, электрон тоног төхөөрөмжийн тэжээлийн үүсгүүр зэрэгт чадлын электроникийн технологийг өргөнөөр ашигладаг. Энэхүү судалгааны өгүүллийн хүрээнд МУИС-ийн чадлын электроникийн судалгааны лабораторийн судлаачдын зүгээс эрчим хүчний системд тулгарсан асуудлууд, сэргээгдэх эрчим хүч, эрчим хүчний тархмал үүсгүүр бүхий системд тулгарсан асуудлуудад шийдвэрлэх ямар шийдэл боловсруулж санал болгосон, өмнө ямар технологи ашиглаж байсан, одоо ямар технологи санал болгож буй, мөн туршилтаар ямар үр дүн гарсан зэргийг эмхэтгэв. Мөн цаашид ямар асуудлууд тулгарч болох, аль чиглэлд судалгаа шинжилгээг хийх шаардлага бий болж буй зэргийг тайлбарлав.
In 2015, three young engineers from Mongolia started to work on CubeSat, which was the very first Mongolian satellite under the BIRDS project at Kyushu Institute of Technology, Japan. The main goal of the BIRDS project was to help to prepare human resources in space technology for developing countries, which was accomplished. Not only those three engineers, but more Mongolian young people are graduated, and some are still studying abroad in the space technology field, nowadays. As we defined, our next step is to build a satellite inside the country to own the space technology which was never done before. A CubeSat is the best option for us, and we started the 1U Cubesat project called Temuulel in 2019. The stakeholders of the project are the National University of Mongolia and the Mongolian Space Technology Association. The satellite will be launched in late 2022. Temuulel is a technology demonstration satellite with ambitious five missions. Missions consist of earth imaging from space, remote data collection system, failure rate determination of high voltage semiconductor device on orbit, reprogramming of standardized interface board on orbit, and sending wishes of citizens into space with non-volatile memory. The paper shows an overview of the mission and development status of the Temuulel project.
Энэ ажлаар практик хэрэглээнд чадлын хагас дамжуулагч төхөөрөмжийн модулд бусад хамгаалалтын хэлхээнүүдийн хамт интеграц хийх боломж бүхий гүйдлийн сенсорыг судалсан. Шинэ төрлийн гүйдлийн сенсор нь PCB хавтангаар хийсэн Роговски ороомог бөгөөд инвертер, конвертерийн түлхүүрийн элементын гүйдэлийн өөрчлөлтөөс шууд хамааралтай хүчдэл үүсгэх төхөөрөмж юм. Эндээс үүсэх хүчдлийн утгаас системийн гаралтын хүчдэлийг энгийн үйлдлийн өсгөгчд суурилсан аналог хэлхээ ашиглан тодорхойлох боломжтой. Уг санаанд суурилсан гйүдэл хэмжих “Envelop tracking” аргыг 1фазын инвертер системд туршиж баталсан ба удирдлагын сигналын (SPWM) хэт нарийн мужд аналог хэлхээнээс үүдэх хэмжүүрийн алдааг засах аналог хэлхээний шинэчлэлтийг мөн хийж туршилтаар баталгаажуулсан.
Health monitoring of the power conversion system is very important. Therefore, we developed a new method for measuring IGBT currents and reproducing average load current to monitor IGBTs. This method was successfully tested on an experimental setup which showed that the tiny PCB sensors can be integrated into intelligent power modules. We proposed an inexpensive analogue circuit which is suitable for capturing current information from a tiny PCB Rogowski coil. The sensors and corresponding circuit can be embedded into an Intelligent Power Module. The method was named “Envelop tracking” as it simultaneously measures the currents of the high and low side switches of a power converter and reproduces the upper and lower edges of the load current which can be averaged by further digital processing.
This paper proposes a practical current sensor integration in the intelligent power modules (IPMs) using simple PCB Rogowski coil sensors. The PCB sensors produce signals that proportional to the high frequency switching current from high and low side IGBTs. Then with only general-purpose Op- Amps and photo-couplers based integrator and sample and hold (S/H) circuits reproduce output current of the inverter. Specifically, the “envelop tracking” method has successfully proved on an experimental inverter setup. A significant accomplishment of an improved new analog circuit is the measurement during narrow pulse width around unity modulation index that leads to higher inverter output power.
In recent years, Ulaanbaatar, a capital of Mongolia has witnessed major problem that air quality reaches hazardous level during the winter season. Coal combustion for heating of every house in "Ger" district is main reason. One way to reduce the air pollution is mass usage of electric heater. However, there are several difficulties such as overload and degradation of transformers and other equipment used in distribution and transmission systems as well as power shortage occurrence in evening peak period due to residential consumption. This study aims to contribute for solving the air pollution and power shortage problem in Mongolia. One possible solution could be distributed generation (DG) with photovoltaic (PV) penetration. In this study, PV with energy storage (ES) hybrid system to reduce peak load is analyzed. We proposed the suitable structure of PV-ES hybrid for Mongolian household, and suggested several operation scenarios. Optimal operation algorithm is carried out based on a comparison aspect from economical, grid impact and PV penetration possibility. The economic analyse shows annual income of 520USD, and has a payback period of 8 years for selected scenario. The proposed PV-ES system structure is verified by experimentation set on the building rooftop in city center. The suggested scenario is planned to apply for system in further research.
