High-Gain DC Converter, Device and Control Method of Multi-Coupled Inductor

Abstract

The present invention provides a high-gain DC converter, device and control method for a multi-coupled inductor. The high-gain DC converter for the multi-coupled inductor includes: an input terminal, a switching tube S, a three-winding coupled inductor, a two-winding coupled inductor, an inductor L1, a plurality of capacitors, a plurality of diodes, and an output circuit. By combining a three-winding coupled inductor and a two-winding coupled inductor, and constructing a circuit topology with inductors, a plurality of capacitors, a plurality of diodes, the switching tube S, the input terminal, and the output circuit elements through a specific connection method, the present invention can more effectively utilize the coupling effect between inductors, achieve a higher voltage gain, and can flexibly design the voltage gain range by reasonably selecting the turns ratio of a plurality of coupled inductors, avoiding the situation of extreme duty cycles in the operation of the switching tube. The entire circuit structure is simple, the control is simple, and the working efficiency is high.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy energy storage grid connection, and particularly to a high-gain DC converter with multiple coupled inductors, a device and a control method thereof. Background Art

[0002] In a new energy power generation system, it is necessary to convert new energy such as new energy into electric energy, and its output voltage is generally between 20 volts (V) and 50 V, which cannot directly meet the requirements of the inverter. Therefore, a boost DC converter is required to boost the low DC voltage to a high DC voltage suitable for inverter conversion (generally 400 V) to complete grid connection by the inverter AC-DC conversion. New energy energy storage systems such as solar energy and wind energy are widely used, but there is a problem that the demand for grid connection voltage is very high during the grid connection process. Therefore, a boost converter with high voltage gain plays a very important role in the new energy energy storage system. On the other hand, during the new energy power generation processes such as solar energy and wind energy, due to the changes in light and wind, the input voltage will fluctuate significantly. To ensure the stability of the output voltage, the boost converter needs to have a wide voltage gain range.

[0003] In related technologies, the actual voltage gain of a common Boost converter is not high, the voltage gain range is narrow, and the duty cycle of the switching tube is relatively high and the conduction time is too long under normal operation, which will increase the conduction loss and reduce the service life. To address this defect, the prior art has proposed a high-boost DC converter based on a coupled inductor structure. By adjusting the turn ratio of the coupled inductor, not only can the pressure on the switching tube be relieved, the voltage gain be increased, but also the reverse recovery problem of the diode caused by low-duty-cycle operation can be alleviated by using its leakage inductance.

[0004] However, with the continuous increase of the power level of the new energy power generation system, the requirement for the voltage gain of the boost converter is also getting higher and higher. The conventional DC converter based on the coupled inductor structure still has the problem of insufficient voltage gain, and the duty cycle of the switching tube is extreme and the boost efficiency is low. Summary of the Invention

[0005] Embodiments of the present invention provide a high-gain DC converter with multiple coupled inductors, a device and a control method thereof to solve the problems that the conventional DC converter based on the coupled inductor structure in the prior art still has the problem of insufficient voltage gain, and the high duty cycle of the switching tube leads to low boost efficiency.

[0006] In a first aspect, embodiments of the present invention provide a high-gain DC converter with multiple coupled inductors, including: an input terminal, a switching tube S, a three-winding coupled inductor, a two-winding coupled inductor, an inductor L1, a plurality of capacitors, a plurality of diodes, and an output circuit;

[0007] The three-winding coupled inductor includes: a primary winding N1, a secondary winding N2, and a secondary winding N3;

[0008] The two-winding coupled inductor includes: a primary winding n1 and a secondary winding n2;

[0009] The positive pole of the input end is connected to one end of the inductor L1, and the other end of the inductor L1 is respectively connected to the drain of the switch tube S, the positive pole of the diode D1, the non-corresponding end of the primary winding N1, and the corresponding end of the secondary winding N3;

[0010] The negative pole of the input end is respectively connected to the source of the switch tube S, the negative pole of the capacitor C1, and the negative pole of the output circuit;

[0011] The corresponding end of the primary winding N1 is respectively connected to the positive pole of the capacitor C1 and the negative pole of the capacitor C2. The positive pole of the capacitor C2 is connected to the non-corresponding end of the secondary winding N2. The corresponding end of the secondary winding N2 is respectively connected to the negative pole of the diode D1, the positive pole of the diode D2, and the negative pole of the capacitor C3;

[0012] The non-corresponding end of the secondary winding N3 is connected to the negative pole of the capacitor C4. The positive pole of the capacitor C4 is respectively connected to the negative pole of the diode D2, the positive pole of the diode D3, the negative pole of the capacitor C5, and the non-corresponding end of the primary winding n1. The corresponding end of the primary winding n1 is connected to the positive pole of the capacitor C3;

[0013] The corresponding end of the secondary winding n2 is respectively connected to the positive pole of the capacitor C5 and the positive pole of the diode D4. The non-corresponding end of the secondary winding n2 is respectively connected to the negative pole of the diode D3 and the negative pole of the capacitor C6. The positive pole of the capacitor C6 is respectively connected to the negative pole of the diode D4 and the positive pole of the diode D5. The negative pole of the diode D5 is connected to the positive pole of the output circuit.

[0014] In a possible implementation, the primary winding N1 includes a leakage inductance L k1 and an exciting inductance L m1 , and the primary winding n1 includes a leakage inductance L k2 and an exciting inductance L m2 .

[0015] In a possible implementation, the output circuit includes: a capacitor C7 and a load;

[0016] The negative pole of the diode D5 is respectively connected to the positive pole of the capacitor C7 and one end of the load. The other end of the load is respectively connected to the negative pole of the capacitor C7, the negative pole of the input end, the source of the switch tube S, and the negative pole of the capacitor C1.

[0017] In a possible implementation, one operating cycle of the DC converter includes a first operating mode, a second operating mode, and a third operating mode;

[0018] The conduction or cutoff of the switching transistor S is used to control the switching of the operating mode of the DC converter.

[0019] In a possible implementation, the first operating mode is as follows: the switching transistor S is conducting, the diodes D2, D3, and D4 are conducting, and the diodes D1 and D5 are blocked;

[0020] The input terminal charges the inductor L1, and the current of the inductor L1 rises linearly;

[0021] The capacitor C1 charges the leakage inductance L k1 and the magnetizing inductance L m1 The leakage inductance L k1 and the magnetizing inductance L m1 Both currents rise linearly;

[0022] The capacitor C1, the capacitor C2, the secondary winding N2, and the secondary winding N3 charge the capacitor C4 through the diode D2;

[0023] The capacitor C3 charges the leakage inductance L k2 and the magnetizing inductance L m2 The leakage inductance L k2 and the magnetizing inductance L m2 Both charging currents rise linearly;

[0024] The secondary winding n2 charges the capacitor C5 through the diode D3 and also charges the capacitor C6 through the diode D4.

[0025] In a possible implementation, the second operating mode is as follows: the switching transistor S is cutoff, the diodes D1 and D5 are conducting, and the diodes D2, D3, and D4 are blocked;

[0026] The input terminal and the inductor L1 charge the capacitor C1;

[0027] The capacitor C4, the magnetizing inductance L m1 the secondary winding N2, and the secondary winding N3 charge the capacitor C3 and the capacitor C2;

[0028] The input terminal, the inductor L1, the secondary winding N3, the secondary winding n2, the capacitor C4, the capacitor C5, and the capacitor C6 charge the capacitor C7;

[0029] The inductor L1, the exciting inductor L m1 , the exciting inductor L m2 , the leakage inductor L k1 and the leakage inductor L k2 have a current drop. The capacitor C2 recovers the energy of the leakage inductor L k1 through the diode D1. The current of the diode D1 drops. When the current of the diode D1 drops to zero, the second operating mode is terminated and the third operating mode is entered.

[0030] In a possible implementation, the third operating mode is: the switch tube S is turned off, the diode D5 is turned on, and the diodes D1, D2, D3 and D4 are blocked;

[0031] The input terminal and the inductor L1 charge the capacitor C1;

[0032] The capacitor C4, the exciting inductor L m1 , the secondary winding N2 and the secondary winding N3 charge the capacitor C3 and the capacitor C2;

[0033] The input terminal, the inductor L1, the secondary winding N3, the secondary winding n2, the capacitor C4, the capacitor C5 and the capacitor C6 charge the capacitor C7;

[0034] The capacitor C7 supplies power to the load.

[0035] In a possible implementation, the calculation formula for the gain G of the output voltage of the output circuit relative to the input voltage of the input terminal is: ; where represents the turns ratio of the secondary winding N2 to the primary winding N1, represents the turns ratio of the secondary winding N3 to the primary winding N1, represents the turns ratio of the secondary winding n2 to the primary winding n1, and D represents the duty cycle of the switch tube S.

[0036] In a second aspect, an embodiment of the present invention provides a high-gain DC conversion device with a multi-coupled inductor, including: a controller, a voltage sampling sensor, and the high-gain DC converter with a multi-coupled inductor provided in the first aspect of the embodiment of the present invention;

[0037] Among them, the positive electrode of the voltage sampling sensor is connected to the positive electrode of the output circuit of the converter, the negative electrode of the voltage sampling sensor is connected to the negative electrode of the output circuit of the converter, the output end of the voltage sampling sensor is connected to the input end of the controller, and the output end of the controller is connected to the switching transistor S.

[0038] In a third aspect, an embodiment of the present invention provides a control method, which is applied to the high-gain DC converter with multi-coupled inductors provided in the first aspect of the embodiment of the present invention, or the high-gain DC conversion device with multi-coupled inductors provided in the second aspect, and includes:

[0039] Collect the output voltage of the output circuit;

[0040] Calculate the error value between the output voltage and the target voltage, and adjust the duty cycle of the switching transistor S according to the error value;

[0041] Generate a pulse width modulation PWM wave signal with the adjusted duty cycle and input it to the switching transistor S to control the conduction or cutoff of the switching transistor S.

[0042] The embodiment of the present invention provides a high-gain DC converter, a device and a control method with multi-coupled inductors. By adopting the combination of a three-winding coupled inductor and a two-winding coupled inductor, and through a specific connection method, a circuit topology is constructed with inductors, multiple capacitors, multiple diodes, a switching transistor S, an input end and each element of the output circuit. This structural design of the multi-coupled inductors can more effectively utilize the coupling effect between the inductors, achieve a higher voltage gain, and can, by reasonably selecting the turns ratio of multiple coupled inductors, achieve a flexible design voltage gain range, avoid the situation of extreme duty cycles in the operation of the switching transistor, and the entire circuit has simple control and high working efficiency. Description of the Drawings

[0043] Figure 1 is a schematic structural diagram of a high-gain DC converter with multi-coupled inductors provided by an embodiment of the present invention;

[0044] Figure 2 is a schematic structural diagram of another high-gain DC converter with multi-coupled inductors provided by an embodiment of the present invention;

[0045] Figure 3 is a schematic structural diagram of the circuit in the first working mode provided by an embodiment of the present invention;

[0046] Figure 4 is a schematic structural diagram of the circuit in the second working mode provided by an embodiment of the present invention;

[0047] Figure 5 is a schematic structural diagram of the circuit in the third working mode provided by an embodiment of the present invention;

[0048] Figure 6 It is a schematic structural diagram of a high-gain DC conversion device with multiple coupled inductors provided by an embodiment of the present invention;

[0049] Figure 7 It is a schematic implementation flowchart of the control method provided by an embodiment of the present invention; Detailed implementation manners

[0050] In order to enable those skilled in the art to better understand this solution, the technical solutions in the embodiments of this solution will be clearly described below in conjunction with the accompanying drawings in the embodiments of this solution. Obviously, the described embodiments are part of the embodiments of this solution, rather than all of the embodiments. Based on the embodiments in this solution, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this solution.

[0051] The term "including" in the specification and claims of this solution and the above-mentioned accompanying drawings, as well as any other variations, means "including but not limited to", and is intended to cover non-exclusive inclusion, not limited to the examples listed in the text. In addition, terms such as "first" and "second" are used to distinguish different objects, rather than to describe a specific order.

[0052] In the related art, in order to solve the problems that the actual voltage gain of a common Boost converter is not high, the voltage gain range is narrow, and the duty cycle of the switching tube is relatively high and the conduction time is too long under normal operation, which will increase the conduction loss and reduce the service life. A high-boost DC converter based on a coupled inductor structure was proposed. Its coupling method is usually a single multi-unit coupled inductor, that is, one primary winding and two or three secondary windings. By adjusting the turn ratio of the coupled inductor, the pressure on the switching tube is relieved and the voltage gain is increased. However, the requirements for the voltage gain of the boost converter in the new energy power generation system are also getting higher and higher. The conventional DC converter based on the coupled inductor structure still has the problem of insufficient voltage gain, and the duty cycle of the switching tube is extreme and the conversion efficiency of the entire circuit is low.

[0053] Aiming at the problems existing in the prior art, the present invention combines a three-winding coupled inductor and a two-winding coupled inductor, and constructs a circuit topology with an inductor, multiple capacitors, multiple diodes, a switching tube S, an input end, and each element of the output circuit through a specific connection method. This structural design of multiple coupled inductors can make more effective use of the coupling effect between inductors, achieve a higher voltage gain, and moreover, by reasonably selecting the turn ratios of multiple coupled inductors, a flexible designed voltage gain range can be achieved, avoiding the situation of extreme duty cycles in the operation of the switching tube, and the entire circuit has simple control and high working efficiency.

[0054] The implementation of the present invention will be described in detail with reference to the specific drawings as follows:

[0055] Figure 1 It is a schematic structural diagram of a high-gain DC converter with multiple coupled inductors provided by an embodiment of the present invention. Referring to Figure 1 , the high-gain DC converter with multiple coupled inductors includes: an input terminal (denoted as V in ), a switching transistor S, a three-winding coupled inductor, a two-winding coupled inductor, an inductor L1, multiple capacitors, multiple diodes, and an output circuit;

[0056] The three-winding coupled inductor includes: a primary winding N1, a secondary winding N2, and a secondary winding N3;

[0057] The two-winding coupled inductor includes: a primary winding n1 and a secondary winding n2;

[0058] The positive pole of the input terminal is connected to one end of the inductor L1, and the other end of the inductor L1 is respectively connected to the drain of the switching transistor S, the positive pole of the diode D1, the non-named end of the primary winding N1, and the named end of the secondary winding N3;

[0059] The negative pole of the input terminal is respectively connected to the source of the switching transistor S, the negative pole of the capacitor C1, and the negative pole of the output circuit;

[0060] The named end of the primary winding N1 is respectively connected to the positive pole of the capacitor C1 and the negative pole of the capacitor C2, the positive pole of the capacitor C2 is connected to the non-named end of the secondary winding N2, and the named end of the secondary winding N2 is respectively connected to the negative pole of the diode D1, the positive pole of the diode D2, and the negative pole of the capacitor C3;

[0061] The non-named end of the secondary winding N3 is connected to the negative pole of the capacitor C4, the positive pole of the capacitor C4 is respectively connected to the negative pole of the diode D2, the positive pole of the diode D3, the negative pole of the capacitor C5, and the non-named end of the primary winding n1, and the named end of the primary winding n1 is connected to the positive pole of the capacitor C3;

[0062] The named end of the secondary winding n2 is respectively connected to the positive pole of the capacitor C5 and the positive pole of the diode D4, the non-named end of the secondary winding n2 is respectively connected to the negative pole of the diode D3 and the negative pole of the capacitor C6, the positive pole of the capacitor C6 is respectively connected to the negative pole of the diode D4 and the positive pole of the diode D5, and the negative pole of the diode D5 is connected to the positive pole of the output circuit.

[0063] In this embodiment, the input terminal is connected to a new energy power generation system, and the electric energy generated by the new energy power generation system is input into the boost circuit through this input terminal. Therefore, when constructing the circuit topology of the high-gain DC converter, the input terminal can be equivalently regarded as an input power source, and the electric energy provided by this input power source for the circuit is the electric energy generated by the new energy power generation system.

[0064] In this embodiment, a plurality of capacitors (C1 - C6) and a plurality of diodes (D1 - D5) form a charge pump circuit, which stores and transfers energy through charging and discharging.

[0065] In this embodiment, by adopting the combination of a three-winding coupled inductor and a two-winding coupled inductor, and through a specific connection method, a circuit topology is constructed with the inductor, a plurality of capacitors, a plurality of diodes, the switch tube S, the input terminal, and each component of the output circuit. This structural design of multiple coupled inductors (three-winding and two-winding) can more effectively utilize the magnetic coupling effect between inductors to superimpose energy. Combining with the charge pump structure composed of a plurality of capacitors and a plurality of diodes, a multi-stage voltage boosting mechanism is formed to double the voltage, achieving a higher voltage gain. Moreover, by reasonably selecting the turns ratio of multiple coupled inductors and cooperating with adjusting the duty cycle of the switch tube S, the output voltage can be greatly increased to meet the high-gain requirement, and a flexible designed voltage gain range can be achieved, avoiding the situation of extreme duty cycles for the switch tube to work. The entire circuit has simple control and high working efficiency. Through the magnetic coupling effect between the three-winding and the two-winding, efficient energy transmission and conversion can be realized. Compared with the traditional single multi-unit coupled inductor structure, the circuit structure is simple, the manufacturing cost is low, and it has a higher power density and conversion efficiency. And adopting the structure of multiple coupled inductors can have multiple energy sources, avoiding excessive voltage stress in the circuit; and it also has the advantages of continuous input current, low voltage stress on the switch tube S, and the input energy source and the load sharing the same ground.

[0066] In a possible embodiment, referring to Figure 2 , the output circuit includes: a capacitor C7 and a load; the negative electrode of the diode D5 is respectively connected to the positive electrode of the capacitor C7 and one end of the load, and the other end of the load is respectively connected to the negative electrode of the capacitor C7, the negative electrode of the input terminal, the source electrode of the switch tube S, and the negative electrode of the capacitor C1.

[0067] In this embodiment, the load can be a resistor R, and the capacitor C7 supplies power to the load, and a stable voltage (denoted as V o ) is output through the capacitor C7 and the load R.

[0068] It can be understood that the primary winding N1 can be equivalently regarded as an ideal coil in parallel with the exciting inductor L m1 and then connected in series with the leakage inductance L k1 ; the primary winding n1 is equivalently regarded as an ideal coil in parallel with the exciting inductor Lm2 After being connected in parallel and then in series with the leakage inductance L k2 in series.

[0069] In the circuit topology provided in this embodiment, the leakage inductance L k1 and the leakage inductance L k2 can recover the leakage inductance energy through components such as diode D1, avoid leakage inductance energy loss, and improve the overall efficiency of the circuit.

[0070] In a possible implementation, one operating cycle of the high-gain DC converter includes a first operating mode, a second operating mode, and a third operating mode; the conduction or cutoff of the switching transistor S is used to control the switching of the operating modes of the DC converter.

[0071] In a possible implementation, the first operating mode is: the switching transistor S is conducting, the diodes D2, D3, and D4 are conducting, and the diodes D1 and D5 are blocked;

[0072] The input terminal charges the inductor L1, and the current of the inductor L1 linearly increases;

[0073] The capacitor C1 charges the leakage inductance L k1 and the exciting inductance L m1 The leakage inductance L k1 and the exciting inductance L m1 both have linearly increasing currents;

[0074] The capacitor C1, the capacitor C2, the secondary winding N2, and the secondary winding N3 charge the capacitor C4 through the diode D2;

[0075] The capacitor C3 charges the leakage inductance L k2 and the exciting inductance L m2 The leakage inductance L k2 and the exciting inductance L m2 both have linearly increasing charging currents;

[0076] The secondary winding n2 charges the capacitor C5 through the diode D3 and also charges the capacitor C6 through the diode D4.

[0077] Specifically, referring to Figure 3 the circuit structure shown, the first operating mode: the switching transistor S is conducting, the diodes D2, D3, and D4 are conducting, and the diodes D1 and D5 are blocked. The input power supply V in charges the inductor L1, so the current of the inductor L1 linearly increases; the leakage inductance L k1 and the exciting inductance L m1 as a whole are charged by the capacitor C1, the leakage inductance Lk1 rises linearly together with the exciting inductance L m1 rises linearly together with the current of the exciting inductance L; the capacitors C1, C2 and the secondary windings N2, N3 release energy to the capacitor C4 through the diode D2; the capacitor C3 discharges to charge the leakage inductance L k2 and the exciting inductance L m2 and the exciting inductance L k2 rises linearly together with the current of the leakage inductance L m2 and the exciting inductance L; the secondary winding n2 charges the capacitors C5 and C6 simultaneously through the diodes D3 and D4.

[0078] In this embodiment, in this first working mode, the energy stored in the capacitors C4, C5, and C6 will be delivered to the load in the second and third working modes to increase the output voltage, and the output capacitor C7 only supplies power to the load R.

[0079] In a possible implementation manner, the second working mode is: the switching transistor S is turned off, the diodes D1 and D5 are turned on, and the diodes D2, D3, and D4 are blocked;

[0080] the input terminal and the inductor L1 charge the capacitor C1;

[0081] the capacitor C4, the exciting inductance L m1 , the secondary winding N2, and the secondary winding N3 charge the capacitor C3 and the capacitor C2;

[0082] the input terminal, the inductor L1, the secondary winding N3, the secondary winding n2, the capacitor C4, the capacitor C5, and the capacitor C6 charge the capacitor C7;

[0083] the current of the inductor L1, the exciting inductance L m1 , the exciting inductance L m2 , the leakage inductance L k1 , and the leakage inductance L k2 decreases, and the capacitor C2 recovers the energy of the leakage inductance L k1 through the diode D1, the current of the diode D1 decreases, and when the current of the diode D1 decreases to zero, the second working mode is terminated and the third working mode is entered.

[0084] Specifically, referring to Figure 4 the circuit structure shown, in the second working mode: the switching transistor S is turned off, the diodes D1 and D5 are turned on, and the diodes D2, D3, and D4 are blocked; the input power supply V in and the inductor L1 release energy to charge the capacitor C1; the capacitor C4 and the exciting inductance L m1, the secondary windings N2 and N3 together charge capacitors C3 and C2; the input power supply and inductor L1, together with the secondary winding N3, the secondary winding n2, and capacitors C4, C5, and C6, charge capacitor C7. Therefore, the currents of inductor L1, magnetizing inductor L m1 、L m2 、leakage inductance L k1 、L k2 all decrease; capacitor C2 recovers the leakage inductance energy through diode D1. When the current of diode D1 drops to zero, this mode terminates.

[0085] In a possible implementation, the third operating mode is: the switch S is turned off, diode D5 is turned on, and diodes D1, D2, D3, and D4 are blocked;

[0086] the input terminal and inductor L1 charge capacitor C1;

[0087] capacitor C4, magnetizing inductor L m1 、secondary winding N2, and secondary winding N3 charge capacitors C3 and C2;

[0088] the input terminal, inductor L1, secondary winding N3, secondary winding n2, capacitor C4, capacitor C5, and capacitor C6 charge capacitor C7;

[0089] capacitor C7 supplies power to the load.

[0090] Specifically, referring to the circuit structure shown in Figure 5 , in the third operating mode, switch S remains off, and all diodes except diode D5 are blocked; input power supply V in and inductor L1 continue to charge capacitor C1; capacitor C4 and magnetizing inductor L m1 、secondary windings N2 and N3 continue to charge capacitors C3 and C2; input power supply V in and inductor L1, together with secondary winding N3, secondary n2, and capacitors C4, C5, and C6, continue to charge capacitor C7.

[0091] In this embodiment, different operating states are switched by controlling the switch tube S, thereby achieving precise control and regulation of the output voltage, enabling the DC converter to achieve specific power conversion and transmission in different operating stages, which helps to improve the efficiency and stability of the converter; in different operating modes, the cooperative working modes among various inductors, capacitors, and diodes can achieve energy storage, transfer, and release, not only meeting the requirements of high-gain DC conversion, but also enabling the efficient transfer of energy between windings due to the magnetic coupling characteristics of the coupled inductors. With the energy storage and buffering effect of the capacitors, the current stress of the switch tube and the voltage stress of the diodes can be reduced, and the switching losses and conduction losses can be decreased. Moreover, components such as capacitors and diodes are reused in different operating modes, reducing the need for additional components. At the same time, under the magnetic energy distribution of the coupled inductors, the working stresses of components such as capacitors and diodes are more balanced and the utilization rate is higher. For example, capacitors C1−C6 not only participate in energy storage but also cooperate in the charge pump circuit, simplifying the circuit topology.

[0092] From the circuit topology of the high-gain DC converter provided in this embodiment, the calculation formula for the gain G of the output voltage of the output circuit relative to the input voltage of the input terminal is as follows: ; where represents the turn ratio of the secondary winding N2 to the primary winding N1, represents the turn ratio of the secondary winding N3 to the primary winding N1, represents the turn ratio of the secondary winding n2 to the primary winding n1, and D represents the duty cycle of the switch tube S.

[0093] It can be clearly seen from the voltage gain calculation formula that by adjusting the turn ratio of the coupled inductor and then cooperating with the adjustment of the duty cycle of the switch tube S, the voltage gain range can be flexibly adjusted to achieve a high voltage gain. For example, when the duty cycle is D = 0.5 and the turn ratios of the coupled inductors are both 2, the voltage gain can reach 42 times.

[0094] Figure 6 is a schematic structural diagram of a high-gain DC conversion device with multiple coupled inductors provided by an embodiment of the present invention. As Figure 6 shown, the high-gain DC conversion device with multiple coupled inductors provided in this embodiment includes: a controller, a voltage sampling sensor, and the high-gain DC converter with multiple coupled inductors provided in the above embodiment;

[0095] Among them, the positive electrode of the voltage sampling sensor is connected to the positive electrode of the output circuit of the converter, the negative electrode of the voltage sampling sensor is connected to the negative electrode of the output circuit of the converter, the output end of the voltage sampling sensor is connected to the input end of the controller, and the output end of the controller is connected to the switch tube S.

[0096] In this embodiment, the voltage sampling sensor may be, but is not limited to, a Hall voltage sampling sensor, and the controller may be, but is not limited to, a Proportional - Integral (PI) controller.

[0097] In this embodiment, the output voltage V of the high - gain DC converter is collected by the Hall voltage sampling sensor o , and the collected output voltage is sent to the PI controller. The target voltage is stored in the PI controller. After the PI controller receives the output voltage V o , it calculates the error value between the output voltage and the target voltage, adjusts the proportional coefficient kp and the integral coefficient ki according to the error value, so that the PI controller reduces the error value, generates a Pulse Width Modulation (PWM) wave signal, and sends this PWM wave signal to the switching transistor S to control the on - off of the switching transistor S, realizing the switching of the working mode of the high - gain DC converter, and making the output voltage V o stabilized to the target voltage value.

[0098] It should be noted that the value of the target voltage is determined according to the voltage value required in the actual application scenario. For example, in the actual application scenario, if it is necessary to boost a low DC voltage to a high DC voltage (generally 400V) suitable for inverter conversion through this high - gain DC conversion device, then the target voltage is set to 400V.

[0099] In the PI controller, the proportional part (kp) outputs a control signal in proportion according to the error value between the current output voltage and the target voltage. When the output voltage of the high - gain DC converter deviates from the target voltage value, the proportional link can respond quickly, generate a corresponding control amount, adjust the working state of the switching transistor, and make the output voltage change in the direction of the target voltage value. For example, if the output voltage is lower than the target voltage, the proportional link (kp) will increase the control signal, increase the on - time of the switching transistor, allow more energy to be transferred to the output end, and increase the output voltage. The integral part (ki) performs an integral operation on the error value, accumulating the error from the beginning to the current moment. As time goes by, even if the error is very small, the integral term will continue to increase, continuously adjusting the control amount until the steady - state error is eliminated and the output voltage is stabilized at the target voltage value. For example, during long - term operation, due to load changes or power supply fluctuations, a small steady - state error is generated, and the integral link can gradually correct it to keep the output voltage stable. The PI controller generates the duty cycle of the PWM wave signal according to the processed error signal. By changing the duty cycle of the PWM wave, it directly controls the on - off time of the switching transistor S in the high - gain DC converter, thereby adjusting the magnitude of the output voltage. For example, when the duty cycle increases, the on - time of the switching transistor becomes longer and the output voltage increases; conversely, the output voltage decreases.

[0100] In this embodiment, the PI controller can optimize the dynamic performance of the high-gain DC converter, enabling it to quickly adjust the output, maintain stable operation, keep the output voltage stable, and enhance the robustness of the system when facing disturbances such as input voltage fluctuations and load mutations. Moreover, the output voltage is collected by a voltage sampling sensor and fed back to the controller. The controller adjusts the duty cycle of the switching transistor according to the error between the output voltage and the target voltage, forming a closed-loop control system. This closed-loop control method can monitor and adjust the output voltage of the high-gain DC converter in real time, improving the overall stability and reliability of the circuit.

[0101] Figure 7 is a schematic diagram of the implementation process of the control method provided by the embodiment of the present invention; as Figure 7 shown, the method provided by this embodiment includes the following steps:

[0102] S701, collect the output voltage of the output circuit.

[0103] S702, calculate the error value between the output voltage and the target voltage, and adjust the duty cycle of the switching transistor S according to the error value.

[0104] S703, generate a pulse width modulation PWM wave signal with the adjusted duty cycle and input it to the switching transistor S to control the conduction or cutoff of the switching transistor S.

[0105] In this embodiment, the execution entity of step S701 can be a voltage sampling sensor, and the execution entities of steps S702 and S703 can be a PI controller.

[0106] In this embodiment, by automatically collecting the output voltage of the high-gain DC converter, automatically adjusting the duty cycle of the switching transistor S according to the error value between the output voltage and the target voltage, and generating a PWM wave signal with the adjusted duty cycle and inputting it to the switching transistor S to control the conduction or cutoff of the switching transistor S, a closed-loop control method of the high-gain DC converter is realized, which can monitor and adjust the output voltage of the high-gain DC converter in real time, enable the output voltage to be stabilized at the target voltage value, and improve the overall stability and reliability of the circuit.

[0107] It should be noted that the detailed implementation process of the method provided by this embodiment can refer to the description in the above-mentioned embodiment of the high-gain DC conversion device with multiple coupled inductors, and will not be repeated here.

[0108] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-gain DC converter with a multi-coupled inductor, characterized in that Comprising: an input terminal, a switching transistor S, a three-winding coupled inductor, a two-winding coupled inductor, an inductor L1, a plurality of capacitors, a plurality of diodes, and an output circuit; The three-winding coupled inductor includes: a primary winding N1, a secondary winding N2, and a secondary winding N3; The two-winding coupled inductor includes: a primary winding n1 and a secondary winding n2; The positive pole of the input terminal is connected to one end of the inductor L1, and the other end of the inductor L1 is respectively connected to the drain of the switching transistor S, the positive pole of the diode D1, the opposite-named end of the primary winding N1, and the same-named end of the secondary winding N3; The negative pole of the input terminal is respectively connected to the source of the switching transistor S, the negative pole of the capacitor C1, and the negative pole of the output circuit; The same-named end of the primary winding N1 is respectively connected to the positive pole of the capacitor C1 and the negative pole of the capacitor C2, the positive pole of the capacitor C2 is connected to the opposite-named end of the secondary winding N2, and the same-named end of the secondary winding N2 is respectively connected to the negative pole of the diode D1, the positive pole of the diode D2, and the negative pole of the capacitor C3; The opposite-named end of the secondary winding N3 is connected to the negative pole of the capacitor C4, the positive pole of the capacitor C4 is respectively connected to the negative pole of the diode D2, the positive pole of the diode D3, the negative pole of the capacitor C5, and the opposite-named end of the primary winding n1, and the same-named end of the primary winding n1 is connected to the positive pole of the capacitor C3; The same-named end of the secondary winding n2 is respectively connected to the positive pole of the capacitor C5 and the positive pole of the diode D4, the opposite-named end of the secondary winding n2 is respectively connected to the negative pole of the diode D3 and the negative pole of the capacitor C6, the positive pole of the capacitor C6 is respectively connected to the negative pole of the diode D4 and the positive pole of the diode D5, and the negative pole of the diode D5 is connected to the positive pole of the output circuit.

2. The high-gain DC converter with multiple coupled inductors according to claim 1, characterized in that The primary winding N1 includes leakage inductance L k1 and magnetizing inductance L m1 , the primary winding n1 includes leakage inductance L k2 and magnetizing inductance L m2 .

3. The high-gain DC converter with multiple coupled inductors according to claim 2, characterized in that, The output circuit includes: a capacitor C7 and a load; The negative pole of the diode D5 is respectively connected to the positive pole of the capacitor C7 and one end of the load, and the other end of the load is respectively connected to the negative pole of the capacitor C7, the negative pole of the input terminal, the source of the switching transistor S, and the negative pole of the capacitor C1.

4. The high-gain DC converter with multiple coupled inductors as claimed in claim 3, wherein One working cycle of the DC converter includes a first working mode, a second working mode, and a third working mode; The conduction or cutoff of the switching transistor S is used to control the switching of the working mode of the DC converter.

5. The high-gain DC converter with multiple coupled inductors according to claim 4, wherein The first working mode is: the switching transistor S is conducting, the diodes D2, D3, and D4 are conducting, and the diodes D1 and D5 are blocked; The input terminal charges the inductor L1, and the current of the inductor L1 linearly increases; The capacitor C1 is the leakage inductance L k1 and the exciting inductance L m1 are charged, and the currents of the leakage inductance L k1 and the exciting inductance L m1 both increase linearly; The capacitors C1, C2, the secondary winding N2, and the secondary winding N3 charge the capacitor C4 through the diode D2; The capacitor C3 is the leakage inductance L k2 and the exciting inductance L m2 are charged. The current for charging the leakage inductance L k2 and the exciting inductance L m2 both linearly increases; The secondary winding n2 charges the capacitor C5 through the diode D3 and also charges the capacitor C6 through the diode D4.

6. The high-gain DC converter with multiple coupled inductors according to claim 5, characterized in that, The second working mode is: the switching transistor S is cutoff, the diodes D1 and D5 are conducting, and the diodes D2, D3, and D4 are blocked; The input terminal and the inductor L1 charge the capacitor C1; the capacitor C4, the excitation inductor L m1 , the secondary winding N2, and the secondary winding N3 charge the capacitor C3 and the capacitor C2; The input terminal, the inductor L1, the secondary winding N3, the secondary winding n2, the capacitors C4, C5, and C6 charge the capacitor C7; The inductor L1, the exciting inductor L m1 , the exciting inductor L m2 , the leakage inductor L k1 and the leakage inductor L k2 have a current drop. The capacitor C2 recovers the energy of the leakage inductor L k1 . The current of the diode D1 drops. When the current of the diode D1 drops to zero, the second operating mode is terminated and the third operating mode is entered.

7. The high-gain DC converter with multiple coupled inductors as claimed in claim 6, wherein The third operating mode is: the switch S is turned off, the diode D5 is turned on, and the diodes D1, D2, D3, and D4 are blocked; The input terminal and the inductor L1 charge the capacitor C1; the capacitor C4, the exciting inductor L m1 charge the capacitor C3 and the capacitor C2; The input terminal, the inductor L1, the secondary winding N3, the secondary winding n2, the capacitors C4, C5, and C6 charge the capacitor C7; The capacitor C7 supplies power to the load.

8. The high-gain DC converter with multiple coupled inductors according to any one of claims 1-7, characterized in that, The calculation formula for the gain G of the output voltage of the output circuit with respect to the input voltage of the input terminal is as follows: ; where represents the turns ratio of the secondary winding N2 to the primary winding N1, represents the turns ratio of the secondary winding N3 to the primary winding N1, represents the turns ratio of the secondary winding n2 to the primary winding n1, and D represents the duty cycle of the switching transistor S.

9. A high-gain DC conversion device with a multi-coupled inductor, characterized in that, Comprising: A controller, a voltage sampling sensor, and the high-gain DC converter with a multi-coupled inductor according to any one of claims 1-8; Wherein, the positive pole of the voltage sampling sensor is connected to the positive pole of the output circuit of the converter, the negative pole of the voltage sampling sensor is connected to the negative pole of the output circuit of the converter, the output terminal of the voltage sampling sensor is connected to the input terminal of the controller, and the output terminal of the controller is connected to the switch S.

10. A control method is applied to the high-gain DC converter of the multi-coupled inductor according to any one of claims 1-8 or the high-gain DC conversion device of the multi-coupled inductor according to claim 9, characterized in that, Comprising: Collect the output voltage of the output circuit; Calculate the error value between the output voltage and the target voltage, and adjust the duty cycle of the switch S according to the error value; Generate a pulse width modulation PWM wave signal with the adjusted duty cycle and input it to the switch S to control the conduction or turn-off of the switch S.

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