Abstract
本論文的主要目的在於研製一軟式切換減振電路共振變流器， 並應用於 間接式磁場導向感應馬達驅動系統，使之具有低切換應力 及損失，可提 高切換頻率以提升其切換操作性能。首先比較介紹常 用變流器調變技術 之原理及特性，為了配合軟式切換變流器之正常 切換操作及獲得良好之 電流追蹤控制特性，選用電流控制空間向量 調變 PWM為變流器之調變技 術。比起其他暨有之軟式切換技術，本 論文所採用之減振電路軟式切換 方式最容易實現,因只要在傳統PWM 變流器之主開關元件中加入輔助共振 支路，由其輔助開關之配合操 控，從事主開關之零電壓轉移，即可成功 的達成軟式切換。在論文 中，將詳細介紹及推導所提減振電路共振軟式 切換變流器於各工作 模式下之操作原理、等效電路及電壓電流主導方程 式，並由之研擬 出一系統化設計步驟，以設計出輔助共振支路所採之元 件值，以及 可使軟式切換穩健操作之主開關與輔助開關延遲觸發控制信 號。本 論文所提軟式共振變流器之主要特色為只要適當控制主開關及輔 助 開關的導通時間延遲即可完成軟式切換，而延遲時間可事先適當地 估 算出，並不需要額外的電壓及電流感測器。所設計之軟式切換變 流器在 經EMTP模擬驗證其可行性後，即從事所設計軟式切換變流器 之電路製作 ，並用於間接磁場導向感應馬達驅動系統。一些實測結 果顯示利用所設 計之變流器，因切換損失之降低而提高了變流器之 轉換效率。另外，變 流器供電馬達驅動系統之電流追蹤控制及速度 動態性能並未受所加軟式 切換之影響。 This thesis presents the design and implementation of a resonant snubber-based soft switching inverter and its application to an indirect field-oriented induction motor drive, such that its switching frequency can be chosen higher to possess better switching operation character- istics. First, according to the comparative survey among the commonly used pulse width modulation(PWM) techniques, the current-controlled space vector PWM is adopted to let this proposed soft switching inverter be normally oper- ated and have good current tracking performance. Compared with the other existed soft switching techniques, the resonant snubber-based soft switching is the easiest one to be implemented, since the soft switching of a tra- ditional PWM inverter can be successfully achieved by simply adding an auxiliary resonant circuit and suitable switching control signals for main and auxiliary switches. The operation, equivalent circuits and governed equations in various modes of the proposed soft switching inverter are analyzed in detail. The accordingly, a systematic design procedure is proposed to design the components of the auxiliary resonant circuit and the delay times of switches for achieving zero voltage transition control. No additional voltage and current sensors are required. Having tested the validity of the designed soft switching scheme by simulation, circuit implementation of the designed soft switching inverter used in an indirect field-oriented induction motor drive is performed. Some measured results show that smaller switching loss and thus higher inverter conversion efficiency are obtained through using the designed soft switching inverter. In addition, the current tracking and speed dynamic responses of the inverter-fed motor drive are not affected by adding the proposed soft switching scheme.