Three-phase llc resonant converter with ultra-wide voltage regulation range

Abstract

The application provides a three-phase LLC resonant converter with an ultra-wide voltage regulating range, comprising a DC input power supply, seven power switching tubes, three resonant inductors, three resonant capacitors, three transformers and their three equivalent excitation inductors, twelve rectifier diodes and an output filter capacitor; the seven power switching tubes form a three-phase bridge inverter circuit; the three resonant inductors, the resonant capacitors and the excitation inductors form three-phase resonant tanks which are connected in a triangle; the three secondary winding of the three transformers are connected to three series H-bridge rectifiers formed by the twelve diodes, and then are connected in parallel with the output filter capacitor and the load; the application has the advantages of providing a three-phase LLC resonant converter with the advantages of large power, high efficiency, narrow working frequency range, ultra-wide output voltage range, ultra-small output current ripple and ultra-small standby power loss, and is widely applied to electric vehicle charging piles and other charging power supplies which require large power and ultra-wide output voltage range.

Description

TECHNICAL FIELD

[0001] The patent relates to a three-phase LLC resonant converter with an ultra-wide voltage regulation range, belonging to the technical field of power electronics. BACKGROUND

[0002] The rapid development of the automobile industry has exacerbated the energy crisis and environmental pollution, and the emergence of electric vehicles in recent years has eased this situation, among which the high-power fast charging system has become an important research direction of the electric vehicle industry. However, due to the non-uniform charging demand of various electric vehicle manufacturers, the large number of charging equipment connected to the network will also bring new impact to the power grid, so there is a demand for high-power, wide-range, high-efficiency, high-power factor for electric vehicle charging equipment, which is also one of the bottlenecks for the large-scale popularization of electric vehicles. The research on electric vehicle charging piles has important industrial value.

[0003] The adoption of charging modules to build a high-power fast charging system for electric vehicles is an ideal solution in the industry, and the performance of the charging module directly affects the performance of the entire fast charging system. Currently, these charging modules are required to have a large power: 15kW, 20kW or 30kW; an ultra-wide output voltage range: 200-750V, compatible with all electric buses and passenger cars, solving the power module selection problem for charging pile system integration customers; an ultra-high efficiency: 97%, greatly improving the charging efficiency of the charging station, bringing huge economic value to customers operating the power station; an ultra-small output ripple: 2V, customers no longer need to worry about the impact of charging ripple voltage and current on the service life of the power battery, especially in winter or high-cold areas, the ultra-small ripple greatly improves the service life of the electric vehicle power battery; an ultra-large power density: 33.75W / in 3 , greatly improving the power density of the charging pile system and reducing system design and construction costs; an ultra-small standby power loss: less than 0.5‰ of the rated power, greatly reducing the operating cost of customers.

[0004] Due to the soft switching characteristics of the LLC resonant converter, high efficiency is achieved, and the main circuit topology of the current charging module usually adopts LLC resonant converter technology, but it is difficult to meet the large power index, ultra-small output ripple index and ultra-large power density index relying on the traditional single-phase LLC resonant converter. Relying on the traditional three-phase LLC resonant converter, it is difficult to meet the ultra-wide output voltage range index, ultra-small standby power loss and high efficiency index in the full load range. SUMMARY

[0005] In view of the above technical defects, the patent provides a three-phase LLC resonant converter with an ultra-wide voltage regulation range, which has the advantages of simple structure, large output power, high output efficiency, large power density, narrow operating frequency range, ultra-wide output voltage range, ultra-small output current ripple, and ultra-small standby power loss.

[0006] The technical scheme adopted by the patent to solve its technical problems is:

[0007] A three-phase LLC resonant converter with an ultra-wide voltage regulation range, characterized in that it comprises a DC input power supply V in , seven power switching tubes Q1-Q7 and their body diodes D1-D7 and parasitic capacitors C1-C7, three resonant inductors L r1 , r2 , r3 , three resonant capacitors C r1 , r2 , r3 , three resonant transformers T1, T2, and T3 with a turn ratio of n, and equivalent excitation inductors L m1 , m2 , m3 , twelve rectifier diodes D8-D 19 , and an output filter capacitor C o ; the seven power switching tubes Q1-Q7 form a three-phase full-bridge inverter circuit of the three-phase LLC resonant converter. Taking all power MOSFETs as an example, the source of power switching tube Q1 is connected to the drain of Q7, the source of Q7 is connected to the drain of Q4, forming the first bridge arm of the three-phase full-bridge inverter circuit; the source of power switching tube Q2 is connected to the drain of Q5, forming the second bridge arm of the three-phase full-bridge inverter circuit; the source of power switching tube Q3 is connected to the drain of Q6, forming the third bridge arm of the three-phase full-bridge inverter circuit; the three bridge arms are connected in parallel, i.e. the drains of power switching tubes Q1, Q2, and Q3 are connected together, and the sources of power switching tubes Q4, Q5, and Q6 are connected together; the positive pole of the DC power supply V in is connected to the drains of power switching tubes Q1, Q2, and Q3, and the negative pole of the DC power supply V in is connected to the sources of power switching tubes Q4, Q5, and Q6; the resonant capacitor C r1 , resonant inductor L r1 , and excitation inductor L m1 are connected in series to form the first phase resonant tank of the three-phase LLC resonant converter, the resonant capacitor C r2 , resonant inductor L r2 , and excitation inductor L m2 are connected in series to form the second phase resonant tank of the three-phase LLC resonant converter, and the resonant capacitor C r3 , resonant inductor L r3 , and excitation inductor L m3The third phase resonant tank of the three-phase LLC resonant converter is constituted in series; the parameters of the three-phase resonant tank are equal, i.e. L m1 = L m2 = L m3 , L r1 = L r2 = L r3 , C r1 = C r2 = C r3 ; the three-phase resonant tank and the three primary winding of the three resonant transformers T1, T2 and T3 are connected in a triangle mode, i.e. one end of the first phase resonant tank is connected to the connection point A of the source of Q1 and the drain of Q7 of the first bridge arm, the other end of the first phase resonant tank is connected to the connection point B of the source of Q2 and the drain of Q5 of the second bridge arm; one end of the second phase resonant tank is connected to the other end B of the first phase resonant tank, the other end of the second phase resonant tank is connected to the connection point C of the source of Q3 and the drain of Q5 of the third bridge arm; one end of the third phase resonant tank is connected to the other end C of the second phase resonant tank, the other end of the third phase resonant tank is connected to the connection point D of the source of Q7 and the drain of Q4 of the first bridge arm; the three secondary winding of the three resonant transformers T1, T2 and T3 are connected to the three H-bridge rectifiers constituted by the rectification diodes D8~D 19 in series, then connected in parallel with the output filter capacitor C o , and the two ends of the output filter capacitor C o are connected to the load resistor R L .

[0008] Based on the three-phase LLC resonant converter with super-wide voltage regulation range, characterized in that: the switch tube Q6 is kept on, the switch tubes Q1, Q3, Q4 and Q7 are kept off, the switch tubes Q2 and Q5 are complementary on and work in a frequency modulation state, the driving signals of the switch tubes Q2 and Q5 have a dead time, which prevents the occurrence of shoot-through phenomenon and can realize soft switching; the transformers T1 and T3 do not work, the transformer T2 works, the other end C of the primary winding of the transformer T2 is directly connected to the negative electrode of the power supply V in , only the second phase resonant tank of the three-phase resonant tank works, the input voltage of the two ends B and C of the second phase resonant tank is a square wave of 0~V in , constituting a single-phase half-bridge LLC resonant converter topology I, the voltage gain of the LLC resonant converter topology I is the voltage gain working in a half-bridge mode; the fundamental equivalent circuit model of the LLC resonant converter topology I includes: a fundamental equivalent voltage source V BC , a resonant capacitor C r2 , a resonant inductor L r2 , an excitation inductor L m2 , a fundamental equivalent load resistor R eq , and the fundamental equivalent voltage source VBC , resonant capacitor C r2 , resonant inductor L r2 , and field inductor L m2 are connected in series, the fundamental equivalent load resistance R eq is connected across the field inductor L m2 ; the three H-bridge rectifiers are connected in series, wherein the second H-bridge rectifier formed by diodes D 12 ~D 15 functions as a rectifier.

[0009] Based on the three-phase LLC resonant converter with the super-wide voltage regulation range, characterized in that: the switching tubes Q1 and Q6 are kept on, the switching tubes Q3, Q4 and Q7 are kept off, the switching tubes Q2 and Q5 are complementary on and work in a frequency modulation state, the driving signals of the switching tubes Q2 and Q5 have a dead time, which prevents the occurrence of a straight-through phenomenon and realizes soft switching; the A end of the first-phase resonant tank is directly connected to the positive pole of the power supply V in , and the C end of the third-phase resonant tank is directly connected to the negative pole of the power supply V in ; the first-phase resonant tank and the second-phase resonant tank work, and the third-phase resonant tank does not work, forming a two-phase input parallel and output series half-bridge LLC resonant converter topology II; under this topology, the input voltages of the A and B ends of the first-phase resonant tank and the B and C ends of the second-phase resonant tank are all square waves of 0~V in ; the first-phase resonant tank and the second-phase resonant tank both work in a half-bridge LLC resonant converter mode, and the two transformers T1 and T2 transmit energy to the load side; the current flowing through the two-phase resonant inductors L r1 , L r2 is equal in size and same in phase; the voltage gain of the LLC resonant converter topology II is the sum of the voltage gains of the first-phase resonant tank and the second-phase resonant tank working in a half-bridge mode; the fundamental equivalent circuit model of the LLC resonant converter topology II includes: fundamental equivalent voltage sources V AB and V BC , resonant capacitor C r1 and C r2 , resonant inductor L r1 and L r2 , field inductor L m1 and L m2 , fundamental equivalent load resistance R eq ; the fundamental equivalent voltage sources V AB and the resonant capacitor C r1 , resonant inductor L r1 , field inductor L m1 are connected in series to form a loop, and the fundamental equivalent voltage sources V BC and the resonant capacitor C r2 , resonant inductor L r2, excitation inductance L m2 forms a loop in series, the tail end of the excitation inductance L m1 connects the head end of the excitation inductance L m2 , the head end of the excitation inductance L m1 and the tail end of the excitation inductance L m2 are connected to the two ends of the fundamental equivalent load resistance R eq respectively; the first H-bridge rectifier composed of diodes D8~D 11 and the second H-bridge rectifier composed of diodes D 12 ~D 15 have a rectification effect.

[0010] Based on the three-phase LLC resonant converter with the super-wide voltage regulation range, characterized in that: the switch tube Q4 is kept on, the switch tubes Q2 and Q5 are kept off, the driving signals of the switch tubes Q1 and Q6 are the same, the driving signals of the switch tubes Q3 and Q7 are the same and complementary to the driving signals of the switch tubes Q1 and Q6, that is, the diagonal driving; the first phase and the second phase resonant tanks are connected in series, the input voltage at the two ends A and C of the first phase and the second phase resonant tanks connected in series is a square wave of -V in ~V in , and the LLC resonant converter works in the full-bridge mode, the input voltage at the two ends C and D of the third phase resonant tank is a square wave of 0~V in , and the LLC resonant converter works in the half-bridge mode, the input ends of the LLC resonant converter working in the full-bridge mode and the LLC resonant converter working in the half-bridge mode are connected in parallel, and the output ends are connected in series, to form an LLC resonant converter topology three; the voltage gain of the LLC resonant converter topology three is the sum of the voltage gain of the first phase resonant tank and the second phase resonant tank working in the full-bridge mode and the voltage gain of the third phase resonant tank working in the half-bridge mode; the currents flowing through the resonant inductances L r1 and L r2 are equal in size and 180 degrees out of phase with the current flowing through the resonant inductance L r3 ; the fundamental equivalent circuit model of the LLC resonant converter topology three includes: a fundamental equivalent voltage source V AC , a series resonant capacitor C r1 and C r2 of resonant capacitors C r1 ', a series resonant inductance L r1 and L r2 of resonant inductances L r1 ', an excitation inductance L m1 and L m2 of excitation inductances L m1 ', a fundamental equivalent voltage source V CD , a resonant capacitor C r3 , a resonant inductance L r3, excitation inductance L m3 , fundamental equivalent load resistance R eq , the fundamental equivalent voltage source V AC and resonance capacitor C r1 ', resonance inductance L r1 ', excitation inductance L m1 ', the fundamental equivalent voltage source V CD and resonance capacitor C r3 , resonance inductance L r3 , excitation inductance L m3 , the excitation inductance L m1 ' of the tail end of the excitation inductance L m3 The head end of the excitation inductance L m1 ' and the excitation inductance L m3 The tail end of the fundamental equivalent load resistance R eq Both ends are connected; the three secondary windings of transformers T1, T2 and T3 are connected to the corresponding H-bridge rectifier circuit, which functions as a rectifier.

[0011] Based on the three-phase LLC resonant converter with a super-wide voltage regulation range, characterized in that: the switch tube Q7 is continuously turned on, the switch tubes Q1 and Q4, Q2 and Q5, Q3 and Q6 form three bridge arms of the three-phase bridge inverter circuit, the driving signals of each bridge arm are complementary and have a dead zone, and the driving signals between the three bridge arms are 120 degrees apart; the three-phase resonant tank and the primary winding of the three transformers T1, T2 and T3 are connected in a triangular shape, the input voltage of the three resonant tanks is a three-phase square wave of -V in ~V in , working in three-phase full-bridge LLC resonant converter mode, forming LLC resonant converter topology four; the voltage gain of the LLC resonant converter topology four is the sum of the voltage gains of the first, second and third phase resonant tanks working in full-bridge mode; the current amplitude through the three-phase resonant inductors L r1 , L r2 , L r3 The phase difference is 120 degrees; the fundamental equivalent circuit model of the LLC resonant converter topology four includes: fundamental equivalent voltage source V AB , V BC , V CD , resonance capacitor C r1 , C r2 , C r3 , resonance inductance L r1 , L r2 , L r3 , excitation inductance L m1 , L m2 , L m3 , fundamental equivalent load resistance R eq, the fundamental equivalent voltage source V AB and resonance capacitor C r1 , resonance inductor L r1 , excitation inductor L m1 in series, the fundamental equivalent voltage source V BC and resonance capacitor C r2 , resonance inductor L r2 , excitation inductor L m2 in series, the fundamental equivalent voltage source V CD and resonance capacitor C r3 , resonance inductor L r3 , excitation inductor L m3 in series, the tail end of the excitation inductor L m1 connects the head end of the excitation inductor L m2 , the tail end of the excitation inductor L m2 connects the head end of the excitation inductor L m3 , the head end of the excitation inductor L m1 and the tail end of the excitation inductor L m3 are respectively connected to both ends of the fundamental equivalent load resistance R eq ; three secondary windings of transformers T1, T2 and T3 are respectively connected to corresponding H-bridge rectifier circuits.

[0012] The voltage gain ranges of the above-mentioned LLC resonant converter topologies one, two, three and four are different, the three-phase LLC resonant converter with super-wide voltage regulation range switches among the above-mentioned four LLC resonant converter topologies, and meets the load demand of large power and super-wide voltage regulation range.

[0013] The patent provides a three-phase LLC resonant converter with super-wide voltage regulation range, according to the size of the required voltage gain, the power switch tubes Q1-Q7 are controlled to be opened and closed, so that the three-phase full-bridge inverter circuit works in four circuit topologies, combined with frequency conversion control, in a very narrow frequency range, the requirement for super-wide voltage gain range of the three-phase LLC resonant converter is met, and the super-wide range output voltage of the three-phase LLC resonant converter is realized. At the same time, through the switching use of the four topologies, the converter works in a very narrow frequency range, which is beneficial to the design of the resonance inductor and the resonance transformer; the technology is applied to a large power switching power supply, has the advantages of super-wide input voltage and output voltage regulation range, low loss, high efficiency, etc., and can avoid the defects of local overheating of switch tubes or rectifier diodes, and excessive voltage and current stress of devices. The achievement of the patent can be widely applied to electric vehicle charging piles and other occasions requiring large power of 10kW or more and super-wide output voltage range of 80-420V or 200-750V.

[0014] The following will be specifically described with examples in combination with the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the embodiments, the following will be briefly introduced the drawings needed to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the patent, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0016] Figure 1 is a circuit topology diagram of the three-phase LLC resonant converter with ultra-wide voltage regulation range provided by the first embodiment of the patent.

[0017] Figure 2 is Figure 1 a circuit topology diagram of the LLC resonant converter topology one with ultra-wide voltage regulation range provided by the second embodiment of the patent.

[0018] Figure 3 is Figure 2 a voltage and current waveform diagram of the second embodiment of the patent.

[0019] Figure 4 is Figure 2 a fundamental equivalent circuit model diagram of the second embodiment of the patent.

[0020] Figure 5 is Figure 1 a circuit topology diagram of the LLC resonant converter topology two with ultra-wide voltage regulation range provided by the third embodiment of the patent.

[0021] Figure 6 is Figure 5 a voltage and current waveform diagram of the third embodiment of the patent.

[0022] Figure 7 is Figure 5 a fundamental equivalent circuit model diagram of the third embodiment of the patent.

[0023] Figure 8 is Figure 1 a circuit topology diagram of the LLC resonant converter topology three with ultra-wide voltage regulation range provided by the fourth embodiment of the patent.

[0024] Figure 9 is Figure 8 a voltage and current waveform diagram of the fourth embodiment of the patent.

[0025] Figure 10 is Figure 8 a fundamental equivalent circuit model diagram of the fourth embodiment of the patent.

[0026] Figure 11 is Figure 1 a circuit topology diagram of the LLC resonant converter topology four with ultra-wide voltage regulation range provided by the fifth embodiment of the patent.

[0027] Figure 12 is Figure 11 the voltage and current waveform diagram of the fifth embodiment of the present patent.

[0028] Figure 13 is Figure 11 the fundamental equivalent circuit model diagram of the fifth embodiment of the present patent.

[0029] Figure 14 is Figure 2 , 5 , 8, 11 the voltage gain curve of the first, second, third, fourth LLC resonant converter topology of the second, third, fourth, fifth embodiment of the present patent.

[0030] In the figure, V in - input voltage, V o - output voltage; G = V o / V in - voltage gain; f s - switching frequency; f r - resonant frequency; f n = f s / f r - normalized switching frequency; Q1 ~ Q7 - power switch; D1 ~ D7 - body diode of power switch Q1 ~ Q7; C1 ~ C7 - parasitic capacitance of power switch Q1 ~ Q7; L r1 , L r2 , L r3 - three-phase resonant inductance; C r1 , C r2 , C r3 - three-phase resonant capacitance; C r1 ' - series resonant capacitance of resonant capacitance C r1 and C r2 ; L r1 ' - series resonant inductance of resonant inductance L r1 and L r2 ; L m1 ' - series excitation inductance of excitation inductance L r1 and L r2 ; T1, T2, T3 - three-phase resonant transformer with turn ratio n; L m1 , L m2 , L m3 - equivalent excitation inductance in parallel at both ends of the primary winding of three-phase resonant transformer T1, T2, T3; D8 ~ D 19 - twelve rectifier diodes; C o - output filter capacitance; V gs - drive voltage amplitude of power switch Q1 ~ Q7; i r1 , i r2 , ir3 - the three-phase resonant current flowing through the three-phase resonant inductance L r1 , L r2 , L r3 and the three-phase resonant capacitance C r1 , C r2 , C r3 ; V gs1 , V gs6 , V gs7 - the driving voltage of the power switch tubes Q1, Q6, Q7; V AB - the voltage between points A and B; V AC - the voltage between points A and C; V BC - the voltage between points B and C; V CD - the voltage between points C and D; R L - the DC load resistance; R eq - the equivalent AC load resistance. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present patent will be described clearly and completely below with reference to the drawings in the embodiments of the present patent. Obviously, the described embodiments are only some of the embodiments of the present patent, rather than all the embodiments. Based on the core idea and the embodiments of the present patent, other embodiments obtained by those skilled in the art without creative work are within the protection scope of the present patent.

[0032] In order to fully understand the present patent, many specific details are mentioned in the following detailed description, but those skilled in the art should understand that the present patent can be implemented without these specific details.

[0033] Embodiment One

[0034] With reference to the drawings Figure 1 , a three-phase LLC resonant converter with an ultra-wide voltage regulation range, characterized in that it comprises a DC input power supply V in , seven power switch tubes Q1-Q7 and their body diodes D1-D7 and parasitic capacitances C1-C7, three resonant inductances L r1 , L r2 , L r3 , three resonant capacitances C r1 , C r2 , C r3 , three resonant transformers T1, T2, T3 with a turn ratio of n, and equivalent excitation inductances L m1 , L m2 , L m3 parallelly connected at both ends of the primary winding of the resonant transformers T1, T2, T3, respectively, twelve rectifier diodes D8-D 19 and an output filter capacitance Co ; the seven power switch tubes Q1-Q7 constitute a three-phase full-controlled bridge inverter circuit of the three-phase LLC resonant converter, taking all power switch tubes as power MOSFETs for example, the source of the power switch tube Q1 and the drain of the power switch tube Q7 are connected, and the source of the power switch tube Q7 and the drain of the power switch tube Q4 are connected, thereby constituting a first bridge arm of the three-phase full-controlled bridge inverter circuit; the source of the power switch tube Q2 and the drain of the power switch tube Q5 are connected, thereby constituting a second bridge arm of the three-phase full-controlled bridge inverter circuit; the source of the power switch tube Q3 and the drain of the power switch tube Q6 are connected, thereby constituting a third bridge arm of the three-phase full-controlled bridge inverter circuit; the three bridge arms are connected in parallel, that is, the drains of the power switch tubes Q1, Q2 and Q3 are connected together, and the sources of the power switch tubes Q4, Q5 and Q6 are connected together; the positive pole of the direct-current power supply V in is connected to the drains of the power switch tubes Q1, Q2 and Q3, and the negative pole of the direct-current power supply V in is connected to the sources of the power switch tubes Q4, Q5 and Q6; the resonant capacitor C r1 , the resonant inductor L r1 and the excitation inductor L m1 are connected in series to constitute a first-phase resonant tank of the three-phase LLC resonant converter, the resonant capacitor C r2 , the resonant inductor L r2 and the excitation inductor L m2 are connected in series to constitute a second-phase resonant tank of the three-phase LLC resonant converter, and the resonant capacitor C r3 , the resonant inductor L r3 and the excitation inductor L m3 are connected in series to constitute a third-phase resonant tank of the three-phase LLC resonant converter; the parameters of the three-phase resonant tanks are equal, that is, L m1 =L m2 =L m3 , L r1 =L r2 =L r3 , C r1 =C r2 =C r3; the three-phase resonant tank and the three primary windings of the three resonant transformers T1, T2 and T3 are connected in a delta connection, that is, one end of the first-phase resonant tank is connected to the connection point A of the source of Q1 and the drain of Q7 of the first bridge arm, the other end of the first-phase resonant tank is connected to the connection point B of the source of Q2 and the drain of Q5 of the second bridge arm; one end of the second-phase resonant tank is connected to the other end B of the first-phase resonant tank, the other end of the second-phase resonant tank is connected to the connection point C of the source of Q3 and the drain of Q5 of the third bridge arm; one end of the third-phase resonant tank is connected to the other end C of the second-phase resonant tank, the other end of the third-phase resonant tank is connected to the connection point D of the source of Q7 and the drain of Q4 of the first bridge arm; the three secondary windings of the three resonant transformers T1, T2 and T3 are connected to the three H-bridge rectifiers composed of rectifier diodes D8~D 19 o o L .

[0035] Embodiment two:

[0036] Referring to the accompanying Figure 2 , 3 , 4, 14, a three-phase LLC resonant converter with an ultra-wide voltage regulation range, characterized in that: the switch tube Q6 is kept on, the switch tubes Q1, Q3, Q4 and Q7 are kept off, the switch tubes Q2 and Q5 are complementary on and work in a frequency modulation state, the drive signals of the switch tubes Q2 and Q5 have a dead time, which can prevent the occurrence of shoot-through phenomenon and realize soft switching; the transformers T1 and T3 do not work, the transformer T2 works, and the other end C of the primary winding of the transformer T2 is directly connected to the negative electrode of the power supply V in ; only the second-phase resonant tank of the three-phase resonant tank works, and the input voltage of the two ends B and C of the second-phase resonant tank is a square wave of 0~V in , constituting a single-phase half-bridge LLC resonant converter topology one, the voltage gain of the LLC resonant converter topology one is the voltage gain working in a half-bridge mode; the fundamental equivalent circuit model of the LLC resonant converter topology one includes: a fundamental equivalent voltage source V BC , a resonant capacitor C r2 , a resonant inductor L r2 , an excitation inductor L m2 , and a fundamental equivalent load resistor R eq , the fundamental equivalent voltage source V BC , the resonant capacitor C r2 , the resonant inductor L r2 and the excitation inductor L m2 are connected in series, and the fundamental equivalent load resistor R eq is connected across the excitation inductor L​​​m2 The three H-bridge rectifiers are connected in series at both ends, with diode D being the main component. 12 ~D 15 The second H-bridge rectifier, as configured, performs the rectification function. The voltage gain curve for the LLC resonant converter topology one described in this embodiment is shown in the appendix. Figure 14 .

[0037] Example 3:

[0038] See attached document Figure 5 , 6 7, 14, A three-phase LLC resonant converter with an ultra-wide voltage regulation range, characterized in that: switching transistors Q1 and Q6 are kept continuously on, switching transistors Q3, Q4, and Q7 are kept continuously off, and switching transistors Q2 and Q5 are complementaryly turned on and operate in frequency modulation mode; the drive signals of switching transistors Q2 and Q5 have dead time, which prevents shoot-through and also realizes soft switching; the A terminal of the first phase resonant slot is directly connected to the power supply V. in The positive terminal of the third phase resonant slot, C-terminal, is directly connected to the power supply V. in The negative terminal of the first phase resonant slot and the second phase resonant slot are active, while the third phase resonant slot is inactive, forming a half-bridge LLC resonant converter topology two with two phase input terminals connected in parallel and the output terminals connected in series. Under this topology, the input voltages at terminals A and B of the first phase resonant slot and terminals B and C of the second phase resonant slot are both 0 to V. in The square wave, the first phase resonant slot and the second phase resonant slot both operate in half-bridge LLC resonant converter mode, the two transformers T1 and T2 transfer energy to the load side, flowing through the two-phase resonant inductor L r1 L r2 The currents are equal in magnitude and have the same phase; the voltage gain of the LLC resonant converter topology two is the sum of the voltage gains of the first and second phase resonant slots operating in half-bridge mode; the fundamental equivalent circuit model of the LLC resonant converter topology two includes: the fundamental equivalent voltage source V AB and V BC Resonant capacitor C r1 and C r2 Resonant inductor L r1 and L r2 Magnetizing inductance L m1 and L m2 The fundamental equivalent load resistance R eq The fundamental equivalent voltage source V AB and resonant capacitor C r1 Resonant inductor L r1 Magnetizing inductance L m1 The fundamental equivalent voltage source V is connected in series to form a circuit. BC and resonant capacitor C r2 Resonant inductor L r2Magnetizing inductance L m2 The magnetizing inductor L forms a circuit in series. m1 The tail end is connected to the excitation inductor L m2 At the beginning, the excitation inductor L m1 The beginning and excitation inductance L m2 The tail ends are respectively connected to the fundamental equivalent load resistance R. eq The two ends; consisting of diodes D8 to D 11 The first H-bridge rectifier is constructed using diode D. 12 ~D 15 The second H-bridge rectifier, as configured, performs the rectification function. The voltage gain curve for the LLC resonant converter topology two described in this embodiment is shown in the appendix. Figure 14 .

[0039] Example 4:

[0040] See attached document Figure 8 , 9 10, 14, A three-phase LLC resonant converter with an ultra-wide voltage regulation range, characterized in that: switch Q4 is kept continuously on, switches Q2 and Q5 are continuously off, the drive signals for switches Q1 and Q6 are the same, and the drive signals for switches Q3 and Q7 are the same and complementary to the drive signals for switches Q1 and Q6, i.e., diagonal drive; the first phase resonant slot and the second phase resonant slot are connected in series, and the input voltage at terminals A and C after the first phase resonant slot and the second phase resonant slot are connected in series is -V. in ~V in The square wave operates in full-bridge LLC resonant converter mode, with the input voltage at terminals C and D of the third phase resonant slot being 0 to V. in A square wave, operating in half-bridge LLC resonant converter mode, is formed by connecting the input terminals of the LLC resonant converter operating in full-bridge mode and the LLC resonant converter operating in half-bridge mode in parallel and the output terminals in series, constituting LLC resonant converter topology three; the voltage gain of LLC resonant converter topology three is the sum of the voltage gain of the first phase resonant slot and the second phase resonant slot in full-bridge mode and the voltage gain of the third phase resonant slot in half-bridge mode; the resonant inductor L... r1 and L r2 The current flowing through the resonant inductor L r3 The currents are equal in magnitude and 180 degrees out of phase; the fundamental equivalent circuit model of the LLC resonant converter topology three includes: fundamental equivalent voltage source V AC Resonant capacitor C r1 and C r2 Series resonant capacitor C r1 '、Resonant inductor L r1 and L r2 Series resonant inductor L r1 Magnetizing inductance Lm1 and L m2 series excitation inductance L m1 ', fundamental equivalent voltage source V CD , resonance capacitor C r3 , resonance inductance L r3 , excitation inductance L m3 , fundamental equivalent load resistance R eq , the fundamental equivalent voltage source V AC and resonance capacitor C r1 ', resonance inductance L r1 ', excitation inductance L m1 ', the fundamental equivalent voltage source V CD and resonance capacitor C r3 , resonance inductance L r3 , excitation inductance L m3 series, the excitation inductance L m1 ' of the tail end is connected to the head end of the excitation inductance L m3 , the head end of the excitation inductance L m1 ' and the tail end of the excitation inductance L m3 are connected to the two ends of the fundamental equivalent load resistance R eq respectively; the three secondary winding of transformer T1, T2, T3 are connected to the corresponding H-bridge rectifier circuit respectively, which functions as rectification. The voltage gain curve of the LLC resonant converter topology three in the embodiment is shown in FIG. 13. Figure 14 .

[0041] Embodiment five:

[0042] Referring to FIG. 14, Figure 11 , 12 , 13, 14, a three-phase LLC resonant converter with super-wide voltage regulation range, characterized in that: the switch tube Q7 is continuously turned on, the switch tubes Q1 and Q4, Q2 and Q5, Q3 and Q6 form three bridge arms of three-phase bridge inverter circuit, the driving signals of each bridge arm are complementary and have dead zones, and the driving signals between the three bridge arms are 120 degrees apart; the three-phase resonant tank and the primary winding of the three transformers T1, T2, T3 are connected in a delta connection mode, the input voltage of the three resonant tanks is a three-phase square wave of -V in ~V in , working in three-phase full-bridge LLC resonant converter mode, forming LLC resonant converter topology four; the voltage gain of the LLC resonant converter topology four is the sum of the voltage gains of the first, second and third phase resonant tanks working in full-bridge mode; the current flowing through the three-phase resonant inductance L r1 , L r2 , L r3The current amplitudes of the two currents are equal, and the phases are different by 120 degrees; the fundamental equivalent circuit model of the LLC resonant converter topology four includes: a fundamental equivalent voltage source V AB BC CD r1 r2 r3 r1 r2 r3 m1 m2 m3 eq The fundamental equivalent voltage source V AB The resonant capacitor C r1 The resonant inductor L r1 The field inductor L m1 The fundamental equivalent voltage source V BC The resonant capacitor C r2 The resonant inductor L r2 The field inductor L m2 The fundamental equivalent voltage source V CD The resonant capacitor C r3 The resonant inductor L r3 The field inductor L m3 The tail end of the field inductor L m1 The head end of the field inductor L m2 The tail end of the field inductor L m2 The head end of the field inductor L m3 The head end of the field inductor L m1 The tail end of the field inductor L m3 The two ends of the fundamental equivalent load resistor R eq The three secondary windings of the transformers T1, T2 and T3 are connected to the corresponding H-bridge rectifier circuits respectively. Figure 14 .

[0043] The voltage gain ranges of the LLC resonant converter topologies one, two, three and four described in the above embodiments two, three, four and five are different, the three-phase LLC resonant converter with super-wide voltage regulation range described in the embodiment one switches among the LLC resonant converter topologies one, two, three and four, and meets the load demand of large power and super-wide voltage regulation range.

[0044] ​​​​​​​​​​​​The above-described embodiments are only preferred embodiments of the present patent, and are not intended to limit the protection scope of the present patent. The principles and implementation manners of the present patent are described in the above multiple embodiments in the specification, which are only used to help understand the method and core idea of the present patent; meanwhile, for those skilled in the art, the specific implementation manners and application ranges will be changed according to the idea of the present patent. Therefore, the content of the specification should not be understood as a limitation of the present patent, and any modification, equivalent replacement and improvement within the spirit and principle of the present patent are included in the protection scope of the present patent.

Claims

1. A three-phase LLC resonant converter with ultra-wide voltage regulation range, characterized by: A direct current power supply V in , seven power switch tubes Q1-Q7 and their body diodes D1-D7 and parasitic capacitors C1-C7, three resonant inductors L r1 , L r2 , L r3 , three resonant capacitors C r1 , C r2 , C r3 , three resonant transformers T1, T2, T3 with a turn ratio of n, and equivalent excitation inductors L m1 , L m2 , L m3 , twelve rectifier diodes D8-D 19 and an output filter capacitor C o ; The seven power switch tubes Q1-Q7 constitute a three-phase full-bridge inverter circuit of the three-phase LLC resonant converter, the source of the power switch tube Q1 and the drain of the power switch tube Q7 are connected, the source of the power switch tube Q7 and the drain of the power switch tube Q4 are connected, thereby constituting a first bridge arm of the three-phase full-bridge inverter circuit; the source of the power switch tube Q2 and the drain of the power switch tube Q5 are connected, thereby constituting a second bridge arm of the three-phase full-bridge inverter circuit; the source of the power switch tube Q3 and the drain of the power switch tube Q6 are connected, thereby constituting a third bridge arm of the three-phase full-bridge inverter circuit; the three bridge arms are connected in parallel, that is, the drains of the power switch tubes Q1, Q2 and Q3 are connected together, and the sources of the power switch tubes Q4, Q5 and Q6 are connected together; the positive pole of the direct current power supply V in is connected to the drains of the power switch tubes Q1, Q2 and Q3, and the negative pole of the direct current power supply V in is connected to the sources of the power switch tubes Q4, Q5 and Q6. the resonance capacitor C r1 , the resonance inductor L r1 , and the field inductor L m1 in series constitute a first phase resonance tank of the three-phase LLC resonant converter, the resonance capacitor C r2 , the resonance inductor L r2 , and the field inductor L m2 in series constitute a second phase resonance tank of the three-phase LLC resonant converter, the resonance capacitor C r3 , the resonance inductor L r3 , and the field inductor L m3 in series constitute a third phase resonance tank of the three-phase LLC resonant converter; the parameters of the three-phase resonance tanks are equal, i.e. m1 L m2 =L m3 , L r1 =L r2 , C r3 =C r1 , and C r2 =C r3 ; The three-phase resonant tank and the three primary windings of the three resonant transformers T1, T2 and T3 are connected in a delta connection, that is, one end of the first-phase resonant tank is connected to the connection point A of the source of Q1 and the drain of Q7 of the first bridge arm, and the other end of the first-phase resonant tank is connected to the connection point B of the source of Q2 and the drain of Q5 of the second bridge arm; one end of the second-phase resonant tank is connected to the other end B of the first-phase resonant tank, and the other end of the second-phase resonant tank is connected to the connection point C of the source of Q3 and the drain of Q5 of the third bridge arm; one end of the third-phase resonant tank is connected to the other end C of the second-phase resonant tank, and the other end of the third-phase resonant tank is connected to the connection point D of the source of Q7 and the drain of Q4 of the first bridge arm; The three secondary winding of the three resonant transformers T1, T2, T3 are connected to three H-bridge rectifiers composed of rectifying diodes D8~D 19 , respectively, which are connected in series and then connected to an output filter capacitor C o in parallel, and the two ends of the output filter capacitor C o are connected to a load resistor R L .

2. The three-phase LLC resonant converter with ultra-wide voltage regulation range according to claim 1, characterized in that: The switch tube Q6 is kept conducting, the switch tubes Q1, Q3, Q4 and Q7 are kept off, the switch tubes Q2 and Q5 are complementary conducting and work in a frequency modulation state, and the drive signals of the switch tubes Q2 and Q5 have a dead time, which prevents the occurrence of a straight-through phenomenon and realizes soft switching; Transformer T1 and T3 do not work, transformer T2 works, the other end C of the primary winding is directly connected to the power supply V in The negative electrode of the three-phase resonant tank only works in the second phase resonant tank, and the input voltage at the two ends B and C of the second phase resonant tank is 0-V in The square wave constitutes a single-phase half-bridge LLC resonant converter topology one; the voltage gain of the LLC resonant converter topology one is the voltage gain working in the half-bridge mode; The fundamental equivalent circuit model of the LLC resonant converter topology one includes: a fundamental equivalent voltage source V BC , a resonant capacitor C r2 , a resonant inductor L r2 , an excitation inductor L m2 , a fundamental equivalent load resistor R eq , the fundamental equivalent voltage source V BC , the resonant capacitor C r2 , the resonant inductor L r2 and the excitation inductor L m2 are connected in series, and the fundamental equivalent load resistor R eq is connected across the excitation inductor L m2 ; The three H-bridge rectifiers are connected in series, with the second H-bridge rectifier formed by diodes D 12 ~D 15 acting as a rectifier.

3. The three-phase LLC resonant converter with ultra-wide voltage regulation range according to claim 1, characterized in that: The switch tube Q1 is kept conducting, the switch tubes Q3, Q4 and Q7 are kept off, the switch tubes Q2 and Q5 are complementary conducting and work in a frequency modulation state, and the drive signals of the switch tubes Q2 and Q5 have a dead time, which prevents the occurrence of a straight-through phenomenon and realizes soft switching; The A end of the first phase resonant tank is directly connected to the positive pole of the power supply V in The C end of the third phase resonant tank is directly connected to the negative pole of the power supply V in The first phase resonant tank and the second phase resonant tank work, and the third phase resonant tank does not work, thereby forming a half-bridge LLC resonant converter topology two with input terminals in parallel and output terminals in series; under the topology, the input voltages of the two ends A and B of the first phase resonant tank and the two ends B and C of the second phase resonant tank are all square waves of 0~V in The first phase resonant tank and the second phase resonant tank both work in the half-bridge LLC resonant converter mode, and the two transformers T1 and T2 transmit energy to the load side, and the current flowing through the two-phase resonant inductors L r1 , L r2 is equal in size and has the same phase. The voltage gain of the LLC resonant converter topology two is the sum of the voltage gain of the first-phase resonant tank working in a half-bridge mode and the voltage gain of the second-phase resonant tank; The fundamental equivalent circuit model of the LLC resonant converter topology two includes: a fundamental equivalent voltage source V AB and V BC , a resonant capacitor C r1 and C r2 , a resonant inductor L r1 and L r2 , an excitation inductor L m1 and L m2 , a fundamental equivalent load resistor R eq , the fundamental equivalent voltage source V AB and the resonant capacitor C r1 , the resonant inductor L r1 , the excitation inductor L m1 are connected in series to form a loop, the fundamental equivalent voltage source V BC and the resonant capacitor C r2 , the resonant inductor L r2 , the excitation inductor L m2 are connected in series to form a loop, the tail end of the excitation inductor L m1 is connected to the head end of the excitation inductor L m2 , and the head end of the excitation inductor L m1 and the tail end of the excitation inductor L m2 are respectively connected to the two ends of the fundamental equivalent load resistor R eq ; The first H-bridge rectifier is composed of diodes D8~D 11 The second H-bridge rectifier is composed of diodes D 12 ~D 15 for rectification.

4. The three-phase LLC resonant converter with ultra-wide voltage regulation range of claim 1, wherein: The switch tube Q4 is kept conducting, the switch tubes Q2 and Q5 are kept off, the drive signals of the switch tubes Q1 and Q6 are the same, the drive signals of the switch tubes Q3 and Q7 are the same and complementary to the drive signals of the switch tubes Q1 and Q6, that is, diagonal driving; The first phase resonant tank and the second phase resonant tank are connected in series, and the input voltage of the two ends A and C of the first phase resonant tank and the second phase resonant tank connected in series is -V in ~V in The input voltage of the two ends C and D of the third phase resonant tank is 0~V in The input end of the LLC resonant converter working in the full-bridge mode and the input end of the LLC resonant converter working in the half-bridge mode are connected in parallel, and the output ends are connected in series, to form an LLC resonant converter topology three. The voltage gain of the LLC resonant converter topology three is the sum of the voltage gain of the first-phase resonant tank and the second-phase resonant tank working in a full-bridge mode and the voltage gain of the third-phase resonant tank working in a half-bridge mode; The current flowing through the resonant inductor L r1 and L r2 is equal in magnitude and 180 degrees out of phase with the current flowing through the resonant inductor L r3 . The fundamental equivalent circuit model of the LLC resonant converter topology three includes: fundamental equivalent voltage source V AC Resonant capacitor C r1 and C r2 Series resonant capacitor C r1 '、Resonant inductor L r1 and L r2 Series resonant inductor L r1 Magnetizing inductance L m1 and L m2 Series excitation inductor L m1 ′、Fundamental equivalent voltage source V CD Resonant capacitor C r3 Resonant inductor L r3 Magnetizing inductance L m3 The fundamental equivalent load resistance R eq The fundamental equivalent voltage source V AC and resonant capacitor C r1 '、Resonant inductor L r1 Magnetizing inductance L m1 'In series, the fundamental equivalent voltage source V CD and resonant capacitor C r3 Resonant inductor L r3 Magnetizing inductance L m3 The excitation inductor L is connected in series. ml The tail end is connected to the magnetizing inductor L. m3 At the beginning, the excitation inductor L m1 'The beginning and excitation inductance L' m3 The tail ends are respectively connected to the fundamental equivalent load resistance R. eq The two ends; The three secondary windings of the transformers T1, T2 and T3 are respectively connected to corresponding H-bridge rectifier circuits for rectification.

5. The three-phase LLC resonant converter with ultra-wide voltage regulation range of claim 1, wherein: The switch tube Q7 is kept conducting, and the switch tubes Q1 and Q4, Q2 and Q5 and Q3 and Q6 form three bridge arms of a three-phase bridge inverter circuit, the drive signals of each bridge arm are complementary and have a dead time, and the drive signals of the three bridge arms are 120 degrees apart from each other; The primary windings of the three transformers T1, T2 and T3 and the three-phase resonant tank are connected in a delta connection, and the input voltages of the three resonant tanks are all three-phase square waves of -V in ~V in The LLC resonant converter topology four is operated in a three-phase full-bridge LLC resonant converter mode, and constitutes an LLC resonant converter topology four; the voltage gain of the LLC resonant converter topology four is the sum of the voltage gains of the first-phase resonant tank, the second-phase resonant tank and the third-phase resonant tank operated in a full-bridge mode. The current flowing through the three-phase resonant inductance L r1 , L r2 , L r3 The current amplitude is equal, and the phase difference is 120 degrees. The fundamental equivalent circuit model of the LLC resonant converter topology four includes: a fundamental equivalent voltage source V AB 、 BC 、 CD 、 a resonant capacitor C r1 、 C r2 、 C r3 、 a resonant inductor L r1 、 L r2 、 L r3 、 a field inductor L m1 、 L m2 、 L m3 、 a fundamental equivalent load resistor R eq , the fundamental equivalent voltage source V AB and the resonant capacitor C r1 , the resonant inductor L r1 , the field inductor L m1 are connected in series, the fundamental equivalent voltage source V BC and the resonant capacitor C r2 , the resonant inductor L r2 , the field inductor L m2 are connected in series, the fundamental equivalent voltage source V CD and the resonant capacitor C r3 , the resonant inductor L r3 , the field inductor L m3 are connected in series, the tail end of the field inductor L m1 connects the head end of the field inductor L m2 , the tail end of the field inductor L m2 connects the head end of the field inductor L m3 , the head end of the field inductor L m1 and the tail end of the field inductor L m3 respectively connect the two ends of the fundamental equivalent load resistor R eq ; The three secondary windings of the transformers T1, T2 and T3 are respectively connected to corresponding H-bridge rectifier circuits.

6. The three-phase LLC resonant converter with ultra-wide voltage regulation range of claim 1, wherein: The three-phase LLC resonant converter switches among the topologies one, two, three and four, and meets the load demand of large power and super-wide voltage regulation range.

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