Auxiliary power supply circuit, balance circuit and power supply system of conversion module

Abstract

An auxiliary power supply circuit of a conversion module is used to supply power to a control unit, and the input end of the conversion module includes an even number of energy storage units connected in series. The auxiliary power supply circuit includes an even number of primary side circuits and secondary side circuits, and each primary side circuit includes a first switching unit, a second switching unit, and a resonant tank. The first switching unit and the second switching unit are connected in series and are correspondingly connected in parallel to one of the energy storage units, and the resonant tank is connected in parallel to the second switching unit. The secondary side circuit couples the resonant tanks of two of the primary side circuits to obtain power and supplies power to the control unit. The present invention also relates to a balancing circuit and a power supply system.

Description

Technical Field

[0001] The present invention relates to an auxiliary power supply circuit, a balancing circuit and a power supply system for a conversion module, and particularly to an auxiliary power supply circuit, a balancing circuit and a power supply system for a conversion module with a voltage equalization function. Background Art

[0002] Please refer to Figure 1 FIG. 1 is a circuit block diagram of an existing power supply system. In a power supply system 100 applied to medium voltage DC (MVDC) on the market at present, it includes a plurality of conversion modules 1-1 to 1-n connected in series at the input ends. For the auxiliary power supply circuit (Auxiliary Power System; APS) that supplies power to the internal controller of the power supply system 100, most use external power supply (indicated by an arrow input to the auxiliary power supply circuit APS), rather than a self-powered form. The reason is that the medium voltage DC usually has a voltage greater than 1500 volts, and even up to dozens of kilovolts. Therefore, the medium voltage DC that the power supply system can usually receive is basically in the kilovolt level. So, if it is in a self-powered form, unless the auxiliary power supply circuit APS has the insulation ability of medium voltage isolation, it can convert the power of up to dozens of kilovolts into power below 50 volts to supply the controller, otherwise external power supply must be used. However, in both cases, it is necessary to use a relatively large-sized and expensive isolation transformer, or an additional power supply to assist in power supply, which will increase the circuit volume and cost.

[0003] Among them, for the auxiliary power supply circuit APS in the self-powered form, usually the conversion modules 1-1 to 1-n are respectively connected to the capacitors C at the input ends to respectively use the power stored in the input capacitors C. Therefore, for the auxiliary power supply circuit APS in the self-powered form, in addition to having the insulation ability of medium voltage isolation, the power supply system 100 must also maintain the balance (voltage equalization) of the power at the input ends of each conversion module 1-1 to 1-n to protect the voltage of the controller (or other circuits, etc.) at the back end of each conversion module 1-1 to 1-n from exceeding the set value and entering the protection state. In this way, it is necessary to additionally attach a voltage equalization circuit, which increases the circuit volume and cost, and the current voltage equalization circuit also has no ability to perform rapid voltage equalization control on the capacitor C.

[0004] Therefore, how to design an auxiliary power supply circuit, a balancing circuit and a power supply system for a conversion module with a voltage equalization function, so that the energy storage voltages of each energy storage unit naturally transfer energy to each other according to the voltage level, and the excessive energy is recycled through the coupling method, is a major research topic that the inventor of the present invention desires to conduct. Summary of the Invention

[0005] To solve the above problems, the present invention provides an auxiliary power supply circuit for a conversion module to overcome the problems of the prior art. Therefore, the auxiliary power supply circuit of the present invention is used to supply power to a control unit. The input end of the conversion module includes an even number of energy storage units connected in series, and each energy storage unit includes a first end and a second end. The auxiliary power supply circuit includes an even number of primary side circuits and secondary side circuits. Each primary side circuit includes a first switching unit, a second switching unit, and a resonant tank, and the secondary side circuit includes at least one induction unit and a rectification circuit. The first switching unit includes a first end and a second end, and the first end of the switching unit is correspondingly coupled to the first end of one of the energy storage units. The second switching unit includes a first end and a second end. The first end of the second switching unit is coupled to the second end of the first switching unit, and the second end of the second switching unit is correspondingly coupled to the second end of the same energy storage unit. The resonant tank is connected in parallel with the second switching unit. At least one induction unit couples the resonant tanks of two of the primary side circuits. The rectification circuit is coupled to at least one induction unit and the control unit, rectifies the power provided by at least one induction unit into DC power, and is used to supply power to the control unit.

[0006] To solve the above problems, the present invention provides a balance circuit for a conversion module to overcome the problems of the prior art. Therefore, the input end of the conversion module of the present invention includes an even number of energy storage units connected in series, and each energy storage unit includes a first end and a second end. The balance circuit includes an even number of primary side circuits and secondary side circuits. Each primary side circuit includes a first switching unit, a second switching unit, and a resonant tank, and the secondary side circuit includes a plurality of induction units. The first switching unit includes a first end and a second end, and the first end of the first switching unit is correspondingly coupled to the first end of one of the energy storage units. The second switching unit includes a first end and a second end. The first end of the second switching unit is coupled to the second end of the first switching unit, and the second end of the second switching unit is correspondingly coupled to the second end of the same energy storage unit. The resonant tank is connected in parallel with the second switch. Each induction unit is connected in parallel and respectively couples the resonant tanks of two of the primary side circuits. Among them, the number of primary side circuits is at least four.

[0007] To solve the above problems, the present invention provides a power supply system to overcome the problems of the prior art. Therefore, the power supply system of the present invention includes a plurality of conversion modules, the input ends of each conversion module are serially coupled, the input end includes an even number of energy storage units coupled in series, and each energy storage unit includes a first end and a second end. Each conversion module includes an auxiliary power supply circuit, a power stage circuit, and a control unit, and the auxiliary power supply circuit includes an even number of primary side circuits and secondary side circuits. Each primary side circuit includes a first switching unit, a second switching unit, and a resonant tank, and the secondary side circuit includes at least one induction unit and a rectification circuit. The first switching unit includes a first end and a second end, and the first end of the first switching unit is correspondingly coupled to the first end of one of the energy storage units. The second switching unit includes a first end and a second end, the first end of the second switching unit is coupled to the second end of the first switching unit, and the second end of the second switching unit is correspondingly coupled to the second end of the same energy storage unit. The resonant tank is connected in parallel with the second switching unit. At least one induction unit is coupled in parallel with each other and respectively coupled to the resonant tanks of two of the primary side circuits. The rectification circuit is coupled to at least one induction unit to rectify the power provided by at least one induction unit into DC power. The power stage circuit is coupled to the input end, the control unit is coupled to the rectification circuit and the power stage circuit, and is used to receive the DC power and operate, and is used to control the power stage circuit.

[0008] The main object and technical effect of the present invention are that the resonant tanks used in the two primary side circuits of the primary side module have a symmetric circuit structure and the same parameters. Under the condition that the parameters of the resonant tank Rt of the same group of primary side circuits are the same, the technical effect that the energy storage voltages of each energy storage unit can naturally transfer energy to each other according to the voltage level can be achieved. Its advantage is that the excessive energy can be recycled through the coupling method, rather than being consumed by a resistor to cause additional power loss, and the response speed is also relatively fast.

[0009] In order to further understand the technologies, means, and technical effects adopted by the present invention to achieve the predetermined purpose, please refer to the following detailed description and drawings of the present invention. It is believed that the purpose, features, and characteristics of the present invention can be deeply and specifically understood therefrom. However, the drawings are only provided for reference and explanation, and are not used to limit the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a circuit block diagram of an existing power supply system;

[0011] Figure 2 is a circuit block diagram of the power supply system of the present invention with a voltage equalization function;

[0012] Figure 3 is a circuit block diagram of the first embodiment of the conversion module of the present invention with a voltage equalization function;

[0013] Figure 4 Schematic diagram of the primary - side module of the present invention;

[0014] Figure 5A Block diagram of the circuit of the second embodiment of the conversion module with voltage - equalizing function of the present invention;

[0015] Figure 5B Block diagram of the circuit of the third embodiment of the conversion module with voltage - equalizing function of the present invention;

[0016] Figure 6A Circuit diagram of the first embodiment of the balance circuit of the present invention; and

[0017] Figure 6B Circuit diagram of the second embodiment of the balance circuit of the present invention. Description of reference numerals: MVDC... Medium - voltage DC voltage; 100... Power supply system; C... Capacitor; 1 - 1~1 - n... Conversion module; 12... Input terminal; 122... Energy - storage unit; A... First terminal; B... Second terminal

[0018] 14, APS... Auxiliary power - supply circuit; 142G... Primary - side module; P... Node

[0019] 142... Primary - side circuit; Q1... First switching unit; Q2... Second switching unit; Rt... Resonant tank; Cr... Capacitor; Lr... Inductor; Np1~Np4... First winding; 144... Secondary - side circuit; Us1~Us2... Induction unit; Ns1~Ns2... Second winding; Ns3~Ns4... Third winding; Br... Rectifying circuit; 146... Module balance circuit; SW... Switch; R... Energy - consuming unit; 15... Balance circuit; T1... First transformer; T2... Second transformer

[0020] 16... Power - stage circuit

[0021] 162... First bus terminal

[0022] 164... Second bus terminal

[0023] 166, 166 - 1~166 - 3... Potential terminal

[0024] 18... Control unit

[0025] Vin1~VinN... Input voltage

[0026] Vb1~Vb4, Vb1~Vb8... Energy - storage voltage

[0027] Vdc... DC power

[0028] Sg1... First control - signal group

[0029] Sg2... Second control - signal group

[0030] Sc1... First control signal

[0031] Sc2…Second control signal Detailed implementation manners

[0032] Regarding the technical content and detailed description of the present invention, it is described in conjunction with the accompanying drawings as follows:

[0033] Please refer to Figure 2 It is a circuit block diagram of a power supply system with an equalizing function according to the present invention. The power supply system 100 is mainly applied to a Solid State Transformer (SST), also known as a power electronic transformer. The power supply system 100 receives a medium-voltage direct current voltage MVDC. In the case of inputting such a high voltage, the input end of the power supply system 100 includes a plurality of capacitors C connected in series to stabilize the voltage value of the medium-voltage direct current voltage MVDC, and a plurality of conversion modules 1-1 to 1-n are used to evenly distribute the medium-voltage direct current voltage MVDC. Specifically, the power supply system 100 includes a plurality of conversion modules 1-1 to 1-n, and the input ends of the conversion modules 1-1 to 1-n are connected in series to evenly distribute the medium-voltage direct current voltage MVDC. That is, the voltage value of the medium-voltage direct current voltage MVDC (the voltage across the plurality of capacitors C connected in series) is the sum of the input voltages Vin1 to VinN of the respective conversion modules 1-1 to 1-n. The output ends (not shown in the figure) of the respective conversion modules 1-1 to 1-n may be connected in series, in parallel, or independently output, which is not limited herein.

[0034] Please refer to Figure 3 It is a circuit block diagram of the first embodiment of the conversion module with an equalizing function according to the present invention, and in combination with reference to Figure 2 . Taking the conversion module 1-1 as an example, the conversion module 1-1 includes an input end 12, an auxiliary power supply circuit 14, a power stage circuit 16, and a control unit 18. The input end 12 receives the input voltage Vin1 and includes an even number of energy storage units 122 connected in series( Figure 3 Four energy storage units 122 are shown, but the present invention is not limited thereto). Among them, the energy storage unit 122 can be a single capacitor or a plurality of capacitor groups connected in series. Each energy storage unit 122 includes a first end A and a second end B, and is connected in series in the manner of taking the first end A as the head and the second end B as the tail. Among them, the sum of the energy storage voltages Vb1 to Vb4 stored in each energy storage unit 122 is the input voltage Vin1. The auxiliary power supply circuit 14 is coupled to the input end 12 and the control unit 18, and is used to convert the input voltage Vin1 to supply power to the control unit 18. The power stage circuit 16 can generally be a switching power conversion circuit, and is usually composed of elements such as but not limited to switches, capacitors, and inductors. For example but not limited to, the power stage circuit 16 can be a neutral point clamped type (such as a three-potential type, a five-potential type) conversion circuit, which is commonly used in high-power applications, especially applications with a power up to several million watts.

[0035] The power supply stage circuit 16 is coupled to the input terminal 12, and the control unit 18 is coupled to the switch inside the power supply stage circuit 16. The control unit 18 controls the switching of the switch by providing the first control signal group Sg1 to control the power supply stage circuit 16 to convert the input voltage Vin1 into the voltage required by other subsequent circuits. Taking the three-potential conversion circuit as an example, the power supply stage circuit 16 includes a first bus terminal 162, a second bus terminal 164, and a potential terminal 166. The first bus terminal 162 is coupled to the first end A of the first energy storage unit 122 connected in series first, and the second bus terminal 164 is coupled to the second end B of the last energy storage unit 122 connected in series. Among them, if the power supply stage circuit 16 is a five-potential conversion circuit, the power supply stage circuit 16 has one first bus terminal 162, one second bus terminal 164, and three potential terminals 166-1 to 166-3.

[0036] The auxiliary power supply circuit 14 includes an even number of primary side circuits 142 and secondary side circuits 144 ( Figure 3 as shown are four primary side circuits 142 and one secondary side circuit 144, but the present invention is not limited thereto). The primary side circuit 142 is coupled to the input terminal 12, and each primary side circuit 142 includes a first switch unit Q1, a second switch unit Q2, and a resonant tank Rt. The secondary side circuit 144 is coupled to the control unit 18, and the secondary side circuit 144 includes a plurality of induction units Us1 to Us2 and a rectification circuit Br. The first switch unit Q1 includes a first end and a second end, and the first end is correspondingly coupled to the first end A of one of the energy storage units 122. The second switch unit Q2 includes a first end and a second end, the first end is coupled to the second end of the first switch unit Q1, and the second end is correspondingly coupled to the second end B of the same energy storage unit 122. The resonant tank Rt is connected in parallel with the second switch unit Q2, and the primary side circuits 142 form a primary side module 142G in groups of two, and the potential terminal 166 is coupled to the node P between the two primary side modules 142G. The resonant tanks Rt of the primary side circuits 142 in the same group have corresponding circuit structures and the same parameters in pairs.

[0037] Furthermore, with reference to Figure 4 is a circuit schematic diagram of the primary side module of the present invention. Corresponding to Figure 3The single primary side module 142G is used for illustration. The resonant tank Rt may include a capacitor Cr, an inductor Lr, and first windings Np1 to Np2. One end of the capacitor Cr is coupled to the second end of the first switching unit Q1, and one end of the inductor Lr is coupled to the other end of the capacitor Cr. One end of the first winding Np1 (Np2) is coupled to the other end of the inductor Lr, and the other end of the first winding Np1 (Np2) is coupled to the second end of the second switching unit Q2. In the same primary side module 142G, the first windings Np1 and Np2 of the two resonant tanks Rt have a common core circuit structure, enabling them to couple and transfer energy to each other. Specifically, taking the primary side circuits 142 with common cores of the energy storage voltages Vb1 and Vb2 as an example, the resonant tanks Rt used in the two primary side circuits 142 of the primary side module 142G have a symmetric circuit structure and the same parameters. Under the condition that the parameters of the resonant tanks Rt of the primary side circuits 142 in the same primary side module 142G are the same, by controlling the complementary switching of the first switching unit Q1 and the second switching unit Q2 with a fixed frequency and duty cycle, the energy storage voltages Vb1 and Vb2 can naturally transfer energy to each other according to the voltage levels. Among them, the duty cycle is preferably 50%, and the frequency can be determined according to the actual circuit requirements (such as but not limited to 50 kHz).

[0038] Therefore, assuming that when the energy storage voltage Vb1 is low, the first winding Np2 can directly couple energy to the first winding Np1 through the shared iron core, enabling the energy storage unit 122 to which the energy storage voltage Vb1 belongs to be quickly charged with energy (and vice versa). Taking Figure 4 as an example, the parameters of the resonant tank Rt include the capacitance value of the capacitor Cr, the inductance value of the inductor Lr, and the number of turns of the first windings Np1 and Np2. However, the types included in the parameters may vary according to the structure of the resonant tank Rt. The main thing is that the parameters of the resonant tanks Rt of the primary side circuits 142 in the same primary side module 142G and the control logic of the first switching unit Q1 and the second switching unit Q2 are the same. It is worth mentioning that in an embodiment of the present invention, the signals for controlling the first switching unit Q1 and the second switching unit Q2 can be provided additionally by the outside of the power supply system 100, or provided by an additional controller (not shown in the figure) inside the power supply system 100, or provided by the control unit 18 that originally controls the power stage circuit 16.

[0039] Specifically, if the signals for controlling the first switching unit Q1 and the second switching unit Q2 are provided by the control unit 18 that originally controls the power stage circuit 16, then in addition to providing the first control signal group Sg1 to control the power stage circuit 16, the control unit 18 also provides a second control signal group Sg2 to control the first switching unit Q1 and the second switching unit Q2. The second control signal group Sg2 includes a first control signal Sc1 and a second control signal Sc2. The first control signal Sc1 controls the first switching unit Q1, and the second control signal Sc2 controls the second switching unit Q2. The first control signal Sc1 and the second control signal Sc2 are signals with complementary waveforms, and the frequency and duty cycle of the signals are fixed values.

[0040] Refer again to Figures 3 - 4 , the induction units Us1 to Us2 are connected in parallel and are respectively coupled to the resonance tanks Rt of the two primary side circuits 142 in the primary side module 142G to form a balanced circuit 15 of the induction units Us1 to Us2 and two (or more) primary side module 142G circuit structures. Further, with reference to Figures 3 - 4 , the induction unit Us1 and the first windings Np1, Np2 have a common iron core circuit structure, and the induction unit Us2 and the first windings Np3, Np4 have a common iron core circuit structure. Since the induction units Us1 to Us2 are connected in parallel, the energy of the energy storage voltages Vb1 to Vb4 can be directly coupled to the lower-energy side in a parallel manner through the induction units Us1 to Us2, without being limited to all windings having a common iron core, so that the energy storage unit 122 belonging to the lower-energy side can be quickly energized and charged. Therefore, Figure 3 The circuit structure and control method of the auxiliary power supply circuit 14 have the advantage that excessive energy can be recycled through coupling, rather than being consumed by a resistor, which causes problems such as additional power loss, heat dissipation, and component cost... and the response speed is also relatively fast.

[0041] Assume a situation where the energy of the energy storage voltage Vb1 is lower than that of the energy storage voltages Vb2 to Vb4. The energy of the energy storage voltages Vb3 and Vb4 is directly coupled to the induction unit Us1 as AC energy in a parallel manner through the induction unit Us2, and is coupled to the first winding Np1 through the circuit structure where the induction unit Us1 and the first winding Np1 share the same iron core. Similarly, the energy of the energy storage voltage Vb2 is coupled to the first winding Np1 through the circuit structure where the first winding Np2 shares the same iron core. Thus, according to the characteristic that the energy can be naturally transferred among the energy storage voltages Vb1 to Vb4 according to their voltage levels, the energy storage unit 122 to which the energy storage voltage Vb1 belongs can be quickly charged and stored with energy. It is worth mentioning that in an embodiment of the present invention, since the balancing circuit 15 needs to transfer energy between two or more primary side modules 142G, the number of the primary side circuits 142 is at least four, and the number of the induction units Us1 to Us2 corresponds to the number of the primary side modules 142G and is plural.

[0042] The rectifying circuit Br is coupled to the induction units Us1 to Us2 and the control unit 18, and is used to rectify the power provided by the induction units Us1 to Us2 into DC power Vdc to supply power to the control unit 18. Among them, the rectifying circuit Br and the control unit 18 are coupled to the potential terminal 166 or the second bus terminal 164 to use the potential of the potential terminal 166 or the second bus terminal 164 as the reference potential (if coupled to the second bus terminal 164, the reference potential is the ground potential). On the other hand, if the power supply stage circuit 16 is a five-potential conversion circuit and has three potential terminals 166-1 to 166-3, the rectifying circuit Br and the control unit 18 can be selectively coupled to one of the potential terminals 166-1 to 166-3.

[0043] Refer to again Figure 3 , the auxiliary power supply circuit 14 further includes a module balancing circuit 146. The module balancing circuit 146 is connected in parallel with the rectifying circuit Br and includes a switch SW and a power-consuming unit R. One end of the switch SW is coupled to one end of the rectifying circuit Br, and the other end of the switch SW is coupled to one end of the power-consuming unit R. The other end of the power-consuming unit R is coupled to the other end of the rectifying circuit Br. The switch SW is turned on when the DC power Vdc is higher than the threshold, and the power-consuming unit R consumes the DC power Vdc according to the conduction of the switch SW. Among them, the power-consuming unit R is, for example but not limited to, an element such as a resistor or an impedance circuit that can consume electrical energy. Specifically, since the power supply system 100 is composed of multiple conversion modules 1-1 to 1-n to evenly distribute the medium-voltage DC voltage MVDC (please refer to Figure 2 ), there is a problem of voltage balance (equal voltage) of the input voltages Vin1 to VinN of each conversion module 1-1 to 1-n. That is, there is a problem that the input voltage Vin1 to VinN of a certain conversion module 1-1 to 1-n is too high. The problem of the too-high input voltage Vin1 to VinN can be solved by, for example,Figures 3 - 4 It is solved by the circuit structure shown to transfer energy to each other naturally.

[0044] However, since the DC power Vdc supplied to the control unit 18 usually must be maintained within a specific range for the control unit 18 to operate properly, an excessively high DC power Vdc may trigger the protection mechanism of the control unit 18, causing the power supply system 100 to fail. Therefore, the DC power Vdc can be maintained within a specific voltage range through the operation of the module balancing circuit 146. Specifically, when the DC power Vdc supplied to the control unit 18 through coupling by the secondary side circuit 144 is too high (i.e., higher than the threshold), the energy-consuming unit R can consume the DC power Vdc by turning on the switch SW, so that the DC power Vdc is maintained within a specific voltage range. In this way, the excess energy of the DC power Vdc can be consumed by the energy-consuming unit R to achieve the function of equalizing the DC power Vdc within each conversion module 1-1 to 1-n.

[0045] It is worth mentioning that in an embodiment of the present invention, the signal for controlling the switch SW can also be provided externally to the power supply system 100, or provided by an additional controller (not shown in the figure) inside the power supply system 100, or provided by the control unit 18 that originally controls the power supply stage circuit 16. If the signal for controlling the switch SW is provided by the control unit 18 that originally controls the power supply stage circuit 16, the control unit 18 sets the threshold and detects the DC power Vdc to control the switch SW to turn on or off according to whether the DC power Vdc is higher than the threshold.

[0046] Please refer to Figure 5A the circuit block diagram of the second embodiment of the conversion module with equalizing function of the present invention, Figure 5B the circuit block diagram of the third embodiment of the conversion module with equalizing function of the present invention, and also refer to Figures 2 - 4 . Compared with Figure 3 , in Figure 5A 's embodiment, the power supply stage circuit 16 is a five-potential conversion circuit, and the power supply stage circuit 16 has a first bus terminal 162, a second bus terminal 164, and three potential terminals 166-1 to 166-3. A group of primary side modules 142G are included between every two potentials respectively, and the secondary side circuit 144 includes a plurality of induction units Us1 to Us4 and a rectification circuit Br. In this embodiment, the characteristics of natural mutual energy transfer are also achieved through the symmetric resonant tank circuit structure, so that the stored energy voltages Vb1 to Vb8 of each energy storage unit 122 are maintained in balance.

[0047] On the other hand, compared with Figure 3 , in Figure 5BThe embodiment shows that the power supply stage circuit 16 is a single-potential conversion circuit, and the power supply stage circuit 16 has a first bus terminal 162 and a second bus terminal 164. A group of primary side modules 142G is included between the first bus terminal 162 and the second bus terminal 164, and the secondary side circuit 144 includes an induction unit Us1 and a rectification circuit Br. In this embodiment, the characteristic of natural mutual energy transfer is also achieved through the symmetrical resonant tank circuit structure, so that the energy storage voltages Vb1 to Vb2 of each energy storage unit 122 are maintained in balance.

[0048] Please refer to Figure 6A the circuit diagram of the first embodiment of the balancing circuit of the present invention, Figure 6B the circuit diagram of the second embodiment of the balancing circuit of the present invention, and also refer to Figures 1 - 5B . In Figures 6A - 6B it mainly shows Figure 3 the implementation manner in which the induction units Us1 to Us2 are paired with the first windings Np1 to Np4 of the common iron core. In Figure 6A each induction unit Us1, Us2 includes a second winding Ns1, Ns2, and each second winding Ns1, Ns2 respectively forms a first transformer T1 with a common iron core with two of the first windings Np1 to Np2, Np3 to Np4 of a group of primary side modules 142G. In Figure 6B each induction unit Us1 to Us2 includes a second winding Ns1, Ns2 and a third winding Ns3, Ns4. The second windings Ns1, Ns2 respectively form a first transformer T1 with a common iron core with the first windings Np1, Np3 of one of the primary side circuits 142, and the third windings Ns3, Ns4 respectively form a second transformer T2 with a common iron core with the first windings Np2, Np4 of the other primary side circuit 142. Since Figure 6A each winding is integrated into two first transformers T1, compared with Figure 6B it, the overall volume of the transformer can be reduced (mainly the iron core is reduced from four to two), and the energy of the first windings Np1 to Np2, Np3 to Np4 with a common iron core can be directly transferred through the coupling on the primary side without passing through the secondary side transmission. Therefore Figure 6A it is a preferred implementation manner.

[0049] However, as described above, it is only the detailed description and drawings of the preferred specific embodiments of the present invention, and the features of the present invention are not limited thereto. It is not used to limit the present invention. The entire scope of the present invention should be based on the claims. All embodiments that conform to the concept of the claims of the present invention and its similar variations should be included in the scope of the present invention. Any changes or modifications that can be easily conceived by any person skilled in the art within the field of the present invention can be covered by the claims of this disclosure.

Claims

1. An auxiliary power supply circuit for a conversion module, used to supply power to a control unit. The input end of the conversion module includes an even number of energy storage units connected in series, and each energy storage unit includes a first end and a second end; the auxiliary power supply circuit includes: An even number of primary side circuits, each primary side circuit including: A first switch unit, including a first end and a second end, the first end of the first switch unit is correspondingly connected to the first end of one of the energy storage units; A second switch unit, including a first end and a second end, the first end of the second switch unit is connected to the second end of the first switch unit, and the second end of the second switch unit is correspondingly connected to the second end of one of the energy storage units; and A resonant tank, connected in parallel with the second switch unit; and A secondary side circuit, including: At least one induction unit, coupling the resonant tanks of two of the primary side circuits; and A rectification circuit, connected to the at least one induction unit and the control unit, rectifying an electric power provided by the at least one induction unit into a direct current power, and used to supply power to the control unit.

2. The auxiliary power supply circuit according to claim 1, further including: A module balancing circuit, connected in parallel with the rectification circuit, and the module balancing circuit includes: A switch, connected to the rectification circuit, and used to conduct according to the direct current power being higher than a threshold value; and A power consumption unit, connected in series with the switch, used to consume the direct current power according to the switch conducting.

3. The auxiliary power supply circuit according to claim 1, wherein the resonant tank of each primary side circuit includes a parameter, and the parameters of two of the primary side circuits are the same.

4. The auxiliary power supply circuit according to claim 3, wherein the resonant tank includes: A capacitor, one end of which is connected to the second end of the first switch unit; An inductor, one end of which is connected to the other end of the capacitor; And A first winding, one end of which is connected to the other end of the inductor, and the other end of which is connected to the second end of the second switch unit; Wherein, the parameter includes a capacitance value of the capacitor, an inductance value of the inductor, and a number of turns of the first winding.

5. The auxiliary power supply circuit according to claim 4, wherein the at least one induction unit includes a second winding, and the second winding and the first windings of two of the primary side circuits form a first transformer sharing a common iron core.

6. The auxiliary power supply circuit according to claim 4, wherein the at least one induction unit includes a second winding and a third winding, the second winding and the first winding of one of the two primary side circuits form a first transformer sharing a common iron core, and the third winding and the first winding of the other of the two primary side circuits form a second transformer sharing a common iron core.

7. The auxiliary power supply circuit according to claim 1, wherein the first switch unit and the second switch unit are switched and controlled complementarily at a frequency and a duty cycle, and the frequency and the duty cycle are fixed values.

8. A balancing circuit for a conversion module, the input end of the conversion module includes an even number of energy storage units connected in series, and each energy storage unit includes a first end and a second end, the balancing circuit includes: An even number of primary side circuits, each primary side circuit including: A first switching unit, including a first end and a second end, the first end of the first switching unit is correspondingly coupled to the first end of one of the energy storage units; A second switching unit, including a first end and a second end, the first end of the second switching unit is coupled to the second end of the first switching unit, and the second end of the second switching unit is correspondingly coupled to the second end of one of the energy storage units; and A resonant tank, connected in parallel with the second switching unit; and A secondary side circuit, including: A plurality of induction units, each induction unit is connected in parallel and respectively coupled to the resonant tanks of two of the primary side circuits; Wherein, the number of the primary side circuits is at least four.

9. The balanced circuit according to claim 8, wherein the resonant tank of each of the primary side circuits includes a parameter, and the parameters of two of the primary side circuits are the same.

10. The balanced circuit according to claim 9, wherein the resonant tank includes: A capacitor, one end of which is coupled to the second end of the first switching unit; An inductor, one end of which is coupled to the other end of the capacitor; And A first winding, one end of which is coupled to the other end of the inductor, and the other end of which is coupled to the second end of the second switching unit; Wherein, the parameter includes a capacitance value of the capacitor, an inductance value of the inductor, and a number of turns of the first winding.

11. The balanced circuit according to claim 10, wherein each induction unit includes a second winding, and the second winding and the first winding of two of the primary side circuits form a first transformer with a common iron core.

12. The balanced circuit according to claim 10, wherein each induction unit includes a second winding and a third winding, the second winding and the first winding of one of the two primary side circuits form a first transformer with a common iron core, and the third winding and the first winding of the other of the two primary side circuits form a second transformer with a common iron core.

13. The balanced circuit according to claim 9, wherein the first switching unit and the second switching unit are switched and controlled complementarily at a frequency and a duty cycle, and the frequency and the duty cycle are fixed values.

14. A power supply system, including: A plurality of conversion modules, an input end of each conversion module is connected in series, the input end includes an even number of energy storage units connected in series, and each energy storage unit includes a first end and a second end; Each of the conversion modules includes: An auxiliary power supply circuit, including: An even number of primary side circuits, each of the primary side circuits includes: A first switching unit, including a first end and a second end, the first end of the first switching unit is correspondingly coupled to the first end of one of the energy storage units; A second switching unit, including a first end and a second end, the first end of the second switching unit is coupled to the second end of the first switching unit, and the second end of the second switching unit is correspondingly coupled to the second end of one of the energy storage units; and A resonant tank, connected in parallel with the second switching unit; and A secondary side circuit, including: At least one induction unit, the at least one induction unit is connected in parallel and respectively coupled to the resonant tanks of two of the primary side circuits; and A rectifying circuit, coupled to the at least one induction unit, and configured to rectify an electric power provided by the at least one induction unit into a direct current power; A power supply stage circuit, coupled to the input terminal; and A control unit, coupled to the rectifying circuit and the power supply stage circuit, operating by receiving the direct current power, and configured to control the power supply stage circuit.

15. The power supply system according to claim 14, wherein the even number of primary side circuits form a primary side module in pairs, and the power supply stage circuit includes: A first bus terminal, coupled to the first end of the first energy storage unit connected in series; And A second bus terminal, coupled to the second end of the last energy storage unit connected in series.

16. The power supply system according to claim 15, wherein the power supply stage circuit further includes: A potential terminal, coupled to a node between two primary side modules; Wherein, the secondary side circuit and the control unit are coupled to the potential terminal or the second bus terminal to use a potential of the potential terminal or the second bus terminal as a reference potential.

17. The power supply system according to claim 15, wherein the auxiliary power supply circuit further includes: A module balancing circuit, connected in parallel with the rectifying circuit, and includes: A switch, coupled to the rectifying circuit; and A power consumption unit, connected in series with the switch, configured to consume the direct current power according to the conduction of the switch; Wherein, the control unit is configured to detect the direct current power, and control the switch to conduct according to the direct current power being higher than a threshold value.

18. The power supply system according to claim 14, wherein the control unit is configured to provide a first control signal group to control the power supply stage circuit, and provide a second control signal group to control the first switch unit and the second switch unit.

19. The power supply system according to claim 18, wherein the second control signal group includes a first control signal for controlling the first switch unit and a second control signal for controlling the second switch unit; the first control signal and the second control signal are complementary in signal, and a frequency and a duty cycle of the first control signal and the second control signal are fixed values.

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