A multi-port converter and a control method thereof

Abstract

The application relates to the technical field of converters, in particular to a multi-port converter and a control method thereof. The multi-port converter comprises a direct-current power supply, an auxiliary battery pack, a first inductor, a transformer, a switch tube, a first diode, a third diode, a fourth diode and an output module. The transformer comprises a primary winding and a secondary winding. The output module comprises a second capacitor and a load. The switch tube comprises a first switch tube, a third switch tube and a fourth switch tube. The multi-port converter provided by the application can realize multiple transformation ratios with a small number of switch devices.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of converters, and particularly relates to a multi-port converter and a control method thereof. BACKGROUND

[0002] In the existing direct-current power distribution system, if a new energy power generation system such as a wind power generation system or a photovoltaic power generation system and an energy storage unit need to be connected, in order to effectively combine the power generation equipment with various types of equipment in the direct-current power distribution system, a plurality of direct-current converters are usually needed to achieve the purpose. The use of a multi-port converter can replace the original plurality of discrete direct-current converters, effectively reduce the volume and weight of the power generation system, improve the power integration degree of the system, and is low in cost. At present, multi-port converters can be divided into multi-input single-output, single-input multi-output, hybrid and bidirectional types according to the different directions of power flow of the ports, and can be divided into three-port converters, four-port converters and the like according to the different numbers of the ports.

[0003] The existing multi-port converters are mostly arrayed, and each port needs a specific architecture of a switch tube circuit or a bridge control circuit, so that the number of switch devices of the multi-port converter is large. The common unidirectional or bidirectional multi-port converter is mostly arrayed, and each port needs a full-bridge or half-bridge control circuit, so that each port needs to be configured with a plurality of switch devices (at least four for a full-bridge and at least two for a half-bridge), and the more the ports are, the more the switch devices of the converter are, resulting in large energy consumption and low efficiency of the converter. SUMMARY

[0004] The present application provides a multi-port converter and a control method thereof to solve the problem of too many switch devices in the existing multi-port converter.

[0005] According to a first aspect of the present application, a multi-port converter is provided, comprising a direct-current power supply, an auxiliary battery pack, a first inductor, a transformer, a switch tube, a first diode, a third diode, a fourth diode and an output module.

[0006] The transformer comprises a primary winding and a secondary winding.

[0007] The output module comprises a second capacitor and a load.

[0008] The switch tube comprises a first switch tube, a third switch tube and a fourth switch tube.

[0009] The positive electrode of the direct-current power supply is connected with the first end of the third switch tube, the negative electrode of the third diode and the first end of the primary winding.

[0010] The negative electrode of the first diode is connected with the second end of the third switch tube, and the negative electrode of the fourth diode is connected with the positive electrode of the third diode.

[0011] The first end of the first inductor is connected with the second end of the third switch tube, and the second end of the first inductor is connected with the positive pole of the auxiliary battery group;

[0012] The first end of the first capacitor is connected with the second end of the primary winding, and the second end of the first capacitor is connected with the positive pole of the third diode;

[0013] The first end of the first switch tube is connected with the second end of the primary winding, and the second end of the first switch tube is connected with the first end of the secondary winding and the first end of the fourth switch tube;

[0014] The first end of the second capacitor is connected with the second end of the secondary winding, and the load is connected in parallel to the two ends of the second capacitor;

[0015] The negative pole of the direct current power supply, the negative pole of the first diode, the negative pole of the fourth diode, the negative pole of the auxiliary battery group, the second end of the fourth switch tube and the second end of the second capacitor are connected with each other.

[0016] Optionally, the switch tube further comprises a second switch tube, the first end of the second switch tube is connected with the positive pole of the auxiliary battery group, the second end of the second switch tube is connected with the positive pole of the second diode, and the negative pole of the second diode is connected with the first end of the fourth switch tube.

[0017] Optionally, the transformer further comprises an excitation inductor and a leakage inductor, the excitation inductor is connected in parallel to the two ends of the primary winding, the first end of the leakage inductor is connected with the second end of the primary winding, and the second end of the leakage inductor is connected with the first end of the first switch tube.

[0018] Optionally, the switch tube is a field effect tube, the first end of the switch tube is the drain electrode of the field effect tube, the second end of the switch tube is the source electrode of the field effect tube, and the third end of the switch tube is the gate electrode of the field effect tube.

[0019] According to the second aspect of the present application, a control method of a multi-port converter is provided, comprising the following steps:

[0020] The first control signal I, the third control signal I and the fourth control signal I are generated, the first control signal I controls the on-off of the first switch tube, the third control signal I controls the on-off of the third switch tube, the fourth control signal I is transmitted to the gate electrode of the fourth switch tube, and the multi-port converter has the following five working modes in a cycle:

[0021] The first working mode I: the first switch tube is off, the third switch tube is on, and the fourth switch tube is on; the direct current power supply charges the first inductor, the current of the first inductor starts to linearly rise, the energy of the excitation inductor is transmitted to the secondary winding and charges the second capacitor, and the current flowing through the excitation inductor starts to drop;

[0022] The second working mode I: the first switch tube is turned on, the third switch tube is turned off, and the fourth switch tube is turned off; the first inductor releases energy to the auxiliary battery set through the first diode; the current flowing through the first inductor starts to linearly decrease; the direct current power supply charges the exciting inductor and the leakage inductor; the current of the exciting inductor and the current of the leakage inductor linearly increase respectively; the first capacitor releases energy until the current of the fourth diode decreases to 0;

[0023] The third working mode I: the first switch tube is turned on, the third switch tube is turned off, and the fourth switch tube is turned off; the first inductor continues to release energy to the auxiliary battery set through the first diode; the current of the first inductor linearly decreases; the direct current power supply continues to charge the exciting inductor and the leakage inductor; the current of the exciting inductor and the current of the leakage inductor linearly increase respectively;

[0024] The fourth working mode I: the first switch tube is turned off, the third switch tube is turned off, and the fourth switch tube is turned on; the first inductor continues to release energy to the auxiliary battery set through the first diode; the current of the first inductor linearly decreases; the energy stored in the leakage inductor is transmitted to the first capacitor until the energy stored in the leakage inductor is completely released; the energy stored in the exciting inductor is transmitted to the secondary winding and charges the second capacitor; the current of the exciting inductor starts to linearly decrease;

[0025] The fifth working mode I: the first switch tube is turned off, the third switch tube is turned off, and the fourth switch tube is turned on; the first inductor continues to release energy to the auxiliary battery set through the first diode; the current of the first inductor linearly decreases; the energy stored in the exciting inductor is transmitted to the secondary winding and charges the second capacitor; the current of the exciting inductor linearly decreases.

[0026] According to a third aspect of the present application, a control method of a multi-port converter is provided, comprising the following steps:

[0027] The first control signal II, the second control signal II and the fourth control signal II are generated; the first control signal II controls the on-off of the first switch tube, the second control signal II controls the on-off of the second switch tube, and the fourth control signal II is transmitted to the gate of the fourth switch tube and makes the multi-port converter have the following five working modes in turn in a period:

[0028] The first working mode II: the first switch tube is turned on, the second switch tube is turned on, and the fourth switch tube is turned off; the direct current power supply charges the exciting inductor and the leakage inductor; the current of the exciting inductor and the current of the leakage inductor linearly increase; the first capacitor releases energy until the current of the fourth diode decreases to 0;

[0029] The second working mode II: the first switch tube is turned on, the second switch tube is turned on, and the fourth switch tube is turned off; the direct current power supply continues to charge the exciting inductor and the leakage inductor; the current of the exciting inductor and the current of the leakage inductor linearly increase;

[0030] The third working mode II: the first switch tube is off, the second switch tube is on, the fourth switch tube is off, the auxiliary battery set transmits energy to the primary winding through the secondary winding, and charges the excitation inductor, the current of the excitation inductor continues to linearly rise, the energy of the leakage inductor is transmitted to the first capacitor until the energy of the leakage inductor is completely released;

[0031] The fourth working mode II: the first switch tube is off, the second switch tube is on, the fourth switch tube is off, the auxiliary battery set transmits energy to the primary winding through the secondary winding, and charges the excitation inductor, the current of the excitation inductor continues to linearly rise;

[0032] The fifth working mode II: the first switch tube is off, the second switch tube is off, the fourth switch tube is on, the energy of the excitation inductor is transmitted to the secondary winding, and charges the second capacitor, and the current of the excitation inductor linearly decreases.

[0033] According to the fourth aspect of the present application, a control method of a multi-port converter is provided, comprising the following steps:

[0034] The first control signal III and the fourth control signal III are generated; the first control signal III controls the on-off of the first switch tube, and the fourth control signal III is transmitted to the gate of the fourth switch tube, and makes the multi-port converter have the following four working modes in a cycle:

[0035] The first working mode III: the first switch tube is on, and the fourth switch tube is off; the DC power source charges the excitation inductor and the leakage inductor at the same time, the current of the excitation inductor and the current of the leakage inductor linearly rise respectively, the first capacitor releases energy until the current of the fourth diode decreases to 0;

[0036] The second working mode III: the first switch tube is on, and the fourth switch tube is off; the DC power source charges the excitation inductor and the leakage inductor at the same time, the current of the excitation inductor and the current of the leakage inductor linearly rise respectively;

[0037] The third working mode III: the first switch tube is off, and the fourth switch tube is on; the energy of the leakage inductor is transmitted to the first capacitor, the energy of the excitation inductor is transmitted to the secondary winding, and charges the second capacitor until the current of the leakage inductor decreases to 0;

[0038] The fourth working mode III: the first switch tube is off, and the fourth switch tube is on, the energy of the leakage inductor is completely released, and the energy of the excitation inductor is transmitted to the secondary winding and continues to charge the second capacitor.

[0039] According to the fifth aspect of the present application, a control method of a multi-port converter is provided, comprising the following steps:

[0040] The second control signal IV is generated and controls the on-off of the second switch tube, and the fourth control signal IV is transmitted to the gate of the fourth switch tube and makes the multi-port converter have the following two working modes in a cycle:

[0041] The first working mode IV: the second switch tube is turned on, the fourth switch tube is turned off, the auxiliary battery pack transmits energy to the primary winding through the secondary winding and charges the excitation inductor, and the current of the excitation inductor linearly rises;

[0042] The second working mode IV: the second switch tube is turned off, the fourth switch tube is turned on, the energy of the excitation inductor is transmitted to the secondary winding and charges the second capacitor.

[0043] According to the sixth aspect of the present application, a control method of a multi-port converter is provided, characterized by comprising the following steps:

[0044] The third control signal V is generated, the third control signal V controls the on-off of the third switch tube, and the multi-port converter has the following two working modes in a cycle:

[0045] The first working mode V: the third switch tube is turned on, the direct current power supply provides energy for the first inductor and the auxiliary battery pack respectively, and the current of the first inductor linearly rises;

[0046] The second working mode V: the third switch tube is turned off, the first inductor releases energy for the auxiliary battery pack through the first diode, and the current of the first inductor linearly decreases.

[0047] Beneficial effects:

[0048] The multi-port converter provided by the present application has the advantages that each switch tube cooperates with each other, instead of the traditional array configuration in which each port needs to be independently configured with multiple switch devices, so that the number of switch devices of the multi-port converter provided by the present application can be effectively reduced; the multi-port converter has multiple working modes and can realize multiple conversion ratios, and the control is simple.

[0049] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0050] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0051] Figure 1A topological structure diagram of a multi-port converter provided by the embodiment is shown.

[0052] Figure 2 A control strategy diagram of five working modes of a multi-port converter provided by the embodiment is shown.

[0053] Figure 3 A working diagram of a first working mode I of a SIDO mode of a multi-port converter provided by the embodiment is shown.

[0054] Figure 4 A working diagram of a second working mode I of a SIDO mode of a multi-port converter provided by the embodiment is shown.

[0055] Figure 5 A working diagram of a third working mode I of a SIDO mode of a multi-port converter provided by the embodiment is shown.

[0056] Figure 6 A working diagram of a fourth working mode I of a SIDO mode of a multi-port converter provided by the embodiment is shown.

[0057] Figure 7 A working diagram of a fifth working mode I of a SIDO mode of a multi-port converter provided by the embodiment is shown.

[0058] Figure 8 A working diagram of a first working mode II of a DISO mode of a multi-port converter provided by the embodiment is shown.

[0059] Figure 9 A working diagram of a second working mode II of a DISO mode of a multi-port converter provided by the embodiment is shown.

[0060] Figure 10 A working diagram of a third working mode II of a DISO mode of a multi-port converter provided by the embodiment is shown.

[0061] Figure 11 A working diagram of a fourth working mode II of a DISO mode of a multi-port converter provided by the embodiment is shown.

[0062] Figure 12 A working diagram of a fifth working mode II of a DISO mode of a multi-port converter provided by the embodiment is shown.

[0063] Figure 13 A working diagram of a first working mode III of a SISO-I mode of a multi-port converter provided by the embodiment is shown.

[0064] Figure 14 Fig. 3 shows a working schematic diagram of the second working mode III of the SISO-I mode of the multi-port converter provided by the embodiment.

[0065] Figure 15 Fig. 4 shows a working schematic diagram of the third working mode III of the SISO-I mode of the multi-port converter provided by the embodiment.

[0066] Figure 16 Fig. 5 shows a working schematic diagram of the fourth working mode III of the SISO-I mode of the multi-port converter provided by the embodiment.

[0067] Figure 17 Fig. 6 shows a working schematic diagram of the first working mode IV of the SISO-II mode of the multi-port converter provided by the embodiment.

[0068] Figure 18 Fig. 7 shows a working schematic diagram of the second working mode IV of the SISO-II mode of the multi-port converter provided by the embodiment.

[0069] Figure 19 Fig. 8 shows a working schematic diagram of the first working mode V of the SISO-III mode of the multi-port converter provided by the embodiment.

[0070] Figure 20 Fig. 9 shows a working schematic diagram of the second working mode V of the SISO-III mode of the multi-port converter provided by the embodiment.

[0071] Figure 21 Fig. 10 shows a working waveform diagram of the main devices in one working cycle of the SIDO mode of the multi-port converter provided by the embodiment.

[0072] Figure 22 Fig. 11 shows a working waveform diagram of the main devices in one working cycle of the DISO mode of the multi-port converter provided by the embodiment.

[0073] Figure 23 Fig. 12 shows a working waveform diagram of the main devices in one working cycle of the SISO-I mode of the multi-port converter provided by the embodiment.

[0074] Figure 24 Fig. 13 shows a working waveform diagram of the main devices in one working cycle of the SISO-II mode of the multi-port converter provided by the embodiment.

[0075] Figure 25 Fig. 14 shows a working waveform diagram of the main devices in one working cycle of the SISO-III mode of the multi-port converter provided by the embodiment.

[0076] Reference signs:

[0077] V in DC power supply; V b auxiliary battery pack;

[0078] D 1 first diode; D 2 second diode; D 3 third diode; D 4 fourth diode;

[0079] S 1 first switch; S 2 second switch; S 3 third switch; S 4 fourth switch;

[0080] L p primary winding; L s secondary winding; L m excitation inductance; L 1k leakage inductance;

[0081] L 1 first inductor;

[0082] C s first capacitor; C o second capacitor;

[0083] R load. DETAILED DESCRIPTION

[0084] The exemplary embodiments will be described in detail herein with reference to the attached drawings. The following description is made with reference to the accompanying drawings in which like reference numerals refer to like elements throughout. The following description is made with reference to the accompanying drawings in which like reference numerals refer to like elements throughout. The embodiments described in the following exemplary embodiments are not meant to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with some aspects of the present application as detailed in the appended claims.

[0085] Example 1

[0086] AsFigure 1 As shown in the figure, the multi-port converter provided by the embodiment of the present application comprises a DC power supply V in , an auxiliary battery pack V b , a first inductor L 1 , a transformer, a switch tube S 1 , S 2 , S 3 , S 4 , a diode D 1 , D 2 , D 3 , D 4 and an output module; the output module comprises a second capacitor C o and a load R ; the transformer comprises a primary winding L p , a secondary winding L s , an excitation inductor L m and a leakage inductor L 1k .

[0087] The positive pole of the DC power supply V in is connected with the first end of the third switch tube S 3 , the negative pole of the third diode D 3 , the first end of the primary winding L p ; the negative pole of the first diode D 1 is connected with the second end of the third switch tube S 3 , the negative pole of the fourth diode D 4 is connected with the positive pole of the third diode D 3 ; the first end of the first inductor L 1 is connected with the second end of the third switch tube S 3 , the second end of the first inductor L 1 is connected with the auxiliary battery pack V bthe positive electrode of the second diode is connected with the positive electrode of the first capacitor.

[0088] the primary winding L p the second end of the leakage inductor L 1k the first end of the excitation inductor is connected with the two ends of the primary winding L m the first capacitor is connected in parallel with the primary winding L p the positive electrode of the first capacitor is connected with the positive electrode of the third diode C s the negative electrode of the first capacitor is connected with the positive electrode of the second diode C s the negative electrode of the first capacitor is connected with the positive electrode of the second diode D 3 the positive electrode of the second diode is connected with the second end of the leakage inductor C s the positive electrode of the first capacitor is connected with the second end of the leakage inductor L 1k the first end of the leakage inductor is connected with the second end of the first switch tube L 1k the second end of the first switch tube is connected with the first end of the primary winding. S 1 the first end of the primary winding is connected with the first end of the second switch tube

[0089] the positive electrode of the auxiliary battery is connected with the first end of the second switch tube V b the second end of the second switch tube is connected with the positive electrode of the second diode S 2 the second end of the second diode is connected with the first end of the first switch tube S 2 the positive electrode of the second diode is connected with the second end of the first switch tube D 2 the negative electrode of the first switch tube is connected with the second end of the fourth switch tube D 2 the first end of the fourth switch tube is connected with the first end of the primary winding. S 1 the negative electrode of the first diode is connected with the second end of the first switch tube S 4 the first end of the fourth switch tube is connected with the first end of the primary winding.

[0090] the negative electrode of the first diode is connected with the negative electrode of the fourth diode D 1 the negative electrode of the fourth diode is connected with the negative electrode of the auxiliary battery D 4 the negative electrode of the auxiliary battery is connected with the negative electrode of the fourth switch tube V b the second end of the fourth switch tube is connected with the negative electrode of the DC power supply S 4 the negative electrode of the DC power supply is connected with the negative electrode of the auxiliary battery V in the negative electrode of the DC power supply is connected with the negative electrode of the auxiliary battery

[0091] the first end of the secondary winding is connected with the first end of the primary winding L s the second end of the secondary winding is connected with the second end of the primary winding S 1the second end of the secondary winding L s the second end of the second capacitor C o the first end of the second capacitor C o the second end of the direct current power supply V in the negative pole of the direct current power supply; the load R is connected in parallel to the second capacitor C o both ends.

[0092] the first end of the primary winding L p the first end of the secondary winding L s the first end of the field effect tube S 1 , S 2 , S 3 , S 4 the switch tube S 1 , S 2 , S 3 , S 4 the first end of the field effect tube S 1 , S 2 , S 3 , S 4 the second end of the field effect tube S 1 , S 2 , S 3 , S 4 the third end of the field effect tube.

[0093] The multi-port converter provided in this embodiment has five operating modes, specifically SIDO (single-input double-output), DISO (double-input single-output), and SISO (single-input single-output). There are three SISO modes: SISO-I, SISO-II, and SISO-III. (DC power supply) V in The input power at both ends is P in Auxiliary battery pack V b The power at both ends is P b ,load R The output power at both ends is P o The control strategy for five operating modes, namely the power flow relationship corresponding to each operating mode and the main control switch reference. Figure 2 As shown.

[0094] In SIDO mode, the first switching transistor S 1 and the third switching transistor S 3 Main control switch, fourth switch tube S 4 With the first switching transistor S 1 Passive switching; first switching transistor S 1 When turned on, the fourth switching transistor S 4 Cut-off; First switching transistor S 1 At cutoff, the fourth switch transistor S 4 On; second switching transistor S 2 Not involved in the operation of this model.

[0095] In SIDO mode, the power flow relationship is as follows: The SIDO mode includes the following five working modes sequentially within a single work cycle:

[0096] refer to Figure 3 As shown, the first operating mode I: the first switching transistor S 1 Turn off, third switch tube S 3 On, fourth switching transistor S 4Conducting; DC power supply V in Charging the first inductor L 1 The current through the first inductor L 1 begins to rise linearly, the magnetizing inductor L m transfers energy to the secondary winding L s and charges the second capacitor C o The current through the magnetizing inductor L m begins to fall.

[0097] Referring to Figure 4 Fig. 2, the second mode of operation I: the first switch S 1 is turned on, the third switch S 3 is turned off, and the fourth switch S 4 is turned off; the first inductor L 1 discharges energy through the first diode D 1 to the auxiliary battery V b , the current through the first inductor L 1 begins to fall linearly, and the DC power supply V in simultaneously charges the magnetizing inductor L m and the leakage inductance L 1k , the current through the magnetizing inductor L m and the current through the leakage inductance L 1k rise linearly, respectively, and the first capacitor C s discharges energy until the current through the fourth diode D 4 decreases to 0.

[0098] Referring to Figure 5 Fig. 3, the third mode of operation I: the first switch S 1 is turned on, the third switch S 3 is turned off, the fourth switch S 4 is turned off, and the first inductor L 1 discharges energy through the first diode D1 Continue to release energy to the auxiliary battery pack V b First Inductor L 1 The current decreases linearly, DC power supply V in Continue to supply the magnetizing inductor L m and leakage L 1k Charging, magnetizing inductor L m Current and leakage inductance L 1k The currents increase linearly.

[0099] refer to Figure 6 As shown, fourth operating mode I: first switching transistor S 1 Turn off, third switch tube S 3 Turn off, fourth switch transistor S 4 On, first inductor L 1 Through the first diode D 1 Continue to release energy to the auxiliary battery pack V b First Inductor L 1 The current decreases linearly, stored in the leakage inductance. L 1k Energy is transferred to the first capacitor C s Up, until stored in the leakage sensing L 1k All the energy is released; the energy stored in the magnetizing inductor is released. L m Energy is transferred to the secondary winding L s and the second capacitor C o Charging, magnetizing inductor L m The current begins to decrease linearly.

[0100] refer to Figure 7 As shown, the fifth operating mode I: the first switching transistor S 1 Turn off, third switch tube S 3 Turn off, fourth switch transistor S 4 On, first inductor L 1 Through the first diodeD 1 Continued energy release to the auxiliary battery V b , the first inductor L 1 The current of the excitation inductor L m Transfers energy to the secondary winding L s And charges the second capacitor C o The current of the excitation inductor L m Linearly decreases.

[0101] The first inductor L 1 The excitation inductor L m The voltage of the five working modes in the SIDO mode, according to the "volt-second balance" principle of the inductor, the steady-state voltage gain in this working mode can be obtained:

[0102]

[0103] In the formula, M1 The output voltage across the load R The voltage gain of the input voltage across the DC power supply V in , V in The input voltage across the DC power supply V in , Vo The output voltage across the load R , D1 The duty cycle of the first switch tube S 1 n is the turns ratio of the transformer; M2 The voltage across the auxiliary battery V b The voltage gain of the input voltage across the DC power supply V in , Vb The input voltage across the auxiliary battery V b , D3 The duty cycle of the third switch tube S 3 .

[0104] In the SIDO mode, the working waveform diagram of the main devices in a working cycle is as shown in Figure 21 , Figure 21 In the formula, iLm Magnetizing inductor L m The current, V L1k Leakage L 1k voltage, i L1 For the first inductor L 1 The current, T S The time of one work cycle in SIDO mode. t 0 、t 1 、t 2 、t 3 、t 4 These correspond to the start times of the first working mode I, the second working mode I, the third working mode I, the fourth working mode I, and the fifth working mode I, respectively. t 5 This refers to the moment when the first working mode I of the next working cycle begins.

[0105] In DISO mode, the first switching transistor S 1 Second switching transistor S 2 Main control switch, fourth switch tube S 4 With the second switching transistor S 2 Passive switching; second switching transistor S 2 When turned on, the fourth switching transistor S 4 Cut-off; second switching transistor S 2 At cutoff, the fourth switch transistor S 4 On; third switching transistor S 3 Not involved in the operation of this model.

[0106] In DISO mode, the power flow relationship is as follows: The DISO mode includes the following five operating modes sequentially within a single work cycle:

[0107] refer to Figure 8 As shown, the first operating mode II: the first switching transistor S 1 Turn on, second switching transistor S 2conducting, fourth switch S 4 off, direct current source V in to excitation inductance L m and leakage inductance L 1k charging, excitation inductance L m and leakage inductance L 1k linearly, first capacitor C s releasing energy, until fourth diode D 4 current decreases to 0.

[0108] reference Figure 9 , second operating mode II: first switch S 1 conducting, second switch S 2 conducting, fourth switch S 4 off, direct current source V in continuing to excitation inductance L m and leakage inductance L 1k charging, excitation inductance L m and leakage inductance L 1k linearly.

[0109] reference Figure 10 , third operating mode II: first switch S 1 off, second switch S 2 conducting, fourth switch S 4 off, auxiliary battery V b secondary winding L s transferring energy to primary winding L p and charging excitation inductance L m charging, excitation inductance L m continuing to linearly rise, leakage inductance L 1k transferring energy to first capacitor C s , until leakage inductanceL 1k All of its energy is released.

[0110] refer to Figure 11 As shown, fourth operating mode II: first switching transistor S 1 Turn off, second switch transistor S 2 Turn on, fourth switch transistor S 4 Shut down the auxiliary battery pack. V b Through the secondary winding L s Energy continues to be transferred to the primary winding. L p and provide excitation inductance L m Charging, magnetizing inductor L m The current continues to rise linearly.

[0111] refer to Figure 12 As shown, the fifth operating mode II: the first switching transistor S 1 Turn off, second switch transistor S 2 Turn off, fourth switch transistor S 4 On, magnetizing inductor L m Energy is transferred to the secondary winding L s and the second capacitor C o Charging, magnetizing inductor L m The current decreases linearly.

[0112] Given the magnetizing inductance L m Based on the "volt-second balance" principle of inductors, the voltages in the five modes of DISO mode can be used to derive the expressions for the output voltage and input voltage in this operating mode:

[0113]

[0114] In the formula, Vin DC power supply V in The input voltage at both ends, Vo For load R The output voltage at both ends, D1 The first switching transistor S 1 duty cycle, D2 For the second switching transistorS 2 the duty cycle of the voltage across the transformer, D3 is a third switch tube S 3 the duty cycle of the voltage across the transformer, n is the turns ratio of the transformer; Vb is an auxiliary battery pack V b the voltage across the two ends.

[0115] In the DISO mode, the working waveform diagram of the main device in one working cycle is as shown in Figure 22 , Figure 22 , i m is the excitation inductance L m the current, i L1k is the leakage inductance L 1k the current, V Lm is the excitation inductance L m the voltage, T S is the time of one working cycle in the DISO mode, t 0 、t 1 、t 2 、t 3 、t 4 respectively correspond to the time corresponding to the start of the first working mode II, the second working mode II, the third working mode II, the fourth working mode II, and the fifth working mode II, t 5 is the time corresponding to the start of the first working mode II of the next working cycle. V Lm The voltage in the first working mode II and the second working mode II is ; V Lm The voltage in the third working mode II and the fourth working mode II is ; V Lm The voltage in the fifth working mode II is .

[0116] In the SISO-I mode, the first switch tube S 1 is the main control switch, and the fourth switch tube S 4 follows the first switch tube S 1Passive on-off; first switch tube S 1 Conducting, fourth switch tube S 4 Off; first switch tube S 1 Off, fourth switch tube S 4 Conducting; second switch tube S 2 , third switch tube S 3 Not involved in the operation of this mode.

[0117] In SISO-I mode, the power flow relationship is ; SISO-I mode includes the following four kinds of working modes in turn in a working cycle:

[0118] Referring to Figure 13 , the first working mode III: the first switch tube S 1 is conducting, and the fourth switch tube S 4 is off; the DC power supply V in is charging the excitation inductance L m and the leakage inductance L 1k , the current of the excitation inductance L m and the current of the leakage inductance L 1k respectively linearly rise, and the first capacitor C s releases energy until the current of the fourth diode D 4 decreases to 0.

[0119] Referring to Figure 14 , the second working mode III: the first switch tube S 1 is conducting, and the fourth switch tube S 4 is off; the DC power supply V in is charging the excitation inductance L m and the leakage inductance L 1k , the current of the excitation inductance L m and the current of the leakage inductance L 1k respectively linearly rise.

[0120] Referring to Figure 15The third working mode III: the first switch tube is turned off S 1 The fourth switch tube is turned on S 4 The energy of the leakage inductance is released L 1k The energy of the excitation inductance is transferred to the secondary winding C s The energy of the excitation inductance is transferred to the secondary winding L m The energy of the leakage inductance is released L s The energy of the leakage inductance is released C o The energy of the leakage inductance is released L 1k The energy of the leakage inductance is released

[0121] Reference Figure 16 The fourth working mode III: the first switch tube is turned off S 1 The fourth switch tube is turned on S 4 The energy of the leakage inductance is released L 1k The energy of the excitation inductance is transferred to the secondary winding L m The energy of the excitation inductance is transferred to the secondary winding L s The energy of the excitation inductance is transferred to the secondary winding C o The energy of the excitation inductance is transferred to the secondary winding

[0122] The energy of the excitation inductance is transferred to the secondary winding L m The voltage of the four working modes in the SISO-I mode can be obtained according to the "volt-second balance" principle of the inductance:

[0123]

[0124] In the formula, M SISO-Ⅰ The voltage gain of the output voltage of the load R and the input voltage between the DC power supply V in The input voltage between the DC power supply Vin The input voltage between the DC power supply V in The input voltage between the DC power supply Vo The output voltage of the load R The output voltage of the load D1 The duty cycle of the first switch tube S 1 The duty cycle of the first switch tube

[0125] In SISO-I mode, the working waveform of main devices in one working cycle is as shown in Figure 23 , Figure 23 , i m is the current of excitation inductance L m , i L1k is the current of leakage inductance L 1k , V Lm is the voltage of excitation inductance L m , T S is the time of one working cycle in SISO-I mode t 0 、t 1 、t 2 、t 3 respectively correspond to the time when the first working mode III, the second working mode III, the third working mode III and the fourth working mode III in one working cycle start, t 4 is the time when the first working mode III in the next working cycle starts. V Lm The voltage in the first working mode III and the second working mode III is ; V Lm The voltage in the third working mode III and the fourth working mode III is . In SISO-II mode, the second switch S 2 is the main control switch, and the fourth switch S 4 is passively turned on and off with the second switch S 2 . When the second switch S 2 is turned on, the fourth switch S 4 is turned off; when the second switch S 2 is turned off, the fourth switch S 4 is turned on; the first switch S 1 and the third switch S 3 do not participate in the operation of this mode.

[0126] In SISO-II mode, the power flow relationship is The SISO-II mode includes the following two operating modes sequentially within a single work cycle:

[0127] refer to Figure 17 As shown, the first operating mode IV: the second switching transistor S 2 Turn on, fourth switch transistor S 4 Shut down the auxiliary battery pack. V b Through the secondary winding L s Energy is transferred to the primary winding. L p and the excitation inductor L m Charging, magnetizing inductor L m The current increases linearly.

[0128] refer to Figure 18 As shown, the second operating mode IV: the second switching transistor S 2 Turn off, fourth switch transistor S 4 On, magnetizing inductor L m Energy is transferred to the secondary winding L s and the second capacitor C o Charge.

[0129] Given the magnetizing inductance L m In SISO-II mode, based on the "volt-second balance" principle of inductors, the steady-state voltage gain in this operating mode can be calculated for the two modes of voltage.

[0130]

[0131] In the formula, M SISO-Ⅱ Load under SISO-II mode R The output voltage at both ends and the auxiliary battery pack V b The gain ratio of the voltages at both ends, Vin DC power supply V in The input voltage at both ends, Vb For auxiliary battery pack V b The voltage at both ends, D2 For the second switching transistor S 2 The duty cycle is denoted by n, where n is the number of turns in the transformer.

[0132] In the SISO-II mode, the working waveform of the main devices in one working cycle is as shown in Figure 24 , Figure 24 , i Lm is the current of the excitation inductor L m , V Lm is the voltage of the excitation inductor L m , T S is the time of one working cycle, t 0 、t 1 respectively correspond to the time when the first working mode IV and the second working mode IV in one working cycle start, t 2 is the time when the first working mode IV in the next working cycle starts. V Lm In the first working mode IV, the voltage is , V Lm In the second working mode IV, the voltage is . In the SISO-III mode, the third switch S 3 is the main control switch, and the first switch S 1 , the second switch S 2 and the fourth switch S 4 do not participate in the operation of this mode.

[0133] In the SISO-III mode, the power flow relationship is ; the SISO-III mode includes two working modes in turn in one working cycle:

[0134] Referring to Figure 19 , the first working mode V: the third switch S 3 is turned on, and the DC power supply V in provides energy for the first inductor L 1 and the auxiliary battery pack V b respectively, and the current of the first inductor L 1 linearly rises.

[0135] Referring to Figure 20 , the second working mode V: the third switchS 3 off, first inductor L 1 through the first diode D 1 to the auxiliary battery pack V b releasing energy, first inductor L 1 linearly.

[0136] known first inductor L 1 In SISO-III mode, the voltage of the two modes can be obtained according to the "volt-second balance" principle of the inductor, and the steady-state voltage gain in this working mode is:

[0137]

[0138] wherein, M SISO-Ⅲ is the voltage across the auxiliary battery pack V b in SISO-III mode, V in is the voltage gain of the input voltage across the DC power supply, D3 is the duty cycle of the third switch tube S 3 .

[0139] In SISO-III mode, the working waveform diagram of the main device in one working cycle is as shown in Figure 25 , Figure 25 wherein, i L1 is the current of the first inductor L 1 , V L1 is the voltage of the first inductor L 1 , T S is the time of one working cycle in SISO-III mode, t 0 、t 1 respectively correspond to the time when the first working mode V and the second working mode V start, t 2 is the time when the first working mode V of the next working cycle starts. V L1 The voltage in the first working mode V is , V L1 The voltage in the second working mode V is .

[0140] The multi-port converter provided by the embodiment corresponds to three port settings, utilizes four switch tubes to realize five working modes, and the four switch tubes cooperate with each other instead of being independently configured with multiple switch devices for each port in a traditional array configuration, so that the number of switch devices of the multi-port converter provided by the embodiment can be effectively reduced, thereby reducing the energy consumption of the multi-port converter and improving the efficiency of the multi-port converter; the five working modes include SISO mode, DISO mode and SIDO mode, and the SISO mode has three modes in total, and the corresponding mode can be selected for use according to actual requirements; the control mode of the multi-port converter is simple, and various transformation ratios can be realized.

[0141] Embodiment 2

[0142] The control method of the first multi-port converter provided by the embodiment includes the following steps:

[0143] generating a first control signal I, a third control signal I and a fourth control signal I;

[0144] the first control signal I controls the on-off of the first switch tube S 1 , the third control signal I controls the on-off of the third switch tube S 3 , and the fourth control signal I is transmitted to the gate of the fourth switch tube S 4 ; the fourth switch tube S 4 follows the first switch tube S 1 to be passively turned on and off;

[0145] the first control signal I, the third control signal I and the fourth control signal I make the multi-port converter work in the SIDO mode, and the SIDO mode has the following five working modes in sequence in one period:

[0146] Referring to Figure 3 , the first working mode I: the first switch tube S 1 is turned off, the third switch tube S 3 is turned on, and the fourth switch tube S 4 is turned on; the direct-current power supply V in charges the first inductor L 1 , the current of the first inductor L 1 begins to linearly rise, and the energy of the excitation inductor L m is transmitted to the secondary windingL s and give the second capacitor C o Charging, current flows through the magnetizing inductor L m The current began to decrease.

[0147] refer to Figure 4 As shown, the second operating mode I: the first switching transistor S 1 On, third switching transistor S 3 Turn off, fourth switch tube S 4 Off; First inductor L 1 Through the first diode D 1 Release energy to the auxiliary battery pack V b Flow through the first inductor L 1 The current begins to decrease linearly, DC power supply V in Simultaneously, the excitation inductor is supplied with... L m and leakage L 1k Charging, magnetizing inductor L m Current and leakage inductance L 1k The currents of the first capacitor increase linearly. C s Energy is released until the fourth diode. D 4 The current decreases to 0.

[0148] refer to Figure 5 As shown, the third operating mode I: the first switching transistor S 1 Turn on, third switch transistor S 3 Turn off, fourth switch transistor S 4 Turn off, first inductor L 1 Through the first diode D 1 Continue to release energy to the auxiliary battery pack V b First Inductor L 1 The current decreases linearly, DC power supply V in Continue to supply the magnetizing inductor L mand leakage inductance L 1k charging, excitation inductance L m current and leakage inductance L 1k current linearly rises, respectively.

[0149] Reference Figure 6 is shown, the fourth working mode I: the first switch tube S 1 off, the third switch tube S 3 off, the fourth switch tube S 4 on, the first inductor L 1 through the first diode D 1 continue to release energy to the auxiliary battery pack V b , the first inductor L 1 current linearly decreases, the energy stored in the leakage inductance L 1k transferred to the first capacitor C s , until the energy stored in the leakage inductance L 1k is fully released; the energy stored in the excitation inductance L m is transferred to the secondary winding L s , and charges the second capacitor C o , the excitation inductance L m current begins to linearly decrease.

[0150] Reference Figure 7 is shown, the fifth working mode I: the first switch tube S 1 off, the third switch tube S 3 off, the fourth switch tube S 4 on, the first inductor L 1 through the first diode D 1 continue to release energy to the auxiliary battery pack V b , the first inductor L 1 current linearly decreases, the energy stored in the excitation inductance L m is transferred to the secondary winding Ls and the second capacitor C o is charged, the excitation inductance L is charged m , the current of the first inductance

[0151] In the SIDO mode, the working waveform diagram of the main devices in one working cycle is as shown in Figure 21 , Figure 21 , i Lm is the current of the excitation inductance L m , V L1k is the voltage of the leakage inductance L 1k , i L1 is the current of the first inductance L 1 , T S is the time of one working cycle in the SIDO mode, t 0 、t 1 、t 2 、t 3 、t 4 respectively correspond to the time corresponding to the start of the first working mode I, the second working mode I, the third working mode I, the fourth working mode I and the fifth working mode I, t 5 is the time corresponding to the start of the first working mode I of the next working cycle.

[0152] Embodiment 3

[0153] The second multi-port converter control method provided in the embodiment comprises the following steps:

[0154] generating a first control signal II, a second control signal II and a fourth control signal II; the first control signal II controls the on-off of the first switch tube S 1 , the second control signal II controls the on-off of the second switch tube S 2 , and the fourth control signal II is transmitted to the gate of the fourth switch tube S 4 , and the fourth switch tube S 4 is passively turned on and off with the second switch tube S 2 ;

[0155] The first control signal II, the second control signal II and the fourth control signal II make the multi-port converter work in the DISO mode, and the DISO mode has the following five working modes in sequence in one period:

[0156] Referring to Figure 8 Fig. 2, the first working mode II is shown as follows: the first switch tube S 1 is turned on, the second switch tube S 2 is turned on, and the fourth switch tube S 4 is turned off. V in The current of the exciting inductance L m and the current of the leakage inductance L 1k linearly rise. L m The first capacitor L 1k releases energy until the current of the fourth diode C s decreases to 0. D 4

[0157] Referring to Figure 9 Fig. 3, the second working mode II is shown as follows: the first switch tube S 1 is turned on, the second switch tube S 2 is turned on, and the fourth switch tube S 4 is turned off. V in The exciting inductance L m and the leakage inductance L 1k continue to be charged. L m The current of the exciting inductance L 1k and the current of the leakage inductance 1 linearly rise.

[0158] Figure 10 Referring to S Fig. 4, the third working mode II is shown as follows: the first switch tube S 2 is turned off, the second switch tube S 4 is turned on, and the fourth switch tube V b is turned off. L s ​Energy is transferred to the primary winding. L p and the excitation inductor L m Charging, magnetizing inductor L m The current continues to rise linearly, leakage inductance L 1k Energy is transferred to the first capacitor C s Up, until leakage sensation L 1k All of its energy is released.

[0159] refer to Figure 11 As shown, fourth operating mode II: first switching transistor S 1 Turn off, second switch transistor S 2 Turn on, fourth switch transistor S 4 Shut down the auxiliary battery pack. V b Through the secondary winding L s Energy continues to be transferred to the primary winding. L p and provide excitation inductance L m Charging, magnetizing inductor L m The current continues to rise linearly.

[0160] refer to Figure 12 As shown, the fifth operating mode II: the first switching transistor S 1 Turn off, second switch transistor S 2 Turn off, fourth switch transistor S 4 On, magnetizing inductor L m Energy is transferred to the secondary winding L s and the second capacitor C o Charging, magnetizing inductor L m The current decreases linearly.

[0161] In DISO mode, the waveforms of the main components within one work cycle are as follows: Figure 22 As shown, Figure 22 middle, i m Magnetizing inductor L m The current, iL1k is the leakage inductance L 1k is the current, V Lm is the voltage of the excitation inductance L m is the voltage of the excitation inductance T S is the time of one working cycle in the DISO mode, t 0 、t 1 、t 2 、t 3 、t 4 respectively correspond to the time corresponding to the start of the first working mode II, the second working mode II, the third working mode II, the fourth working mode II and the fifth working mode II, t 5 is the time corresponding to the start of the first working mode II of the next working cycle.

[0162] Embodiment 4

[0163] The third multi-port converter control method provided in the embodiment comprises the following steps:

[0164] generating a first control signal III and a fourth control signal III; the first control signal III controls the on-off of the first switch tube S 1 , and the fourth control signal III is transmitted to the gate of the fourth switch tube S 4 ; the fourth switch tube S 4 is passively turned on and off with the first switch tube S 1 ; when the first switch tube S 1 is turned on, the fourth switch tube S 4 is turned off; when the first switch tube S 1 is turned off, the fourth switch tube S 4 is turned on;

[0165] The first control signal III and the fourth control signal III make the multi-port converter have the following four working modes in one cycle:

[0166] Referring to Figure 13 , the first working mode III: the first switch tube S 1 is turned on, and the fourth switch tube S 4 is turned off; the direct current power supplyV in Simultaneously, the excitation inductor L m and leakage L 1k Charging, magnetizing inductor L m Current and leakage inductance L 1k The currents of the first capacitor increase linearly. C s Energy is released until the fourth diode. D 4 The current decreases to 0.

[0167] refer to Figure 14 As shown, the second operating mode III: the first switching transistor S 1 Turn on, fourth switch transistor S 4 Off; DC power supply V in Simultaneously, the excitation inductor L m and leakage L 1k Charging, magnetizing inductor L m Current and leakage inductance L 1k The currents increase linearly.

[0168] refer to Figure 15 As shown, the third operating mode III: the first switching transistor S 1 Turn off, fourth switch transistor S 4 Conductivity; Leakage inductance L 1k Energy is transferred to the first capacitor C s Magnetizing inductor L m Energy is transferred to the secondary winding L s and the second capacitor C o Charge until leakage inductance is reached. L 1k The current drops to zero.

[0169] refer to Figure 16 As shown, fourth operating mode III: first switching transistor S 1 Turn off, fourth switch transistor S 4 Conductivity, leakage inductance L 1kThe energy of the excitation inductance L m is transmitted to the secondary winding L s And continues to charge the second capacitor C o .

[0170] In the SISO-I mode, the working waveform diagram of the main device in one working cycle is as shown in Figure 23 , Figure 23 , i m The current of the excitation inductance L m , i L1k The current of the leakage inductance L 1k , V Lm The voltage of the excitation inductance L m , T S The time of one working cycle in the SISO-I mode t 0 、t 1 、t 2 、t 3 Corresponding to the time when the first working mode III, the second working mode III, the third working mode III and the fourth working mode III in one working cycle start respectively, t 4 The time when the first working mode III in the next working cycle starts.

[0171] Embodiment 5

[0172] The fourth multi-port converter control method provided by the embodiment comprises the following steps:

[0173] Generating a second control signal IV and a fourth control signal IV; the second control signal IV controls the on-off of the second switch tube S 2 The fourth control signal IV is transmitted to the gate of the fourth switch tube S 4 The fourth switch tube S 4 Is passively turned on and off with the second switch tube S 2 When the second switch tube S 2 Is turned on, the fourth switch tube S 4 Is turned off; when the second switch tubeS 2 the fourth switch tube is turned off S 4 conducting;

[0174] and the multi-port converter has the following two working modes in sequence in a cycle:

[0175] Referring to Figure 17 Fig. 4, the first working mode IV: the second switch tube is turned on S 2 conducting, and the fourth switch tube is turned off S 4 conducting, and the auxiliary battery pack is charged V b energy is transmitted to the primary winding through the secondary winding L s the energy of the primary winding is transmitted to the secondary winding L p , and the current of the excitation inductor is charged L m , and the current of the excitation inductor is charged L m linearly rises.

[0176] Referring to Figure 18 Fig. 5, the second working mode IV: the second switch tube is turned off S 2 conducting, and the fourth switch tube is turned on S 4 conducting, and the energy of the excitation inductor is transmitted to the secondary winding L m the energy of the primary winding is transmitted to the secondary winding L s , and the second capacitor is charged C o .

[0177] In the SISO-II mode, the working waveform diagram of the main devices in a working cycle is as shown in Figure 24 Fig. 6, Figure 24 wherein, i Lm is the current of the excitation inductor L m is the voltage of the excitation inductor V Lm is the current of the excitation inductor L m is the voltage of the excitation inductor T S is the time of a working cycle in the SISO-II mode t 0 、t 1 respectively correspond to the time when the first working mode IV and the second working mode IV start in a working cycle t 2The time corresponding to the start of the first operation mode IV of the next operation cycle.

[0178] Embodiment 6

[0179] The fifth multi-port converter control method provided in the embodiment comprises the following steps:

[0180] The third control signal V is generated, and the third control signal V controls the on-off of the third switch tube S 3 , and makes the multi-port converter have the following two operation modes in sequence in one cycle:

[0181] Reference Figure 19 is shown, the first operation mode V: the third switch tube S 3 is turned on, and the DC power supply V in provides energy for the first inductor L 1 and the auxiliary battery pack V b respectively, and the current of the first inductor L 1 linearly rises.

[0182] Reference Figure 20 is shown, the second operation mode V: the third switch tube S 3 is turned off, and the first inductor L 1 releases energy for the auxiliary battery pack D 1 through the first diode V b , and the current of the first inductor L 1 linearly decreases.

[0183] In the SISO-III mode, the working waveform diagram of the main device in one operation cycle is as shown in Figure 25 , Figure 25 , i L1 is the current of the first inductor L 1 , V L1 is the voltage of the first inductor L 1 , T S is the time of one operation cycle in the SISO-III mode, t 0 、t 1corresponding to the first working mode V, and the time corresponding to the start of the second working mode V, t 2 corresponding to the start of the first working mode V of the next working cycle.

[0184] In addition, each functional unit in each embodiment of the present application can be integrated in one processing module, or each unit can be physically present separately, or two or more units can be integrated in one module. The integrated module can be realized in the form of hardware, or in the form of a software functional module. When the integrated module is realized in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer readable storage medium.

[0185] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc.

[0186] In the description of the present specification, the description referring to the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0187] Although the embodiments of the present application have been shown and described above, it should be understood that the above-described embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A multi-port converter, characterized by, The transformer comprises a primary winding (Lp) and a secondary winding (Ls); The transformer comprises a primary winding (Lp) and a secondary winding (Ls); The output module comprises a second capacitor (Co) and a load (R); The switch tube comprises a first switch tube (S1), a third switch tube (S3) and a fourth switch tube (S4); The positive pole of the direct current power supply (Vin) is connected with the first end of the third switch tube (S3), the negative pole of the third diode (D3) and the first end of the primary winding (Lp); The negative pole of the first diode (D1) is connected with the second end of the third switch tube (S3), and the negative pole of the fourth diode (D4) is connected with the positive pole of the third diode (D3); The first end of the first inductor (L1) is connected with the second end of the third switch tube (S3), and the second end of the first inductor (L1) is connected with the positive pole of the auxiliary battery pack (Vb); The first end of the first capacitor (Cs) is connected with the second end of the primary winding (Lp), and the second end of the first capacitor (Cs) is connected with the positive pole of the third diode (D3); The first end of the first switch tube (S1) is connected with the second end of the primary winding (Lp), and the second end of the first switch tube (S1) is connected with the first end of the secondary winding (Ls) and the first end of the fourth switch tube (S4); The first end of the second capacitor (Co) is connected with the second end of the secondary winding (Ls), and the load (R) is connected across the second capacitor (Co); The negative pole of the direct current power supply (Vin), the negative pole of the first diode (D1), the negative pole of the fourth diode (D4), the negative pole of the auxiliary battery pack (Vb), the second end of the fourth switch tube (S4) and the second end of the second capacitor (Co) are connected with each other; The switch tube further comprises a second switch tube (S2), the first end of the second switch tube (S2) is connected with the positive pole of the auxiliary battery pack (Vb), the second end of the second switch tube (S2) is connected with the positive pole of the second diode (D2), and the negative pole of the second diode (D2) is connected with the first end of the fourth switch tube (S4).

2. A multi-port converter according to claim 1, characterized in that, The transformer further comprises an excitation inductor (Lm) and a leakage inductor (L1k), the excitation inductor (Lm) is connected across the primary winding (Lp) in parallel, the first end of the leakage inductor (L1k) is connected with the second end of the primary winding (Lp), and the second end of the leakage inductor (L1k) is connected with the first end of the first switch tube (S1).

3. A multi-port converter according to claim 2, wherein, The switch tube is a field effect tube, the first end of the switch tube is the drain of the field effect tube, the second end of the switch tube is the source of the field effect tube, and the third end of the switch tube is the gate of the field effect tube.

4. A method of controlling a multi-port converter as claimed in claim 3, characterized by The method comprises the following steps: The first control signal I, the third control signal I and the fourth control signal I are generated, the first control signal I controls the on-off of the first switch tube (S1), the third control signal I controls the on-off of the third switch tube (S3), and the fourth control signal I is transmitted to the gate of the fourth switch tube (S4) and makes the multi-port converter have the following five working modes in a cycle: The first working mode I: the first switch (S1) is off, the third switch (S3) is on, and the fourth switch (S4) is on; the direct current power supply (Vin) charges the first inductor (L1), the current of the first inductor (L1) starts to linearly rise, the energy of the excitation inductor (Lm) is transmitted to the secondary winding (Ls), and the second capacitor (Co) is charged, and the current flowing through the excitation inductor (Lm) starts to decrease; The second working mode I: the first switch (S1) is on, the third switch (S3) is off, and the fourth switch (S4) is off; The first inductor (L1) releases energy to the auxiliary battery pack (Vb) through the first diode (D1), the current flowing through the first inductor (L1) starts to linearly decrease, the direct current power supply (Vin) charges the excitation inductor (Lm) and the leakage inductor (L1k) at the same time, the current of the excitation inductor (Lm) and the current of the leakage inductor (L1k) linearly rise respectively, and the first capacitor (Cs) releases energy until the current of the fourth diode (D4) decreases to 0; The third working mode I: the first switch (S1) is on, the third switch (S3) is off, and the fourth switch (S4) is off; the first inductor (L1) continues to release energy to the auxiliary battery pack (Vb) through the first diode (D1), the current of the first inductor (L1) linearly decreases, the direct current power supply (Vin) continues to charge the excitation inductor (Lm) and the leakage inductor (L1k), and the current of the excitation inductor (Lm) and the current of the leakage inductor (L1k) linearly rise respectively; The fourth working mode I: the first switch (S1) is off, the third switch (S3) is off, and the fourth switch (S4) is on; the first inductor (L1) continues to release energy to the auxiliary battery pack (Vb) through the first diode (D1), the current of the first inductor (L1) linearly decreases, the energy stored in the leakage inductor (L1k) is transmitted to the first capacitor (Cs), and the energy stored in the leakage inductor (L1k) is fully released until the energy stored in the excitation inductor (Lm) is transmitted to the secondary winding (Ls) and charges the second capacitor (Co), and the current of the excitation inductor (Lm) starts to linearly decrease; The fifth working mode I: the first switch (S1) is off, the third switch (S3) is off, and the fourth switch (S4) is on; the first inductor (L1) continues to release energy to the auxiliary battery pack (Vb) through the first diode (D1), the current of the first inductor (L1) linearly decreases, the energy stored in the excitation inductor (Lm) is transmitted to the secondary winding (Ls) and charges the second capacitor (Co), and the current of the excitation inductor (Lm) linearly decreases.

5. A method of controlling a multi-port converter as claimed in claim 3, characterized by, The method comprises the following steps: generating a first control signal II, a second control signal II and a fourth control signal II; the first control signal II controls the on-off of the first switch (S1), the second control signal II controls the on-off of the second switch (S2), and the fourth control signal II is transmitted to the gate of the fourth switch (S4) and makes the multi-port converter have the following five working modes in a cycle: The first working mode II: the first switch (S1) is turned on, the second switch (S2) is turned on, the fourth switch (S4) is turned off, the direct current power supply (Vin) charges the excitation inductor (Lm) and the leakage inductor (L1k), the current of the excitation inductor (Lm) and the current of the leakage inductor (L1k) linearly rise, the first capacitor (Cs) releases energy, and the current of the fourth diode (D4) decreases to 0; The second working mode II: the first switch (S1) is turned on, the second switch (S2) is turned on, the fourth switch (S4) is turned off, the direct current power supply (Vin) continues to charge the excitation inductor (Lm) and the leakage inductor (L1k), the current of the excitation inductor (Lm) and the current of the leakage inductor (L1k) linearly rise; The third working mode II: the first switch (S1) is turned off, the second switch (S2) is turned on, the fourth switch (S4) is turned off, the auxiliary battery group (Vb) secondary winding (Ls) transmits energy to the primary winding (Lp) and charges the excitation inductor (Lm), the current of the excitation inductor (Lm) continues to linearly rise, the energy of the leakage inductor (L1k) is transmitted to the first capacitor (Cs), and the energy of the leakage inductor (L1k) is fully released; The fourth working mode II: the first switch (S1) is turned off, the second switch (S2) is turned on, the fourth switch (S4) is turned off, the auxiliary battery group (Vb) transmits energy to the primary winding (Lp) through the secondary winding (Ls) and charges the excitation inductor (Lm), and the current of the excitation inductor (Lm) continues to linearly rise; The fifth working mode II: the first switch (S1) is turned off, the second switch (S2) is turned off, the fourth switch (S4) is turned on, the energy of the excitation inductor (Lm) is transmitted to the secondary winding (Ls) and charges the second capacitor (Co), and the current of the excitation inductor (Lm) linearly decreases.

6. A control method of a multi-port converter according to claim 3, characterized by, The method comprises the following steps: The first control signal III and the fourth control signal III are generated; the first control signal III controls the on-off of the first switch (S1), and the fourth control signal III is transmitted to the gate of the fourth switch (S4) and makes the multi-port converter have the following four working modes in a cycle: The first working mode III: the first switch (S1) is turned on, and the fourth switch (S4) is turned off; the direct current power supply (Vin) charges the excitation inductor (Lm) and the leakage inductor (L1k) at the same time, the current of the excitation inductor (Lm) and the current of the leakage inductor (L1k) linearly rise respectively, the first capacitor (Cs) releases energy, and the current of the fourth diode (D4) decreases to 0; The second working mode III: the first switch (S1) is turned on, and the fourth switch (S4) is turned off; The direct current power supply (Vin) charges the excitation inductor (Lm) and the leakage inductor (L1k) at the same time, the current of the excitation inductor (Lm) and the current of the leakage inductor (L1k) linearly rise respectively; The third working mode III: the first switch (S1) is off, and the fourth switch (S4) is on; the energy of the leakage inductor (L1k) is transmitted to the first capacitor (Cs), the energy of the excitation inductor (Lm) is transmitted to the secondary winding (Ls), and the second capacitor (Co) is charged until the current of the leakage inductor (L1k) drops to zero; The fourth working mode III: the first switch (S1) is off, and the fourth switch (S4) is on; the energy of the leakage inductor (L1k) is fully released, the energy of the excitation inductor (Lm) is transmitted to the secondary winding (Ls), and the second capacitor (Co) is continuously charged.

7. A method of controlling a multi-port converter according to any one of claims 2-3, characterized by, The steps include: The second control signal IV and the fourth control signal IV are generated; the second control signal IV controls the on-off of the second switch (S2), and the fourth control signal IV is transmitted to the gate of the fourth switch (S4), and the multi-port converter has the following two working modes in a cycle: The first working mode IV: the second switch (S2) is on, and the fourth switch (S4) is off; the auxiliary battery pack (Vb) transmits energy to the primary winding (Lp) through the secondary winding (Ls), and charges the excitation inductor (Lm), and the current of the excitation inductor (Lm) linearly rises; The second working mode IV: the second switch (S2) is off, and the fourth switch (S4) is on; the energy of the excitation inductor (Lm) is transmitted to the secondary winding (Ls), and the second capacitor (Co) is charged.

8. A method of controlling a multi-port converter according to any one of claims 2-3, characterized by, The steps include: The third control signal V is generated, the third control signal V controls the on-off of the third switch (S3), and the multi-port converter has the following two working modes in a cycle: The first working mode V: the third switch (S3) is on, and the DC power supply (Vin) provides energy for the first inductor (L1) and the auxiliary battery pack (Vb) respectively, and the current of the first inductor (L1) linearly rises; The second working mode V: the third switch (S3) is off, and the first inductor (L1) releases energy to the auxiliary battery pack (Vb) through the first diode (D1), and the current of the first inductor (L1) linearly decreases.

Images