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Isolated bi-directional full-bridge soft-switching dc-dc converter with active and passive snubbers
No full text[[abstract]]An isolated bi-directional full-bridge soft-switching dc-dc converter with high conversion ratio, high output power, soft start-up and soft-switching capability for battery charging/discharging is proposed in this paper. The use of an active flyback and two passive capacitor-diode snubbers can alleviate the voltage spike caused by the current difference between the leakage inductance of the transformer and the current-fed inductor, can reduce the current spike due to diode reverse recovery, and can reduce current and voltage stresses, while achieving near ZVS and ZCS soft-switching features for the switches on the both sides. It can improve system reliability for high power applications. In the paper, operational principle of the proposed converter will be first described, and analysis and design of the proposed converter is then presented. A 1.5 kW prototype with low-side voltage of 48 V and high-side voltage of 360 V has been implemented, from which experimental results have verified its feasibility.[[fileno]]2030197030010[[department]]電機工程學
對稱式取樣與預測式電流控制之5kW雙向換流器研製
No full text[[abstract]]本研究提出雙向換流器之研製，可應用於直流微電網上，且具有太陽能市電併聯與功因修正兩項功能，適用於任何氣候下操作。本系統使用微處理器TMS320LF2406A來實現雙向全橋換流器之預測式電流控制，並改良傳統取樣方式，提出對稱式取樣，以節省A/D取樣的時間，而且由於取樣的時間點固定，可事先將取樣時間計算出來，可減少被雜訊干擾的機率，還可以精準將參考電流值建表，準確的達到雙向轉換之功能。最後，本研究實際製作一5kW的雙向換流器，並由實測結果得知其轉換效率可達98%，來驗證本研究所使用之取樣方法的可行性。[[fileno]]2030197030016[[department]]電機工程學
Narrow pulsed electric field generator using forward / flyback hybrid converters for liquid food processing
No full text[[abstract]]This paper presents a high pulsed electric field generator for microbial inhibition of liquid food in continuous treatment applications. The proposed pulsed electric field generator adopts forward/flyback hybrid converters to achieve a bidirectional narrow pulse voltage output. With this circuit structure, the proposed one can reduce voltage stresses of output diodes and switches in secondary winding of transformer, resulting in a lower cost. It can also decrease voltage variation of components at turn-on and turn-off transitions to avoid noise interference. Furthermore, the proposed generator uses two active clamp circuits to recover the energy trapped in the leakage inductance of transformer with high turns ratio, while a half-bridge inverter is adopted to drive piezoelectric devices for clearing the inhibiting electrodes. To simplify circuit structure of the proposed system, a synchronous switch technique is used to integrate switches between active clamp flyback/forward hybrid converters and half-bridge inverter to increase conversion efficiency and reduce volume, size, weight and cost. Finally, a prototype with maximum output electric field intensity of 50 kV/cm and repetitive rate of 6 Hz has been implemented to prove the feasibility of the proposed pulsed electric field generator.[[fileno]]2030197030038[[department]]電機工程學
複合動力機車引擎點火系統研製
No full text[[abstract]]本論文之主要目的為研製適用於複合動力機車之引擎點火系統。由於複合動力機車於高速行駛期間，其動力來源為引擎，故需要一個點火系統以使引擎正常持續運轉。本論文之引擎點火系統採用返馳式轉換器結合電容放電式點火電路。於論文中並針對引擎轉速的不同，將本文所提之點火電路與傳統電池供電之電容放電式點火電路做性能比較，可作為複合動力機車之引擎點火時的選擇依據。最後，將實際製作引擎點火系統作效率的評估及性能的測試，以驗證所研製的引擎點火系統應用在複合動力機車之可行性。[[fileno]]2030197030049[[department]]電機工程學
複合動力機車資料擷取系統
No full text[[abstract]]本論文研究重點在於探討複合動力機車之資料擷取系統的建立。本論文的資料擷取系統是建立在FPGA(Field-Programmable Gate Array)晶片上的模組化儀器CompactRIO(Compact Reconfigurable Input and Output)，並採用LabVIEW圖控語言完成所需的量測程式。首先將建立可即時監控複合動力機車的系統，量測所想要得知的波形，之後建立可以搭配行車時記錄波形的行車記錄程式，供研究人員對此記錄數據做分析。在測試階段中，複合動力機車內部的重要訊號採用CAN(Control Area Network) Bus的通訊介面傳遞，避免複合動力機車在嚴酷環境下騎乘時訊號受到干擾。因此為了提供開發人員於測試時能方便接收CAN Bus格式的資料，在此利用模組化儀器CompactRIO建立可接收CAN Bus外部訊號的接收程式，供研發人員監控資料。論文中將搭配實車量測機車上的儀錶板訊號、馬達轉速、引擎轉速、油門把手、電池電壓及電池溫度等參數，由這些參數驗證本文所提出監控系統的可行性。[[fileno]]2030197030054[[department]]電機工程學
A Parallel-APF System with Current Sharing Controller and Load-Path Control Center to Improve Dynamic Response and Achieve Weighting Current Distribution
No full text[[abstract]]This paper presents design and implementation of a paralleled active power filter (APF) system with current sharing controller (CSC) and load-path control center (LPCC). This system can filter harmonic currents, compensate reactive power and improve power factor. In the system, each APF module is directly tied to the load, source and buses, and there is no need of communication with other modules. Through CSC and LPCC, the modules can share the total reactive and harmonic currents of the loads according to their power ratings. With the proposed control scheme, power capacity of the system can be readily and flexibly expanded. Since there is no communication between modules, system expandability and flexibility will increase, and hot-swap feature can be readily achieved. Simulations and experimental results have verified the feasibility and performance of the proposed parallel-APF system.[[fileno]]2030197030069[[department]]電機工程學
Fast Transition Current-Type Burst-Mode Dimming Control for the LED Back-Light Driving System of LCD-TV
No full text[[abstract]]In fact, the title does not propagate the content of this paper. It should be changed to "Ripple Free Converter for Driving LED Backlight of LCD TVs." Due to improvement on luminous efficacy, long life and wide color gamut, LED has gradually substituted for cold cathode fluorescent lamp as backlight. The proposed driving system adopts sequential color scanning scheme to improve light utilization efficiency by removing color filter. To meet display performance requirement that chromaticity variation duv needs to be limited below 0.002, this paper also proposes a family of output current ripple free topologies to reduce chromaticity variation caused by ripple current. In addition, magnetic amplifiers are introduced to achieve accurate current control among multi-LED strings, and a driving voltage reseter is introduced to eliminate current spikes, improving backlight uniformity, reliability and availability significantly. A forward-type output current ripple free topology with magnetic amplifiers has been built to sequentially drive color LED arrays, from which experimental measurements have verified the discussed performance and feasibility of the proposed system.[[fileno]]2030197030070[[department]]電機工程學
A Compensation Strategy for Parallel Inverters to Achieve Precise Weighting Current Distribution
No full text[[abstract]]This paper proposes a compensation strategy for parallel inverters to achieve weighting current distribution. In addition to the conventional current weighting distribution control (CWDC), the reference current of each inverter is fed back as a compensation signal to improve weighting current distribution. With the proposed compensation strategy, the output current of each inverter module can precisely track weighting current command. Experimental and simulated results from a three-inverter system with equal or different power ratings and with different kinds of loads have demonstrated the feasibility of the proposed strategy.[[fileno]]2030197030088[[department]]電機工程學