Non-isolated quasi-series-parallel combined converter based on switched capacitor network

Abstract

The invention discloses a non-isolated quasi-series-parallel combined converter based on a switched capacitor network. The converter comprises the switched capacitor network, a non-isolated DC-DC converter, an output filter capacitor Co and a load resistor R. The combined converter gives full play to the advantages of high power density and high efficiency of a non-voltage-regulation mode of the resonant switched capacitor converter, the resonant switched capacitor network and the DC-DC chopper converter are subjected to topological combination through a partial power processing technology, and the combination has the advantages of high power density and high efficiency of the non-voltage-regulation mode of the resonant switched capacitor network and also has the advantages of high power density and high efficiency of the non-voltage-regulation mode of the DC-DC chopper converter. And the advantage of wide voltage regulation range of the DC-DC chopper converter is also fused. By means of the time-sharing charging and discharging characteristics of the capacitors, the resonant switched capacitor network and the DC-DC chopper converter are connected in series on the input side to reduce voltage stress and are connected in parallel on the output side to replace a traditional two-stage cascade mode, and higher total electric energy conversion efficiency is achieved.

Description

Technical Field

[0001] The invention relates to a combined converter based on a resonant switched capacitor, in particular to a non-isolated quasi-series-parallel combined converter based on a switched capacitor network. Background Art

[0002] The energy density of capacitors is 10 to 1000 times that of inductors. Therefore, the switched capacitor converter that uses capacitors as the main energy storage element has a higher power density than the switched inductor converter that uses inductors to store energy. However, the switched capacitor converter has problems of inrush current and hard switching of the switch tube at the moment of capacitor charging and discharging. On this basis, a hollow inductor or stray inductance in the line is connected in series on the switched capacitor branch as a resonant inductor to form a resonant switched capacitor converter, which can eliminate the inrush current and has the advantages of soft switching of the switch tube, low electromagnetic noise of the converter and high power density.

[0003] When the resonant switched capacitor converter is used as a DC transformer (DCX), the working efficiency of the resonant switched capacitor converter is very high. For example, the switch slot converter based on the resonant switched capacitor network has the advantages of consistent switch tube voltage stress, modularization, and easy expansion, and is widely used in low-voltage DC conversion occasions such as data center power supply. However, the resonant switched capacitor converter used as a DC transformer (DCX) has a fixed input voltage and output voltage ratio, which is related to the circuit structure and cannot be adjusted.

[0004] Figure 1 It is a series-parallel buck resonant switched capacitor converter. The switched capacitor network includes seven switch tubes Q A1 , Q B1 , Q B2 , Q C1 , Q C2 , Q D1 , Q D2 , two resonant tanks (resonant inductance L r1 With the resonant capacitor C r1 Series, resonant inductor L r2 With the resonant capacitor C r2 The input power voltage is V in , the output voltage of the converter is V o , the output filter capacitor is C o , the load resistance is R. The input current of the converter is i in , the output current is i o The resonant inductor current is i Lr1 and i Lr2 .

[0005] In order to obtain higher power conversion efficiency, the resonant switched capacitor converter needs to work in full resonance mode, that is, the resonant capacitor C r1 and C r2 Both include a complete charging process and a complete discharging process.

[0006] like Figure 2 As shown, when the resonant capacitor C r1 and C r2 When charging in series, the power supply supplies power to two resonant capacitors and load resistor R at the same time, so there are voltage equations and current equations:

[0007] V in =V Cr1 +V Cr2 +V o (1)

[0008] i in =i Lr1 =i Lr2 =i o (2)

[0009] Where V Cr1 and V Cr2 are the resonant capacitor voltage v Cr1 and v Cr2 The average value of .

[0010] like Figure 3 As shown, when the resonant capacitor C r1 and C r2 When discharging in parallel, the resonant capacitor supplies power to the load resistor R, and then there are voltage equations and current equations:

[0011] V o =V Cr1 =V Cr2 (3)

[0012] i o =-i Lr1 -i Lr2 (4)

[0013] From the voltage relationship during the charging and discharging process of the resonant capacitor, it can be obtained that the input voltage of the series-parallel step-down resonant switched capacitor converter is always equal to three times the output voltage, and the voltage cannot be adjusted.

[0014] V in =3V o (5)

[0015] According to the ampere-second balance principle of capacitors, when the converter enters steady-state operation, the average value of the charging current of each resonant capacitor is equal to the average value of the discharging current. Therefore, the average output current is three times the average input current:

[0016] I o =3I in (6)

[0017] In the formula, I in The converter input current i in The average value of I o is the converter output current i o The average value of .

[0018] The resonant switched capacitor converter has poor continuous voltage regulation capability, the voltage regulation range is greatly affected by the load, and the voltage regulation efficiency is low. In contrast, the DC chopper converter has the advantages of a wide voltage regulation range and little influence by load conditions, but requires a large inductor as the main energy storage element, and the switch tube of the DC chopper converter generally works in a hard switching mode, with large switching losses, which is not conducive to the miniaturization and high frequency of equipment.

[0019] In this regard, literature 1 (S. Han, Y. Wang, Y. Guan and D. Xu, "Analysis and Design of a Modular Switched Capacitor Converter With Adjustable Output Voltage in DC Microgrid," in IEEE Journal on Emerging and Selected Topics in Circuits and Systems, vol. 12, no. 1, pp. 232-241, March 2022.) and literature 2 (S. Han, Y. Wang, Z. Xie, Y. Guan, JM Alonso and D. Xu, "Continuously Adjustable Modular Bidirectional Switched-Capacitor DC–DC Converter," in IEEE Transactions on Power Electronics, vol. 37, no. 11, pp. 12944-12948, Nov. 2022.) proposed a two-stage cascaded non-isolated combined converter based on a three-port switched capacitor network. Figure 4As shown, the circuit consists of three parts: a three-port series switched capacitor network on the input side, an adjustable voltage Buck converter, and a resonant switched capacitor converter. The front-stage circuit uses a three-port series switched capacitor network to divide the input voltage into two series switched capacitors according to a certain proportion, one of which is used for a fixed step-down conversion through a resonant switched capacitor converter at the rear stage, while the other switched capacitor adjusts the output voltage through a rear-stage Buck converter. Therefore, the two-stage cascaded non-isolated combined converter based on the three-port switched capacitor network solves the problem of a small voltage regulation range of the traditional resonant switched capacitor converter. However, the three-port series switched capacitor network of the above-mentioned combined converter needs to use two large capacitors to provide a stable DC voltage support for the rear-stage buck circuit, and the switch tube of the rear-stage Buck converter is a hard switch. In addition, the power supply on the input side cannot supply power to the load while charging the front-stage switched capacitor, and the front-stage circuit can only supply power to the load during the discharge of the switched capacitor, which makes the power conversion efficiency of the front-stage three-port series switched capacitor network low and the output ripple large.

[0020] Since the front-stage three-port series switch capacitor network and the rear-stage Buck DC chopper circuit drive signal in the two-stage structure combination converter of References 1 and 2 must work synchronously, the voltage regulation range of the rear-stage Buck DC chopper circuit is limited. Figure 5 As shown, document 3 (S.Han, J.Tan, Y.Wang, Y.Guan and D.Xu, "Multifrequency Single-Stage Hybrid Switched-Capacitor Converter," in IEEETransactions on Power Electronics, vol.39, no.3, pp.3438-3451, March 2024.) is in Figure 4 Based on this, the positions of the back-stage Buck converter and the resonant switched capacitor converter are swapped, and an improved two-stage cascaded non-isolated combined converter based on a three-port switched capacitor network is proposed, such as Figure 5 As shown, the circuit also consists of three parts: a three-port series switched capacitor network on the input side, an adjustable voltage Buck converter, and a resonant switched capacitor converter. Figure 5In the converter shown, the working states of the front-stage three-port series switch capacitor network and the rear-stage Buck DC chopper circuit are independent of each other, which enables the rear-stage Buck DC chopper circuit to operate in a wider voltage regulation range. However, the switch tubes in the combined converter are hard switches, and the switching loss is large. The two-stage structure combined converter has the same problem as the reference 1 and reference 2, that is, the power supply on the input side cannot supply power to the load while charging the front-stage switch capacitor, and the front-stage circuit can only supply power to the load during the discharge of the switch capacitor, which makes the power conversion efficiency of the front-stage series switch capacitor network low and the output ripple large. Summary of the invention

[0021] The purpose of the present invention is to provide a non-isolated quasi-series-parallel combination converter based on a switched capacitor network, which gives full play to the advantages of high power density and high efficiency in the non-voltage regulation mode of the resonant switched capacitor converter, and topologically combines the resonant switched capacitor network with the DC-DC chopper converter through partial power processing technology. This combination not only has the advantages of high power density and high efficiency in the non-voltage regulation mode of the resonant switched capacitor network, but also integrates the advantages of the wide voltage regulation range of the DC-DC chopper converter. In addition, it also has the characteristic of small input series voltage stress. The present invention utilizes the time-sharing charging and discharging characteristics of the capacitor to realize the connection of the resonant switched capacitor network and the DC-DC chopper converter in series on the input side and in parallel on the output side, and achieves a higher total power conversion efficiency by adopting an output parallel structure to replace the traditional two-stage cascade mode. Compared with the isolation transformer primary-side series and secondary-side parallel structure, the non-isolated quasi-series-parallel structure of the present invention uses a capacitor to replace the isolation transformer, thereby improving the power density of the converter.

[0022] The objective of the present invention is achieved through the following technical solutions:

[0023] A non-isolated quasi-series-parallel combined converter based on a switched capacitor network includes a switched capacitor network, a non-isolated DC-DC converter, an output filter capacitor Co and a load resistor R, wherein:

[0024] The switched capacitor network consists of three switches Q A , Q B , Q D , a resonant tank, the resonant tank consists of a resonant inductor L r and resonant capacitor C r composition;

[0025] The switch tube Q A The drain of the external power supply V in Phase connected, switch tube Q A The source of the resonant capacitor C r One end and the switch tube Q B The drain of is connected;

[0026] The switch tube Q B The source of the output filter capacitor C o One end of the load resistor R and a non-isolated DC-DC converter are connected;

[0027] The resonant capacitor C r The other end of the resonant inductor L r One end of the resonant inductor L r The other end is connected to the switch tube Q D The drain of the non-isolated DC-DC converter is connected;

[0028] The switch tube Q D The source is grounded;

[0029] The output filter capacitor C o One end of the switch tube Q B The source of, one end of the load resistor R, and the non-isolated DC-DC chopper converter are connected, and the other end of the output filter capacitor Co is grounded;

[0030] One end of the load resistor R is connected to the switch tube Q B The source of the output filter capacitor C o One end of the load resistor R is connected to the non-isolated DC-DC chopper converter, and the other end of the load resistor R is grounded.

[0031] A non-isolated quasi-series-parallel combination converter based on n-unit switched capacitors includes the following four types of non-isolated quasi-series-parallel combination converters based on n-unit switched capacitors:

[0032] Class I non-isolated quasi-series-parallel combined converter based on n-unit switched capacitors: includes n switched capacitor units and a non-isolated quasi-series-parallel combined converter based on a switched capacitor network, wherein the n switched capacitor units are located between the power input and the non-isolated quasi-series-parallel combined converter based on a switched capacitor network, and each switched capacitor unit includes three switch tubes Q kA , Q kC and Q kD , a switched capacitor C fk or a resonant tank, the resonant tank consists of a resonant capacitor C rk and a resonant inductor L rk The switch capacitor units are composed of a series connection, k=1, 2, ..., n; two adjacent switch capacitor units use switch capacitor and resonant tank structures respectively, wherein: the switch capacitor unit connected to the power input side uses the resonant tank structure, and the switch capacitor unit connected to the non-isolated quasi-series-parallel combination converter based on the switch capacitor network uses the switch capacitor structure;

[0033] Class II non-isolated quasi-series-parallel combined converter based on n-unit switched capacitors: includes n switched capacitor units and a non-isolated quasi-series-parallel combined converter based on a switched capacitor network, wherein the n switched capacitor units are located between the power input and the non-isolated quasi-series-parallel combined converter based on a switched capacitor network, and each switched capacitor unit includes three switch tubes Q kA , Q kC and Q kD , a switched capacitor C fk or a resonant tank, the resonant tank consists of a resonant capacitor C rk and a resonant inductor L rk The switching capacitor units are connected in series, k=1, 2, ..., n; two adjacent switching capacitor units use switching capacitor and resonant tank structures respectively, wherein: the switching capacitor unit connected to the power input side and the switching capacitor unit connected to the non-isolated quasi-series-parallel combination converter based on the switching capacitor network both use the resonant tank structure; in the non-isolated quasi-series-parallel combination converter based on the switching capacitor network, the resonant tank is replaced by the switching capacitor C f ;

[0034] Class III non-isolated quasi-series-parallel combined converter based on n-unit switched capacitors: includes n switched capacitor units and a non-isolated quasi-series-parallel combined converter based on a switched capacitor network, wherein the n switched capacitor units are located between the non-isolated quasi-series-parallel combined converter based on a switched capacitor network and the output side load resistor, and each switched capacitor unit includes three switch tubes Q kB , Q kC and Q kD , a switched capacitor C fk or a resonant tank, the resonant tank consists of a resonant capacitor C rk and a resonant inductor L rk The series connection is composed of k=1, 2, ..., n; two adjacent switched capacitor units use two structures, switched capacitor and resonant tank, respectively, wherein: the switched capacitor unit connected to the non-isolated quasi-series-parallel combined converter based on the switched capacitor network uses the switched capacitor structure, and the switched capacitor unit connected to the load resistor uses the resonant tank structure;

[0035] Class IV non-isolated quasi-series-parallel combined converter based on n-unit switched capacitors: includes n switched capacitor units and a non-isolated quasi-series-parallel combined converter based on a switched capacitor network, wherein the n switched capacitor units are located between the non-isolated quasi-series-parallel combined converter based on a switched capacitor network and the output side load resistor, and each switched capacitor unit includes three switch tubes Q kB , Q kC and Q kD , a switched capacitor C fk or a resonant tank, the resonant tank consists of a resonant capacitor Crk and a resonant inductor L rk The switching capacitor units are connected in series, k=1, 2, ..., n; two adjacent switching capacitor units use two structures, namely, the switching capacitor unit connected to the non-isolated quasi-series-parallel combination converter based on the switching capacitor network and the switching capacitor unit connected to the load resistor both use the resonant tank structure; in the non-isolated quasi-series-parallel combination converter based on the switching capacitor network, the resonant tank is replaced by the switching capacitor C f .

[0036] Compared with the prior art, the present invention has the following advantages:

[0037] 1) The present invention utilizes the characteristics of the switched capacitor including two modes of charging and discharging in each switching cycle to realize the time-sharing series and parallel connection between the switched capacitor network and the DC-DC direct current chopper converter. That is, when the switched capacitor in the switched capacitor network is charged, the switched capacitor network is connected in series with the DC-DC direct current chopper converter on the input side; when the switched capacitor in the switched capacitor network is discharged, the switched capacitor network is connected in parallel with the DC-DC direct current chopper converter on the output side.

[0038] 2) The present invention can reduce the voltage stress of the resonant switch capacitor network and the DC-DC chopper converter through the input side series connection mode.

[0039] 3) The present invention uses a switched capacitor network and a DC-DC chopper converter to connect in series on the input side, and uses a DC voltage source and a switched capacitor network to provide a stable input voltage for the DC-DC chopper converter. Therefore, no additional voltage stabilizing capacitor is required on the input side of the DC-DC chopper converter.

[0040] 4) The combined converter of the present invention utilizes the time-sharing series and parallel connection of the switch capacitor network and the DC-DC chopper converter to realize a single-stage combined circuit structure of quasi-series-parallel connection, which can reduce the volume of the converter and improve efficiency.

[0041] 5) When the switch capacitor in the three-port switch capacitor network of the present invention is working in the charging process, the switch capacitor and the load are connected in series, so that the power supply can supply power to the switch capacitor and the load at the same time. When the switch capacitor in the three-port switch capacitor network is working in the discharging process, the switch capacitor supplies power to the load. Compared with the circuit structure in which only the switch capacitor discharges to supply power to the load, the three-port switch capacitor network proposed by the present invention has high power conversion efficiency, less energy storage required by the capacitor, smaller required capacitance, and reduced ripple on the output side.

[0042] 6) The resonant switched capacitor network of the present invention operates in a non-voltage regulated DCX mode, realizes a fixed DC voltage transformation ratio, does not participate in voltage regulation, and enables the resonant switched capacitor network to operate at an efficient and optimal operating point.

[0043] 7) The present invention uses a DC-DC chopper converter to achieve wide-range voltage regulation of the combined converter, solving the problem of small voltage regulation range of the resonant switched capacitor converter. Since the DC-DC chopper converter only needs to process a small part of the power, the inductor stores less energy and a smaller inductor can be selected.

[0044] 8) The non-isolated quasi-series-parallel combination converter based on the switched capacitor network proposed in the present invention reuses the existing switch tubes of the three-port switched capacitor network, and only needs to add an additional filter inductor to form a Buck chopper circuit. Therefore, compared with the conventional input series output parallel combination converter, the non-isolated quasi-series-parallel combination converter based on the switched capacitor network proposed in the present invention has the advantage of fewer switch tubes under the condition of the same DC voltage ratio.

[0045] 9) Non-isolated DC-DC converters can use DC-DC chopper converters such as Buck converter and Zeta converter.

[0046] 10) The non-isolated quasi-series-parallel combination converter based on the switched capacitor network of the present invention can be combined with n switched capacitor units to obtain a multi-level circuit structure, thereby further reducing the voltage stress of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a series-parallel step-down resonant switched capacitor converter;

[0048] Figure 2 The switching capacitor charging mode diagram of the series-parallel buck resonant switching capacitor converter;

[0049] Figure 3 It is the switch capacitor discharge mode diagram of the series-parallel buck resonant switch capacitor converter;

[0050] Figure 4 It is a two-stage cascaded non-isolated combined converter based on a three-port switched capacitor network;

[0051] Figure 5 It is an improved two-stage cascaded non-isolated combined converter based on a three-port switched capacitor network;

[0052] Figure 6 It is a non-isolated quasi-series-parallel combination converter based on a switched capacitor network;

[0053] Figure 7 The switching capacitor charging mode diagram of the non-isolated quasi-series-parallel combination converter based on the switching capacitor network;

[0054] Figure 8The switching capacitor discharge mode diagram of the non-isolated quasi-series-parallel combination converter based on the switching capacitor network;

[0055] Fig. 9 It is a type I non-isolated quasi-series-parallel combination converter based on n-unit switched capacitors;

[0056] Fig.10 It is a type II non-isolated quasi-series-parallel combination converter based on n-unit switched capacitors;

[0057] Fig.11 It is a Class III non-isolated quasi-series-parallel combination converter based on n-unit switched capacitors;

[0058] Fig.12 It is a Class IV non-isolated quasi-series-parallel combination converter based on n-unit switched capacitors;

[0059] Fig.13 It is a Class I non-isolated quasi-series-parallel combination converter based on two units;

[0060] Fig.14 It is a Class II non-isolated quasi-series-parallel combination converter based on three units;

[0061] Fig.15 It is a Class III non-isolated quasi-series-parallel combination converter based on two units;

[0062] Fig.16 It is a Class IV non-isolated quasi-series-parallel combination converter based on 3 units. DETAILED DESCRIPTION

[0063] The technical solution of the present invention is further described below in conjunction with the accompanying drawings, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be included in the protection scope of the present invention.

[0064] The present invention will Figure 1 The resonant tank unit (switch tube Q B2 , Q C1 , Q C2 , Q D2 and resonant inductor L r2 , resonant capacitor C r2 ) is replaced by a DC-DC chopper converter, and we get Figure 6 The non-isolated quasi-series-parallel combined converter based on the switched capacitor network is shown in FIG. Figure 6 As shown, the non-isolated quasi-series-parallel combined converter includes a switch capacitor network, a non-isolated DC-DC converter, an output filter capacitor C o and load resistor R, the input of the switched capacitor network is connected to the external power supply V in, one of the output terminals is connected to a load R, and the other output terminal is connected to a DC-DC chopper converter. The switch capacitor network includes three switch tubes Q A , Q B , Q D , a resonant tank, the resonant tank consists of a resonant inductor L r and resonant capacitor C r Composition: The switch tube Q A The drain of the external power supply V in Phase connected, switch tube Q A The source of the resonant capacitor C r One end and the switch tube Q B The drain of the switch tube Q B The source of the output filter capacitor C o One end of the resonant capacitor C is connected to one end of the load resistor R and a non-isolated DC-DC converter; r The other end of the resonant inductor L r One end of the resonant inductor L r The other end is connected to the switch tube Q D The drain of the switch tube Q is connected to the non-isolated DC-DC converter; D The source of the output filter capacitor C o One end of the switch tube Q B The source of the load resistor R is connected to one end of the non-isolated DC-DC chopper converter, and the other end of the output filter capacitor Co is grounded; one end of the load resistor R is connected to the switch tube Q B The source of the output filter capacitor C o One end of the load resistor R is connected to the non-isolated DC-DC chopper converter, and the other end of the load resistor R is grounded. Figure 6 The non-isolated quasi-series-parallel combined converter shown is a single-stage structure. By coordinating the charging and discharging process of the switched capacitor network with the chopping phase of the non-isolated DC-DC converter, no additional voltage stabilizing capacitor is required between the two circuits.

[0065] The resonant capacitor C in the switched capacitor network r It is divided into two working modes: charging and discharging, where:

[0066] like Figure 7 As shown, when the power is supplied to the resonant capacitor C r While charging, the power supply supplies power to the load resistor R through the DC-DC chopper converter, and then there are voltage equations and current equations:

[0067] V in =V Cr +V b (7)

[0068] I in =I charge (8)

[0069] Where V Cr is the resonant capacitor C r Voltage Cr The average value, V b I is the DC input voltage of the DC-DC chopper converter. in is the average value of the combined converter input current, I charge is the resonant capacitor C r The average value of the charging current.

[0070] At the same time, through the DC-DC chopper converter, the output voltage of the combined converter can be adjusted over a wide range, and the voltage equation and current equation are:

[0071] V o =M(D)V b (9)

[0072]

[0073] Where M(D) is the voltage gain function of the DC-DC chopper converter, D is the duty cycle of the chopper, and I reg is the average value of the output current of the DC-DC chopper converter.

[0074] like Figure 8 As shown, the resonant capacitor C r Including a complete discharge process, the resonant capacitor C r When the load resistor R is powered together with the DC-DC chopper converter, the voltage equation and current equation are:

[0075] V Cr =V o (11)

[0076] I o =I discharge +I reg (12)

[0077] In the formula, I o is the output current i of the combined converter o The average value of I discharge is the resonant capacitor C r The average value of the discharge current.

[0078] When the converter enters steady-state operation, the ampere-second balance principle of the capacitor shows that: Figure 7 and Figure 8 The average value of the charging and discharging current of the resonant capacitor Cr is equal, that is:

[0079] Iin =I charge =I discharge (13)

[0080] Will Figure 6 The non-isolated quasi-series-parallel combination converter based on the switched capacitor network shown in FIG. 1 is combined with n switched capacitor units to obtain the following Figures 9 to 12 Four types of non-isolated quasi-series-parallel combination converters based on n-unit switched capacitors are shown.

[0081] Fig. 9 It is a type I non-isolated quasi-series-parallel combination converter based on n-unit switched capacitors. r and C r1 is the resonant capacitor, L r and L r1 is the resonant inductor, C fn The converter circuit is characterized by: 1) n switched capacitor units are located between the power input and the non-isolated quasi-series-parallel combined converter based on the switched capacitor network; 2) each switched capacitor unit contains three switch tubes Q kA , Q kC and Q kD , (k=1,2,…,n); 3) Each switched capacitor unit contains a switched capacitor C fk or a resonant tank, the resonant tank consists of a resonant capacitor C rk and a resonant inductor L rk Series composition, (k=1,2,…,n); 4) two adjacent switched capacitor units use switched capacitor and resonant tank structures respectively. The switched capacitor unit connected to the power input side uses the resonant tank structure, and the switched capacitor unit connected to the non-isolated quasi-series-parallel combination converter based on the switched capacitor network uses the switched capacitor structure.

[0082] Fig.10 It is a type II non-isolated quasi-series-parallel combination converter based on n-unit switched capacitors. r1 and C rn is the resonant capacitor, L r1 and L rn is the resonant inductor, C f The converter circuit is characterized by: 1) n switched capacitor units are located between the power input and the non-isolated quasi-series-parallel combined converter based on the switched capacitor network; 2) each switched capacitor unit contains three switch tubes Q kA , Q kC and Q kD , (k=1,2,…,n); 3) Each switched capacitor unit contains a switched capacitor C fk or a resonant tank, the resonant tank consists of a resonant capacitor C rkand resonant inductor L rk 4) Two adjacent switched capacitor units use switched capacitor and resonant tank structures respectively. The switched capacitor unit connected to the power input side and the switched capacitor unit connected to the non-isolated quasi-series-parallel combined converter based on the switched capacitor network both use the resonant tank structure; 5) In the non-isolated quasi-series-parallel combined converter based on the switched capacitor network, a switched capacitor C is used. f Replace the LC tank.

[0083] Fig.11 It is a Class III non-isolated quasi-series-parallel combination converter based on n-unit switched capacitors. f1 is the switching capacitor, C r and C rn is the resonant capacitor, L r and L rn The converter circuit is characterized by: 1) n switching capacitor units are located between the non-isolated quasi-series-parallel combination converter based on the switching capacitor network and the output side load resistor; 2) each switching capacitor unit contains three switching tubes Q kB , Q kC and Q kD , (k=1,2,…,n); 3) Each switched capacitor unit contains a switched capacitor C fk or a resonant tank, the resonant tank consists of a resonant capacitor C rk and resonant inductor L rk Series composition, (k = 1, 2, ..., n); 4) two adjacent switched capacitor units use switched capacitor and resonant tank structures respectively. The switched capacitor unit connected to the non-isolated quasi-series-parallel combination converter based on the switched capacitor network uses a switched capacitor structure, and the switched capacitor unit connected to the load resistor uses a resonant tank structure.

[0084] Fig.12 It is a Class IV non-isolated quasi-series-parallel combination converter based on n-unit switched capacitors. f is the switching capacitor, C r1 and C rn is the resonant capacitor, L r1 and L rn The converter circuit is characterized by: 1) n switching capacitor units are located between the non-isolated quasi-series-parallel combination converter based on the switching capacitor network and the output side load resistor; 2) each switching capacitor unit contains three switching tubes Q kB , Q kC and Q kD , (k=1,2,…,n); 3) Each switched capacitor unit contains a switched capacitor C fk or a resonant tank, the resonant tank consists of a resonant capacitor Crk and resonant inductor L rk 4) Two adjacent switched capacitor units use switched capacitor and resonant tank structures respectively. The switched capacitor unit connected to the non-isolated quasi-series-parallel combined converter based on the switched capacitor network and the switched capacitor unit connected to the load resistor both use the resonant tank structure. 5) In the non-isolated quasi-series-parallel combined converter based on the switched capacitor network, a switched capacitor C is used. f Replace the LC tank.

[0085] Example:

[0086] Taking the Buck chopper circuit as an example, implementation Figures 9 to 12 The non-isolated DC-DC converter in Figure 13 to Figure 16 The four types of non-isolated quasi-series-parallel combined converters based on n-unit switched capacitors are shown. The characteristics of the converter circuit are: only one filter inductor L is required. m By reusing the existing switch tubes in the three-port switch capacitor network, a Buck chopper circuit can be constructed.

[0087] Fig.13 This is a Class I non-isolated quasi-series-parallel combination converter based on two-unit switched capacitors. r1 and C r3 is the resonant capacitor, L r1 and L r3 is the resonant inductor, C f2 is the switching capacitor, L m The three-port switch capacitor network and the Buck chopper circuit reuse the switch tube Q 3D .

[0088] Fig.14 This is a Class II non-isolated quasi-series-parallel combination converter based on three-unit switched capacitors. r1 and C r3 is the resonant capacitor, L r1 and L r3 is the resonant inductor, C f2 and C f4 is the switching capacitor, L m The three-port switch capacitor network and the Buck chopper circuit reuse the switch tube Q 4D .

[0089] Fig.15 This is a Class III non-isolated quasi-series-parallel combination converter based on two-unit switched capacitors. r1 and C r3 is the resonant capacitor, L r1 and L r3 is the resonant inductor, Cf2 is the switching capacitor, L m The three-port switch capacitor network and the Buck chopper circuit reuse the switch tube Q 1D .

[0090] Fig.16 This is a Class IV non-isolated quasi-series-parallel combination converter based on 3-unit switched capacitors. r2 and C r4 is the resonant capacitor, L r2 and L r4 is the resonant inductor, C f1 and C f3 is the switching capacitor, L m The three-port switch capacitor network and the Buck chopper circuit reuse the switch tube Q 1D .

Claims

1. A non-isolated quasi-series-parallel combination converter based on a switched capacitor network, characterized in that The converter includes a switched capacitor network, a non-isolated DC-DC converter, an output filter capacitor Co and a load resistor R, wherein: The switched capacitor network consists of three switches Q A , Q B , Q D , a resonant tank, the resonant tank consists of a resonant inductor L r and resonant capacitor C r composition; The switch tube Q A The drain of the external power supply V in Phase connected, switch tube Q A The source of the resonant capacitor C r One end and the switch tube Q B The drain of is connected; The switch tube Q B The source of the output filter capacitor C o One end of the load resistor R and a non-isolated DC-DC converter are connected; The resonant capacitor C r The other end of the resonant inductor L r One end of the resonant inductor L r The other end is connected to the switch tube Q D The drain of the non-isolated DC-DC converter is connected; The switch tube Q D The source is grounded; The output filter capacitor C o One end of the switch tube Q B The source of, one end of the load resistor R, and the non-isolated DC-DC chopper converter are connected, and the other end of the output filter capacitor Co is grounded; One end of the load resistor R is connected to the switch tube Q B The source of the output filter capacitor C o One end of the load resistor R is connected to the non-isolated DC-DC chopper converter, and the other end of the load resistor R is grounded.

2. The non-isolated quasi-series-parallel combined converter based on a switched capacitor network according to claim 1, characterized in that The resonant capacitor C r It is divided into two working modes: charging and discharging, where: When the power supply is given to the resonant capacitor C r While charging, the power supply supplies power to the load resistor R through the DC-DC chopper converter, and then there are voltage equations and current equations: V in =V Cr +V b I in =I charge Where V Cr is the resonant capacitor C r Voltage Cr The average value, V b I is the DC input voltage of the DC-DC chopper converter. in is the average value of the combined converter input current, I charge is the average value of the charging current of the resonant capacitor Cr; At the same time, through the DC-DC chopper converter, the output voltage of the combined converter can be adjusted over a wide range, and the voltage equation and current equation are: In o =M(D)V b Where M(D) is the voltage gain function of the DC-DC chopper converter, D is the duty cycle of the chopper, and I reg is the average value of the output current of the DC-DC chopper converter; Resonant capacitor C r Including a complete discharge process, the resonant capacitor C r When the load resistor R is powered together with the DC-DC chopper converter, the voltage equation and current equation are: V Cr =V o I o =I discharge +I reg In the formula, I o is the output current i of the combined converter o The average value of I discharge is the resonant capacitor C r The average value of the discharge current; When the converter enters steady-state operation, according to the ampere-second balance principle of the capacitor, the average value of the charging and discharging current of the resonant capacitor Cr is equal, that is: I in =I charge =I discharge 。 3. A non-isolated quasi-series-parallel combination converter based on n-unit switched capacitors, characterized in that The converter comprises n switching capacitor units and the non-isolated quasi-series-parallel combination converter based on the switching capacitor network according to any one of claims 1-2, wherein the n switching capacitor units are located between the power input and the non-isolated quasi-series-parallel combination converter based on the switching capacitor network, and each switching capacitor unit comprises three switching tubes Q kA , Q kC and Q kD , a switched capacitor C fk or a resonant tank, the resonant tank consists of a resonant capacitor C rk and a resonant inductor L rk The switch capacitor units are connected in series, k=1, 2, ..., n; two adjacent switch capacitor units use switch capacitor and resonant tank structures respectively, wherein: the switch capacitor unit connected to the power input side uses the resonant tank structure, and the switch capacitor unit connected to the non-isolated quasi-series-parallel combination converter based on the switch capacitor network uses the switch capacitor structure.

4. A non-isolated quasi-series-parallel combination converter based on n-unit switched capacitors, characterized in that The converter comprises n switching capacitor units and the non-isolated quasi-series-parallel combination converter based on the switching capacitor network according to any one of claims 1-2, wherein the n switching capacitor units are located between the power input and the non-isolated quasi-series-parallel combination converter based on the switching capacitor network, and each switching capacitor unit comprises three switching tubes Q kA , Q kC and Q kD , a switched capacitor C fk or a resonant tank, the resonant tank consists of a resonant capacitor C rk and a resonant inductor L rk The switching capacitor units are connected in series, k=1, 2, ..., n; two adjacent switching capacitor units use switching capacitor and resonant tank structures respectively, wherein: the switching capacitor unit connected to the power input side and the switching capacitor unit connected to the non-isolated quasi-series-parallel combination converter based on the switching capacitor network both use the resonant tank structure; in the non-isolated quasi-series-parallel combination converter based on the switching capacitor network, the resonant tank is replaced by the switching capacitor C f .

5. A non-isolated quasi-series-parallel combination converter based on n-unit switched capacitors, characterized in that The converter comprises n switching capacitor units and the non-isolated quasi-series-parallel combination converter based on the switching capacitor network according to any one of claims 1-2, wherein the n switching capacitor units are located between the non-isolated quasi-series-parallel combination converter based on the switching capacitor network and the output side load resistor, and each switching capacitor unit comprises three switching tubes Q kB , Q kC and Q kD , a switched capacitor C fk or a resonant tank, the resonant tank consists of a resonant capacitor C rk and a resonant inductor L rk The switch capacitor units are connected in series, k=1, 2, ..., n; two adjacent switch capacitor units use switch capacitor and resonant tank structures respectively, wherein: the switch capacitor unit connected to the non-isolated quasi-series-parallel combination converter based on the switch capacitor network uses a switch capacitor structure, and the switch capacitor unit connected to the load resistor uses a resonant tank structure.

6. A non-isolated quasi-series-parallel combination converter based on n-unit switched capacitors, characterized in that The converter comprises n switching capacitor units and the non-isolated quasi-series-parallel combination converter based on the switching capacitor network according to any one of claims 1-2, wherein the n switching capacitor units are located between the non-isolated quasi-series-parallel combination converter based on the switching capacitor network and the output side load resistor, and each switching capacitor unit comprises three switching tubes Q kB , Q kC and Q kD , a switched capacitor C fk or a resonant tank, the resonant tank consists of a resonant capacitor C rk and a resonant inductor L rk The switching capacitor units are connected in series, k=1, 2, ..., n; two adjacent switching capacitor units use two structures, namely, the switching capacitor unit connected to the non-isolated quasi-series-parallel combination converter based on the switching capacitor network and the switching capacitor unit connected to the load resistor both use the resonant tank structure; in the non-isolated quasi-series-parallel combination converter based on the switching capacitor network, the resonant tank is replaced by the switching capacitor C f .

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