A current conversion device

Abstract

The present invention discloses a current conversion device, which relates to a power electronic current conversion technology, and includes: a direct current power supply, a switch unit, a primary resonant circuit, a first comparison unit, a dual integration unit, and a second comparison unit; wherein the first comparison unit, the dual integration unit, and the second comparison unit constitute a controller; the switch unit is composed of no less than one switch component, and in two working states, the current in the primary inductor is magnetically coupled to induce a current in a secondary energy receiving unit; a voltage sensor is provided in the primary resonant circuit, and the obtained signal is sent to the controller to control the switch unit to switch between the first working state and the second working state; different from the traditional current conversion device, the present invention divides an energy transmission process into independent current injection and resonance processes, and gets rid of the constraint that the operating frequency and phase of the switch component in the traditional inductive coupling energy transmission system must be consistent with the resonant circuit, avoids frequency detuning, and reduces the difficulty of the control strategy.

Description

Technical Field

[0001] The embodiments of the present invention relate to a power electronic conversion technology, and in particular to the fields of converters, wireless energy transmission, induction heating and electric welding equipment. Background Art

[0002] A converter is a device that converts power, such as DC / DC (direct current / direct current conversion), AC / DC (alternating current / direct current conversion), DC / AC (direct current / alternating current conversion), and AC / AC (alternating current / alternating current conversion). The theoretical basis of the converter is the principle of energy transfer using wireless energy transmission between the primary (primary side) and the secondary (secondary side). That is, a converter is used on the primary (primary side) to convert DC or low-frequency grid power into high-frequency power to drive the transmitting coil, and the transmitting coil transfers the high-frequency energy to the secondary (secondary side) through magnetic coupling, which is the so-called inductive coupling energy transfer technology (IPT). In principle, the IPT system is a transformer system that forms a magnetic coupling link through a pair of coils to transfer energy from the primary side to the secondary side. However, due to the leakage inductance of the magnetic coupling system, especially the mutual inductance of loosely coupled transformer systems such as wireless energy transmission systems is much smaller than the leakage inductance, and the coupling ability between the primary side and the secondary side is poor. The presence of leakage inductance causes the emergence of reactive power and reduces the transmission efficiency. Usually, the problem of poor coupling ability is solved by adding a resonant compensation network to the primary and secondary circuits, such as LLC resonant compensation. Due to the addition of a resonant network in the circuit, the converter and the resonant circuit are strongly coupled to each other, which requires the operating frequency and phase of the converter to be consistent with the resonant network. Also, due to the strong coupling between the converter and the resonant network, the soft switching conditions of the switching devices in the converter are not easy to obtain, which greatly increases the difficulty of the switch control strategy. In actual use, the converter needs to adjust the power. Currently, the commonly used methods for adjusting power include phase shifting and frequency conversion. However, due to the strong coupling between the converter and the resonant network, these power adjustment methods have problems such as the deviation of the switching devices from the soft switching conditions or the deviation of the operating frequency from the resonant point. In addition, the actual application scenario of the IPT system is relatively complex. It is a variable parameter system, such as load changes, coil asymmetry, air gap changes, etc. Parameter changes will cause the resonant network frequency to drift, resulting in detuning between the converter and the resonant network and difficulty in frequency tracking, which greatly affects the practical application of the IPT system. Therefore, many scholars and engineers are looking for better control devices and methods for controlling the IPT system. Summary of the invention

[0003] The embodiment of the present invention provides a converter device and a control method thereof, so as to reduce the control difficulty of the converter system.

[0004] The present invention provides a current conversion device, comprising:

[0005] DC power supply; switch unit; primary resonant circuit; first comparison unit; double integration unit; second comparison unit;

[0006] in:

[0007] The primary resonant circuit includes a primary capacitor, a primary inductor and a voltage sensor V connected in parallel between the first port B1 and the second port B2, and the primary resonant circuit is connected to the secondary energy receiving unit through electromagnetic coupling;

[0008] The switch unit includes at least one switch component. If the switch unit is in a first working state, the switch unit injects current into the primary resonant circuit. If the switch unit is in a second working state, the switch unit stops injecting current into the primary resonant circuit, and the primary resonant circuit resonates.

[0009] The first comparison unit includes at least one software comparator or hardware comparator, and its input is the output signal V of the voltage sensor;

[0010] The dual integration unit includes at least one software integrator or hardware integrator, and the output of the dual integration unit is Dn.

[0011] The second comparison unit includes at least one software comparator or hardware comparator, whose output is Gm, and the input of the second comparison unit includes the dual integration unit output Dn and the reference value Fjn;

[0012] The first comparison unit, the dual integration unit, and the second comparison unit constitute a controller, the input of the controller is the input signal V of the voltage sensor and the reference quantity Fjn, and the output quantity is the output Gm of the second comparison unit;

[0013] The controller generates a control output Gm according to the voltage sensor output signal V and the reference quantity Fin, and Gm is used to control each switch component in the switch unit.

[0014] The reference quantity Fjn is used to control the switch unit to maintain in the first working state, and the resonant frequency of the primary resonant circuit is used to control the maintenance time of the switch unit in the second working state.

[0015] The voltage sensor monitors the working state of the primary resonant circuit, and the controller autonomously controls the switch unit to automatically switch between the first working state and the second working state during operation according to the output signal V of the voltage sensor and the reference quantity Fjn.

[0016] The dual integration unit includes a first integration loop and a second integration loop formed by a first integration resistor RI1, a second integration resistor RI2, a common integration capacitor CI1 and a clamping diode DI1.

[0017] The DC power input is connected to a single-phase or three-phase power supply grid, including a rectifier bridge, a ballast inductor Le, and a bus capacitor Ce.

[0018] The DC power source may be a battery.

[0019] The converter device further comprises the secondary energy receiving unit, which receives energy transferred by the primary resonant circuit through electromagnetic coupling.

[0020] The voltage sensor V includes a first sampling resistor RV1, a second sampling resistor RV2, a third sampling resistor RV3 and a fourth sampling resistor RV4; the first sampling resistor RV1 and the second sampling resistor RV2 form a first voltage divider, and the voltage at point B1 of the primary resonant circuit is stepped down by the first voltage divider and sent to the input terminal C- of the first comparison unit; the third sampling resistor RV3 and the fourth sampling resistor RV4 form a second voltage divider, and the voltage at point B2 of the primary resonant circuit is stepped down by the second voltage divider and sent to the input terminal C+ of the first comparison unit;

[0021] The switch unit includes a first switch component S1 and a first diode D1, wherein:

[0022] When the first switch component S1 is in the on state and the first diode D1 is in the off state, the switch unit is in the first current injection mode of the first working state, and the first current injection mode is that the switch unit injects current into the B1 point of the primary resonant circuit;

[0023] When the first switch component S1 is in the off state and the first diode D1 is in the on state, the switch unit is in the second current injection mode of the first working state, and the second current injection mode is that the switch unit injects current into the point B2 of the primary resonant circuit;

[0024] When the first switch component S1 is in the cut-off state and the first diode D1 is in the cut-off state, the switch unit is in the second working state.

[0025] The switch unit may further include a second switch component S2, a third switch component S3, a fourth switch component S4, a fifth switch component S5 and a second diode D2, a third diode D3, a fourth diode D4, and a fifth diode D5, wherein:

[0026] When the second switch component S2 and the fifth switch component S5 are in the on state, and the remaining switch components and all diodes are in the off state, or when the third diode D3 and the fourth diode D4 are in the on state, and the remaining diodes and all switch components are in the off state, the switch unit is in the first current injection mode of the first working state, and the first current injection mode is that the switch unit injects current into the B1 point of the primary resonant circuit;

[0027] When all the switch components and the third diode D3 and the fourth diode D4 are in the off state, the second diode D2 and the fifth diode D5 are in the on state, and when the third switch component S3 and the fourth switch component S4 are in the on state, and the remaining switch components and all diodes are in the off state, the switch unit is in the second current injection mode of the first working state, and the second current injection mode is that the switch unit injects current into the B2 point of the primary resonant circuit;

[0028] When all the switch components and all the diodes are in the cut-off state, the switch unit is in the second working state.

[0029] The reference quantity Fjn can be used to adjust the output power of the converter.

[0030] Compared with the prior art, the present invention has the following improvements:

[0031] In the converter provided by the embodiment, if the switch unit is in the first working state, the switch unit inputs current into the primary inductor, the magnetic field energy increases to store energy, and the primary inductor transmits energy to the secondary energy receiving unit through electromagnetic coupling; if the switch unit is in the second working state, the switch unit stops injecting current into the primary inductor, and the primary resonant circuit starts to resonate, and during the resonance process, the primary inductor transmits energy to the secondary energy receiving unit through electromagnetic coupling. In the first working state of the converter, the primary inductor is decoupled from the primary capacitor, and the process of injecting current from the switch unit into the primary inductor is not affected by the primary capacitor; in the second working state of the converter, the switch unit is decoupled from the primary resonant circuit, and the resonance of the primary resonant circuit is not affected by the switch unit.

[0032] Compared with the pain point of strong coupling in traditional converters, the switch unit of the present invention is completely decoupled from the primary resonant circuit. Therefore, the switch components in the switch unit can ensure that they all work under soft switching conditions, and the switch control strategy is simple and reliable.

[0033] Compared with the difficulty of traditional converter power control, since in the first working state, the switch unit independently injects current into the primary inductor to increase the magnetic field energy, the system power can be controlled simply by controlling the maintenance time of the first working state, and the power regulation method is simple and reliable.

[0034] The voltage sensor monitors the working state of the primary resonant circuit, and the controller controls the switch unit to autonomously and periodically switch between the first working state and the second working state during operation according to the output signal V of the voltage sensor and the reference quantity Fjn, thereby realizing autonomous closed-loop control of the system. Therefore, compared with the pain point that the traditional converter and the resonant circuit need to resonate at the same frequency, the converter switch unit of the present invention and the primary resonant circuit do not need to resonate at the same frequency, thus avoiding the problem of difficult frequency tracking. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The figure is a schematic diagram of an application of a current conversion device of the present invention.

[0036] Figure 2 It is a schematic diagram of a first injection current mode of a switch unit in a first working state of the present invention.

[0037] Figure 3 It is a schematic diagram of a second injection current mode of a switch unit in a first working state of the present invention.

[0038] Figure 4 Schematic diagram of the relationship between the switch unit and the primary resonant circuit when the switch unit is in the second working state of the present invention.

[0039] Figure 5 This is a topological diagram of the DC power supply structure of the present invention.

[0040] Figure 6 It is a schematic diagram of the structure of the controller of the present invention.

[0041] Figure 7 This is a schematic diagram of the operation of the dual-integral unit when the switch unit of the present invention is in the second operation mode.

[0042] Figure 8 This is a schematic diagram of the operation of the dual-integral unit when the switch unit of the present invention is in the first operation mode.

[0043] Fig. 9 FIG. 4 is a schematic diagram of the relationship between the voltage sensor and the first comparison unit of the present invention.

[0044] Fig.10 It is a schematic diagram of the relationship between the first implementation scheme of the switch unit of the present invention and the primary resonant circuit.

[0045] Fig.11 This is a first injection current mode in which the switch unit injects current into the primary resonant circuit in the first working state of the first implementation scheme of the switch unit of the present invention.

[0046] Fig.12In the first working state of the first implementation scheme of the switch unit of the present invention, the switch unit injects current into the primary resonant circuit in a second injection current mode.

[0047] Fig.13 A schematic diagram of the relationship between the switch unit and the primary resonant circuit in the second working state of the first embodiment of the switch unit of the present invention.

[0048] Fig.14 This is a schematic diagram of an example of a first implementation scheme of the converter device of the present invention.

[0049] Fig.15 This is a schematic diagram of the main waveforms of a first implementation example of a current converter of the present invention.

[0050] Fig.16 It is a schematic diagram of the relationship between the second implementation scheme of the switch unit of the present invention and the primary resonant circuit.

[0051] Fig.17 This is a schematic diagram of the working mode in which the third diode and the fourth diode are turned on in the first injection current mode in which the switch unit injects current into the primary resonant circuit in the first working state of the second implementation scheme of the switch unit of the present invention.

[0052] Fig.18 This is a schematic diagram of the working mode in which the second switch component and the fifth switch component are turned on in the first injection current mode in which the switch unit injects current into the primary resonant circuit in the first working state of the second implementation scheme of the switch unit of the present invention.

[0053] Fig.19 This is a schematic diagram of the working mode in which the second diode and the fifth diode are turned on in the second injection current mode in which the switch unit injects current into the primary resonant circuit in the first working state of the second implementation scheme of the switch unit of the present invention.

[0054] Fig. 20 This is a schematic diagram of the working mode in which the third switch component and the fourth switch component are turned on in the second injection current mode in which the switch unit injects current into the primary resonant circuit in the first working state of the second implementation scheme of the switch unit of the present invention.

[0055] Fig.21 A schematic diagram of the relationship between the switch unit and the primary resonant circuit in the second working state of the second embodiment of the switch unit of the present invention.

[0056] Fig. 22 This is a schematic diagram of an example of a second implementation scheme of the converter device of the present invention.

[0057] Fig.23 This is a schematic diagram of the main waveforms of a second implementation example of a current converter of the present invention. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0059] It should be noted that when a component is said to be "fixed to" another component, it can be directly on another component or there can be a central component. When a component is said to be "connected to" another component, it can be directly connected to another component or there can be a central component at the same time.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0061] In order to at least partially solve the problems existing in the prior art, for example, how to solve the problems of converter frequency tracking and / or converter switch device state change control. An embodiment of the present invention provides a converter, wherein the converter comprises:

[0062] DC power supply; switch unit; primary resonant circuit; first comparison unit; double integration unit; second comparison unit;

[0063] in:

[0064] The primary resonant circuit has a resonant circuit formed by connecting the primary capacitor and the primary inductor in parallel between the first port B1 and the second port B2, and the primary resonant circuit is connected to the secondary energy receiving unit through magnetic coupling. The primary resonant circuit is configured with a voltage sensor V, and the voltage sensor V is used to monitor the working state of the primary resonant circuit, such as the resonant frequency and phase.

[0065] If the switch unit is in the first working state, the switch unit injects current into the primary resonant circuit; if the switch unit is in the second working state, the switch unit stops injecting current into the primary resonant circuit, and the primary resonant circuit resonates; in the two working states of the switch unit, energy is sent from the primary resonant circuit to the secondary energy receiving unit through electromagnetic coupling.

[0066] The first comparison unit, the dual integration unit, and the second comparison unit constitute a controller, the input of which is the output signal V of the voltage sensor and a reference quantity Fjn for controlling power, and the output of which is the output Gm of the second comparison unit.

[0067] The reference quantity Fjn is used to control the time that the switch unit is in the first working state; the resonant frequency of the primary resonant circuit is used to control the time that the switch unit is in the second working state.

[0068] The controller output Gm controls the switch component in the switch unit, driving the switch unit to switch between the first working state and the second working state, thereby forming an autonomous closed-loop control system: switch unit → primary resonant circuit → voltage sensor V → controller → switch unit.

[0069] In the converter provided by the embodiment, if the switch unit is in the first working state, the switch unit inputs current into the primary inductor, the magnetic field energy increases to store energy, and at the same time, the primary inductor transmits energy to the secondary energy receiving unit through electromagnetic coupling. If the switch unit is in the second working state, the switch unit stops injecting current into the primary inductor, the magnetic field energy stored in the primary inductor excites the primary resonant circuit to start resonance, and during the resonance, the primary inductor transmits energy to the secondary energy receiving unit through electromagnetic coupling. In the first working state of the converter, the primary inductor is decoupled from the primary capacitor, and the process of injecting current from the switch unit into the primary inductor is not affected by the primary capacitor. In the second working state of the converter, the switch unit is decoupled from the primary resonant circuit, and the resonance of the primary resonant circuit is not affected by the switch unit.

[0070] Since the switch unit is completely decoupled from the primary resonant circuit, the switch components in the switch unit can ensure that they all work under soft switching conditions, and the switch control strategy is simple and reliable. Since in the first working state, the switch unit independently injects current into the primary inductor to increase the magnetic field energy, the system power can be controlled simply by controlling the maintenance time of the first working state, and the power regulation method is simple and reliable.

[0071] The voltage sensor monitors the working state of the primary resonant circuit, and the controller controls the switch unit to autonomously and periodically switch between the first working state and the second working state during operation according to the output signal V of the voltage sensor and the reference quantity Fjn, thereby realizing autonomous closed-loop control of the system. Therefore, compared with the pain point that the traditional converter and the resonant circuit need to resonate at the same frequency, the converter switch unit of the present invention and the primary resonant circuit do not need to resonate at the same frequency, thus avoiding the problem of difficult frequency tracking.

[0072] The embodiment of the present invention provides a current conversion device, which can convert the power grid frequency AC power supply or the battery DC power supply into a high-frequency AC current, and the high-frequency AC current is electromagnetically coupled with the secondary energy receiving unit through the primary inductor, and a secondary current is induced in the secondary energy receiving unit. In this way, energy is transferred from the primary to the secondary.

[0073] Figure 1 This is a schematic diagram of the application of the converter device of the present invention provided in an embodiment of the present invention. Figure 1 The power supply system is a power supply system that converts the power grid frequency AC power or battery DC power into high-frequency AC power and provides energy to the secondary energy receiving unit by electromagnetic coupling. The power supply system includes a DC power supply 1, a switch unit 2, a primary resonant circuit 3, a secondary energy receiving unit 4, a first comparison unit 5, a dual integration unit 6, and a second comparison unit 7.

[0074] The DC power supply 1 can rectify the industrial frequency AC power of the city power grid into DC power, or directly use the DC power of the battery as the power supply of the converter. The output positive electrode Dc+ of the DC power supply 1 is connected to the A1 port of the switch unit 2, and the output negative electrode Dc- is connected to the A2 port. The voltage level of the power supply is not specifically limited here.

[0075] The switch unit 2 includes a plurality of switch components and a plurality of diodes, and the working states of the switch components and the diodes determine the working state of the switch unit. The two outputs of the switch unit are respectively connected to the B1 and B2 ports of the primary resonant circuit 3. In the first working state of the switch unit, the switch unit injects current into the B1 or B2 port of the primary resonant circuit, and in the second working state of the switch unit, the switch unit stops injecting current into the B1 or B2 port.

[0076] The primary resonant circuit 3 is composed of a primary capacitor 31 and a primary inductor 33 connected in parallel between B1 and B2, and a voltage sensor 32 is also connected in parallel between B1 and B2. The primary inductor transmits energy to the secondary energy receiving unit 4 through electromagnetic coupling.

[0077] The first comparison unit 5, the dual integration unit 6, and the second comparison unit 7 constitute a controller, the input of which is the input signal V of the voltage sensor and the reference quantity Fjn, and the output of which is the output Gm of the second comparison unit.

[0078] The voltage sensor 32 detects the working state of the primary resonant circuit in real time, and its output signal V is used as the input of the first comparison unit 5, and the signal V is used to determine the state of the output terminal Cn of the comparison unit 5. The output terminal Cn has a 0 level state and a high impedance state, which are used to characterize the real-time working condition of the primary resonant circuit, and the high impedance state means that the output terminal Cn is in an isolated state.

[0079] The output terminal Cn signal of the comparison unit 5 is sent to the dual integration unit 6 , and the dual integration unit generates an output signal Dn according to the working state of the Cn signal. The output signal Dn of the dual integration unit is sent to the second comparison unit 7 .

[0080] The reference quantity Fjn and the dual integration unit output signal Dn are used as input signals of the second comparison unit 7. According to the input signal Dn and the input signal Fjn, the second comparison unit generates an output signal Gm. Further, the output signal Gm is used to control the control signal of the switch component in the switch unit 2, control the working state of the switch component, and further control the working state of the switch unit.

[0081] Figure 2 is a schematic diagram of a first injection current mode of the switch unit in the first working state, see Figure 2 After the output current Ib1 of the switch unit 2 flows into the point B1 of the primary resonant circuit 3, it flows into the primary inductor 33 to form a primary inductor current IL1, and the magnetic field energy in the primary resonant circuit increases.

[0082] Figure 3 is a schematic diagram of a second current injection mode of the switch unit in the first working state, see Figure 3 After the output current Ib2 of the switch unit 2 flows into the point B2 of the primary resonant circuit 3, it flows in the reverse direction into the primary inductor 33 to form a primary inductor current IL2, and the magnetic field energy in the primary resonant circuit increases in the reverse direction.

[0083] Figure 4 Schematic diagram of the relationship between the switch unit and the primary resonant circuit when the switch unit is in the second working state. In this state, the switch unit 2 stops injecting current into the primary resonant circuit, and the primary capacitor 31 and the primary inductor 33 in the primary resonant circuit resonate to form a resonant current Ic1 in the primary resonant circuit.

[0084] Figure 5 The structure topology diagram of a DC power supply 1 includes a rectifier bridge 11, a ballast inductor Le (12), and a bus capacitor Ce (13). The input end of the rectifier bridge is connected to a three-phase or single-phase power grid, the positive end (+) of the output is connected to one end of the ballast inductor Le, and the negative end (-) is connected to one end of the bus capacitor Ce and serves as the negative end Dc- of the DC power supply. The other end of the ballast inductor and the other end of the bus capacitor serve as the positive end Dc+ of the DC power supply.

[0085] Figure 6 for Figure 1 The controller structure diagram described in Figure 6The controller includes a first comparing unit 5, a dual integrating unit 6, and a second comparing unit 7.

[0086] The first comparison unit 5 comprises a first open collector (open drain) comparator 51, the positive input terminal of the open collector comparator serving as the input terminal C+ of the controller, and the negative input terminal serving as the input terminal C- of the controller.

[0087] The dual integration unit 6 includes a first integration resistor RI1 (61), a second integration resistor RI2 (63), a common integration capacitor CI1 (64) and a clamping diode DI1 (62). The dual integration unit also includes a first reference voltage EI1, a second reference voltage EI2 and a third reference voltage EI3.

[0088] One end of the first integrating resistor RI1 (61) is connected to the first reference voltage EI1, and the other end is connected to one end of the common integrating capacitor CI1 (64) at point GI1 to form a first integrating loop; one end of the second integrating resistor RI2 (63) is connected to the third reference voltage EI3, and the other end is connected to the other end of the common integrating capacitor CI1 (64) at point GI2 to form a second integrating loop;

[0089] The output Cn of the first comparison unit 5 is connected to the point GI1. When the output Cn of the first comparison unit is in the 0 level state, the point GI1 is clamped at 0 potential, and the first integration loop stops the integration function. When the output Cn of the first comparison unit is in the high impedance state, the first integration loop starts the integration function.

[0090] When the first integration loop stops the integration function, the second integration loop starts the integration function, and when the first integration loop starts the integration function, the second integration loop stops the integration function.

[0091] The cathode of the clamping diode DI1 is connected to the second reference voltage EI2, and the anode is connected to the point GI2, so the voltage at the point GI2 cannot be greater than the second reference voltage EI2.

[0092] The point GI2 is the output Dn of the dual integration unit.

[0093] The second comparison unit 7 comprises a second open collector (open drain) comparator 71, the positive input terminal of the open collector comparator is connected to the reference quantity Fjn, and the negative terminal is connected to the output Dn of the dual integration unit.

[0094] Figure 7The schematic diagram of the working state of the dual integration unit 6 of the switch unit 5 in the second working mode of the present invention. When the switch unit 2 is in the second working state, the output Cn of the first comparison unit 5 is in a high impedance state, the diode DI1 (62) is turned on, and the dual integration unit GI2 (Dn) point is clamped to the second reference voltage EI2. The first integration loop is working, and the first reference voltage EI1 charges the common integration capacitor CI1 (64) through the first integration resistor RI1 (61), and the charging current Ic2. During the charging process, the Cn signal rises with the first reference voltage EI1 as the expected value.

[0095] Figure 8 The schematic diagram of the working state of the dual integration unit 6 of the switch unit 5 in the first working mode of the present invention. When the switch unit works in the first working mode, the output Cn of the first comparison unit 5 is in the 0 level state, the dual integration unit GI1 (Cn) point is clamped at the 0 level, the diode DI1 (62) is cut off, the second integration loop works, and the third reference voltage EI3 is reversely charged to the common integration capacitor CI1 (64) through the second integration resistor RI2 (63), and the charging current Ic3. During the charging process, the Dn signal rises with the third reference voltage EI3 as the expected value.

[0096] Fig. 9 The figure is a schematic diagram of the relationship between the voltage sensor 32 and the first comparison unit 5 of the controller. The voltage sensor includes: a first sampling resistor RV1 (321), a second sampling resistor RV2 (322), a third sampling resistor RV3 (323) and a fourth sampling resistor RV4 (324). The first sampling resistor and the second sampling resistor form a first voltage divider. The voltage at the point B1 of the primary resonant circuit is stepped down by the first voltage divider and sent to the input terminal C- of the first comparison unit 5 of the controller; the third sampling resistor and the fourth sampling resistor form a second voltage divider. The voltage at the point B2 of the primary resonant circuit is stepped down by the second voltage divider and sent to the input terminal C+ of the first comparison unit.

[0097] Fig.10 Schematic diagram of the relationship between the first implementation scheme of the switch unit 2 and the primary resonant circuit. Fig.10 The switch unit includes a first diode D1 (21) and a first switch component S1 (22), and the switch component has three ports: a drain, a source, and a gate.

[0098] See also Fig.10 The input terminal A1 of the switch unit is directly connected to the point B1 of the primary resonant circuit, the input terminal A2 is connected to the anode of the first diode D1 and the source of the first switch component S1, and the drain of the first switch component is connected to the cathode of the first diode and then to the point B2 of the primary resonant circuit.

[0099] Fig.11 In the first working state of the first implementation scheme of the switch unit, the switch unit injects a current into the primary resonant circuit in a first injection current mode. Fig.11 , the first diode D1 is turned off and the first switch component S1 is turned on. The current flows into the switch unit through Ib from A1, forming an output current Ib1 that flows into the primary resonant circuit B1. Further, Ib1 flows into the primary inductor 33, forming a primary inductor current IL1, and then flows back to the A2 port through the first switch component S1.

[0100] Fig.12 In the first working state of the first implementation scheme of the switch unit, the switch unit injects a second current injection mode of current into the primary resonant circuit. Fig.12 , the first diode D1 is turned on and the first switch component S1 is turned off. The current Ib flows into the switch unit via A2, and forms an output current Ib2 through the first diode D1 and flows into the primary resonant circuit B2. Further, Ib2 flows in the primary inductor 33 in the reverse direction, forms a reverse primary inductor current IL2, and then flows back to the switch unit and flows out of the A1 port.

[0101] Fig.13 FIG. 1 is a schematic diagram showing the relationship between the switch unit and the primary resonant circuit in the second working state of the first embodiment of the switch unit. Fig.13 In the second working state, the first switch component S1 and the first diode D1 are both in the cut-off state, and no current flows into the primary resonant circuit B1 or B2. When the switch unit is in the second working state, the primary capacitor 31 and the primary inductor 33 resonate in the primary resonant circuit to form a resonant current Ic2.

[0102] Fig.14 This is a schematic diagram of an embodiment of the first embodiment of the converter device of the present invention, which includes: a DC power supply 1, a switch unit 2, a primary resonant circuit 3, a controller 1 and a first switch drive circuit. The controller 1 includes a first comparison unit 5, a dual integration unit 6, and a second comparison unit 7. The concept and principle structure of the controller 1 can be referred to as Figure 1 , Figure 6 The first switch driving circuit is used to convert the output signal Gm of the controller 1 into a switch signal g1 for driving the switch component S1.

[0103] refer to Figure 1 , Figure 6 , Fig.14The working process of the first embodiment of a converter device of the present invention is as follows: the input terminals P and N of the DC power supply 1 are respectively connected to the live wire and the neutral wire of the city power grid to rectify the AC power of the city power grid into DC power. The DC power rectified by the DC power supply is sent to the switch unit 2, the positive pole Dc+ of the DC power supply is connected to A1, the negative pole Dc- is connected to A2, and the output of the switch unit 2 is respectively connected to the points B1 and B2 of the primary resonant circuit. The voltage sensor 32 in the primary resonant circuit 3 detects the working state of the primary resonant circuit, and its output C- and C+ are respectively sent to the input terminals C- and C+ of the controller 1. According to the working state of the primary resonant circuit sent by the voltage sensor, the first comparison unit 5, the dual integration unit 6 and the second comparison unit 7 in the controller 1 work together to obtain the control signal Gm for the first switch component in the switch unit 2. The control signal Gm is further converted by the first switch drive circuit to form a drive signal g1 for driving the first switch component S1. Through this process, a converter device of the present invention realizes system autonomous closed-loop control.

[0104] Through the closed-loop control of the system, the switch unit 2 periodically operates between the first working state and the second working state, converting the low-frequency AC power of the city grid or the DC power of the battery into high-frequency AC power, and then transferring the energy to the secondary energy receiving unit through the AC magnetic flux between the primary inductor 33 and the secondary energy receiving unit 4.

[0105] Fig.15 This is a schematic diagram of the main waveforms of the first embodiment of the converter device of the present invention. Fig.14 , Fig.15 , Fig.15 The output current Ib of the switch unit 2, the current IL of the primary inductor 33, the input signals C- and C+ of the first comparison unit 5, the signal waveforms of the dual integration unit GI1 (Cn) point, GI2 (Dn) point and the first switch drive circuit output g1 point are indicated, where the C- signal and the Fjn signal are indicated with dotted lines for a clearer comparison of the waveforms.

[0106] refer to Figure 7 , Fig.14 , Fig.15 In the interval [t0, t1] ([t3, t4]), signal C+>signal C-, the first comparison unit 5 works in the second working state, the output Cn is in a high impedance state, the first integral loop works, and the Cn signal rises with the first reference voltage EI1 as the expected value. Fig.15 It can be seen that in the interval [t0, t1] ([t3, t4]), Ib=0, the switch unit 2 stops outputting current to the primary resonant circuit 3, and IL1 changes in a sinusoidal form, indicating that the primary resonant circuit is resonant at this time. Fig.15It can also be seen that during this period Dn>Fjn, the second comparison unit outputs a low level signal Gm, the first switch driving circuit outputs a low level signal g1, and the switch component S1 is turned off.

[0107] refer to Figure 8 , Fig.14 , Fig.15 In the time interval [t1, t3], signal C+ < signal C-, the output Cn of the first comparison unit is in the 0 level state, the second integration loop works, and the Dn signal drops to less than Fjn and then rises linearly. Since in the time interval [t1, t3], Dn < Fjn, the output Gm signal of the second comparison unit is high level, the output signal g1 of the switch drive circuit is high level, the first switch component S1 in the switch unit is turned on, and the switch unit outputs current to the primary resonant circuit, Ib = IL1, and Ib rises linearly with IL1.

[0108] At time t3, when the Dn signal rises to Dn=Fjn signal, the second comparison unit output Gm changes to a low level again, and the switch drive circuit output g1 is also a low level to turn off the switch component S1. The switch unit returns to the second working mode and starts a new working cycle.

[0109] refer to Fig.12 , Fig.13 , Fig.14 , Fig.15 In the first implementation example of the converter device of the present invention, by sampling and comparing the voltage changes at points B1 and B2 in the primary resonant circuit 3, a feedback control link is formed by using a first comparison unit 5, a dual integration unit 6 and a second comparison unit 7 to perform closed-loop control on the switch unit 2, so that the switch unit can switch autonomously between the first working mode and the second working mode, thereby converting the low-frequency alternating current provided by the city power grid into high-frequency alternating current, and the high-frequency alternating current is coupled with the magnetic flux of the secondary energy receiving unit 4 through the primary inductance, and the energy is sent to the secondary energy receiving unit.

[0110] Fig.16 Schematic diagram of the relationship between the second embodiment of the switch unit 2 of the present invention and the primary resonant circuit. Fig.16 The switch unit includes a second switch component S2 (23), a third switch component S3 (25), a fourth switch component S4 (27), a fifth switch component S5 (29), a second diode D2 (24), a third diode D3 (26), a fourth diode D4 (28), and a fifth diode D5 (210), and the switch component has three ports: a drain, a source, and a gate.

[0111] See also Fig.16The drain of the second switch component S2 (23) and the third switch component S3 (25) is connected to the cathode of the second diode D2 (24) and the third diode D3 (26) at the input terminal A1 of the switch unit. The source of the fourth switch component S4 (27) and the fifth switch component S5 (29) is connected to the anode of the fourth diode D4 (28) and the fifth diode D5 (210) at the input terminal A2 of the switch unit. The source S2 (23) of the second switch component and the drain of the fourth switch component S4 (27) are connected to the anode of the second diode D2 (24) and the cathode of the fourth diode D4 (28) at the point B1 of the primary resonant circuit. The source of the third switch component S3 (25) and the drain of the fifth switch component S5 (29) are connected to the anode of the third diode D3 (26) and the cathode of the fifth diode D5 (210) and D5 (210) and then connected to the point B2 of the primary resonant circuit.

[0112] Fig.17 This is a schematic diagram of the first working state of the second implementation scheme of the switch unit of the present invention, in which the third and fourth diodes are turned on in the first injection current mode in which the switch unit injects current into the primary resonant circuit.

[0113] See also Fig.17 , current Ib flows into the switch unit input terminal A2, flows out of the switch unit through the fourth diode D4 and flows into the primary resonant circuit point B1. The current flowing into point B1 flows into the primary inductor 33 to form current IL. Further, IL flows out from point B2 and flows out of the switch unit input terminal A1 through the third diode D3 (26).

[0114] Fig.18 This is a schematic diagram of the working mode in which the second and fifth switch components are turned on in the first injection current mode in which the switch unit injects current into the primary resonant circuit in the first working state of the second implementation scheme of the present invention.

[0115] See also Fig.18 , the second switch component S2 and the fifth switch component S5 are turned on in the working mode that the current Ib flows into the input terminal A1 of the switch unit, flows out of the switch unit after passing through the second switch component S2 and flows into the point B1 of the primary resonant circuit. The current flowing into the point B1 flows into the primary inductor 33 to form the current IL. Further, IL flows out from the point B2 and flows out of the input terminal A2 of the switch unit through the fifth switch component S5.

[0116] Fig.19 This is a schematic diagram of the first working state of the second implementation scheme of the switch unit of the present invention, in the second injection current mode in which the switch unit injects current into the primary resonant circuit, and the second diode D2 (24) and the fifth diode D5 (210) are turned on.

[0117] See also Fig.19 , the second diode D2 (24) and the fifth diode D5 (210) are turned on in the working mode that the current Ib flows into the switch unit input terminal A2, flows out of the switch unit through the fifth diode D5 (210) and flows into the primary resonant circuit point B2. The current flowing into point B2 flows into the primary inductor 33 to form a current IL. Further, IL flows out from point B1 and flows out of the switch unit input terminal A1 through the second diode D2 (24).

[0118] Fig. 20 This is a schematic diagram of the first working state of the second implementation scheme of the switch unit of the present invention, in the second injection current mode in which the switch unit injects current into the primary resonant circuit, and the third switch component S3 (25) and the fourth switch component S4 (27) are turned on.

[0119] See also Fig. 20 , the third switch component S3 (25) and the fourth switch component S4 (27) are in the conducting working mode, and the current Ib flows into the switch unit input terminal A1, flows out of the switch unit through the third switch component S3 and flows into the primary resonant circuit point B2. The current flowing into point B2 flows into the primary inductor 33 to form a current IL. Further, IL flows out from point B1 and flows out of the switch unit input terminal A2 through the fourth switch component S4.

[0120] Fig.21 This is a schematic diagram of the relationship between the switch unit and the primary resonant circuit in the second working state of the second embodiment of the switch unit of the present invention.

[0121] See also Fig.21 In the second working state, the second switch component S2, the third switch component S3, the fourth switch component S4, the fifth switch component S5 and the second diode D2, the third diode D3, the fourth diode D4, the fifth diode D5 (210) are all in the cut-off state, and no current flows into the primary resonant circuit B1 or B2. In the second state of the switch unit, the primary capacitor 31 and the primary inductor 33 resonate in the primary resonant circuit to form a resonant current Ic3.

[0122] Fig. 22 This is a schematic diagram of a second embodiment of the converter device of the present invention. This embodiment includes: a DC power supply 1, a switch unit 2, a primary resonant circuit 3, a controller 2, a controller 3, a second switch driving circuit, and a third switch driving circuit.

[0123] refer to Fig. 22 The DC power supply 1 is used to convert the AC power of the single-phase power grid into DC power to provide energy for the converter of the present invention. The switch unit 2 has a structure of Fig.16 The second embodiment of the switch unit. The primary resonant circuit includes a primary resonant capacitor 31, a voltage sensor 32 and a primary inductor 33. The concepts and structures of the controllers 2 and 3 are as follows: Figure 6 The function of the switch unit is to analyze and process the signal sent by the voltage sensor to generate control signals Gm2 and Gm3 for controlling each switch component in the switch unit. The second switch driving circuit and the third switch driving circuit convert the Gm2 and Gm3 signals into signals g2, g3, g4, and g5 that can directly drive the switch components.

[0124] Fig.23 This is a schematic diagram of the main waveforms of the second embodiment of the converter device of the present invention, referring to Fig. 22 , Fig.23 , Fig.23 The output current IA1 of the DC power supply 1, the current IL of the primary inductor 33, the voltages UB1, UB2 between the points B1, B2 of the primary resonant circuit, and the switch component drive signals g2, g3, g4, g5 are indicated.

[0125] See also Fig.19 , Fig. 20 , Fig. 22 , Fig.23 In the interval [t0, t1] and [t4, t5], the second diode D2 (24), the fifth diode D5 (210) or the third switch component S3 and the fourth switch component S4 are turned on, the switch unit 2 is in the first working state, and current is injected into the primary resonant circuit 3. Fig.17 , Fig.18 , Fig. 22 , Fig.23 In the interval [t2, t3] and [t6, t7], the third diode D3, the fourth diode D4 or the second switch component S2 and the fifth switch component S5 are turned on, and the switch unit 2 is also in the first working state, injecting current into the primary resonant circuit 3. Fig.21 , Fig. 22 , Fig.23 , all switch components in the intervals [t1, t2], [t3, t4], and [t7, t8] are turned off, the switch unit 2 is in the second working state, and the current injection into the primary resonant circuit 3 stops. The DC power supply output current IA1=0, and the primary resonant circuit is in a resonant state.

[0126] refer to Fig. 22 , Fig.23In the second implementation example of the converter device of the present invention, by sampling the voltage changes at points B1 and B2 in the primary resonant circuit 3, the controller 2 and the controller 3 form a feedback control link, and the switch unit 2 is closed-loop controlled, so that the switch unit switches autonomously between the first working mode and the second working mode, thereby converting the low-frequency alternating current provided by the city power grid into high-frequency alternating current, and the high-frequency alternating current is coupled with the magnetic flux of the secondary energy receiving unit 4 through the primary inductance, and the energy is sent to the secondary energy receiving unit.

[0127] refer to Fig.14 , Fig.15 , Fig. 22 , Fig.23 In the examples of two implementation schemes of the converter device of the present invention, changing the reference value Fjn can change the duration of the first working state of the switch unit, and then change the duration of the switch unit injecting current into the primary resonant circuit. Therefore, the reference value Fjn is used to control the output power of the system.

[0128] It is understandable that Figure 7-8 , 11-13, 17-21, the circuits and components through which current flows are indicated by black solid lines, and the circuits and components through which current does not flow are indicated by dotted lines. The diodes D1-D5 may be body diodes of the switch components S1-S5, respectively.

[0129] Those skilled in the art can understand that all or part of the steps of implementing the above method embodiments can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above method embodiments; and the aforementioned storage medium includes (but is not limited to): read-only memory (ROM), random access memory (RAM), magnetic disk or optical disk, etc., various media that can store program codes.

[0130] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A current conversion device, characterized in that: include: DC power supply; Switching unit; Primary resonant circuit; a first comparison unit; Double integration unit; a second comparison unit; in: The primary resonant circuit includes a primary capacitor, a primary inductor and a voltage sensor V connected in parallel between the first port B1 and the second port B2, and the primary resonant circuit is connected to the secondary energy receiving unit through electromagnetic coupling; The switch unit includes at least one switch component. If the switch unit is in a first working state, the switch unit injects current into the primary resonant circuit. If the switch unit is in a second working state, the switch unit stops injecting current into the primary resonant circuit, and the primary resonant circuit resonates. The first comparison unit includes at least one software comparator or hardware comparator, and its input is the output signal V of the voltage sensor; The dual integration unit includes at least one software integrator or hardware integrator, and the output of the dual integration unit is Dn; The second comparison unit includes at least one software comparator or hardware comparator, whose output is Gm, and the input of the second comparison unit includes the dual integration unit output Dn and the reference value Fjn; The first comparison unit, the dual integration unit, and the second comparison unit constitute a controller, the input of the controller is the output signal V of the voltage sensor and the reference quantity Fjn, and the output quantity is the output Gm of the second comparison unit; The controller generates a control output Gm according to the voltage sensor output signal V and the reference value Fin to control each switch component in the switch unit; The voltage sensor V includes a first sampling resistor RV1, a second sampling resistor RV2, a third sampling resistor RV3 and a fourth sampling resistor RV4; the first sampling resistor RV1 and the second sampling resistor RV2 form a first voltage divider, and the voltage at point B1 of the primary resonant circuit is stepped down by the first voltage divider and sent to the input terminal C- of the first comparison unit; the third sampling resistor RV3 and the fourth sampling resistor RV4 form a second voltage divider, and the voltage at point B2 of the primary resonant circuit is stepped down by the second voltage divider and sent to the input terminal C+ of the first comparison unit.

2. The current conversion device according to claim 1, characterized in that: The reference quantity Fjn is used to control the switch unit to maintain in the first working state; the resonant frequency of the primary resonant circuit is used to control the maintenance time of the switch unit in the second working state; The voltage sensor monitors the working state of the primary resonant circuit, and the controller autonomously controls the switch unit to automatically switch between the first working state and the second working state during operation according to the output signal V of the voltage sensor and the reference quantity Fjn.

3. The current conversion device according to claim 1, characterized in that: The dual integration unit includes a first integration loop and a second integration loop. The first integration loop and the second integration loop include a first integration resistor RI1, a second integration resistor RI2, a common integration capacitor CI1 and a clamping diode DI1.

4. The current conversion device according to claim 1, characterized in that: The DC power input is connected to a single-phase or three-phase power supply grid, including a rectifier bridge, a ballast inductor Le, and a bus capacitor Ce.

5. The current conversion device according to claim 1, characterized in that: The DC power source is a battery.

6. The current conversion device according to claim 1, characterized in that: The device also includes the secondary energy receiving unit, which receives energy transferred by the primary resonant circuit through electromagnetic coupling.

7. The current conversion device according to any one of claims 1 to 6, characterized in that: The switch unit includes a first switch component S1 and a first diode D1, wherein: When the first switch component S1 is in the on state and the first diode D1 is in the off state, the switch unit is in the first current injection mode of the first working state, and the first current injection mode is that the switch unit injects current into the B1 point of the primary resonant circuit; When the first switch component S1 is in the off state and the first diode D1 is in the on state, the switch unit is in the second current injection mode of the first working state, and the second current injection mode is that the switch unit injects current into the point B2 of the primary resonant circuit; When the first switch component S1 is in the cut-off state and the first diode D1 is in the cut-off state, the switch unit is in the second working state.

8. The current conversion device according to any one of claims 1 to 6, characterized in that: The switch unit includes a second switch component S2, a third switch component S3, a fourth switch component S4, a fifth switch component S5 and a second diode D2, a third diode D3, a fourth diode D4, and a fifth diode D5, wherein: When the second switch component S2 and the fifth switch component S5 are in the on state, and the remaining switch components and all diodes are in the off state, or when the third diode D3 and the fourth diode D4 are in the on state, and the remaining diodes and all switch components are in the off state, the switch unit is in the first current injection mode of the first working state, and the first current injection mode is that the switch unit injects current into the B1 point of the primary resonant circuit; When all the switch components and the third diode D3 and the fourth diode D4 are in the off state, the second diode D2 and the fifth diode D5 are in the on state, and when the third switch component S3 and the fourth switch component S4 are in the on state, and the remaining switch components and all diodes are in the off state, the switch unit is in the second current injection mode of the first working state, and the second current injection mode is that the switch unit injects current into the B2 point of the primary resonant circuit; When all the switch components and all the diodes are in the cut-off state, the switch unit is in the second working state.

9. The current conversion device according to claim 2, characterized in that: The reference quantity Fin is used to adjust the output power of the converter.

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