A three-port bidirectional power converter

Abstract

The invention discloses a three-port bidirectional power converter, which can realize bidirectional flow of energy in the same circuit. The converter comprises: a three-phase H-bridge circuit unit, a bus capacitor, a first full-bridge network, a resonance unit and a second full-bridge network; the three-phase H-bridge circuit comprises a first bridge arm, a second bridge arm and a third bridge arm connected in parallel and spanning across the two ends of the bus capacitor, and a first inductor, a second inductor and a third inductor respectively connected to the midpoints of the three bridge arms, the first inductor and the second inductor are connected to the first AC port, the third inductor and the second inductor are connected to the second AC port, the first full-bridge network comprises a fourth bridge arm and a fifth bridge arm connected in parallel and spanning across the two ends of the bus capacitor; the second full-bridge network comprises a sixth bridge arm and a seventh bridge arm connected in parallel, and the two ends of the sixth bridge arm and the seventh bridge arm in parallel are connected to a DC power supply port; the two ends of the resonance unit are respectively connected to the midpoints of the two bridge arms of the first full-bridge network and the midpoints of the two bridge arms of the second full-bridge network.

Description

Technical Field

[0001] The invention relates to the technical field of power electronics, and in particular to a three-port bidirectional power converter. Background Art

[0002] In a system with mixed power supply of AC and DC energy, it is expected that the power electronic conversion device will act like an energy pipeline, allowing energy to flow bidirectionally at each energy port, forming an AC / DC mixed energy pipeline system. Figure 1 As shown, it is a typical schematic diagram of an AC / DC hybrid energy pipeline system, which consists of two AC power ports and one DC power port. The first AC power port, the second AC power port and the DC power port are coupled to a common DC bus through a first bidirectional AC / DC converter 01, a second bidirectional AC / DC converter 02 and a bidirectional DC / DC converter 03, respectively. The common DC bus acts as an energy buffer. AC energy can flow bidirectionally between the first AC power port and the second AC power port, and DC energy and AC energy can also flow bidirectionally between the DC power port and the first AC power port and the second AC power port. In the above AC / DC hybrid energy pipeline system, how to cleverly construct a bidirectional AC / DC converter and a bidirectional DC / DC converter is a direction worthy of research.

[0003] Taking the construction of a bidirectional DC / DC converter in an AC / DC hybrid energy pipeline system as an example, there are several ways to do this:

[0004] The first one, such as Figure 2a As shown, two independent DC / DC converters are used, and the two DC / DC converters work independently to respectively realize the conversion from the first DC port to the second DC port, and the conversion from the second DC port to the first DC port;

[0005] The second type, such as Figure 2b As shown, two independent DC / DC converters are integrated to achieve partial device sharing. When energy is converted from the first DC port to the second DC port and from the second DC port to the first DC port, it will pass through some common units or devices. In this way, the partial common units or devices can reduce the cost of the bidirectional DC-DC converter. Among them, a very extreme case is to use only one DC / DC converter and two selection units, such as Figure 2c As shown, by selecting units, local sharing is achieved, thereby reducing system costs.

[0006] The AC / DC hybrid energy pipeline system using the above two bidirectional DC / DC converters cannot achieve a true bidirectional flow of energy in the same loop. Summary of the invention

[0007] The present invention provides a three-port bidirectional power converter, which can realize the bidirectional flow of energy in the same circuit in a true sense, and provide different energy pipelines for the AC / DC hybrid system using the three-port bidirectional power converter.

[0008] The present invention provides a three-port bidirectional power converter, which comprises: a three-phase H-bridge circuit unit, a bus capacitor, a first full-bridge network, a resonant unit and a second full-bridge network connected in sequence;

[0009] The three-phase H-bridge circuit unit includes a first bridge arm, a second bridge arm, a third bridge arm, a first inductor, a second inductor and a third inductor, the first bridge arm includes a first switch and a second switch connected in series, the second bridge arm includes a third switch and a fourth switch connected in series, the third bridge arm includes a fifth switch and a sixth switch connected in series, the first bridge arm, the second bridge arm and the third bridge arm are connected in parallel and are respectively connected across the two ends of the bus capacitor, the first end of the first inductor is connected to the midpoint of the first bridge arm, the first end of the second inductor is connected to the midpoint of the second bridge arm, the first end of the third inductor is connected to the midpoint of the third bridge arm, the second end of the first inductor and the second end of the second inductor are connected to the first AC power supply port, and the second end of the third inductor and the second end of the second inductor are connected to the second AC power supply port;

[0010] The first full-bridge network includes a fourth bridge arm and a fifth bridge arm, and the fourth bridge arm and the fifth bridge arm are connected in parallel and are respectively connected across two ends of the bus capacitor;

[0011] The second full-bridge network includes a sixth bridge arm and a seventh bridge arm connected in parallel, and two ends of the sixth bridge arm and the seventh bridge arm of the second full-bridge network connected in parallel are connected to a DC power supply port;

[0012] The first full-bridge network is synchronously modulated with the second full-bridge network;

[0013] The input end of the resonance unit is connected to the midpoint of the fourth bridge arm and the midpoint of the fifth bridge arm respectively, and the output end of the resonance unit is connected to the midpoint of the sixth bridge arm and the midpoint of the seventh bridge arm respectively.

[0014] In a possible implementation manner, the fourth bridge arm includes a first component and a second component connected in series, and the fifth bridge arm includes a third component and a fourth component connected in series;

[0015] The first component, the second component, the third component and the fourth component are all fully controllable switch components; or,

[0016] The first component and the second component are fully controlled switch components, and the third component and the fourth component are capacitor elements; or,

[0017] The first component and the second component are capacitor elements, and the third component and the fourth component are fully controlled switch components; or,

[0018] The first component and the third component are fully controlled switch components, and the second component and the fourth component are two primary windings of the same coupling transformer; or,

[0019] The first component and the third component are two primary windings of the same coupling transformer, and the second component and the fourth component are fully controlled switch components;

[0020] The fully-controlled switch assembly includes a fully-controlled switch device, or includes a fully-controlled switch device and a capacitor element connected in parallel.

[0021] In a possible implementation manner, the sixth bridge arm includes a fifth component and a sixth component connected in series, and the seventh bridge arm includes a seventh component and an eighth component connected in series;

[0022] The fifth component, the sixth component, the seventh component and the eighth component are all fully controlled switch components; or,

[0023] The fifth component and the sixth component are fully controlled switch components, and the seventh component and the eighth component are capacitor elements; or,

[0024] The fifth component and the sixth component are capacitor elements, and the seventh component and the eighth component are fully controlled switch components; or,

[0025] The fifth component and the seventh component are fully controlled switch components, and the sixth component and the eighth component are two secondary windings of the same coupling transformer; or,

[0026] The fifth component and the seventh component are two secondary windings of the same coupling transformer, and the sixth component and the eighth component are fully controlled switch components.

[0027] In a possible implementation manner, the resonance unit includes a first resonance circuit. When the first full-bridge network and / or the second full-bridge network includes a capacitive element, the first resonance circuit includes a first resonance inductor.

[0028] In a possible implementation, the resonance unit includes a first resonance circuit, and the first resonance circuit includes a first resonance inductor and a first resonance capacitor connected in series.

[0029] In a possible implementation manner, the resonance unit further includes an excitation inductor, and the excitation inductor is connected across two branches of the first resonance circuit.

[0030] In a possible implementation, the resonance unit further includes a transformer, and the first resonance circuit is connected in series to a primary winding of the transformer.

[0031] In a possible implementation, when the first full-bridge network includes two primary windings of the same coupling transformer, the two primary windings of the same coupling transformer in the first full-bridge network are the primary windings of the transformer in the resonant unit;

[0032] When the second full-bridge network includes two secondary windings of the same coupling transformer, the two secondary windings of the same coupling transformer in the second full-bridge network are the secondary windings of the transformer in the resonant unit.

[0033] In a possible implementation manner, the resonance unit further includes a second resonance circuit, and the second resonance circuit is connected in series to the secondary winding of the transformer in the resonance unit;

[0034] The second resonant circuit includes a second resonant capacitor and / or a second resonant inductor.

[0035] In a possible implementation manner, a current sampling device is further included, and the current sampling device is respectively connected in series with the first inductor, the second inductor, and the third inductor.

[0036] The beneficial effects of the present invention are as follows: in the three-port bidirectional power converter provided by the embodiment of the present invention, the first inductor and the second inductor are coupled to the first AC power port, the second inductor and the third inductor are coupled to the second AC power port, the second full-bridge network is coupled to the DC power port, the first bridge arm, the first inductor L1, the second bridge arm and the second inductor L2 constitute a first bidirectional AC / DC converter, the second bridge arm is a common bridge arm, the second bridge arm, the second inductor L2, the third bridge arm and the third inductor L3 constitute a second bidirectional AC / DC converter, the first full-bridge network 200, the resonant unit 300 and the second full-bridge network 400 constitute a bidirectional DC / DC converter, and the first bidirectional AC / DC converter, the second bidirectional AC / DC converter, and the bidirectional DC / DC converter are all connected across the two ends of the bus capacitor. The three-port bidirectional power converter forms a three-port AC / DC hybrid energy pipeline system, wherein the first bidirectional AC / DC converter, the second bidirectional AC / DC converter and the bidirectional DC / DC converter can all realize the bidirectional flow of energy in the same circuit, and can provide different energy pipeline systems for the AC / DC hybrid power supply system using the three-port bidirectional power converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural schematic diagram of an AC / DC hybrid energy pipeline system in the prior art;

[0038] Figure 2a , Figure 2b and Figure 2c It is a structural schematic diagram of a bidirectional DC / DC converter in the prior art;

[0039] Figure 3 A schematic diagram of the structure of a three-port bidirectional power converter provided by an embodiment of the present invention;

[0040] Figure 4a A schematic diagram of the structure of a first full-bridge network provided by an embodiment of the present invention;

[0041] Figure 4b A schematic diagram of the structure of a second full-bridge network provided by an embodiment of the present invention;

[0042] Figure 5a , Figure 5b , Figure 5c , Figure 5d , Figure 5e , Figure 5f , Figure 5g , Figure 5h , Figure 5i and Figure 5j A schematic diagram of the structure of a first full-bridge network or a second full-bridge network provided by an embodiment of the present invention;

[0043] Figure 6a and Figure 6b A schematic diagram of the structure of a resonance unit provided by an embodiment of the present invention;

[0044] Figure 7a and Figure 7b A schematic diagram of the structure of a resonance unit provided by an embodiment of the present invention;

[0045] Figure 8a , Figure 8b and Figure 8c A schematic diagram of the structure of a resonance unit provided by an embodiment of the present invention;

[0046] Figure 9a , Figure 9b , Fig.9c , Figure 9d , Fig.9c , Fig.9e , Figure 9f , Figure 9g , Figure 9h A schematic diagram of the structure of a resonance unit provided by an embodiment of the present invention;

[0047] Fig.10 A schematic diagram of the structure of a three-port bidirectional power converter provided by an embodiment of the present invention;

[0048] Fig.11A schematic structural diagram of an AC / DC hybrid power supply system provided in an embodiment of the present invention;

[0049] Fig.12 A schematic diagram of the structure of another three-port bidirectional power converter provided by an embodiment of the present invention;

[0050] Fig.13 A schematic diagram of the structure of another three-port bidirectional power converter provided by an embodiment of the present invention;

[0051] Fig.14 A schematic diagram of the structure of another three-port bidirectional power converter provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] In order to solve the problems in the prior art, an embodiment of the present invention provides a three-port bidirectional power converter, which can realize the bidirectional flow of energy in the same circuit in a true sense, and provide different energy pipelines for the AC / DC hybrid power supply system using the three-port bidirectional power converter.

[0054] The three-port bidirectional power converter provided by the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0055] The embodiment of the present invention provides a three-port bidirectional power converter, such as Figure 3 As shown, the three-port bidirectional power converter includes: a three-phase H-bridge circuit unit 100, a bus capacitor C, a first full-bridge network 200, a resonant unit 300 and a second full-bridge network 400 connected in sequence;

[0056] The three-phase H-bridge circuit unit 100 includes a first bridge arm, a second bridge arm, a third bridge arm, a first inductor L1, a second inductor L2 and a third inductor L3, the first bridge arm includes a first switch S1 and a second switch S2 connected in series, the second bridge arm includes a third switch S3 and a fourth switch S4 connected in series, the third bridge arm includes a fifth switch S5 and a sixth switch S6 connected in series, the first bridge arm, the second bridge arm and the third bridge arm are connected in parallel and are respectively connected across the bus capacitor C, the first end of the first inductor L1 is connected to the midpoint of the first bridge arm, the first end of the second inductor L2 is connected to the midpoint of the second bridge arm, the first end of the third inductor L3 is connected to the midpoint of the third bridge arm, the second end of the first inductor L1 and the second end of the second inductor L2 are connected to the first AC power supply port, and the second end of the third inductor L3 and the second end of the second inductor L2 are connected to the second AC power supply port; specifically, the midpoint of the first bridge arm is the series connection point of the first switch and the second switch, and the midpoint of the second bridge arm is the series connection point of the third switch and the fourth switch;

[0057] The first full-bridge network 200 includes a fourth bridge arm and a fifth bridge arm, which are connected in parallel and are respectively connected across two ends of the bus capacitor C;

[0058] The second full-bridge network 400 includes a sixth bridge arm and a seventh bridge arm connected in parallel, and both ends of the sixth bridge arm and the seventh bridge arm of the second full-bridge network 200 connected in parallel are connected to a DC power supply port;

[0059] The first full-bridge network is synchronously modulated with the second full-bridge network;

[0060] The input end of the resonance unit 300 is connected to the midpoint of the fourth bridge arm and the midpoint of the fifth bridge arm respectively, and the output end of the resonance unit 300 is connected to the midpoint of the sixth bridge arm and the midpoint of the seventh bridge arm respectively.

[0061] In a specific implementation, the AC / DC hybrid power supply system applies the above-mentioned three-port bidirectional power converter. Specifically, in the above-mentioned three-port bidirectional power converter, the second end of the first inductor L1 and the second end of the second inductor L2 are coupled to the first AC power port, the second end of the second inductor L2 and the second end of the third inductor L3 are coupled to the second AC power port, and the sixth bridge arm and the seventh bridge arm of the second full-bridge network 400 are coupled to the DC power port in parallel. The three-port bidirectional power converter forms a three-port AC / DC hybrid energy pipeline system.

[0062] In the three-port bidirectional power converter provided in the above-mentioned embodiment of the invention, the three-phase H-bridge circuit unit 100 can form two bidirectional AC / DC converters. Specifically, the first bridge arm, the first inductor L1, the second bridge arm and the second inductor L2 form a first full-bridge rectifier / inverter, and the second bridge arm is a common bridge arm, and the third bridge arm, the third inductor L3, the second bridge arm and the second inductor L2 form a second full-bridge rectifier / inverter; when the three-port bidirectional power converter is working normally, the first full-bridge rectifier / inverter and the second full-bridge rectifier / inverter can both adopt a unipolar modulation mode, and the second bridge arm can both be used as the industrial frequency conduction bridge arm; the third switch S3 and the fourth switch S4 can be used as the power frequency conduction bridge arm. The switch S4 is turned on at the industrial frequency and complementarily clamps the voltage at the first end of the second inductor L2 to the potential of one end or the other end of the bus capacitor C. The first switch S1 and the second switch S2 are also turned on at high frequency and complementarily after being modulated according to the sinusoidal wave signal, and the first full-bridge rectifier / inverter constitutes a first bidirectional AC / DC converter; at the same time, the third switch S3 and the fourth switch S4 are turned on at the industrial frequency and complementarily clamps the voltage at one end of the second inductor L2 to the potential of one end or the other end of the bus capacitor C, and the fifth switch S5 and the sixth switch S6 are also turned on at high frequency and complementarily after being modulated according to the sinusoidal wave signal, and the second full-bridge rectifier / inverter constitutes a second bidirectional AC / DC converter.

[0063] In the three-port bidirectional power converter provided by the above-mentioned embodiment of the invention, the first full-bridge network 200, the resonant unit 300 and the second full-bridge network 400 can constitute a bidirectional DC / DC converter. Specifically, when the first full-bridge network 200 and the second full-bridge network 400 are modulated in a synchronous modulation mode, the first full-bridge network 200 and the second full-bridge network 400 maintain a synchronized on-time within a high-frequency switching cycle. During the on-time, the DC side terminal voltage of the first full-bridge network 200 is coupled to the input terminal of the resonant unit 300 to form a voltage V1, and the DC side terminal voltage of the second full-bridge network 400 is coupled to the output terminal of the resonant unit 300 to form a voltage V2. Since the resonant unit 300 is an inductor element or a combination of an inductor element and a capacitor element, its high-frequency characteristics are manifested as certain impedance characteristics. The voltage V1 and the voltage V2 form a certain voltage difference at both ends of the resonant unit 300. According to the positive and negative of the voltage difference, the direction of the average current flowing through the resonant unit 300 is determined. The high-frequency impedance characteristics of the resonant unit 300 can limit the rapid rise of the current and avoid current out of control. Therefore, the energy conversion direction of the bidirectional DC / DC converter composed of the first full-bridge network 200, the resonant unit 300 and the second full-bridge network 400 can automatically adjust the direction of the average current according to the change of the external DC side voltage, thereby realizing the true bidirectional flow of energy in the same loop, just like an energy pipeline.

[0064] In a specific implementation, the first full-bridge network 200, the resonant unit 300 and the second full-bridge network 400 form a bidirectional DC / DC converter. The first bidirectional AC / DC converter and / or the second bidirectional AC / DC converter are superimposed with a bidirectional DC / DC converter. The final functional unit is still a bidirectional AC / DC converter. Adding a bidirectional DC / DC can achieve isolation, voltage matching and other purposes.

[0065] In the above three-port bidirectional power converter, the first inductor and the second inductor are coupled to the first AC power port, the second inductor and the third inductor are coupled to the second AC power port, the second full-bridge network is coupled to the DC power port, the first bridge arm, the first inductor L1, the second bridge arm and the second inductor L2 constitute a first bidirectional AC / DC converter, the second bridge arm is a common bridge arm, the second bridge arm, the second inductor L2, the third bridge arm and the third inductor L3 constitute a second bidirectional AC / DC converter, the first full-bridge network 200, the resonant unit 300 and the second full-bridge network 400 constitute a bidirectional DC / DC converter, and the first bidirectional AC / DC converter, the second bidirectional AC / DC converter, and the bidirectional DC / DC converter are all connected across the two ends of the bus capacitor. The three-port bidirectional power converter forms a three-port AC / DC hybrid energy pipeline system, wherein the first bidirectional AC / DC converter, the second bidirectional AC / DC converter and the bidirectional DC / DC converter can all realize the bidirectional flow of energy in the same circuit, and can provide different energy pipeline systems for the AC / DC hybrid power supply system using the three-port bidirectional power converter.

[0066] In a specific implementation manner, the first switch S1, the second switch S2, the third switch S3, the fourth switch S4, the fifth switch S5 and the sixth switch S6 are all fully controlled switch devices, for example, they may be metal-oxide-semiconductor field-effect transistors (MOSFET) or insulated gate bipolar transistors (IGBT).

[0067] In the above-mentioned invention embodiment, the structure of the first full-bridge network 200 is as follows: Figure 4a As shown, the fourth bridge arm includes a first component ZJ1 and a second component ZJ2 connected in series, the fifth bridge arm includes a third component ZJ3 and a fourth component ZJ4 connected in series, the midpoint of the fourth bridge arm is the series connection point of the first component ZJ1 and the second component ZJ2, the midpoint of the fifth bridge arm is the series connection point of the third component ZJ3 and the fourth component ZJ4, and the first full-bridge network 200 can have the following specific implementations:

[0068] Method 1: The first component ZJ1, the second component ZJ2, the third component ZJ3 and the fourth component ZJ4 are all fully controlled switch components, such as Figure 5a , Figure 5b shown.

[0069] In a specific implementation, the fully-controlled switch assembly includes a fully-controlled switch device, or includes a fully-controlled switch device and a capacitor element connected in parallel, such as Figure 5a , Figure 5b shown.

[0070] Mode 2: The first component ZJ1 and the second component ZJ2 are fully controlled switch components, and the third component ZJ3 and the fourth component ZJ4 are capacitor components, such as Figure 5c , Figure 5d As shown; or, the first component ZJ1 and the second component ZJ2 are capacitor elements, and the third component ZJ3 and the fourth component ZJ4 are fully controlled switch components, such as Figure 5e , Figure 5f shown.

[0071] Mode 3: The first component ZJ1 and the third component ZJ3 are fully controlled switch components, and the second component ZJ2 and the fourth component ZJ4 are two primary windings of the same coupling transformer, such as Figure 5g , Figure 5h As shown; or, the first component ZJ1 and the third component ZJ3 are two primary windings of the same coupling transformer, and the second component ZJ2 and the fourth component ZJ4 are fully controlled switch components, such as Figure 5i , Figure 5j shown.

[0072] It should be noted that the relative positions of the above-mentioned first component ZJ1, second component ZJ2, third component ZJ3 and fourth component ZJ4 are only for the convenience of describing the technical solution. The interchange of the positions of the first component ZJ1, second component ZJ2 and third component ZJ3, fourth component ZJ4, and the overall interchange of the positions of the first component ZJ1, second component ZJ2, third component ZJ3 and fourth component ZJ4 do not affect the structure of the circuit and all fall within the scope of protection of the present invention.

[0073] In practical applications, the first full-bridge network 200 can be configured in one of the three specific implementations described above, which is not limited here.

[0074] In the above-mentioned invention embodiment, the structure of the second full-bridge network 400 is as follows: Figure 4bAs shown, the sixth bridge arm includes a fifth component ZJ5 and a sixth component ZJ6 connected in series, the seventh bridge arm includes a seventh component ZJ7 and an eighth component ZJ8 connected in series, the midpoint of the seventh bridge arm is the series connection point of the fifth component ZJ5 and the sixth component ZJ6, and the eighth bridge arm is the series connection point of the seventh component ZJ7 and the eighth component ZJ8. The second full-bridge network 400 can have the following specific implementations:

[0075] Method 1: The fifth component ZJ5, the sixth component ZJ6, the seventh component ZJ7 and the eighth component ZJ8 are all fully controlled switch components, such as Figure 5a , Figure 5b In a specific embodiment, the fully-controlled switch assembly includes a fully-controlled switch device, or includes a fully-controlled switch device and a capacitor element connected in parallel, such as Figure 5a , Figure 5b shown.

[0076] Method 2: The fifth component ZJ5 and the sixth component ZJ6 are fully controlled switch components, and the seventh component ZJ7 and the eighth component ZJ8 are capacitor components, such as Figure 5c , Figure 5d As shown; or, the fifth component ZJ5 and the sixth component ZJ6 are capacitor elements, and the seventh component ZJ7 and the eighth component ZJ8 are fully controlled switch components, such as Figure 5e , Figure 5f Show.

[0077] Method 3: The fifth component ZJ5 and the seventh component ZJ7 are fully controlled switch components, and the sixth component ZJ6 and the eighth component ZJ8 are two secondary windings of the same coupling transformer, such as Figure 5g , Figure 5h As shown; or, the fifth component ZJ5 and the seventh component ZJ7 are two secondary windings of the same coupling transformer, and the sixth component ZJ6 and the eighth component ZJ8 are fully controlled switch components, such as Figure 5i , Figure 5j shown.

[0078] It should be noted that the relative positions of the fifth component ZJ5, the sixth component ZJ6, the seventh component ZJ7 and the eighth component ZJ8 are only for the convenience of describing the technical solution. The interchange of the positions of the fifth component ZJ5, the sixth component ZJ6 and the seventh component ZJ7 and the eighth component ZJ8, as well as the overall interchange of the positions of the fifth component ZJ5, the sixth component ZJ6, the seventh component ZJ7 and the eighth component ZJ8 do not affect the structure of the circuit and all fall within the scope of protection of the present invention.

[0079] In practical applications, the second full-bridge network 400 can be configured in one of the three specific implementations described above, which is not limited here.

[0080] In the above-mentioned three-port bidirectional power converter, the first full-bridge network 200 and the second full-bridge network 400 are controlled using a synchronous modulation mode. In a specific implementation, when the first component ZJ1 to the eighth component ZJ8 are all fully controlled switch components, the bridge arms of the first full-bridge network 200 and the second full-bridge network 400 are controlled using complementary drive signals, and the first component ZJ1 of the first full-bridge network 200 is at least completely synchronized with the drive signal of the fifth component ZJ5 or the sixth component ZJ6 of the second full-bridge network 400, and the bridge arms of the first full-bridge network 200 and the second full-bridge network 400 are respectively set with dead time.

[0081] In the above three-port bidirectional power converter, specifically, the first full-bridge network 200 and the second full-bridge network 400 can simultaneously adopt a PFM mode with a fixed duty cycle and an adjustable frequency for synchronous modulation; or, the first full-bridge network 200 and the second full-bridge network 400 can also simultaneously adopt a PWM mode with a fixed frequency and an adjustable duty cycle for synchronous modulation;

[0082] In one possible implementation, the first full-bridge network 200 and the second full-bridge network 400 are controlled using a set of complementary drive signals with a duty cycle of 50%. Specifically, when the first component ZJ1 to the eighth component ZJ8 are all fully controlled switch components, the first component ZJ1, the fourth component ZJ4 of the first full-bridge network 200 and the fifth component ZJ5 and the eighth component ZJ8 of the second full-bridge network 400 are controlled using drive signals from the same source, and the second component ZJ2, the third component ZJ3 of the first full-bridge network 200 and the sixth component ZJ6 and the seventh component ZJ7 of the second full-bridge network 400 are controlled using signals complementary to the above drive signals.

[0083] In the above-mentioned embodiment of the invention, specifically, the resonance unit 300 may include a first resonance circuit, and the first resonance circuit includes a first resonance inductor Lr1 and a first resonance capacitor Cr1 connected in series. Figure 6a As shown, the first resonant capacitor Cr1 and the first resonant inductor Lr1 form a resonant network, which provides zero voltage turn-on or zero current turn-off conditions for the fully controlled switching devices in the first full-bridge network 200 and the second full-bridge network 400, produces a soft switching effect, reduces switching losses, and improves the conversion efficiency of the bidirectional DC / DC converter.

[0084] In a specific implementation, when the first full-bridge network 200 and / or the second full-bridge network 400 includes a capacitor element, for example, the first component ZJ1 and the second component ZJ2 are fully-controlled switch components, the third component ZJ3 and the fourth component ZJ4 are capacitor elements, or the fully-controlled switch component includes a fully-controlled switch device and a capacitor element connected in parallel, the first resonant circuit may only be provided with the first resonant inductor Lr1, such as Figure 6bAs shown, the capacitor elements in the first full-bridge network 200 and / or the second full-bridge network 400 and the first resonant inductor Lr1 form a resonant network, which creates a zero voltage turn-on condition during the turn-on process of the fully-controlled switching devices in the first full-bridge network 200 and the second full-bridge network 400, or creates a zero current turn-off condition during the turn-on process of the fully-controlled switching devices in the first full-bridge network 200 and the second full-bridge network 400, thereby producing a soft switching effect, reducing switching losses, and improving the conversion efficiency of the bidirectional DC / DC converter.

[0085] In a specific implementation, the resonance unit 300 further includes an excitation inductor Lm, and the excitation inductor Lm is connected across two branches of the first resonance circuit. Figure 7a and Figure 7b As shown, by increasing the excitation inductance Lm, the impedance characteristic curve of the resonant cavity can be changed, thereby changing the gain curve of the resonant unit 300.

[0086] In a possible implementation manner, the resonance unit 300 further includes a transformer T, and the first resonance circuit is connected in series to the primary winding of the transformer T. Figure 8a and Figure 8b As shown, the resonance unit 300 can achieve high frequency isolation, and the energy of the resonance cavity is transmitted through the transformer T, which can increase the voltage range of the DC port. Specifically, the transformer T is designed according to a preset turns ratio, and the voltage amplitude at both ends of the transformer T can be matched. In a specific implementation, the transformer T can be an isolation transformer.

[0087] In a specific implementation, when the first full-bridge network 200 includes two primary windings of the same coupling transformer, the two primary windings of the same coupling transformer in the first full-bridge network 200 are the primary windings of the transformer T in the resonance unit 300; when the second full-bridge network 400 includes two secondary windings of the same coupling transformer, the two secondary windings of the same coupling transformer T in the second full-bridge network 400 are the secondary windings of the transformer T in the resonance unit 300.

[0088] In a specific implementation, when the resonance unit 300 includes a transformer T, the first resonance circuit is connected in series to the primary winding of the transformer T, and the excitation inductance Lm is connected in parallel to both ends of the primary winding of the transformer T. Figure 8c shown.

[0089] In a possible implementation, when the resonance unit 300 includes a transformer T, the resonance unit 300 further includes a second resonance circuit, which is connected in series to the secondary winding of the transformer T; the second resonance circuit includes a second resonance capacitor Cr2 and / or a second resonance inductor Lr2, such as Figure 9a , Figure 9b and Fig.9cIn a specific implementation, the resonance unit 300 may be composed of a first resonance circuit, an excitation inductor Lm, a transformer T, and a second resonance circuit, as shown in FIG. Figure 9d Alternatively, the resonant unit 300 may be composed of a first resonant circuit, a transformer T and a second resonant circuit, as shown in Fig.9e , Figure 9f , Figure 9g and Figure 9h shown.

[0090] It should be noted that the inductance elements and capacitance elements on both sides of the transformer T can always be equivalent to one side of the transformer T, and the inductance elements and capacitance elements on the opposite side of the transformer T can also be equivalent to both sides of the transformer T.

[0091] In a possible implementation manner, the three-port bidirectional power converter further includes a current sampling device Sam, such as Fig.10 As shown, the current sampling device can be a Hall current sampling device, a current transformer, or a shunt meter. The current sampling device is connected in series with the first inductor L1, the second inductor L2, and the third inductor L3, respectively, so as to realize the collection, detection, and observation of the current.

[0092] In real applications, the energy pipeline system is widely used. For example, the first AC power port is connected to the mains, the second AC power port is connected to a load with an energy feedback system, such as a motor load, and the first DC port is connected to a DC energy storage device. In such a system, the mains and the battery can simultaneously power the load, and the load feedback energy can also be fed back to the grid or stored in the battery. The mains can also charge the battery alone, and the battery can also be used to compensate for the power factor of the mains. In another application, the first AC power port is connected to the mains, the second AC power port is connected to another AC power supply (wind power generation, oil engine, uninterruptible power supply), and the first DC power port is connected to a DC energy storage device; when the second AC power port is connected to a wind power generation device, a microgrid power generation system can be formed; when the second AC power port is connected to an oil engine device, a starting and power generation device shared by AC and DC can be formed; when the second AC power port is connected to an uninterruptible power supply device, a stable and reliable DC power supply device can be formed at the first DC power port. Therefore, depending on the different devices coupled to each port, the application of AC / DC hybrid bidirectional energy pipeline system is very extensive.

[0093] The three-port bidirectional power converter provided by the above-mentioned embodiment of the invention provides different energy pipeline systems according to different types of power sources coupled to the second AC power port.

[0094] In a possible implementation, Figure 3As shown, in the above three-port bidirectional power converter, the first AC power port is coupled to the mains, the second AC power port is coupled to the second AC source, and the DC power port is coupled to the DC energy storage device, that is, the second end of the first inductor L1 is coupled to the first live wire L of the mains, and the third inductor L3 is coupled to the second AC source. Since the second bridge arm is a common bridge arm, the second end of the second inductor L2 is coupled to the mains and the neutral wire N of the second AC source, and the two ends of the sixth bridge arm and the seventh bridge arm in parallel in the second full-bridge network 400 are coupled to the DC energy storage device, and the mains and the second AC source can provide energy for the DC energy storage device at the same time; when the mains is off, the second AC source and the DC energy storage device can also jointly supply power to the load connected to the mains side according to a preset energy distribution ratio.

[0095] In another possible implementation, Fig.11 As shown, in the three-port bidirectional power converter, the second AC power port can also be coupled to the energy feedback load, that is, the second end of the first inductor L1 is coupled to the first live wire L of the mains, the second end of the third inductor L3 is coupled to the energy feedback load, the second end of the second inductor L2 is coupled to the mains and the neutral wire N of the second AC source, the mains and the DC energy storage device can jointly provide energy for the energy feedback load at the same time, and when the energy feedback load feeds back energy, it can choose to feed back the energy to the DC energy storage device or the mains according to the pre-set conditions, or feed back to the mains and the DC energy storage device at the same time;

[0096] Several implementation methods of a three-port bidirectional power converter are described in detail below.

[0097] In a possible implementation, Fig.12As shown, in the above three-port bidirectional power converter, the first component ZJ1, the second component ZJ2, the third component ZJ3 and the fourth component ZJ4 in the first full-bridge network 200 are the seventh switch S7, the eighth switch S8, the ninth switch S9 and the tenth switch S10 respectively, the resonant unit 300 includes a first resonant inductor Lr1, a first resonant capacitor Cr1, an excitation inductor Lm and a transformer T, and the fifth component ZJ5, the sixth component ZJ6, the seventh component ZJ7 and the eighth component ZJ8 in the second full-bridge network 400 are the eleventh switch S11, the twelfth switch S12 and the twelfth switch S13 respectively. The switch S12, the thirteenth switch S13 and the fourteenth switch S14, the seventh switch S7, the tenth switch S10, the eleventh switch S11 and the fourteenth switch S14 are controlled by synchronous modulation, and keep synchronous on-time in a high-frequency switching cycle, the seventh switch S7, the tenth switch S10 and the eighth switch S8, the ninth switch S9 use complementary drive signals and set dead time, the eleventh switch S11, the fourteenth switch S14 and the twelfth switch S12, the thirteenth switch S13 use complementary drive signals and set dead time. In this embodiment, the first resonant inductor Lr1 and the first resonant capacitor Cr1 are not adjacently connected in series, but if the current flows completely through the series circuit, then the position swap of the components in the series circuit has no effect.

[0098] The first full-bridge network 200 and the second full-bridge network 400 are controlled in a synchronous modulation mode. During a high-frequency synchronous opening time, the voltage on the DC side of the first full-bridge network 200 is coupled to the voltage on one side of the resonance unit 300 as V1, and the voltage on the DC side of the second full-bridge network 400 is coupled to the voltage on the other side of the resonance unit 300 as V2. If the transformation ratio of the transformer TT is N:1, when V1 is greater than N×V2, the working state of the first full-bridge network 200 is equivalent to that in the full-bridge chopping mode, and the working state of the second full-bridge network 400 is equivalent to that in the full-bridge chopping mode. The working state of 0 is equivalent to the full-bridge rectification mode, and the flow direction of the active energy is from the first full-bridge network 200 to the second full-bridge network 400; when V1 is less than N×V2; the working state of the first full-bridge network 200 is equivalent to the full-bridge rectification mode, and the working state of the second full-bridge network 400 is equivalent to the full-bridge chopping mode, and the flow direction of the active energy is from the second full-bridge network 400 to the first full-bridge network 200; when V1 is equal to N×V2; the average active energy between the first full-bridge network 200 and the second full-bridge network 400 is zero.

[0099] In a possible implementation, Fig.13As shown, in the above three-port bidirectional power converter, the first component ZJ1, the second component ZJ2, the third component ZJ3 and the fourth component ZJ4 in the first full-bridge network 200 are the seventh switch S7, the eighth switch S8, the first capacitor C1 and the second capacitor C2 respectively, and the fifth component ZJ5, the sixth component ZJ6, the seventh component ZJ7 and the eighth component ZJ8 in the second full-bridge network 400 are the eleventh switch S11, the twelfth switch S12, the thirteenth switch S13 and the fourteenth switch S14 respectively. The first resonant inductor Lr1 and the first capacitor C1 and the second capacitor C2 of the first full-bridge network 200 form a series resonance. The first full-bridge network 200 and the second full-bridge network 400 are controlled in a synchronous modulation mode. During a high-frequency synchronous opening time, the voltage on the DC side of the first full-bridge network 200 is coupled to the voltage on one side of the resonance unit 300 as V1, and the voltage on the DC side of the second full-bridge network 400 is coupled to the voltage on the other side of the resonance unit 300 as V2. If the transformation ratio of the transformer TT is N:1, when V1 is greater than N×V2, the working state of the first full-bridge network 200 is equivalent to the half-bridge chopping mode, the working state of the second full-bridge network 400 is equivalent to the full-bridge rectification mode, and the flow direction of the active energy is from the first full-bridge network 200 to the second full-bridge network 400; when V1 is less than N×V2, the working state of the first full-bridge network 200 is equivalent to the voltage doubling rectification state, the working state of the second full-bridge network 400 is equivalent to the full-bridge rectification mode, and the flow direction of the active energy is from the second full-bridge network 400 to the first full-bridge network 200.

[0100] In a possible implementation, Fig.14As shown, in the above three-port bidirectional power converter, the first component ZJ1, the second component ZJ2, the third component ZJ3 and the fourth component ZJ4 in the first full-bridge network 200 are respectively fully-controlled switch components, and the fully-controlled switch components include fully-controlled switch devices and capacitor elements connected in parallel, that is, the first full-bridge network 200 includes a seventh switch S7, an eighth switch S8, a ninth switch S9, a tenth switch S10, a first capacitor C1, a second capacitor C2, a third capacitor C3 and a fourth capacitor C4, and the first capacitor C1, the second capacitor C2, the third capacitor C3, the fourth capacitor C4 in the first full-bridge component are harmoniously The first resonant inductor Lr1 of the resonator unit 300 forms a series resonance, and the resonator unit 300 includes a three-winding transformer T, the first winding is used as the primary side of the transformer T, the second winding and the third winding are used as the secondary side of the transformer T, and the second winding and the third winding are respectively shared with the sixth component ZJ6 and the eighth component ZJ8 of the second full-bridge network 400. Specifically, the fifth component ZJ5, the sixth component ZJ6, the seventh component ZJ7 and the eighth component ZJ8 of the second full-bridge network 400 are respectively the eleventh switch S11, the second winding of the transformer T, the twelfth switch, and the third winding of the transformer T. According to the above-mentioned similar analysis method, the two working states of the first full-bridge network 200 can be equivalent to the full-bridge chopping mode and the double full-bridge rectification mode, respectively, and the two working states of the second full-bridge network 400 can be equivalent to the push-pull chopping mode and the full-wave rectification mode, respectively.

[0101] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the technical field not disclosed in the present disclosure. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present disclosure are indicated by the following claims.

[0102] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A three-port bidirectional power converter, characterized in that: It includes a three-phase H-bridge circuit unit, a bus capacitor, a first full-bridge network, a resonant unit and a second full-bridge network connected in sequence; The three-phase H-bridge circuit unit includes a first bridge arm, a second bridge arm, a third bridge arm, a first inductor, a second inductor and a third inductor, the first bridge arm includes a first switch and a second switch connected in series, the second bridge arm includes a third switch and a fourth switch connected in series, the third bridge arm includes a fifth switch and a sixth switch connected in series, the first bridge arm, the second bridge arm and the third bridge arm are connected in parallel and are respectively connected across the two ends of the bus capacitor, the first end of the first inductor is connected to the midpoint of the first bridge arm, the first end of the second inductor is connected to the midpoint of the second bridge arm, the first end of the third inductor is connected to the midpoint of the third bridge arm, the second end of the first inductor and the second end of the second inductor are connected to the first AC power supply port, and the second end of the third inductor and the second end of the second inductor are connected to the second AC power supply port; The first full-bridge network includes a fourth bridge arm and a fifth bridge arm, the fourth bridge arm and the fifth bridge arm are connected in parallel and are respectively connected across the two ends of the bus capacitor, wherein the fourth bridge arm includes a first component and a second component connected in series, and the fifth bridge arm includes a third component and a fourth component connected in series; The first component, the second component, the third component and the fourth component are all fully controllable switch components; or, The first component and the second component are fully controlled switch components, and the third component and the fourth component are capacitor elements; or, The first component and the second component are capacitor elements, and the third component and the fourth component are fully controlled switch components; or, The first component and the third component are fully controlled switch components, and the second component and the fourth component are two primary windings of the same coupling transformer; or, The first component and the third component are two primary windings of the same coupling transformer, and the second component and the fourth component are fully controlled switch components; The fully-controlled switch assembly includes a fully-controlled switch device, or includes a fully-controlled switch device and a capacitor element connected in parallel; The second full-bridge network includes a sixth bridge arm and a seventh bridge arm connected in parallel, and both ends of the sixth bridge arm and the seventh bridge arm of the second full-bridge network are connected in parallel to a DC power supply port, wherein the sixth bridge arm includes a fifth component and a sixth component connected in series, and the seventh bridge arm includes a seventh component and an eighth component connected in series; The fifth component, the sixth component, the seventh component and the eighth component are all fully controlled switch components; or, The fifth component and the sixth component are fully controlled switch components, and the seventh component and the eighth component are capacitor elements; or, The fifth component and the sixth component are capacitor elements, and the seventh component and the eighth component are fully controlled switch components; or, The fifth component and the seventh component are fully controlled switch components, and the sixth component and the eighth component are two secondary windings of the same coupling transformer; or, The fifth component and the seventh component are two secondary windings of the same coupling transformer, and the sixth component and the eighth component are fully controlled switch components; The first full-bridge network is synchronously modulated with the second full-bridge network; The input end of the resonance unit is connected to the midpoint of the fourth bridge arm and the midpoint of the fifth bridge arm respectively, and the output end of the resonance unit is connected to the midpoint of the sixth bridge arm and the midpoint of the seventh bridge arm respectively.

2. The three-port bidirectional power converter according to claim 1, characterized in that: The resonance unit includes a first resonance circuit. When the first full-bridge network and / or the second full-bridge network includes a capacitive element, the first resonance circuit includes a first resonance inductor.

3. The three-port bidirectional power converter according to claim 1, characterized in that: The resonance unit includes a first resonance circuit including a first resonance inductor and a first resonance capacitor connected in series.

4. The three-port bidirectional power converter according to claim 3, characterized in that: The resonance unit further includes an excitation inductor, and the excitation inductor is connected across two branches of the first resonance circuit.

5. The three-port bidirectional power converter according to claim 3, characterized in that: The resonance unit further includes a transformer, and the first resonance circuit is connected in series to the primary winding of the transformer.

6. The three-port bidirectional power converter according to claim 5, characterized in that: When the first full-bridge network includes two primary windings of the same coupling transformer, the two primary windings of the same coupling transformer in the first full-bridge network are the primary windings of the transformer in the resonant unit; When the second full-bridge network includes two secondary windings of the same coupling transformer, the two secondary windings of the same coupling transformer in the second full-bridge network are the secondary windings of the transformer in the resonant unit.

7. The three-port bidirectional power converter according to claim 5 or 6, characterized in that: The resonance unit further comprises a second resonance circuit, wherein the second resonance circuit is connected in series to the secondary winding of the transformer in the resonance unit; The second resonant circuit includes a second resonant capacitor and / or a second resonant inductor.

8. The three-port bidirectional power converter according to claim 1, characterized in that: It also includes a current sampling device, which is connected in series with the first inductor, the second inductor and the third inductor respectively.

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