Coupled inductor DC-DC converter and power equipment

Abstract

The invention discloses a coupling inductor DC-DC converter and power equipment, the DC-DC converter comprises a boost circuit and a post-stage circuit, the boost circuit comprises a plurality of boost diodes and a boost inductor, and the post-stage circuit comprises a switch tube, a coupling inductor, a fly-wheel diode and an energy storage capacitor; wherein the plurality of boost diodes are sequentially connected in series, the first boost diode is connected with a positive electrode of a power supply, the last boost diode is connected to the coupling inductor through the fly-wheel diode, the boost inductor is connected in parallel with two series-connected ends of two adjacent boost diodes, the coupling inductor is connected with a load through the fly-wheel diode, and a drain electrode of the switch tube is connected with the last boost diode. The energy storage capacitor is connected with the coupling inductor, the fly-wheel diode and the last boost diode. According to the coupling inductor DC-DC converter, the boost topological structure is optimized, the loss of a system can be effectively reduced, and the efficiency of the system is improved.

Description

Technical Field

[0001] This invention relates to the field of DC-DC converter technology, and more particularly to a coupled inductor DC-DC converter and power equipment. Background Technology

[0002] Currently, the electrical energy output by photovoltaic panels is often in the form of low-voltage DC. To ensure high transmission efficiency, this low-voltage DC energy needs to be converted into a higher voltage level DC voltage via a DC-DC converter to form a DC bus for energy transmission, or further converted into AC voltage via an inverter circuit for transmission. Based on the boost principle of circuit topology, high-voltage DC-DC converters can be divided into isolated topologies and non-isolated topologies.

[0003] For DC-DC converters, isolated DC-DC converters often have higher losses and their efficiency is often lower than that of non-isolated DC-DC converters. For existing non-isolated DC-DC converters, which rely solely on capacitors, inductors, diodes, or switching transistors, there is often a voltage difference between the parallel capacitors during mode switching. During the balancing process of the two capacitor voltages, unavoidable charging and discharging losses will occur, resulting in low system efficiency. Summary of the Invention

[0004] This invention provides a coupled inductor DC-DC converter and power equipment, aiming to solve the problem of low system efficiency caused by high losses in existing non-isolated DC-DC converters.

[0005] In a first aspect, embodiments of the present invention provide a coupled inductor DC-DC converter, comprising:

[0006] The boost circuit includes multiple boost diodes and a boost inductor, and the subsequent circuit includes a switching transistor, a coupling inductor, a freewheeling diode, and an energy storage capacitor.

[0007] In this configuration, multiple boost diodes are connected in series. The first boost diode is connected to the positive terminal of the power supply, and the last boost diode is connected to the coupling inductor through the freewheeling diode. The boost inductor is connected in parallel across the two adjacent boost diodes connected in series. The coupling inductor is connected to the load through the freewheeling diode. The drain of the switching transistor is connected to the last boost diode, and the source is connected to the negative terminal of the power supply. The energy storage capacitor is connected to the coupling inductor, the freewheeling diode, and the last boost diode.

[0008] Furthermore, the boost diodes are configured to be an odd number, and the odd number of boost diodes are connected in series in the same polarity manner. The anode of the first boost diode is connected to the positive terminal of the power supply, and the cathode of the last boost diode is connected to the coupling inductor through the freewheeling diode. The drain of the switching transistor and the energy storage capacitor are both connected to the cathode of the last boost diode.

[0009] Furthermore, the boost diode is configured as a first diode, a second diode, and a third diode. The anode of the first diode is connected to the positive terminal of the power supply, the cathode of the first diode is connected to the cathode of the second diode, the anode of the second diode is connected to the anode of the third diode, and the cathode of the third diode is connected to the coupling inductor through the freewheeling diode. The drain of the switching transistor and the energy storage capacitor are both connected to the cathode of the third diode.

[0010] Furthermore, the plurality of boost inductors are configured as a first inductor and a second inductor. One end of the first inductor is connected to the anode of the first diode, and the other end is connected between the anode of the second diode and the anode of the third diode. One end of the second inductor is connected between the cathode of the first diode and the cathode of the second diode, and the other end is connected to the cathode of the third diode.

[0011] Furthermore, the coupled inductor has a first winding, a second winding, and a third winding. The cathode of the third diode is connected to the first winding through the freewheeling diode. The second winding is connected to the negative terminal of the power supply through the energy storage capacitor. The third winding is connected to the load through the freewheeling diode.

[0012] Furthermore, the subsequent circuit also includes a magnetizing inductor, one end of which is connected to the midpoint of the winding of the coupling inductor, and the other end is connected between the freewheeling diode and the first winding.

[0013] Furthermore, the energy storage capacitor is configured as a first capacitor and a second capacitor. One end of the first capacitor is connected to the second winding, and the other end is connected to the negative terminal of the power supply. One end of the second capacitor is connected to the cathode of the third diode, and the other end is connected between the third winding and the freewheeling diode.

[0014] Furthermore, the freewheeling diode is configured as a fourth diode and a fifth diode. The anode of the fourth diode is connected to the cathode of the third diode, and the cathode is connected to the first winding. The anode of the fifth diode is connected to the third winding, and the cathode is connected to the load.

[0015] Furthermore, the subsequent circuit also includes a filter capacitor, one end of which is connected to the cathode of the fifth diode, and the other end is connected to the negative terminal of the power supply.

[0016] In a second aspect, the present invention provides a power device comprising the DC-DC converter described in the first aspect above.

[0017] This invention provides a coupled-inductor DC-DC converter and a power device. The DC-DC converter includes a boost circuit and a subsequent stage circuit. The boost circuit includes multiple boost diodes and a boost inductor. The subsequent stage circuit includes a switching transistor, a coupled inductor, a freewheeling diode, and an energy storage capacitor. The multiple boost diodes are connected in series, with the first boost diode connected to the positive terminal of the power supply. The last boost diode is connected to the coupled inductor via a freewheeling diode. The boost inductor is connected in parallel across the series connection of two adjacent boost diodes. The coupled inductor is connected to the load via the freewheeling diode. The drain of the switching transistor is connected to the last boost diode, and its source is connected to the negative terminal of the power supply. The energy storage capacitor is connected to the coupled inductor, the freewheeling diode, and the last boost diode. By optimizing the boost topology, the voltage gain is reduced due to the constraints of the coupled inductor coefficient and duty cycle, thereby reducing system losses and improving system efficiency. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A circuit diagram of a DC-DC converter provided in an embodiment of the present invention;

[0020] Figure 2 A partial circuit diagram of a DC-DC converter provided in an embodiment of the present invention;

[0021] Figure 3 A circuit diagram of the DC-DC converter in the on state of the switching transistor provided in an embodiment of the present invention;

[0022] Figure 4 The circuit diagram of the DC-DC converter with the switching transistor in the off state is provided for an embodiment of the present invention.

[0023] Figure label:

[0024] 10. Boost circuit; 20. Subsequent stage circuit; 21. Coupled inductor. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0027] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0028] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0029] As used in this specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrases "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."

[0030] To facilitate understanding of the present invention, the DC-DC converter provided in the embodiments of the present invention will first be described. Please refer to... Figures 1 to 4 For details, please refer to Figure 1This invention provides a coupled inductor DC-DC converter, comprising: a boost circuit 10 and a subsequent circuit 20. The boost circuit 10 includes multiple boost diodes and a boost inductor. The subsequent circuit 20 includes a switching transistor Q1, a coupled inductor 21, a freewheeling diode, and an energy storage capacitor. The multiple boost diodes are connected in series, with the first boost diode connected to the positive terminal of the power supply, and the last boost diode connected to the coupled inductor 21 via the freewheeling diode. The boost inductor is connected in parallel across the two adjacent boost diodes connected in series. The coupled inductor 21 is connected to a load R via the freewheeling diode. The drain of the switching transistor Q1 is connected to the last boost diode, and its source is connected to the negative terminal of the power supply. The energy storage capacitor is connected to the coupled inductor 21, the freewheeling diode, and the last boost diode.

[0031] In specific implementation, the coupled inductor DC-DC converter is a non-isolated DC-DC converter. Specifically, high-voltage DC-DC converters can be divided into isolated and non-isolated topologies. Non-isolated topologies can be further classified into switched capacitor type, switched inductor type, and coupled inductor type, depending on the components used. For DC-DC converters, the commonly used isolation circuit is a transformer-based topology. The introduction of a transformer effectively alleviates the voltage boosting pressure on other circuit components. However, because isolated converter topologies often operate in a hard-switching state, switching losses are significant. Furthermore, in applications where input and output isolation is not mandatory, isolated DC-DC converters often have higher losses, resulting in lower efficiency compared to non-isolated topologies. For existing non-isolated DC-DC converters, relying solely on capacitors, inductors, diodes, or switching transistors often leads to voltage differences between parallel capacitors during mode switching. The balancing process of these voltages causes unavoidable charging and discharging losses, reducing system efficiency.

[0032] Therefore, this embodiment of the coupled inductor DC-DC converter constructs a novel boost topology. Specifically, the coupled inductor DC-DC converter is non-isolated and designed using a type I boost topology. The coupled inductor DC-DC converter consists of a boost circuit 10 and a subsequent circuit 20. The boost circuit 10 is composed of multiple boost diodes and a boost inductor, and the subsequent circuit 20 is composed of a switching transistor Q1, a coupled inductor, a freewheeling diode, and an energy storage capacitor. Figure 1 Diodes D1, D2, and D3 shown are all boost diodes, and inductors L1 and L2 are both boost inductors. The number of boost inductors can be one less than the number of boost diodes. Figure 1 Diodes D4 and D5 are both freewheeling diodes, and capacitors C1 and C2 are both energy storage capacitors. Figure 1 The boost circuit 10 can be modified and adjusted to obtain the following: Figure 2The equivalent circuit shown is as follows: Figure 2 As shown, multiple boost diodes are connected in series. The first boost diode is connected to the positive terminal of the power supply Vin, and the last boost diode is connected to the coupling inductor 21 through a freewheeling diode. The last boost diode is connected in series with the last boost diode. Figure 2 Diode D1 is the first boost diode, and diode D3 is the last boost diode. The power supply Vin can be provided by a battery or a photovoltaic panel. The boost inductor is connected in parallel across the terminals of two adjacent boost diodes connected in series, which is equivalent to having two boost diodes connected in series between the terminals of each boost inductor. For example... Figure 1 As shown, the coupling inductor 21 is connected to the load R through the freewheeling diode. The load R is typically the electrical equipment or circuit connected to the converter. The coupling inductor 21 can be a three-winding coupled inductor or an inductor with other coupling structures. The drain of the switching transistor Q1 is connected to the last boost diode, meaning the drain of the switching transistor Q1 is connected to the last boost diode connected in series. The source of the switching transistor Q1 is connected to the negative terminal of the power supply Vin. The switching transistor Q1 can be switched on and off under the drive of the PWM signal. The energy storage capacitor connects the coupling inductor 21, the freewheeling diode, and the last boost diode. The energy storage capacitor mainly serves the function of charging and discharging, achieving power output by cooperating with the high-frequency switching of the switching transistor Q1.

[0033] In practical applications, the coupled inductor DC-DC converter operates in two modes: one with switch Q1 on and the other with switch Q1 off. In the on mode, some boost diodes are forward-biased while others are reverse-biased. All boost inductors are charged by the input power supply Vin, the freewheeling diode is reverse-biased, and the energy storage capacitor is simultaneously charging and discharging. In the off mode, the boost diodes are in the opposite state to those in the on mode. All boost inductors discharge in parallel, the freewheeling diode is forward-biased, and the energy storage capacitor's charging and discharging states are opposite to those in the on mode.

[0034] In a further embodiment, refer to Figures 1 to 4The boost diodes are configured with an odd number, connected in series with the same polarity. The anode of the first boost diode is connected to the positive terminal of the power supply, and the cathode of the last boost diode is connected to the coupling inductor 21 via a freewheeling diode. The drain of the switching transistor Q1 and the energy storage capacitor are both connected to the cathode of the last boost diode. In a specific implementation, the number of boost diodes is odd, specifically, there can be three boost diodes, and the number of boost inductors is one less than the number of boost diodes, which can be two boost inductors. The odd number of boost diodes are connected in series with the same polarity, meaning anode to anode and cathode to cathode. The anode of the first boost diode is connected to the positive terminal of the power supply Vin, and the cathode of the last boost diode is connected to the coupling inductor 21 via a freewheeling diode. One boost inductor is connected in parallel across two adjacent boost diodes. The drain of the switching transistor Q1 and the energy storage capacitor are both connected to the cathode of the last boost diode.

[0035] In a further embodiment, refer to Figures 1 to 4 The boost diodes are configured as a first diode D1, a second diode D2, and a third diode D3. The anode of the first diode D1 is connected to the positive terminal of the power supply, the cathode of the first diode D1 is connected to the cathode of the second diode D2, the anode of the second diode D2 is connected to the anode of the third diode D3, and the cathode of the third diode D3 is connected to the coupling inductor 21 through the freewheeling diode. The drain of the switching transistor Q1 and the energy storage capacitor are both connected to the cathode of the third diode D3. In a specific implementation, three boost diodes are used, namely the first diode D1, the second diode D2, and the third diode D3. The three diodes are connected in series with the same polarity. The anode of the first diode D1 is connected to the positive terminal of the power supply Vin, the cathode of the first diode D1 is connected to the cathode of the second diode D2, the anode of the second diode D2 is connected to the anode of the third diode D3, and the cathode of the third diode D3 is connected to the coupling inductor 21 through the freewheeling diode. The drain of the power switch and the energy storage capacitor are both connected to the cathode of the third diode D3.

[0036] In a further embodiment, refer to Figures 1 to 4The multiple boost inductors are designated as a first inductor L1 and a second inductor L2. One end of the first inductor L1 is connected to the anode of the first diode D1, and the other end is connected between the anode of the second diode D2 and the anode of the third diode D3. One end of the second inductor L2 is connected between the cathode of the first diode D1 and the cathode of the second diode D2, and the other end is connected to the cathode of the third diode D3. In a specific implementation, two boost inductors are used, designated as the first inductor L1 and the second inductor L2. One end of the first inductor L1 is connected to the anode of the first diode D1, and the other end of the first capacitor C1 is connected between the anode of the second diode D2 and the anode of the third diode D3. One end of the second inductor L2 is connected between the cathodes of the first diode D1 and the second diode D2, and the other end of the second diode D2 is connected to the cathode of the third diode D3. Overall, the first capacitor C1 is connected in parallel across the series connection of the first diode D1 and the second diode D2, and the second capacitor C2 is connected in series across the series connection of the second diode D2 and the third diode D3.

[0037] In a further embodiment, refer to Figure 1 The coupled inductor 21 has a first winding N1, a second winding N2, and a third winding N3. The cathode of the third diode D3 is connected to the first winding N1 through the freewheeling diode. The second winding N2 is connected to the negative terminal of the power supply through the energy storage capacitor. The third winding N3 is connected to the load R through the freewheeling diode. In a specific implementation, the coupled inductor 21 adopts a three-winding coupled structure inductor. The coupled inductor 21 has three windings, namely the first winding N1, the second winding N2, and the third winding N3. One end of the first winding N1, the second winding N2, and the third winding N3 are connected together as a midpoint. The other end of the first winding N1, the second winding N2, and the third winding N3 are used as connection terminals. The cathode of the third diode D3 is connected to the first winding N1 of the coupled inductor 21 through the freewheeling diode. The second winding N2 of the coupled inductor 21 is connected to the negative terminal of the power supply Vin through the energy storage capacitor. The third winding N3 of the coupled inductor 21 is connected to the load R through the freewheeling diode.

[0038] In a further embodiment, refer to Figure 1The subsequent circuit 20 also includes a magnetizing inductor Lm. One end of the magnetizing inductor Lm is connected to the midpoint of the winding of the coupling inductor 21, and the other end is connected between the freewheeling diode and the first winding N1. In a specific implementation, the subsequent circuit 20 further includes a magnetizing inductor Lm, one end of which is connected to the midpoint of the winding of the coupling inductor 21, that is, the midpoint where the first winding N1, the second winding N2, and the third winding N3 are connected, and the other end is connected between the freewheeling diode and the first winding N1. In practical applications, the magnetizing inductor Lm can provide excitation for the core of the coupling inductor 21, maintaining the stability of the main magnetic flux of the coupling inductor 21.

[0039] In one embodiment, reference is made to Figure 1 The energy storage capacitors are designated as a first capacitor C1 and a second capacitor C2. One end of the first capacitor C1 is connected to the second winding N2, and the other end is connected to the negative terminal of the power supply. One end of the second capacitor C2 is connected to the cathode of the third diode D3, and the other end is connected between the third winding N3 and the freewheeling diode. In a specific implementation, two energy storage capacitors are used, designated as a first capacitor C1 and a second capacitor C2. One end of the first capacitor C1 is connected to the second winding N2 of the coupling inductor 21, and the other end is connected to the negative terminal of the power supply Vin. One end of the second capacitor C2 is connected to the cathode of the third diode D3, and the other end is connected between the third winding N3 of the coupling inductor 21 and the freewheeling diode. In specific applications, the charging and discharging states of the first capacitor C1 and the second capacitor C2 switch with the on / off mode of the switch Q1. In the on mode of the switch Q1, the first capacitor C1 discharges and the second capacitor C2 charges; in the off mode of the switch Q1, the first capacitor C1 charges and the second capacitor C2 discharges.

[0040] In one embodiment, reference is made to Figure 1The freewheeling diodes are configured as a fourth diode D4 and a fifth diode D5. The anode of the fourth diode D4 is connected to the cathode of the third diode D3, and the cathode is connected to the first winding N1. The anode of the fifth diode D5 is connected to the third winding N3, and the cathode is connected to the load R. In a specific implementation, two freewheeling diodes are used, namely the fourth diode D4 and the fifth diode D5. The anode of the fourth diode D4 is connected to the cathode of the third diode D3, and the cathode of the fourth diode D4 is connected to the first winding N1 of the coupling inductor 21. The anode of the fifth diode D5 is connected to the third winding N3 of the coupling inductor 21, and the cathode of the fifth inductor is connected to the load R. In specific applications, the conduction state of the fourth diode D4 and the fifth diode D5 switches with the on / off mode of the switch Q1. In the on mode of the switch Q1, both the fourth diode D4 and the fifth diode D5 are in the reverse cutoff state. In the off mode of the switch Q1, both the fourth diode D4 and the fifth diode D5 are in the forward conduction state.

[0041] In a further embodiment, refer to Figure 1 The subsequent circuit 20 also includes a filter capacitor C0. One end of the filter capacitor C0 is connected to the cathode of the fifth diode D5, and the other end is connected to the negative terminal of the power supply. In a specific implementation, the subsequent circuit 20 further includes a filter capacitor C0, with one end connected to the cathode of the fifth diode D5 and the other end connected to the negative terminal of the power supply Vin. Overall, the filter capacitor C0 is connected in parallel across the load R. In practical applications, the filter capacitor C0 can smooth the output voltage, reduce the ripple of the output voltage, and thus make the voltage output to the load R more stable.

[0042] In one embodiment, to further understand the invention, the following will be combined with... Figure 3 and Figure 4 The coupled inductor DC-DC converter is described in detail.

[0043] When switch Q1 is on, in boost circuit 10, diode D2 is reverse-biased and cut off, while diodes D4 and D5 are also cut off. At this time, capacitor C2 in subsequent circuit 20 charges, capacitor C1 discharges, and inductors L1 and L2 in boost circuit 10 are charged by the input power supply Vin. The three current paths involved in this state are as follows: Figure 3 The dashed line indicates that, according to Kirchhoff's laws, the corresponding KVL equation for this circuit is:

[0044] V in =V L1

[0045] V in =V L2

[0046] V C2 +V N3 =V C1 +V N2

[0047] Where Vin represents the power supply voltage, V L1 This represents the voltage across inductor L1 when switch Q1 is on, in V. L2 This represents the voltage across inductor L2 when switch Q1 is on, in V. C1 This represents the voltage across capacitor C1 when switch Q1 is on, in V. C2 This represents the voltage across capacitor C2 when switch Q1 is on, in V. N2 This represents the voltage across the second winding N2 of the three-winding coupled inductor when the switching transistor Q1 is on. (V) N3 This represents the voltage of the third winding N3 of the three-winding coupled inductor when the switching transistor Q1 is on.

[0048] With switch Q1 off, diodes D1 and D3 in boost circuit 10 are reverse-biased and cut off. Capacitor C2 in subsequent circuit 20 begins to discharge, while capacitor C1 charges. Inductors L1 and L2 in boost circuit 10 discharge in series. The three current paths in this state are as follows: Figure 4 The dashed line indicates that, according to Kirchhoff's laws, the corresponding KVL equation for this circuit is:

[0049] V in =V' L1 +V' L2 +V' N1 +V' N2 +V C1

[0050] V in +V C2 =V' L1 +V' L2 +V0

[0051] V C1 +V' N2 =V0-V' N3

[0052] Where Vin represents the power supply voltage, and V′ L1 This represents the voltage across inductor L1 when switch Q1 is off, V′ L2 This represents the voltage across inductor L2 when switch Q1 is off, in V. C1 This represents the voltage across capacitor C1 when the switching transistor is off, in V. C2 V' represents the voltage across capacitor C2 when the switch Q1 is off, and V0 represents the voltage across capacitor C0 when the switch Q1 is off. N1V′ represents the voltage across the first winding N1 of the three-winding coupled inductor when the switching transistor Q1 is off. N2 This represents the voltage V′ on the second winding N2 of the three-winding coupled inductor when the switching transistor Q1 is off. N3 This represents the voltage of the third winding N3 of the three-winding coupled inductor when the switching transistor Q1 is off.

[0053] Let K represent the winding coefficient of the three-winding coupled inductor. The expression for K is:

[0054]

[0055] Where N1 represents the number of turns in the first winding N1 of the three-winding coupled inductor, N2 represents the number of turns in the second winding N2 of the three-winding coupled inductor, and N3 represents the number of turns in the third winding N3 of the three-winding coupled inductor.

[0056] The average voltage across inductors L1 and L2 is calculated over one cycle for both the on and off states of switch Q1. According to the volt-second balance principle, this average value should be zero. Therefore, the voltages across capacitors C1 and C2 are as follows:

[0057]

[0058] Where Vin represents the power supply voltage, V C1 This represents the voltage across capacitor C1, in V. C2 Let C2 represent the voltage across capacitor C2, and D represent the duty cycle of the drive signal for switch Q1. Let G represent the boost ratio of the circuit. Based on the above formula, the boost ratio of the circuit can be calculated as follows:

[0059]

[0060] As can be seen from the above formula, compared with the boost ratio of the basic three-winding coupled inductor topology, the boost capability of the circuit is effectively improved, and the working characteristics of the three-winding coupled inductor and its network are not changed. Under ideal conditions, the system voltage gain continuously increases with the increase of winding coefficient and duty cycle.

[0061] The voltage stresses on the three diodes D1, D2, and D3 in the boost circuit 10 are as follows:

[0062]

[0063] V D2 =V in

[0064] Using a similarity analysis method with the basic three-winding coupled inductor topology, the drain-source voltage of the switching transistor Q1 can be expressed as: The voltage across diode D4 in the three-winding coupled inductor circuit is: The voltage across diode D5 can be expressed as: Therefore, compared with the basic three-winding coupled inductor topology, the voltage oscillation and voltage stress of the diodes in the circuit are reduced, which can improve the stability of the system.

[0065] In summary, the coupled inductor DC-DC converter of this invention optimizes the boost topology, thereby reducing the constraints of the coupling inductance coefficient and duty cycle on the voltage gain. This effectively reduces system losses, improves efficiency, and reduces diode voltage oscillation and voltage stress, resulting in higher system stability.

[0066] This invention also provides a power device, which includes the coupled inductor DC-DC converter described in the above embodiments. The power device can be an inverter, an on-board charger, or other similar equipment. The coupled inductor DC-DC converter can be integrated into the power device to realize its functions. Since the specific structure and working principle of the coupled inductor DC-DC converter have been described in detail in the preceding specification, they will not be repeated here for the sake of brevity.

[0067] The power equipment in this embodiment, being a coupled inductor DC-DC converter used in the above embodiment, consumes less power and has higher energy efficiency in actual applications.

[0068] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions are intended to be within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A coupled inductor DC-DC converter, characterized in that, include: The boost circuit includes multiple boost diodes and a boost inductor, and the subsequent circuit includes a switching transistor, a coupling inductor, a freewheeling diode, and an energy storage capacitor. In this configuration, multiple boost diodes are connected in series. The first boost diode is connected to the positive terminal of the power supply, and the last boost diode is connected to the coupling inductor through the freewheeling diode. The boost inductor is connected in parallel across the two adjacent boost diodes connected in series. The coupling inductor is connected to the load through the freewheeling diode. The drain of the switching transistor is connected to the last boost diode, and the source is connected to the negative terminal of the power supply. The energy storage capacitor is connected to the coupling inductor, the freewheeling diode, and the last boost diode.

2. The coupled inductor DC-DC converter according to claim 1, characterized in that, The boost diodes are configured to be an odd number, and the odd number of boost diodes are connected in series in the same polarity. The anode of the first boost diode is connected to the positive terminal of the power supply, and the cathode of the last boost diode is connected to the coupling inductor through the freewheeling diode. The drain of the switching transistor and the energy storage capacitor are both connected to the cathode of the last boost diode.

3. The coupled inductor DC-DC converter according to claim 2, characterized in that, The boost diode is configured as a first diode, a second diode, and a third diode. The anode of the first diode is connected to the positive terminal of the power supply, the cathode of the first diode is connected to the cathode of the second diode, the anode of the second diode is connected to the anode of the third diode, and the cathode of the third diode is connected to the coupling inductor through the freewheeling diode. The drain of the switching transistor and the energy storage capacitor are both connected to the cathode of the third diode.

4. The coupled inductor DC-DC converter according to claim 3, characterized in that, The plurality of boost inductors are configured as a first inductor and a second inductor. One end of the first inductor is connected to the anode of the first diode, and the other end is connected between the anode of the second diode and the anode of the third diode. One end of the second inductor is connected between the cathode of the first diode and the cathode of the second diode, and the other end is connected to the cathode of the third diode.

5. The coupled inductor DC-DC converter according to claim 4, characterized in that, The coupled inductor has a first winding, a second winding, and a third winding. The cathode of the third diode is connected to the first winding through the freewheeling diode. The second winding is connected to the negative terminal of the power supply through the energy storage capacitor. The third winding is connected to the load through the freewheeling diode.

6. The coupled inductor DC-DC converter according to claim 5, characterized in that, The subsequent circuit also includes a magnetizing inductor, one end of which is connected to the midpoint of the winding of the coupling inductor, and the other end is connected between the freewheeling diode and the first winding.

7. The coupled inductor DC-DC converter according to claim 5, characterized in that, The energy storage capacitor is configured as a first capacitor and a second capacitor. One end of the first capacitor is connected to the second winding and the other end is connected to the negative terminal of the power supply. One end of the second capacitor is connected to the cathode of the third diode and the other end is connected between the third winding and the freewheeling diode.

8. The coupled inductor DC-DC converter according to claim 5, characterized in that, The freewheeling diodes are configured as a fourth diode and a fifth diode. The anode of the fourth diode is connected to the cathode of the third diode, and the cathode is connected to the first winding. The anode of the fifth diode is connected to the third winding, and the cathode is connected to the load.

9. The coupled inductor DC-DC converter according to claim 8, characterized in that, The subsequent circuit also includes a filter capacitor, one end of which is connected to the cathode of the fifth diode, and the other end is connected to the negative terminal of the power supply.

10. An electrical device, characterized in that, Includes the coupled inductor DC-DC converter according to any one of claims 1-9.

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