TWI728927B

TWI728927B - Zero-voltage switching bidirectional direct-to-ac conversion circuit structure and its modulation method

Info

Publication number: TWI728927B
Application number: TW109135567A
Authority: TW
Inventors: 廖益弘; 李冠輝
Original assignee: 廖益弘
Priority date: 2020-10-14
Filing date: 2020-10-14
Publication date: 2021-05-21
Also published as: TW202215766A

Abstract

A zero-voltage switching (ZVS) bidirectional DC-AC converter structure is disclosed. In an embodiment of the invention, the converter structure consists of an active switch, a resonant inductor, a clamping capacitor, and two diodes. It placed between the DC bus and the three-phase six-switch. In addition, a new carrier switching scheme is proposed and combined with discontinuous pulse width modulation (DPWM1) to generate the bidirectional control signals for this structure. In this way, the inverter mode and the rectifier mode can realize zero-voltage switching operation in all switching devices and suppress the reverse recovery current in all antiparallel diodes.

Description

零電壓切換雙向直交流轉換電路結構及其調變方法 Zero-voltage switching bidirectional direct-to-ac conversion circuit structure and its modulation method

本發明涉及電力電子設備及其調變方法，特別是一種零電壓切換雙向直交流轉換電路結構及其調變方法。 The invention relates to power electronic equipment and a modulation method thereof, in particular to a zero-voltage switching bidirectional DC-AC conversion circuit structure and a modulation method thereof.

為了因應再生能源的間歇性與不穩定性，大型儲能系統成為了微電網中的關鍵角色，而作為中樞的雙向電能轉換器，能使儲能系統發揮其最大效益。傳統的三相六開關直流-交流電路架構被廣泛的應用於大功率的系統當中，其具有電流應力低、效率高等優點，且此架構的反流器與整流器具有相同拓樸，只是功率流動方向相反，因此非常適合用作雙向電能轉換器的應用。但是，此架構六開關的背接二極體都會有反向恢復的過程，這將會導致大量的開關切換損耗與電磁干擾問題(EMI)。 In order to cope with the intermittency and instability of renewable energy, large-scale energy storage systems have become a key role in the microgrid, and as the central bidirectional power converter, the energy storage system can maximize its benefits. The traditional three-phase six-switch DC-AC circuit architecture is widely used in high-power systems. It has the advantages of low current stress and high efficiency, and the inverter and rectifier of this architecture have the same topology, but the power flow direction On the contrary, it is therefore very suitable for applications as a bidirectional power converter. However, the back-connected diodes of the six switches of this architecture will all have a reverse recovery process, which will cause a lot of switching losses and electromagnetic interference (EMI) problems.

至目前為止已有許多關於三相反流器與整流器的柔切技術研究，此技術可以使開關在零電壓或零電流的條件下導通或截止，因此能解決背接二極體的反向恢復問題，並減少開關切換損耗與電磁干擾。比較常見的方法是增加輔助諧振電路，其中又有交流側輔助電路與直流側輔助電路兩種電路配置。交流側輔助電路主要並聯於三相六開關轉換器的交流側，因此不會是直-交流轉換電路的主要電流路徑，不會造成額外傳導損耗。但由於每一相都要有獨立的輔助電路，因此元件的使用量較大。直流側輔助電路主要放置於直流匯流排與三相六開關之間，只需要一組輔助電路即可，在直流匯流排電壓為零時，讓三相六開關在相應的時間點進行柔切。但是直流側輔助電路位於主要的電流路徑上，因此不同的輔助電路架構可能會在元件上施加直流鏈電壓1~3倍不等的電壓應力。 So far, there have been many researches on the soft-cutting technology of three-phase inverters and rectifiers. This technology can make the switch turn on or off under the condition of zero voltage or zero current, so it can solve the reverse recovery problem of back-connected diodes. , And reduce switching loss and electromagnetic interference. The more common method is to add an auxiliary resonant circuit, in which there are two circuit configurations of AC side auxiliary circuit and DC side auxiliary circuit. The AC side auxiliary circuit is mainly connected in parallel to the AC side of the three-phase six-switch converter, so it will not be the main current path of the DC-AC conversion circuit and will not cause additional conduction loss. However, since each phase must have an independent auxiliary circuit, the use of components is relatively large. The auxiliary circuit on the DC side is mainly placed between the DC bus and the three-phase six switches. Only one set of auxiliary circuits is needed. Yes, when the DC bus voltage is zero, let the three-phase six-switch perform soft-cutting at the corresponding point in time. However, the DC side auxiliary circuit is located on the main current path, so different auxiliary circuit architectures may impose a voltage stress ranging from 1 to 3 times the DC link voltage on the component.

文獻[D.Xu,B.Feng,R.Li,K.Mino and H.Umida,"A Zero Voltage Switching SVM(ZVS-SVM)Controlled Three-Phase Boost Rectifier," in IEEE Transactions on Power Electronics,vol.22,no.3,pp.978-986,May 2007(以下簡稱習知技術A)]提出了由ZVS-SVM所控制的三相升壓整流器電路拓樸，使用由一個主動式開關，一個諧振電感，一個箝位電容所組成的直流側輔助電路，並使用作者提出的改良SVM方案進行控制。其開關背接二極體的反向恢復抑制成效很好，但開關電壓應力稍微高於直流鏈電壓(大約直流鏈電壓1.01~1.1倍)。 Literature [D.Xu,B.Feng,R.Li,K.Mino and H.Umida,"A Zero Voltage Switching SVM(ZVS-SVM)Controlled Three-Phase Boost Rectifier," in IEEE Transactions on Power Electronics,vol. 22, no.3, pp.978-986, May 2007 (hereinafter referred to as conventional technology A)] proposed a three-phase boost rectifier circuit topology controlled by ZVS-SVM, using an active switch, a resonance Inductance, a DC side auxiliary circuit composed of a clamping capacitor, and use the improved SVM scheme proposed by the author to control. The reverse recovery suppression effect of the switch back-connected diode is very good, but the switch voltage stress is slightly higher than the DC link voltage (about 1.01~1.1 times the DC link voltage).

文獻[R.Li,K.Ma and D.Xu,"A Novel Minimum Voltage Active Clamping SVM(MVAC-SVM)Controlled Three-Phase PFC," 2009 Twenty-Fourth Annual IEEE Applied Power Electronics Conference and Exoosition,Washington,DC,2009,pp.1879-1885(以下簡稱習知技術B)]提出了一種最小電壓主動箝位(Minimum Voltage Active Clamping,MVAC)ZVS三相升壓整流器電路拓樸，其架構與前述習知技術A相似，僅更改了箝位電容C_c的位置，並使用與習知技術A相同之改良SVM方案進行控制。其開關電壓應力等於直流鏈電壓，但是諧振電感的參數設計有較多限制，如設計不良將使箝位電容電壓不平衡且無法建立，無法實現ZVS條件，即使實現ZVS條件亦將導致開關背接二極體之反向恢復損耗增加。 Literature [R.Li,K.Ma and D.Xu,"A Novel Minimum Voltage Active Clamping SVM(MVAC-SVM)Controlled Three-Phase PFC," 2009 Twenty-Fourth Annual IEEE Applied Power Electronics Conference and Exoosition,Washington,DC ,2009,pp.1879-1885 (hereinafter referred to as conventional technology B)] proposed a minimum voltage active clamping (Minimum Voltage Active Clamping, MVAC) ZVS three-phase boost rectifier circuit topology, its architecture and the aforementioned conventional technology A is similar, only _{the position of the clamping capacitor C c} is changed, and the same improved SVM scheme as the prior art A is used for control. The switch voltage stress is equal to the DC link voltage, but the parameter design of the resonant inductor has many restrictions. If the design is not good, the clamping capacitor voltage will be unbalanced and cannot be established, and the ZVS condition cannot be achieved. Even if the ZVS condition is achieved, the switch will be back connected. The reverse recovery loss of the diode increases.

文獻[R.Li and D.Xu,"A Zero-Voltage Switching Three-Phase Inverter," in IEEE Transactions on Power Electronics,vol.29,no.3,pp.1200-1210,March 2014]提出一種主動箝位ZVS三相反流器，其拓樸結構同樣類似習知技術A提出的ZVS-SVM整流器拓樸，再使用作者提出的特殊調變方案後，可以實現所有開關元件的ZVS。雖然能夠抑制開關背接二極體的反向恢復電流，但其開關電壓應力稍微高於直流鏈電壓(大約直流鏈電壓1.01~1.1倍)，且作者提出的調變方案會讓此反流器出現上下臂開關同時導通的現象，這會增加開關的電流應力。 Literature [R.Li and D.Xu,"A Zero-Voltage Switching Three-Phase Inverter," in IEEE Transactions on Power Electronics, vol. 29, no. 3, pp. 1200-1210, March 2014] proposes an active clamp ZVS three-phase inverter, and its topology is similar to that of conventional technology A. The topology of the ZVS-SVM rectifier can realize the ZVS of all switching elements after using the special modulation scheme proposed by the author. Although the reverse recovery current of the switch back connected to the diode can be suppressed, the switching voltage stress is slightly higher than the DC The link voltage (approximately 1.01~1.1 times the DC link voltage), and the author's modulation scheme will cause the inverter to have the upper and lower arm switches on at the same time, which will increase the current stress of the switch.

文獻[R.Li,Z.Ma and D.Xu,"A ZVS Grid-Connected Three-Phase Inverter," in IEEE Transactions on Power Electronics,vol.27,no.8,pp.3595-3604,Aug.2012.]提出另一種ZVS三相反流器，此拓樸結構類似習知技術B提出的MVAC整流器拓樸，其開關電壓應力等於直流鏈電壓，同時能抑制開關背接二極體的反向恢復電流。 Literature [R.Li,Z.Ma and D.Xu,"A ZVS Grid-Connected Three-Phase Inverter," in IEEE Transactions on Power Electronics,vol.27,no.8,pp.3595-3604,Aug.2012 .] Another ZVS three-phase inverter is proposed. This topology is similar to the MVAC rectifier topology proposed by the prior art B. Its switching voltage stress is equal to the DC link voltage, and at the same time, it can suppress the reverse recovery current of the switch back connected to the diode. .

文獻[何金滿及彭常益，“具零電壓零電流柔切特性之三相六開關整流器”，中華民國第三十一屆電力工程研討會，台灣，台南，2010.12.3-4]提出一種SSMR電路架構，其包含輔助開關SA、諧振電感LR、額外電壓源(變壓器Tr)、阻隔二極體DR1、箝位電路RC-DC-CC以及諧振電容，結合三相六開關切換式整流器，進而實現一種具有穩定輸出電壓、高效率、高功因與低電磁干擾等特性的新式三相柔切整流器，採用SPWM調變策略(上臂或下臂三個功率開關同時導通)，具有簡化開關控制電路之優點。 Literature [He Jinman and Peng Changyi, "Three-phase six-switch rectifier with zero-voltage and zero-current soft-cutting characteristics", the 31st Power Engineering Symposium of the Republic of China, Tainan, Taiwan, 2010.12.3-4] proposed a kind of SSMR Circuit architecture, which includes auxiliary switch SA, resonant inductor LR, additional voltage source (transformer Tr), blocking diode DR1, clamp circuit RC-DC-CC and resonant capacitor, combined with a three-phase six-switch switching rectifier, and then realize A new three-phase soft-cut rectifier with stable output voltage, high efficiency, high power factor and low electromagnetic interference. It adopts SPWM modulation strategy (the upper arm or lower arm is turned on at the same time), and has a simplified switch control circuit. advantage.

本發明的目的在於提出一種零電壓切換(ZVS)雙向直交流轉換電路結構及其調變方法，以實現整合整流器與反流器之功能的拓樸結構。 The purpose of the present invention is to propose a zero voltage switching (ZVS) bidirectional direct AC The conversion circuit structure and its modulation method are used to realize the topological structure that integrates the functions of the rectifier and the inverter.

為實現上述目的，本發明零電壓切換(ZVS)雙向直交流轉換電路結構基本上是和標準三相六開關架構以及直流電源匯流排一起構成包含整流器與反流器之功能的拓樸結構。 In order to achieve the above objectives, the zero-voltage switching (ZVS) bidirectional DC-AC conversion circuit structure of the present invention basically forms a topology including the functions of a rectifier and an inverter together with a standard three-phase six-switch architecture and a DC power bus.

本發明零電壓切換(ZVS)雙向直交流轉換電路結構的一種實施例構造，包括：反向並聯有二極體的一輔助開關、一諧振電感、一箝位電容、一第1二極體和一第2二極體，輔助開關的兩端並聯一電容，在所述的三相六開關切換式整流器的母線及其輸出儲能電容器之間接入由輔助開關連接箝位電容的串聯支路，輔助開關和箝位電容構成的串聯支路的兩端跨接諧振電感，諧振電感和輔助開關連接的一端連接於母線，箝位電容的兩端分別串接第1二極體和第2二極體的一端，第1二極體和第2二極體的另一端連接輸出儲能電容器。 An embodiment structure of the zero voltage switching (ZVS) bidirectional direct-to-ac conversion circuit structure of the present invention includes: an auxiliary switch with diodes in anti-parallel, a resonant inductor, a clamping capacitor, a first diode, and A second diode, a capacitor is connected in parallel at both ends of the auxiliary switch, and a series branch connected by the auxiliary switch to the clamping capacitor is connected between the bus bar of the three-phase six-switch switching rectifier and its output energy storage capacitor, The two ends of the series branch formed by the auxiliary switch and the clamp capacitor are connected across the resonant inductor, one end of the resonant inductor and the auxiliary switch is connected to the bus bar, and the two ends of the clamp capacitor are respectively connected in series with the first diode and the second diode One end of the body, the other ends of the first diode and the second diode are connected to an output energy storage capacitor.

作為本發明零電壓切換(ZVS)雙向直交流轉換電路結構的一種較佳實施例構造，其中零電壓切換雙向直交流轉換電路結構連接在三相六開關切換式整流器的正極母線和輸出儲能電容器之間；所述的零電壓切換雙向直交流轉換電路結構包括：反向並聯有二極體的一輔助開關、一諧振電L_r、一箝位電容、一第1二極體和一第2二極體，輔助開關的兩端並聯一電容，在三相六開關切換式整流器的正極母線和輸出儲能電容器之間接入由輔助開關的集極連接箝位電容的正極的串聯支路，輔助開關和箝位電容構成的串聯支路的兩端跨接所述的諧振電感，其中第1二極體的陰極連接箝位電容的正極，第2二極體的陽極連接箝位電容的負極，第1二極體的陽極連第2二極體的陰極和輸出儲能電容器。 As a preferred embodiment structure of the zero-voltage switching (ZVS) bidirectional direct-to-ac conversion circuit structure of the present invention, the zero-voltage switching bidirectional direct-to-ac conversion circuit structure is connected to the positive bus of the three-phase six-switch switching rectifier and the output energy storage capacitor Between; the zero-voltage switching bidirectional direct-to-ac conversion circuit structure includes: an auxiliary switch with diodes connected in parallel in reverse, a resonant electric L _r , a clamping capacitor, a first diode and a second A diode, a capacitor is connected in parallel at both ends of the auxiliary switch, and a series branch is connected between the positive bus bar of the three-phase six-switch switching rectifier and the output energy storage capacitor by connecting the collector of the auxiliary switch to the positive electrode of the clamping capacitor. The two ends of the series branch formed by the switch and the clamping capacitor are connected across the resonant inductor, wherein the cathode of the first diode is connected to the positive electrode of the clamping capacitor, and the anode of the second diode is connected to the negative electrode of the clamping capacitor, The anode of the first diode is connected to the cathode of the second diode and the output storage capacitor.

作為本發明零電壓切換(ZVS)雙向直交流轉換電路結構的一種較佳實施例構造，其中零電壓切換雙向直交流轉換電路結構連接在三相六開關切換式整流器的負極母線和輸出儲能電容器之間；零電壓切換雙向直交流轉換電路結構包括：反向並聯有二極體的一輔助開關、一諧振電感、一箝位電容、一第1二極體和一第2二極體，該輔助開關的兩端並聯一電容，在該三相六開關切換式整流器的負極母線和輸出儲能電容器之間接入由輔助開關的射極連接箝位電容的負極的串聯支路，輔助開關和箝位電容構成的串聯支路的兩端跨接該振電感，第1二極體的陽極連接箝位電容的負極，第2二極體的陰極連接箝位電容的正極，該第1二極體的陰極連接該第2二極體的陽極和該輸出儲能電容器。 As a preferred embodiment structure of the zero-voltage switching (ZVS) bidirectional direct-to-ac conversion circuit structure of the present invention, the zero-voltage switching bidirectional direct-to-ac conversion circuit structure is connected to the negative bus of the three-phase six-switch switching rectifier and the output energy storage capacitor Between; the zero-voltage switching bidirectional direct-to-ac conversion circuit structure includes: an auxiliary switch with diodes in anti-parallel, a resonant inductor, a clamping capacitor, a first diode and a second diode, the A capacitor is connected in parallel at both ends of the auxiliary switch, and a series branch is connected between the negative bus bar of the three-phase six-switch switching rectifier and the output energy storage capacitor by connecting the emitter of the auxiliary switch to the negative electrode of the clamping capacitor, the auxiliary switch and the clamp The two ends of the series branch formed by the bit capacitor are connected across the vibration inductance, the anode of the first diode is connected to the negative electrode of the clamping capacitor, and the cathode of the second diode is connected to the positive electrode of the clamping capacitor. The first diode The cathode of the second diode is connected to the anode of the second diode and the output storage capacitor.

本發明的一方面包括用於所述零電壓切換(ZVS)雙向直交流轉換電路結構的調變方法，包括： One aspect of the present invention includes a modulation method for the zero voltage switching (ZVS) bidirectional direct-to-ac conversion circuit structure, including:

在反流模式和整流模式中使用以鋸齒波作為載波的不連續脈波寬度調變(DPWM1)訊號及其載波切換方式，控制三相六開關切換式整流器中構成三相橋臂的六個主開關在三相電源週期中的開關動作，其中輔助開關調變訊號和主開關調變訊號頻率相同，所述的不連續脈波寬度調變訊號在每個三相電源週期中每隔60°區間將某一相的電壓箝位在±V_dc/2，其中V_dc表示三相橋臂的直流側電壓； The discontinuous pulse width modulation (DPWM1) signal and its carrier switching method using sawtooth wave as the carrier are used in the reverse current mode and rectification mode to control the six main components of the three-phase bridge arm in the three-phase six-switch switching rectifier. The switching action of the switch in a three-phase power cycle, where the auxiliary switch modulation signal and the main switch modulation signal have the same frequency, and the discontinuous pulse width modulation signal is every 60° interval in each three-phase power cycle Clamp the voltage of a phase to ±V _dc /2, where V _dc represents the DC side voltage of the three-phase bridge arm;

當所述的區間的電壓箝位在+V_dc/2時，選擇V₇(111)作為零向量使該相的上臂開關保持開啟狀態，下臂開關保持關閉狀態；當所述的區間的電壓箝位在-V_dc/2時，選擇V₀(000)作為零向量使該相的上臂開關保持關閉狀態，下臂開關保持開啟狀態； When the voltage in the interval is clamped at +V _dc /2, select V ₇ (111) as the zero vector to keep the upper arm switch of this phase in the on state and the lower arm switch in the off state; when the voltage in the interval is When the clamp is at -V _dc /2, select V ₀ (000) as the zero vector to keep the upper arm switch of this phase closed and the lower arm switch open;

其中在反流模式，當所述的區間的電壓箝位在+V_dc/2時，所述的區間的鋸齒波為上升鋸齒波，當所述的區間的電壓箝位在-V_dc/2時，所述的區間的鋸齒波為下降鋸齒波； Wherein in the reverse current mode, when the voltage in the interval is clamped at +V _dc /2, the sawtooth wave in the interval is a rising sawtooth wave, and when the voltage in the interval is clamped at -V _dc /2 When, the sawtooth wave in the interval is a falling sawtooth wave;

其中在整流模式，當所述的區間的電壓箝位在+V_dc/2時，所述的區間的鋸齒波為下降鋸齒波，當所述的區間的電壓箝位在-V_dc/2時，所述的區間的鋸齒波為上升鋸齒波。 Wherein in the rectification mode, when the voltage in the interval is clamped at +V _dc /2, the sawtooth wave in the interval is a falling sawtooth wave, and when the voltage in the interval is clamped at -V _dc /2 , The sawtooth wave in the interval is a rising sawtooth wave.

其中所述的三相電源週期以每60°區分為六個該區間，每個該區間包含電壓箝位分別為+V_dc/2和-V_dc/2的兩個子區間。 Wherein, the three-phase power cycle is divided into six intervals every 60°, and each interval includes _{two sub-intervals with voltage clamps of +V dc} /2 and -V _dc /2, respectively.

本發明之電路架構在反流模式(inverter mode)與整流模式(rectifier mode)下都能實現三相六開關與輔助開關的零電壓切換，且抑制所有開關背接二極體的反向恢復電流。本發明提出的調變方法，結合不連續脈波寬度調變(DPWM1)和載波切換方式產生適用於本發明上述電路架構的雙向控制，並在一3kW的電路模擬與硬體實測中驗證其功效及可行性。 The circuit structure of the present invention can realize zero-voltage switching between three-phase six-switches and auxiliary switches in inverter mode and rectifier mode, and suppresses the reverse recovery current of all the switches connected to the diodes. . The modulation method proposed by the present invention combines discontinuous pulse width modulation (DPWM1) and carrier switching methods to produce bidirectional control suitable for the above-mentioned circuit architecture of the present invention, and its efficacy is verified in a 3kW circuit simulation and hardware actual measurement And feasibility.

C_c:箝位電容 C _c : Clamping capacitance

C_dc:輸出儲能電容器 C _dc : output energy storage capacitor

C_r1~C_r7:電容 C _r1 ~C _r7 : Capacitance

D₁~D₇:背接二極體 D ₁ ~D ₇ : Back-connected diode

DERs:分散式儲能系統 DERs: Distributed Energy Storage System

D_inv:第1二極體 D _inv : the first diode

D_rec:第2二極體 D _rec : the second diode

i_a:A相電流 i _a : A phase current

i_b:B相電流 i _b : Phase B current

ic:C相電流 ic: C phase current

i_ce:主開關之電流 i _ce : current of main switch

i_Lr:諧振電感電流 i _Lr : Resonant inductor current

L_a、L_b、L_c:儲能電感 L _a , L _b , L _c : energy storage inductance

L_r:諧振電感 L _r : resonant inductance

S₁~S₆:主開關 S ₁ ~S ₆ : Main switch

S₇:輔助開關 S ₇ : auxiliary switch

V_a、V_b、V_c:三相電源 V _a , V _b , V _c : three-phase power supply

V_Cc:箝位電容電壓 V _Cc : Clamping capacitor voltage

V_ce:主開關之電壓 V _ce : the voltage of the main switch

V_dc:三相橋臂的直流側電壓 V _dc : DC side voltage of the three-phase bridge arm

第1圖，繪示本發明零電壓切換(ZVS)雙向直交流轉換電路結構的一種實施例的拓樸結構圖。 Figure 1 shows a topological structure diagram of an embodiment of the zero-voltage switching (ZVS) bidirectional DC-AC conversion circuit structure of the present invention.

第2圖，繪示不連續脈波寬度調變(DPWM1)訊號與零序訊號波形。 Figure 2 shows the discontinuous pulse width modulation (DPWM1) signal and zero sequence signal waveforms.

第3圖，繪示不連續脈波寬度調變(DPWM1)訊號零狀態區間圖。 Figure 3 shows the interval diagram of the zero state of the discontinuous pulse width modulation (DPWM1) signal.

第4圖，繪示是反流模式的載波切換方式的載波波形。 Figure 4 shows the carrier waveform of the carrier switching method in the reverse flow mode.

第5-1圖至第5-9圖，繪示在反流模式下各個操作階段對應的電路動作示意圖。 Figures 5-1 to 5-9 show the circuit actions corresponding to each operation stage in the reverse flow mode intention.

第6圖，繪示反流模式之區間01的理論波形。 Figure 6 shows the theoretical waveform of interval 01 in the reflux mode.

第7圖，繪示整流模式的載波切換方式的載波波形。 Figure 7 shows the carrier waveform of the carrier switching mode in rectification mode.

第8-1圖至第8-9圖，繪示在整流模式下各個操作階段對應的電路動作示意圖。 Figures 8-1 to 8-9 show schematic diagrams of the circuit actions corresponding to each operation stage in the rectification mode.

第9圖，繪示整流模式之區間01的理論波形圖。 Figure 9 shows the theoretical waveform of the interval 01 in the rectification mode.

第10圖，繪示反流模式在3kW輸出功率下之電網相電壓與相電流模擬波形。 Figure 10 shows the simulated waveforms of phase voltage and phase current of the grid under 3kW output power in reverse current mode.

第11圖，繪示反流模式之主開關S₄電壓與電流波形。 Figure 11, shows the main switch S ₄ Reflux mode of voltage and current waveforms.

第12圖，繪示反流模式之主開關S₆電壓與電流波形。 Figure 12 shows the voltage and current waveforms of the main switch S _{6 in the reverse current mode.}

第13圖，繪示反流模式之輔助開關S₇電壓與電流波形。 Figure 13 shows the voltage and current waveforms of the auxiliary switch S _{7 in the reverse current mode.}

第14圖，繪示反流模式之主開關S₂電壓與電流波形。 Figure 14 shows the voltage and current waveforms of the main switch S _{2 in the reverse current mode.}

第15圖，繪示反流模式之主開關S₃電壓與電流波形。 Figure 15, illustrates the main switch reflux Mode S ₃ voltage and current waveforms.

第16圖，繪示反流模式之主開關S₅電壓與電流波形。 Figure 16, the main switch S ₅ shows voltage and current waveforms of the reflux mode.

第17圖，繪示反流模式之箝位電容電壓與諧振電感電流波形。 Figure 17 shows the clamp capacitor voltage and resonant inductor current waveforms in the reverse current mode.

第18圖，繪示反流模式之第1二極體D_inv電壓與電流波形。 Figure 18 shows the voltage and current waveforms of the first diode D _{inv in the reverse current mode.}

第19圖，繪示反流模式之第2二極體D_rec電壓與電流波形。 Figure 19 shows the voltage and current waveforms of the _{second diode D rec in the reverse current mode.}

第20圖，繪示整流模式在3kW輸出功率下之電網相電壓與相電流模擬波形。 Figure 20 shows the simulation waveforms of phase voltage and phase current of the grid under 3kW output power in rectifier mode.

第21圖，繪示整流模式之主開關S₃電壓與電流波形。 FIG 21, illustrates the main switch S ₃ commutation mode of voltage and current waveforms.

第22圖，繪示整流模式之主開關S₅電壓與電流波形。 FIG. 22, the main switch S ₅ shows voltage and current waveforms of the rectified mode.

第23圖，繪示整流模式之輔助開關S₇電壓與電流波形。 Figure 23 shows the voltage and current waveforms of the auxiliary switch S _{7 in rectification mode.}

第24圖，繪示整流模式之主開關S₂電壓與電流波形。 Figure 24 shows the voltage and current waveforms of the main switch S _{2 in rectification mode.}

第25圖，繪示整流模式之主開關S₄電壓與電流波形。 Figure 25 shows the voltage and current waveforms of the main switch S _{4 in rectification mode.}

第26圖，繪示整流模式之主開關S₆電壓與電流波形。 Figure 26 shows the voltage and current waveforms of the main switch S _{6 in rectification mode.}

第27圖，繪示整流模式之箝位電容電壓與諧振電感電流波形。 Figure 27 shows the clamp capacitor voltage and resonant inductor current waveforms in rectification mode.

第28圖，繪示整流模式之第1二極體D_inv電壓與電流波形。 Figure 28 shows the voltage and current waveforms of the first diode D _{inv in the rectification mode.}

第29圖，繪示整流模式之第2二極體D_rec電壓與電流波形。 Figure 29 shows the voltage and current waveforms of the _{second diode D rec in rectification mode.}

第30圖，繪示本發明零電壓切換(ZVS)雙向直交流轉換電路結構的另一種實施例的拓樸結構圖。 FIG. 30 is a topological structure diagram of another embodiment of the zero-voltage switching (ZVS) bidirectional DC-AC conversion circuit structure of the present invention.

首先請參閱第1圖，繪示了應用本發明零電壓切換(ZVS)雙向直交流轉換電路結構進而實現整流器與反流器功能的拓樸結構。本發明零電壓切換(ZVS)雙向直交流轉換電路結構基本上是一種諧振輔助電路，並且是配置於三相六開關(全橋式)切換式整流器(基本上就是一種標準的三相六開關架構)以及直流電源匯流排之間，其中所述的直流電源匯流排例如但不限於再生能源的分散式儲能系統(distributed energy resources,DERs)。 First of all, please refer to Figure 1, which shows the topological structure of applying the zero-voltage switching (ZVS) bidirectional DC-AC conversion circuit structure of the present invention to realize the functions of the rectifier and the inverter. The zero-voltage switching (ZVS) bidirectional direct-to-ac conversion circuit structure of the present invention is basically a resonance auxiliary circuit, and is configured in a three-phase six-switch (full-bridge) switching rectifier (basically a standard three-phase six-switch architecture ) And DC power bus bars, where the DC power bus bars are, for example, but not limited to, distributed energy resources (DERs) of renewable energy.

其中三相六開關切換式整流器包含：由六個反向並聯有二極體的主開關S₁~S₆構成的三相橋臂(換言之，每個橋臂由上下兩個主開關及與其反向並聯的二極體組成)、分別連接在三相電源V_a、V_b、V_c和三相橋臂的各相橋臂中點之間的三個儲能電感La、L_b、L_c，以及跨接於三相橋臂中的上部橋臂和下部橋臂之間的一輸出儲能電容器C_dc，其中六個主開關S₁~S₆分別並聯有電容C_r1~C_r6。 Among them, the three-phase six-switch switching rectifier includes: _{a three-phase bridge arm composed of six main switches S 1} to S ₆ with diodes connected in parallel in reverse (in other words, each bridge arm consists of two upper and lower main switches and its opposite diodes connected in parallel to the composition), the inductor are connected between the three phase arm three-phase power V _a, V _b, V _c, and the three-phase bridge arm midpoint La, L _b, L _c _{, And an output energy storage capacitor C dc} connected across the upper bridge arm and the lower bridge arm of the three-phase bridge arm, in which the six main switches S ₁ to S ₆ are respectively connected in parallel with capacitors C _r1 to C _r6 .

本發明零電壓切換(ZVS)雙向直交流轉換電路結構包括：反向並聯有二極體的一輔助開關S₇、一諧振電感L_r、一箝位電容C_c、一第1二極體D_inv和一第2二極體D_rec。請參閱第1圖的拓樸結構，本發明零電壓切換(ZVS)雙向直交流轉換電路結構基本上是串連在三相六開關切換式整流器的母線和輸出儲能電容器C_dc之間。其具有以下兩種可行的實施例構造。 The structure of the zero-voltage switching (ZVS) bidirectional direct-to-ac conversion circuit of the present invention includes: an auxiliary switch S ₇ with diodes connected in anti-parallel, a resonant inductor L _r , a clamping capacitor C _c , and a first diode D _inv and a second diode D _rec . Please refer to the topological structure in Figure 1. The zero voltage switching (ZVS) bidirectional direct-to-ac conversion circuit structure of the present invention is basically connected in series between the bus bar of the three-phase six-switch switching rectifier and the output energy storage capacitor C _dc . It has the following two possible embodiment configurations.

請參閱第2圖，在第一種實施例中，本發明零電壓切換(ZVS)雙向直交流轉換電路結構是連接在三相六開關切換式整流器的正極母線和輸出儲能電容器C_dc之間。其中輔助開關S₇的兩端並聯一電容C_r7，在所述的三相六開關切換式整流器的正極母線和及其輸出儲能電容器C_dc之間接入由輔助開關S₇的集極連接箝位電容C_c的正極的串聯支路，輔助開關S₇和箝位電容C_c構成的串聯支路的兩端跨接諧振電感L_r，第1二極體D_inv的陰極連接箝位電容C_c的正極，第2二極體D_rec的陽極連接箝位電容C_c的負極，第1二極體D_inv的陽極連接第2二極體D_rec的陰極和輸出儲能電容器。 Please refer to Figure 2. In the first embodiment, the zero voltage switching (ZVS) bidirectional direct-to-ac conversion circuit structure of the present invention is connected between the positive bus of the three-phase six-switch switching rectifier and the output energy storage capacitor C _dc . The two ends of the auxiliary switch S ₇ are connected in parallel with a capacitor C _r7 , and the collector connection clamp of the auxiliary switch S ₇ is connected between the positive bus of the three-phase six-switch switching rectifier and its output energy storage capacitor C _dc The series branch of the positive pole of the position capacitor C _c , the two ends of the series branch formed by the _{auxiliary switch S 7} and the clamping capacitor C _c _{are connected across the resonant inductance L r} , and the cathode of the first diode D _inv is connected to the clamping capacitor C _{The anode of c} , the anode of the second diode D _rec is connected to the cathode of the clamping capacitor C _c , and the anode of the first diode D _inv is connected to _{the cathode of the second diode D rec} and the output storage capacitor.

請參閱第30圖，在第二種實施例中，本發明零電壓切換(ZVS)雙向直交流轉換電路結構是連接在三相六開關切換式整流器的負極母線和輸出儲能電容器C_dc之間，和第1圖的實施例的區別在於電路元件的極性及匹配關係相反而已；如第30圖繪示的實施例構造，其中輔助開關S₇的兩端並聯電容C_r7，在三相六開關切換式整流器的負極母線和輸出儲能電容器之間接入由輔助開關S₇的射極連接箝位電容C_c的負極的串聯支路，輔助開關S₇和箝位電容C_c構成的串聯支路的兩端跨接諧振電感L_r，第1二極體D_inv的陽極連接箝位電容C_c的負極，第2二極體D_rec的陰極連接箝位電容C_c的正極，第1二極體D_inv的陰極連接第2二極體D_rec的陽極和輸出儲能電容器。 Please refer to Figure 30. In the second embodiment, the zero voltage switching (ZVS) bidirectional direct-to-ac conversion circuit structure of the present invention is connected between the negative bus of the three-phase six-switch switching rectifier and the output energy storage capacitor C _dc , and the difference between the embodiment of FIG. 1 in that the relationship between the matching circuit element and the polarity opposite to it; constructed as shown in the embodiment of FIG. 30, wherein the auxiliary switch S in parallel across the capacitor C ₇ is _R7, six three-phase switch access by the series arrangement of the anode exit auxiliary switch S ₇ is connected between the clamp capacitor C _c and an output storage capacitor negative bus SMRs auxiliary switches S ₇ and the clamp capacitor C _c series branch constituted Connect both ends of the resonant inductor L _r , the anode of the first diode D _inv _{is connected to the negative electrode of the clamping capacitor C c} , the cathode of the second diode D _rec is connected to the positive electrode of the _{clamping capacitor C c, and the first diode} The cathode of the body D _inv _{is connected to the anode of the second diode D rec} and the output storage capacitor.

其中輔助開關S₇在大部分時間都是導通狀態，此時能量在輔助電路中循環，直到輔助開關S₇截止時，儲存在諧振電感L_r中的能量會使主電路開關的寄生電容放電，並在零電壓的條件下依序讓三相開關導通，同時諧振電感L_r也會抑制開關背接二極體的反向恢復電流。 The auxiliary switch S ₇ is turned on most of the time. At this time, the energy circulates in the auxiliary circuit until the auxiliary switch S ₇ is turned off. The energy stored in the resonant inductor L _r will discharge the parasitic capacitance of the main circuit switch. And under the condition of zero voltage, the three-phase switches are turned on sequentially, and at the same time, the resonant inductance L _r will also suppress the reverse recovery current of the switch back connected to the diode.

本發明進一步提出一種用於前述第1、30圖繪示之零電壓切換(ZVS)雙向直交流轉換電路結構的調變方法，在反流模式和整流模式中使用以鋸齒波作為載波的不連續脈波寬度調變(DPWM1)訊號及其載波切換方式，控制三相六開關切換式整流器中構成三相橋臂的六個主開關在三相電源週期中的開關動作，其中在任兩臂的主開關進行同步動作時，輔助開關S₇此時才會動作，使得輔助開關S₇調變訊號與主開關調變訊號頻率相同；所述的不連續脈波寬度調變訊號在每個三相電源週期中每隔60°區間將某一相的電壓箝位在±V_dc/2，可以減少每個週期的開關次數，其波形與零序訊號波形請見第2圖，其中V_dc表示三相橋臂的直流側電壓。 The present invention further proposes a modulation method for the zero voltage switching (ZVS) bidirectional direct-to-ac conversion circuit structure shown in Figures 1 and 30, which uses a sawtooth wave as the carrier discontinuity in the reverse current mode and the rectification mode. The pulse width modulation (DPWM1) signal and its carrier switching mode control the switching actions of the six main switches that constitute the three-phase bridge arm in the three-phase power cycle in the three-phase six-switch switching rectifier. When the switch performs synchronous action, the auxiliary switch S ₇ will act at this time, so that the auxiliary switch S ₇ modulation signal and the main switch modulation signal have the same frequency; the discontinuous pulse width modulation signal is in each three-phase power supply Clamp the voltage of a certain phase to ±V _dc /2 every 60° in the cycle, which can reduce the number of switching times per cycle. See Figure 2 for its waveform and zero-sequence signal waveform, where V _dc represents three-phase The DC side voltage of the bridge arm.

如第3圖所示，每一個週期內由V₁(100)~V₆(101)區分出六個區間，每個區間又可以再根據DPWM1的±V_dc/2箝位分出兩個子區間，換言之，六個區間V₁(100)~V₆(101)的每個區間包含電壓箝位分別為+V_dc/2和-V_dc/2的兩個子區間。當所述的區間的電壓箝位在+V_dc/2時，選擇V₇(111)作為零向量使該相的上臂開關保持開啟狀態，下臂開關保持關閉狀態；當所述的區間的電壓箝位在-V_dc/2時，選擇V₀(000)作為零向量使該相的上臂開關保持關閉狀態，下臂開關保持開啟狀態。 As shown in Figure 3, each cycle is _{divided into six sections by V 1} (100) ~ V ₆ (101), and each section can be divided into two sub- _{sections according to the ±V dc /2 clamp of DPWM1.} The interval, in other words, each of the six intervals V ₁ (100) to V ₆ (101) includes two sub-intervals with voltage clamps of +V _dc /2 and -V _dc /2, respectively. When the voltage in the interval is clamped at +V _dc /2, select V ₇ (111) as the zero vector to keep the upper arm switch of this phase in the on state and the lower arm switch in the off state; when the voltage in the interval is When the clamp is at -V _dc /2, select V ₀ (000) as the zero vector to keep the upper arm switch of this phase closed and the lower arm switch open.

在反流模式和整流模式中，作為不連續脈波寬度調變(DPWM1)訊號的載波的鋸齒波具有不同的切換方式。下文僅以第1圖繪示的零電壓切換(ZVS)雙向直交流轉換電路結構作為代表，說明在反流模式和整流模式的調變操作如下。 In the reverse flow mode and the rectification mode, the sawtooth wave, which is the carrier of the discontinuous pulse width modulation (DPWM1) signal, has different switching methods. The following only uses the zero-voltage switching (ZVS) bidirectional DC-to-AC conversion circuit structure shown in Figure 1 as a representative to illustrate that in the reverse current mode and the adjustment The modulation operation of the streaming mode is as follows.

【反流模式】【Reflux Mode】

請參閱第4圖，在反流模式(inverter mode)，當所述的區間的電壓箝位在+V_dc/2時，所述的區間的鋸齒波為上升鋸齒波，當所述的區間的電壓箝位在-V_dc/2時，所述的區間的鋸齒波為下降鋸齒波；換言之，鋸齒波會每隔60°區間做一次變換。這種載波的切換方式結合不連續脈波寬度調變(DPWM1)，就會產生如表1所示的開關調變順序。 Please refer to Figure 4, in the inverter mode, when the voltage in the interval is clamped at +V _dc /2, the sawtooth wave in the interval is a rising sawtooth wave, and when the voltage in the interval is clamped at +V dc /2, When the voltage is clamped at -V _dc /2, the sawtooth wave in the interval is a falling sawtooth wave; in other words, the sawtooth wave will be transformed every 60° interval. This carrier switching method combined with discontinuous pulse width modulation (DPWM1) will produce the switching modulation sequence shown in Table 1.

下文以區間01為例進行分析，其開關的調變順序為111→100→110→111，此時三相電流分別為i_a>0、i_b<0、i_c<0。在反流模式下的操作包含下列幾個階段，其對應的電路動作與理論波形請參閱第5-1圖至第5-9圖以及第6圖所示內容。 The following analysis takes the interval 01 as an example. The modulation sequence of the switches is 111→100→110→111. At this time, the three-phase currents are i _a > 0, i _b <0, and i _c <0. The operation in the reverse flow mode includes the following stages. For the corresponding circuit actions and theoretical waveforms, please refer to the contents shown in Figure 5-1 to Figure 5-9 and Figure 6.

階段一：[t₀

t<t₁] Phase 1: [t ₀

t<t ₁ ]

此時電路狀態處於111，主開關S₁，輔助開關S₇，背接二極體D₃、D₅為導通狀態，箝位電容C_c對諧振電感L_r進行充電動作。第1二極體 D_inv即將由導通轉為截止狀態，第2二極體D_rec即將由截止轉為導通狀態。 At this time, the circuit state is at 111, the main switch S ₁ , the auxiliary switch S ₇ , the back-connected diodes D ₃ and D ₅ are in the on state, and the clamping capacitor C _c charges the resonant inductor L _r. The first diode D _inv is about to switch from conducting to the cut-off state, and the second diode D _rec is about to switch from cut-off to the conducting state.

階段二：[t₁

t<t₂] Phase 2: [t ₁

t<t ₂ ]

諧振電感L_r與電容C_r2、C_r4、C_r6、C_r7進行諧振，輔助開關S₇因諧振而在ZVS條件下截止於t₁，此時電容C_r2、C_r4、C_r6進行放電動作，電容C_r7進行充電動作。第1二極體D_inv轉為截止狀態，第2二極體D_rec轉為導通狀態。多餘的能量經由第2二極體D_rec回流至分散式儲能系統DERs。 The resonant inductor L _r resonates with the capacitors C _r2 , C _r4 , C _r6 , and C _r7 . The auxiliary switch S ₇ _{is cut off at t 1} under the ZVS condition due to resonance. At this time, the capacitors C _r2 , C _r4 , and C _r6 are discharged , The capacitor C _r7 performs charging action. The first diode D _inv turns into a cut-off state, and the second diode D _rec turns into a conductive state. The excess energy flows back to the distributed energy storage system DERs via the second diode D _rec.

階段三：[t₂

t<t₃] Phase 3: [t ₂

t<t ₃ ]

此時電容C_r2、C_r4、C_r6之電壓放電至零，電容C_r7之電壓充電至V_dc+V_Cc，背接二極體D₂、D₃、D₄、D₅、D₆為導通狀態。主開關S₄、S₆在ZVS條件下導通，諧振電感L_r抑制了背接二極體D₃的反向恢復電流。第1二極體D_inv即將由截止轉為導通狀態，第2二極體D_rec即將由導通為截止狀態。多餘的能量經由第2二極體D_rec回流至分散式儲能系統DERs。 At this time _{, the voltages of the capacitors C r2} , C _r4 , and C _{r6 are} discharged to zero, and the voltage of the _{capacitor C r7} _{is charged to V dc} +V _Cc , and the diodes D ₂ , D ₃ , D ₄ , D ₅ , and D ₆ are connected back to Conduction state. The main switches S ₄ and S ₆ are turned on under the ZVS condition, and the resonant inductor L _r suppresses the reverse recovery current of the back-connected diode D _3. The first diode D _inv is about to change from cut-off to the on state, and the second diode D _rec is about to change from on to the cut off state. The excess energy flows back to the distributed energy storage system DERs via the second diode D _rec.

階段四：[t₃

t<t₄] Phase Four: [t ₃

t<t ₄ ]

此時主開關S₁、S₄、S₆已導通，諧振電感L_r抑制了背接二極體D₂、D₅的反向恢復電流，電容C_r7之電壓放電至V_dc。第1二極體D_inv轉為導通狀態，第2二極體D_rec轉為截止狀態，功率由DC側流至AC側。 At this time, the main switches S ₁ , S ₄ , and S ₆ are turned on, the resonant inductor L _r suppresses the reverse recovery current of the back-connected diodes D ₂ , D ₅ , and the voltage of the _{capacitor C r7} _{is discharged to V dc} . The first diode D _inv turns to the on state, the second diode D _rec turns to the off state, and the power flows from the DC side to the AC side.

階段五：[t₄

t<t₅] Stage Five: [t ₄

t<t ₅ ]

諧振電感L_r與電容C_r2、C_r3、C_r5、C_r7進行諧振，背接二極體D₇即將導通於t₅，此時電容C_r2、C_r3、C_r5進行充電動作，電容C_r7進行放電動作。第1二極體D_inv為導通狀態，第2二極體D_rec為截止狀態，功率由DC側流至AC側。 The resonant inductor L _r resonates with the capacitors C _r2 , C _r3 , C _r5 , and C _r7 . The back-connected diode D ₇ is about to be turned on at t ₅ , and the capacitors C _r2 , C _r3 and C _r5 are charged at this time, and the capacitor C _r7 performs discharge action. The first diode D _inv is in the on state, the second diode D _rec is in the off state, and the power flows from the DC side to the AC side.

階段六：[t₅

t<t₆] Stage six: [t ₅

t<t ₆ ]

此時電路狀態處於100，主開關S₁、S₄、S₆為導通狀態，輔助開關S₇也因諧振而在ZVS條件下導通，諧振電感L_r對箝位電容C_c進行充電動作，第1二極體D_inv為導通狀態，第2二極體D_rec為截止狀態，功率由DC側流至AC側。 At this time, the circuit state is at 100, the main switches S ₁ , S ₄ , and S ₆ are turned on, and the auxiliary switch S ₇ is also turned on under the ZVS condition due to resonance. The resonant inductor L _r charges the clamping capacitor C _c. 1 The diode D _inv is in the on state, and the second diode D _rec is in the off state, and the power flows from the DC side to the AC side.

階段七：[t₆

t<t₇] Stage Seven: [t ₆

t<t ₇ ]

此時B相電流i_b對電容C_r3進行放電動作，對電容C_r4進行充電動作，主開關S₄在ZVS條件下截止。第1二極體D_inv為導通狀態，第2二極體D_rec為截止狀態，功率由DC側流至AC側。 At this time, the phase B current i _b discharges the capacitor C _r3 and charges the capacitor C _r4 , and the main switch S ₄ is turned off under the ZVS condition. The first diode D _inv is in the on state, the second diode D _rec is in the off state, and the power flows from the DC side to the AC side.

階段八：[t₇

t<t₈] Phase eight: [t ₇

t<t ₈ ]

此時電路狀態處於110，主開關S₁、S₆，輔助開關S₇，背接二極體D₃為導通狀態，第1二極體D_inv為導通狀態，第2二極體D_rec為截止狀態，功率由DC側流至AC側。 At this time, the circuit state is at 110, the main switch S ₁ , S ₆ , the auxiliary switch S ₇ , the back-connected diode D ₃ is in the conducting state, the first diode D _inv is in the conducting state, and the second diode D _rec is In the off state, power flows from the DC side to the AC side.

階段九：[t₈

t<t₉] Stage 9: [t ₈

t<t ₉ ]

此時C相電流i_c對電容C_r5進行放電動作，對電容C_r6進行充電動作，主開關S₆在ZVS條件下截止。第1二極體D_inv為導通狀態，第2二極體D_ree為截止狀態，功率由DC側流至AC側。在此階段之後，回到t₀~t₁階段，重新開始新的週期。 At this time, C-phase current i _c of the capacitor C discharging operation _R5, _R6 capacitor C charging operation, the main switch S ₆ is turned off under ZVS condition. The first diode D _inv is in the on state, and the second diode D _ree is in the off state, and power flows from the DC side to the AC side. After this stage, return to the t ₀ ~ t ₁ stage, and start a new cycle.

【整流模式】【Rectification Mode】

請參閱第7圖，在整流模式(rectifier mode)的載波切換方式基本上和反流模式的載波切換方式相反，當所述的區間的電壓箝位在+V_dc/2時，所述的區間的鋸齒波為下降鋸齒波，當所述的區間的電壓箝位在-V_dc/2時，所述的區間的鋸齒波為上升鋸齒波。這種載波的切換方式結合不連續脈波寬度調變(DPWM1)，就會產生如表2所示的開關調變順序。 Please refer to Figure 7. The carrier switching method in rectifier mode is basically the opposite of the carrier switching method in reverse flow mode. When the voltage in the interval is clamped at +V _dc /2, the interval The sawtooth wave in is a falling sawtooth wave, and when the voltage in the interval is clamped at -V _dc /2, the sawtooth wave in the interval is a rising sawtooth wave. This carrier switching method combined with discontinuous pulse width modulation (DPWM1) will produce the switching modulation sequence shown in Table 2.

下文以區間01為例進行分析，其開關的調變順序為111→110→100→111，此時三相電流分別為i_a>0、i_b<0、i_c<0。在整流模式下的操作包含下列幾個階段，其對應的電路動作與理論波形請參閱第8-1圖至第8-9圖以及第9圖所示內容。 The following analysis takes the interval 01 as an example. The modulation sequence of the switches is 111→110→100→111. At this time, the three-phase currents are i _a > 0, i _b <0, and i _c <0. The operation in the rectification mode includes the following stages. For the corresponding circuit actions and theoretical waveforms, please refer to the contents shown in Figure 8-1 to Figure 8-9 and Figure 9.

階段一：[t₀

t<t₁] Phase 1: [t ₀

t<t ₁ ]

此時電路狀態處於100，背接二極體D₁、D₄、D₆，輔助開關S₇為導通狀態，箝位電容C_c對諧振電感L_r進行充電動作。第1二極體D_inv為截止狀態，第2二極體D_rec為導通狀態，功率由AC側流至DC側。 At this time, the circuit state is at 100, the diodes D ₁ , D ₄ , and D _{6 are} back connected, the auxiliary switch S ₇ is turned on, and the clamping capacitor C _c charges the resonant inductor L _r. The first diode D _inv is in the off state, and the second diode D _rec is in the on state, and the power flows from the AC side to the DC side.

階段二：[t₁

t<t₂] Phase 2: [t ₁

t<t ₂ ]

諧振電感L_r與電容C_r2、C_r3、C_r5、C_r7進行諧振，輔助開關S₇因諧振而在ZVS條件下截止於t₁，此時電容C_r2、C_r3、C_r5進行放電動作，電容C_r7進行充電動作。第1二極體D_inv為截止狀態，第2二極體D_rec為導通狀態，功率由AC側流至DC側。 The resonant inductor L _r resonates with the capacitors C _r2 , C _r3 , C _r5 , and C _r7 . The auxiliary switch S ₇ _{is cut off at t 1} under the ZVS condition due to resonance. At this time, the capacitors C _r2 , C _r3 , and C _r5 are discharged , The capacitor C _r7 performs charging action. The first diode D _inv is in the off state, and the second diode D _rec is in the on state, and the power flows from the AC side to the DC side.

階段三：[t₂

t<t₃] Phase 3: [t ₂

t<t ₃ ]

此時電容C_r2、C_r3、C_r5之電壓放電至零，電容C_r7之電壓充電至V_dc+V_Cc，背接二極體D₁、D₂、D₃、D₄、D₅、D₆皆為導通狀態。主開關S₃、S₅在ZVS條件下導通，諧振電感L_r抑制了背接二極體D₂、D₄的反向恢復電流。第1二極體D_inv為截止狀態，第2二極體D_rec為導通狀態，由AC側流至DC側的功率逐漸減少。 At this time _{, the voltages of the capacitors C r2} , C _r3 , and C _{r5 are} discharged to zero, and the voltage of the _{capacitor C r7} _{is charged to V dc} +V _Cc , and the diodes D ₁ , D ₂ , D ₃ , D ₄ , D ₅ , D ₆ are all on. The main switches S ₃ and S ₅ are turned on under the ZVS condition, and the resonant inductor L _r suppresses the reverse recovery current of the back-connected diodes D ₂ and D _4. The first diode D _inv is in the off state, and the second diode D _rec is in the on state, and the power flowing from the AC side to the DC side gradually decreases.

階段四：[t₃

t<t₄] Phase Four: [t ₃

t<t ₄ ]

此時主開關S₃、S₅，背接二極體D₁已導通，諧振電感L_r抑制了背接二極體D₆的反向恢復電流。第1二極體D_inv即將由截止轉為導通狀態，第2二極體D_rec即將由導通轉為截止狀態，由AC側流至DC側的功率在t₄時降為零。 At this time, the main switches S ₃ , S ₅ and the back-connected diode D ₁ have been turned on, and the resonant inductor L _r suppresses the reverse recovery current of the back-connected diode D _6. The first diode D _inv is about to turn from cut-off to the on state, and the second diode D _rec is about to turn from on to the off state, and the power flowing from the AC side to the DC side drops to zero _{at t 4.}

階段五：[t₄

t<t₅] Stage Five: [t ₄

t<t ₅ ]

諧振電感L_r與電容C_r2、C_r4、C_r6、C_r7進行諧振，此時電容C_r2、C_r4、C_r6進行充電動作，電容C_r7進行放電動作。第1二極體D_inv轉為導通狀態，第2二極體D_rec轉為截止狀態。多餘的能量透過第1二極體D_inv經由B相與C相回流至AC市電系統。 The resonant inductor L _r resonates with the capacitors C _r2 , C _r4 , C _r6 , and C _r7 . At this time, the capacitors C _r2 , C _r4 , and C _r6 perform charging operations, and the capacitor C _r7 performs discharge operations. The first diode D _inv turns into the on state, and the second diode D _rec turns into the off state. The excess energy flows back to the AC mains system through the B phase and C phase through the first diode D _inv.

階段六：[t₅

t<t₆] Stage six: [t ₅

t<t ₆ ]

此時電路狀態處於111，主開關S₃、S₅，背接二極體D₁為導通狀態，輔助開關S₇因諧振而在ZVS條件下導通，諧振電感L_r對箝位電容C_c進行充電動作。第1二極體D_inv即將由導通轉為截止狀態，第2二極體D_rec即將由截止轉為導通狀態。 At this time, the circuit state is 111, the main switches S ₃ , S ₅ and the back-connected diode D ₁ are turned on. The auxiliary switch S ₇ is turned on under the ZVS condition due to resonance. The resonance inductance L _{r acts} on the clamping capacitor C _c . Charging action. The first diode D _inv is about to switch from conducting to the cut-off state, and the second diode D _rec is about to switch from cut-off to the conducting state.

階段七：[t₆

t<t₇] Stage Seven: [t ₆

t<t ₇ ]

此時C相電流i_c對電容C_r6進行放電動作，對電容C_r5進行充電動作，主開關S₅在ZVS條件下截止。第1二極體D_inv轉為截止狀態，第2二極體D_rec轉為導通狀態，功率由AC側流至DC側。 At this time, C-phase current i _c of the capacitor C discharging operation _R6, _R5 capacitor C charging operation, the main switch S ₅ is turned off under ZVS condition. The first diode D _inv turns to the off state, the second diode D _rec turns to the on state, and the power flows from the AC side to the DC side.

階段八：[t₇

t<t₈] Phase eight: [t ₇

t<t ₈ ]

此時電路狀態處於110，主開關S₃，背接二極體D₁、D₆、D₇為導通狀態。第1二極體D_inv為截止狀態，第2二極體D_rec為導通狀態，功率由AC側流至DC側。 At this time, the circuit state is at 110, the main switch S ₃ and the back-connected diodes D ₁ , D ₆ , and D ₇ are in a conducting state. The first diode D _inv is in the off state, and the second diode D _rec is in the on state, and the power flows from the AC side to the DC side.

階段九：[t₈

t<t₉] Stage 9: [t ₈

t<t ₉ ]

此時B相電流i_b對電容C_r4進行放電動作，對電容C_r3進行充電動作，主開關S₃在ZVS條件下截止。第1二極體D_inv為截止狀態，第2二極體D_rec為導通狀態，功率由AC側流至DC側。在此階段之後，回到t₀~t₁，重新開始新的週期。 At this time, the B-phase current i _b of the capacitor C _r4 discharge operation, the capacitor C _r3 charging operation, the main switch S ₃ is turned off under ZVS condition. The first diode D _inv is in the off state, and the second diode D _rec is in the on state, and the power flows from the AC side to the DC side. After this stage, return to t ₀ ~ t ₁ and start a new cycle.

【模擬結果】 [Simulation results]

下列的模擬採用Solore公司所開發之電路模擬軟體PSIM(Power Simulation)，分析前述拓樸結構中各個電路元件與節點之電壓電流波形與數值，並驗證本發明零電壓切換雙向直交流轉換電路結構與雙向電力潮流控制方案的功效。 The following simulation uses the circuit simulation software PSIM (Power Simulation) developed by Solore to analyze the voltage and current waveforms and values of each circuit element and node in the aforementioned topology, and verify the structure of the zero-voltage-switching bidirectional DC-AC conversion circuit of the present invention. The effectiveness of the two-way power flow control scheme.

反流模式之模擬，請參閱第10圖為反流模式在3kW輸出功率下之電網相電壓與相電流模擬波形，THD為0.724%。在區間01中，主開關S₄與S₆之電壓v_ce與電流i_ce波形如第11圖和第12圖所示，從第11圖和第12圖中可以看出在主開關S₄與S₆導通之前，電容C_r4與C_r6先放電至零開關才開始導通，即ZVS導通。 For the simulation of the reverse current mode, please refer to Figure 10 for the simulation waveforms of the phase voltage and phase current of the grid under the output power of 3kW in the reverse current mode. The THD is 0.724%. In interval 01, the waveforms of voltage v _ce and current i _{ce of} _{main switches S 4} and S _{6 are} shown in Figs. 11 and 12. From Fig. 11 and Fig. 12, it can be seen that the main switch S ₄ and Before S _{6 is} turned on, the capacitors C _r4 and C _{r6 are} discharged to zero before the switch starts to be turned on, that is, ZVS is turned on.

輔助開關S₇之電壓v_ce與電流i_ce波形如第13圖所示。在輔助開關S₇導通之前，電容C_r7先放電至零開關才開始導通，因此輔助開關S₇也在ZVS條件下導通。而在區間01中，主開關S₂、S₃和S₅之背接二極體反向恢復電流受到諧振電感L_r的抑制到零，其波形如第14圖、第15圖和第16圖所示。 The waveforms of voltage v _ce and current i _{ce of the} auxiliary switch S _{7 are} shown in Figure 13. Before the auxiliary switch S _{7 is} turned on, the capacitor C _{r7 is} discharged to zero before the switch starts to be turned on. Therefore, the auxiliary switch S _{7 is} also turned on under the ZVS condition. In interval 01, the reverse recovery currents of the back diodes of the _{main switches S 2} , S ₃ and S ₅ _{are suppressed to zero by the resonant inductance L r} . The waveforms are shown in Figure 14, Figure 15, and Figure 16. Shown.

請參閱第17圖，為輔助電路中的箝位電容電壓V_Cc與諧振電感電流i_Lr波形，可以看出輔助電路在達到諧振時的充放電情況。第18圖和第19圖為第1二極體D_inv和第2二極體D_rec之電壓與電流波形。在反流模式時，第1二極體D_inv大部分時間為導通狀態，而第2二極體D_rec大部分時間為截止狀態，在此狀態下功率由DC側流至AC側。當第1二極體D_inv為截止狀態，第2二極體D_rec為導通狀態時，在此狀態下多餘的能量經由第2二極體D_rec回流至分散式儲能系統DERs。 Please refer to Figure 17, which shows the waveforms of the clamping capacitor voltage V _Cc and the resonant inductor current i _{Lr in the} auxiliary circuit. It can be seen that the auxiliary circuit is charged and discharged when it reaches resonance. Figures 18 and 19 show the voltage and current waveforms of the _{first diode D inv} and the second diode D _rec. In the reverse flow mode, the first diode D _inv is in the on state most of the time, and the second diode D _rec is in the off state most of the time, and in this state, the power flows from the DC side to the AC side. When the first diode D _inv is in the off state and the second diode D _rec is in the on state, the excess energy in this state flows back to the distributed energy storage system DERs _{via the second diode D rec.}

整流模式之模擬，請參閱第20圖為整流模式在3kW輸出功率下之電網相電壓與相電流模擬波形，功率因數PF為0.99%。在區間01中，主開關S₃與S₅之電壓v_ce與電流i_ce波形如第21圖和第22圖所示，從第21圖和第22圖中可以看出在主開關S₃與S₅導通之前，電容C_r3與C_r5先放電至零，開關才開始導通，即ZVS導通。 For the simulation of the rectification mode, please refer to Figure 20 for the simulation waveforms of the phase voltage and phase current of the grid under the output power of 3kW in the rectification mode. The power factor PF is 0.99%. In interval 01, the waveforms of voltage v _ce and current i _{ce of} _{main switches S 3} and S _{5 are} as shown in Fig. 21 and Fig. 22. From Fig. 21 and Fig. 22, it can be seen that the main switch S ₃ and Before S _{5 is} turned on, the capacitors C _r3 and C _{r5 are} discharged to zero before the switch starts to be turned on, that is, ZVS is turned on.

輔助開關S₇之電壓v_ce與電流i_ce波形如第23圖所示。在輔助開關S₇導通之前，電容C_r7先放電至零開關才開始導通，因此輔助開關S₇也在ZVS條件下導通。而在區間01中，主開關S2、S₃和S₅之背接二極體的反向恢復電流受到諧振電感L_r的抑制到零，其波形如第24圖、第25圖和第26圖所示。第27圖為輔助電路中的箝位電容電壓V_Cc與諧振電感電流i_Lr波形，可以看出輔助電路在達到諧振時的充放電情況。 The waveforms of voltage v _ce and current i _{ce of the} auxiliary switch S _{7 are} shown in Figure 23. Before the auxiliary switch S _{7 is} turned on, the capacitor C _{r7 is} discharged to zero before the switch starts to be turned on. Therefore, the auxiliary switch S _{7 is} also turned on under the ZVS condition. In section 01, the main switch S2, S ₃ and S ₅ of the back contact of the diode reverse recovery current is suppressed to resonant inductor L _r is zero, as the waveform of FIG. 24, FIGS. 25 and 26 of FIG. Shown. Figure 27 shows the clamp capacitor voltage V _Cc and the resonant inductor current i _Lr waveforms in the auxiliary circuit. It can be seen that the auxiliary circuit charges and discharges when it reaches resonance.

第28圖和第29圖為第1二極體D_inv和第2二極體D_rec之電壓與電流波形。在整流模式時，第1二極體D_inv大部分時間為截止狀態，而第2二極體D_rec大部分時間為導通狀態，在此狀態下功率由AC側流至DC側。當第1二極體D_inv為導通狀態，第2二極體D_rec為截止狀態時，在此狀態下多餘的能量可以透過第1二極體D_inv經由B相與C相回流至AC市電系統。 Figures 28 and 29 show the voltage and current waveforms of the _{first diode D inv} and the second diode D _rec. In the rectification mode, the first diode D _inv is in the off state most of the time, and the second diode D _rec is in the on state most of the time. In this state, the power flows from the AC side to the DC side. When the first diode D _inv is in the on state and the second diode D _rec is in the off state, the excess energy in this state can pass through the first diode D _inv and return to the AC mains via phase B and phase C system.

雖然本發明之技術特徵、功效及其示例性的實施方式已通過上述的實施例公開如上，然其並非用以限定本發明，本領域技術人員，在不脫離本發明的精神和範圍內，當可作些許的更動與潤飾，因此本發明的專利保護範圍須視本申請的權利要求所界定者為准。 Although the technical features, effects and exemplary embodiments of the present invention have been disclosed above through the above-mentioned embodiments, they are not intended to limit the present invention. Those skilled in the art, without departing from the spirit and scope of the present invention, should Some changes and modifications can be made, so the patent protection scope of the present invention shall be subject to those defined by the claims of this application.

C_c:箝位電容 C _c : Clamping capacitance

C_dc:輸出儲能電容器 C _dc : output energy storage capacitor

C_r1~C_r7:電容 C _r1 ~C _r7 : Capacitance

D₁~D₇:背接二極體 D ₁ ~D ₇ : Back-connected diode

DERs:分散式儲能系統 DERs: Distributed Energy Storage System

D_inv:第1二極體 D _inv : the first diode

D_rec:第2二極體 D _rec : the second diode

i_a:A相電流 i _a : A phase current

i_b:B相電流 i _b : Phase B current

i_c:C相電流 i _c : C phase current

i_Lr:諧振電感電流 i _Lr : Resonant inductor current

L_a、L_b、L_c:儲能電感 L _a , L _b , L _c : energy storage inductance

L_r:諧振電感 L _r : resonant inductance

S₁~S₆:主開關 S ₁ ~S ₆ : Main switch

S₇:輔助開關 S ₇ : auxiliary switch

V_a、V_b、V_c:三相電源 V _a , V _b , V _c : three-phase power supply

Claims

一種零電壓切換雙向直交流轉換電路結構，係配置於三相六開關切換式整流器以及直流電源匯流排之間，其中三相六開關切換式整流器包含：由六個反向並聯有二極體的主開關構成的三相橋臂、分別連接在三相電源和該三相橋臂的各相橋臂中點之間的三個儲能電感L_a、L_b、L_c，以及跨接於該三相橋臂中的上部橋臂和下部橋臂之間的一輸出儲能電容器C_dc，該六個主開關分別並聯有電容C_r1-C_r6；其特徵在於：該零電壓切換雙向直交流轉換電路結構串連在該三相六開關切換式整流器的母線和該輸出儲能電容器C_dc之間；該零電壓切換雙向直交流轉換電路結構包括：反向並聯有二極體的一輔助開關S₇、一諧振電感L_r、一箝位電容C_c、一第1二極體D_inv和一第2二極體D_rec，該輔助開關S₇的兩端並聯一電容C_r7，在該三相六開關切換式整流器的母線和該輸出儲能電容器之間接入由該輔助開關S₇連接該箝位電容C_c的串聯支路，該輔助開關S₇和該箝位電容C_c構成的串聯支路的兩端跨接該諧振電感L_r，該諧振電感L_r和該輔助開關S₇連接的一端連接於該母線，該箝位電容C_c的兩端分別串接該第1二極體D_inv和該第2二極體D_rec的一端，該第1二極體D_inv和該第2二極體D_rec的另一端連接該輸出儲能電容器。 A zero-voltage switching bidirectional DC-AC conversion circuit structure, which is arranged between a three-phase six-switch switching rectifier and a DC power bus bar. The three-phase six-switch switching rectifier includes: six anti-parallel diodes three-phase bridge arm constituted of a main switch, are connected between the three inductor L _a midpoint of each phase arm of the three-phase power and three-phase bridge arm, L _b, L _c, and a jumper to the _{An output energy storage capacitor C dc} between the upper bridge arm and the lower bridge arm in the three-phase bridge arm, the six main switches are respectively connected with capacitors C _r1 -C _{r6 in} parallel; it is characterized in that: the zero voltage switching bidirectional direct AC The conversion circuit structure is connected in series between the bus bar of the three-phase six-switch switching rectifier and the output energy storage capacitor C _dc ; the zero-voltage switching bidirectional direct-to-ac conversion circuit structure includes: an auxiliary switch connected in reverse parallel with a diode S ₇ , a resonant inductor L _r , a clamping capacitor C _c , a first diode D _inv and a second diode D _rec _{, a capacitor C r7 is} connected in parallel at both ends of the auxiliary switch S ₇ Between the bus bar of the three-phase six-switch switching rectifier and the output energy storage capacitor is connected _{a series branch connected by the auxiliary switch S 7} to the clamping capacitor C _c , and the auxiliary switch S ₇ and the clamping capacitor C _{c are} formed The two ends of the series branch are connected across the resonant inductor L _r , one end of the resonant inductor L _r and the auxiliary switch S ₇ is connected to the bus bar, _{and both ends of the clamping capacitor C c} are connected in series to the first two poles. one end of the body and a second D _inv diode D _rec the other end of the first diode D _inv and the second diode D _rec connected to the output of the storage capacitor.

如請求項1所述之零電壓切換雙向直交流轉換電路結構，其中該零電壓切換雙向直交流轉換電路結構連接在該三相六開關切換式整流器的正極母線和該輸出儲能電容器C_dc之間；該零電壓切換雙向直交流轉換電路結構包括：反向並聯有二極體的一輔助開關S₇、一諧振電感L_r、一箝位電容C_c、一第1二極體D_inv和一第2二極體D_rec，該輔助開關S₇的兩端並聯一電容C_r7，在該三相六開關切換式整流器的正極母線和該輸出儲能電容器之間接入由該輔助開關S₇的集極連接該箝位電容C_c的正極的串聯支路，該輔助開關S₇和該箝位電容C_c構成的串聯支路的兩端跨接該諧振電感L_r，該第1二極體D_inv的陰極連接該箝位電容C_c的正極，該第2二極體D_rec的陽極連接該箝位電容C_c的負極，該第1二極體D_inv的陽極連接該第2二極體D_rec的陰極和該輸出儲能電容器。 The zero-voltage-switching bidirectional DC-AC conversion circuit structure according to claim 1, wherein the zero-voltage-switching bidirectional DC-AC conversion circuit structure is connected between the positive bus of the three-phase six-switch switching rectifier and the output energy storage capacitor C _dc The zero-voltage switching bidirectional direct-to-ac conversion circuit structure includes: an auxiliary switch S ₇ with diodes in anti-parallel, a resonant inductor L _r , a clamping capacitor C _c , a first diode D _inv and a second diode D _rec, both ends of the auxiliary switch S ₇ a parallel capacitance C _r7, accessed by the auxiliary switch S ₇ between the positive electrode bus bar three-phase six switching rectifiers and the output storage capacitor the collector electrode connected to the positive electrode of the clamp capacitor C _c of the series branch, both ends of the auxiliary switch S ₇ and the clamping capacitor C _c series branch constituted across the resonant inductor L _r, of the first diode The cathode of the body D _inv _{is connected to the positive electrode of the clamping capacitor C c} , the anode of the second diode D _rec is connected to the _{negative electrode of the clamping capacitor C c} , and the anode of the first diode D _inv is connected to the second diode. The cathode of the polar body D _rec and the output energy storage capacitor.

如請求項1所述之零電壓切換雙向直交流轉換電路結構，其中該零電壓切換雙向直交流轉換電路結構連接在該三相六開關切換式整流器的負極母線和該輸出儲能電容器C_dc之間；該零電壓切換雙向直交流轉換電路結構包括：反向並聯有二極體的一輔助開關S₇、一諧振電感L_r、一箝位電容C_c、一第1二極體D_inv和一第2二極體D_rec，該輔助開關S₇的兩端並聯一電容C_r7，在該三相六開關切換式整流器的負極母線和該輸出儲能電容器之間接入由該輔助開關S₇的射極連接該箝位電容C_c的負極的串聯支路，該輔助開關S₇和該箝位電容C_c構成的串聯支路的兩端跨接該諧振電感L_r，該第1二極體D_inv的陽極連接該箝位電容C_c的負極，該第2二極體D_rec的陰極連接該箝位電容C_c的正極，該第1二極體D_inv的陰極連接該第2二極體D_rec的陽極和該輸出儲能電容器。 The zero-voltage-switching bidirectional DC-AC conversion circuit structure according to claim 1, wherein the zero-voltage-switching bidirectional DC-AC conversion circuit structure is connected between the negative bus of the three-phase six-switch switching rectifier and the output energy storage capacitor C _dc The zero-voltage switching bidirectional direct-to-ac conversion circuit structure includes: an auxiliary switch S ₇ with diodes in anti-parallel, a resonant inductor L _r , a clamping capacitor C _c , a first diode D _inv and a second diode D _rec, both ends of the auxiliary switch S ₇ a parallel capacitance C _r7, accessed by the auxiliary switch S ₇ between the negative electrode bus bar three-phase six switching rectifiers and the output storage capacitor emitter connected to the negative electrode of the clamp capacitor C _c of the series branch, and the auxiliary switch S ₇ across the series branch of the configuration of the clamp capacitor C _c connected across the resonant inductor L _r, of the first diode The anode of the body D _inv _{is connected to the negative electrode of the clamping capacitor C c} , the cathode of the second diode D _rec is connected to the _{positive electrode of the clamping capacitor C c} , and the cathode of the first diode D _inv is connected to the second diode. The anode of the pole body D _rec and the output energy storage capacitor.

一種用於請求項1所述零電壓切換(ZVS)雙向直交流轉換電路結構的調變方法，包括： A modulation method for the zero-voltage switching (ZVS) bidirectional direct-to-ac conversion circuit structure of claim 1, including:

在反流模式和整流模式中使用以鋸齒波作為載波的不連續脈波寬度調變(DPWM1)訊號及其載波切換方式，控制構成該三相橋臂的六個該主開關在三相電源週期中的開關動作，該輔助開關調變訊號和該主開關調變訊號頻率相同，該不連續脈波寬度調變訊號在每個三相電源週期中每隔60°區間將某一相的電壓箝位在±V_dc/2，其中V_dc表示該三相橋臂的直流側電壓； The discontinuous pulse width modulation (DPWM1) signal and its carrier switching method using sawtooth wave as the carrier are used in the reverse current mode and rectification mode to control the six main switches that constitute the three-phase bridge arm during the three-phase power cycle The auxiliary switch modulation signal and the main switch modulation signal have the same frequency, and the discontinuous pulse width modulation signal clamps the voltage of a certain phase every 60° in each three-phase power cycle. Position at ±V _dc /2, where V _dc represents the DC side voltage of the three-phase bridge arm;

當該區間的電壓箝位在+V_dc/2時，選擇V₇(111)作為零向量使該相的上臂開關保持開啟狀態，下臂開關保持關閉狀態；當該區間的電壓箝位在-V_dc/2時，選擇V₀(000)作為零向量使該相的上臂開關保持關閉狀態，下臂開關保持開啟狀態； When the voltage in this interval is clamped at +V _dc /2, select V ₇ (111) as the zero vector to keep the upper arm switch of this phase on and the lower arm switch off; when the voltage in this interval is clamped at- When V _dc /2, select V ₀ (000) as the zero vector to keep the upper arm switch of this phase closed and the lower arm switch open;

其中在反流模式，當該區間的電壓箝位在+V_dc/2時，該區間的鋸齒波為上升鋸齒波，當該區間的電壓箝位在-V_dc/2時，該區間的鋸齒波為下降鋸齒波； Among them, in the reverse current mode, when the voltage in this interval is clamped at +V _dc /2, the sawtooth wave in this interval is a rising sawtooth wave, and when the voltage in this interval is clamped at -V _dc /2, the sawtooth wave in this interval is The wave is a falling sawtooth wave;

其中在整流模式，當該區間的電壓箝位在+V_dc/2時，該區間的鋸齒波為下降鋸齒波，當該區間的電壓箝位在-V_dc/2時，該區間的鋸齒波為上升鋸齒波。 Among them, in the rectification mode, when the voltage in this interval is clamped at +V _dc /2, the sawtooth wave in this interval is a falling sawtooth wave, and when the voltage in this interval is clamped at -V _dc /2, the sawtooth wave in this interval is It is a rising sawtooth wave.

如請求項4所述零電壓切換(ZVS)雙向直交流轉換電路結構的調變方法，該三相電源週期以每60°區分為六個該區間，每個該區間包含電壓箝位分別為+V_dc/2和-V_dc/2的兩個子區間。 As described in claim 4, the zero voltage switching (ZVS) bidirectional direct-to-ac conversion circuit structure modulation method, the three-phase power cycle is divided into six sections every 60°, and each section contains voltage clamps of + Two sub-intervals of V _dc /2 and -V _{dc /2.}