Coupled inductor ultra-high gain dc-dc converter, apparatus, and control method

Abstract

The application discloses a coupled inductor super-high gain DC-DC converter, a device and a control method, and belongs to the technical field of renewable energy storage grid connection, wherein the DC-DC converter integrates quadratic structure, switched capacitor, three-winding coupled inductor and voltage multiplication unit technology, realizes super-high voltage gain without relying on extreme duty cycle, and provides three degrees of freedom of flexibly adjustable output voltage; the coupled inductor super-high gain DC-DC conversion device comprises a voltage sampling sensor, a controller, a PWM signal generator and the DC-DC converter; the control method is applied to the DC-DC conversion device. In addition, while obtaining high voltage gain, the DC-DC converter can effectively reduce the voltage stress borne by the switch tube, and is suitable for occasions with high requirements for high voltage conversion performance in a renewable energy power generation system.

Description

Technical Field

[0001] This invention relates to the field of renewable energy storage and grid connection technology, and more specifically, to a coupled inductor ultra-high gain DC-DC converter, device, and control method. Background Technology

[0002] Driven by the urgent need to address global climate change and achieve sustainable development, traditional power generation methods primarily reliant on fossil fuels are gradually being replaced by clean and renewable energy sources such as photovoltaics, wind power, and fuel cells. However, the DC output voltage of these new energy power generation units is typically low (for example, the output voltage of a single photovoltaic module is generally between 20V and 50V), making it difficult to directly meet the voltage requirements of grid-connected inverters or high-voltage DC buses. Therefore, DC-DC converters with high voltage conversion ratios are needed as power interfaces to achieve efficient connections between low-voltage power generation units and high-voltage application systems. Furthermore, the input voltage of new energy power generation systems fluctuates significantly due to environmental factors such as sunlight and wind, requiring boost converters to have a wide voltage gain range to maintain stable output voltage.

[0003] In related technologies, traditional boost converters, while simple in structure, suffer from severely limited actual voltage gain due to parasitic parameters, making it difficult to achieve high boost ratios under non-extreme duty cycles. Excessively high duty cycles not only increase conduction losses and reduce system efficiency but also trigger severe diode reverse recovery problems, limiting their application in high-gain applications. To address this deficiency, existing technologies have proposed a series of high-boost DC-DC converters based on coupled inductor structures. By adjusting the turns ratio of the coupled inductor, these converters can effectively reduce the voltage stress on the switching transistors, significantly improve voltage gain, and utilize the inherent leakage inductance of the coupled inductor to suppress the diode's reverse recovery current, thus improving electromagnetic compatibility characteristics.

[0004] However, with the continuous increase in the power level of new energy power generation systems and the increasing complexity of application scenarios, the performance requirements for boost converters are becoming increasingly stringent. Conventional DC-DC converters based on coupled inductors still face the following technical problems in practical applications: First, due to the limitations of the topology, the voltage gain improvement is limited, and in applications requiring ultra-high voltage conversion ratios (such as boosting from 24V to 800V), the duty cycle still tends to be extreme; second, if the energy stored in the leakage inductance of the coupled inductor is not effectively managed and recovered, it will induce voltage spikes at the moment the main switch turns off, which not only increases the voltage stress on power devices but also generates additional losses, restricting further improvement in overall efficiency; in addition, some existing topologies often require the introduction of complex clamping circuits or multi-stage cascaded structures to achieve higher voltage gains, resulting in an increase in the number of components and a decrease in power density. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a coupled-inductor ultra-high gain DC-DC converter, device, and control method. This DC-DC converter integrates a switched capacitor structure, a voltage multiplier unit, and a three-winding coupled inductor technology into a quadratic Boost circuit topology. It achieves ultra-high voltage gain without relying on extreme duty cycles and provides three degrees of freedom for flexibly adjusting the output voltage. Furthermore, while achieving high voltage gain, the DC-DC converter effectively reduces the voltage stress on the switching transistors.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] According to a first aspect of the present invention, a coupled-inductor ultra-high gain DC-DC converter is provided, comprising: an input port, an output port, an energy storage inductor, a first power switch, a second power switch, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a sixth diode, and a three-winding coupled inductor. The input port is used to connect to an input voltage source; the output port is used to connect to a load; the three-winding coupled inductor includes a primary winding, a first secondary winding, and a second secondary winding; wherein, the positive terminal of the input voltage source is connected to a first terminal of the energy storage inductor, and the negative terminal of the input voltage source is connected to the negative terminal of the first capacitor, the source of the first power switch, and the cathode of the second diode; the second terminal of the energy storage inductor is connected to the anode of the first diode, the drain of the first power switch, and the positive terminal of the second capacitor; the cathode of the first diode is connected to the positive terminal of the first capacitor, and the... The anode of the third diode and the drain of the second power switch; the cathode of the second capacitor is connected to the anode of the second diode and the opposite terminal of the primary winding; the source of the second power switch is connected to the same terminal of the primary winding and the cathode of the third capacitor; the cathode of the third diode is connected to the anode of the third capacitor, the cathode of the fourth capacitor, and the anode of the fourth diode; the anode of the fourth capacitor is connected to the opposite terminal of the first secondary winding; the cathode of the fourth diode is connected to the anode of the fifth diode and the opposite terminal of the second secondary winding; the same terminal of the first secondary winding is connected to the cathode of the fifth diode and the anode of the sixth diode; the cathode of the sixth diode is connected to the anode of the fifth capacitor; the same terminal of the second secondary winding is connected to the cathode of the fifth capacitor and the anode of the sixth capacitor; the cathode of the sixth capacitor is connected to the anode of the primary winding; the anode and cathode of the output port are respectively connected to the anode of the fifth capacitor and the cathode of the sixth capacitor.

[0008] Furthermore, the primary winding is equivalent to the magnetizing inductance connected in parallel with the primary winding of an ideal transformer, and then connected in series with the leakage inductance.

[0009] Furthermore, the first power switch and the second power switch are turned on and off simultaneously with completely consistent timing; the DC-DC converter is divided into a first operating mode and a second operating mode within one switching cycle according to the on and off states of the first power switch and the second power switch.

[0010] First operating mode: When the switch trigger pulse signal is at a high level, the DC-DC converter enters the first operating mode; in the current mode, the first power switch and the second power switch are turned on, the fourth diode and the sixth diode are turned on, and the first diode, the second diode, the third diode and the fifth diode are turned off;

[0011] Second operating mode: When the switch trigger pulse signal is at a low level, the DC-DC converter enters the second operating mode; in the current mode, the first power switch and the second power switch are turned off, the fourth diode and the sixth diode are turned off, and the first diode, the second diode, the third diode and the fifth diode are turned on;

[0012] Furthermore, the specific operation mode of the first working mode is as follows:

[0013] When the switch trigger pulse signal is at a high level, the first power switch and the second power switch are turned on simultaneously, and the input voltage source charges the energy storage inductor through the first power switch, and the current of the energy storage inductor increases linearly.

[0014] The first capacitor and the second capacitor are connected in series. The first power switch and the second power switch charge the primary winding together. The current of the magnetizing inductor increases linearly, which causes the magnetic flux in the magnetic core to change. The changing magnetic flux passes through the first secondary winding and the second secondary winding at the same time, thereby inducing corresponding voltages at the two ends of the first secondary winding and the second secondary winding.

[0015] The first capacitor, the second capacitor, the third capacitor, and the second secondary winding are connected in series, and the sixth capacitor is charged together by the first power switch, the second power switch, and the fourth diode.

[0016] The first capacitor, the second capacitor, the third capacitor, the fourth capacitor and the first secondary winding are connected in series, and the fifth capacitor and the sixth capacitor are charged together by the first power switch, the second power switch and the sixth diode;

[0017] The fifth and sixth capacitors together provide energy to the load;

[0018] Kirchhoff's Voltage Law (KVL) equation in the first operating mode is as follows:

[0019] ;

[0020] in, Indicates the input voltage source; , , , , and These are the voltages of the first capacitor, the second capacitor, the third capacitor, the fourth capacitor, the fifth capacitor, and the sixth capacitor, respectively. , , and These are the voltages of the energy storage inductor, primary winding, first secondary winding, and second secondary winding under the first operating mode, respectively. and These are the turns ratios of the three-winding coupled inductors, where... This is the turns ratio of the first secondary winding to the primary winding; This is the turns ratio of the second secondary winding to the primary winding.

[0021] Furthermore, the specific operation mode of the second working mode is as follows:

[0022] When the switch trigger pulse signal is at a low level, the first power switch and the second power switch are turned off simultaneously. The input voltage source and the energy storage inductor are connected in series, and the first and second diodes charge the first and second capacitors respectively.

[0023] The energy of the leakage inductance is absorbed by the third capacitor through the third diode;

[0024] The sixth capacitor, primary winding, first secondary winding, and second secondary winding are connected in series and charge the third and fourth capacitors together through the fifth diode.

[0025] The fifth and sixth capacitors together provide energy to the load;

[0026] Kirchhoff's Voltage Law (KVL) equation in the second operating mode is as follows:

[0027] ;

[0028] in, Indicates the input voltage source. , , , and These are the voltages of the first capacitor, the second capacitor, the third capacitor, the fourth capacitor, and the sixth capacitor, respectively. , , and These are the voltages of the energy storage inductor, primary winding, first secondary winding, and second secondary winding in the second operating mode, respectively. and These are the turns ratios of the three-winding coupled inductors, where... This is the turns ratio of the first secondary winding to the primary winding; This is the turns ratio of the second secondary winding to the primary winding.

[0029] Furthermore, the voltage gain of the DC-DC converter... Represented as:

[0030] ;

[0031] in, Indicates the input voltage source; This represents the output voltage of the DC-DC converter; This indicates the duty cycle of the first power switch and the second power switch; This is the turns ratio of the first secondary winding to the primary winding; This is the turns ratio of the second secondary winding to the primary winding.

[0032] Furthermore, the capacitance values ​​of the first capacitor, second capacitor, third capacitor, fourth capacitor, fifth capacitor, and sixth capacitor respectively satisfy the following:

[0033] ;

[0034] in, This represents the input current of the DC-DC converter; , , , , and These represent the allowable peak values ​​of capacitor voltage ripple for the first, second, third, fourth, fifth, and sixth capacitors, respectively. This indicates the switching frequency of the first power switch and the second power switch; This indicates the duty cycle of the first power switch and the second power switch; This is the turns ratio of the first secondary winding to the primary winding; This is the turns ratio of the second secondary winding to the primary winding; This indicates the voltage gain of the DC-DC converter.

[0035] Furthermore, the inductance values ​​of the energy storage inductor and the magnetizing inductor in the DC-DC converter satisfy the following relationship:

[0036] ;

[0037] in, and These represent the allowable peak values ​​of the inductor current ripple for the energy storage inductor and the magnetizing inductor, respectively. This indicates the switching frequency of the first power switch and the second power switch; This indicates the duty cycle of the first power switch and the second power switch.

[0038] According to a second aspect of the present invention, a coupled inductor ultra-high gain DC-DC converter is provided, comprising: a voltage sampling sensor, a controller, a PWM signal generator, and the DC-DC converter; wherein, the positive and negative terminals of the voltage sampling sensor are respectively connected to the two ends of the load of the DC-DC converter; the input terminal of the controller is connected to the output terminal of the voltage sampling sensor; the output terminal of the controller is connected to the input terminal of the PWM signal generator; the output terminal of the PWM signal generator is connected to the gate driver; and the gate driver is connected to the gates of the first power switch and the second power switch.

[0039] According to a third aspect of the present invention, a method for controlling the coupled inductor ultra-high gain DC-DC converter is provided, the method comprising:

[0040] The voltage sampling sensor is used to acquire the output voltage across the load terminals of the DC-DC converter.

[0041] The controller calculates the error value between the output voltage and the set reference voltage, adjusts the required duty cycle of the first power switch and the second power switch according to the error value, and transmits the adjusted required duty cycle to the PWM signal generator.

[0042] The PWM signal generator transmits the required duty cycle to the gates of the first power switch and the second power switch.

[0043] Compared with existing technologies, the present invention offers the following advantages through the above design scheme: It provides a coupled-inductor ultra-high gain DC-DC converter, device, and control method. The invention integrates a switched-capacitor structure, a voltage multiplier unit, and a three-winding coupled-inductor technology into a quadratic Boost circuit topology, achieving ultra-high voltage gain without relying on extreme duty cycles and providing three degrees of freedom for flexibly adjusting the output voltage. Simultaneously, the original diode-capacitor branch in the circuit is reused as a passive clamping circuit to recover leakage inductance energy and suppress voltage spikes in the switching transistor. Furthermore, while achieving high voltage gain, the DC-DC converter effectively reduces the voltage stress on the switching transistor, making it suitable for renewable energy power generation systems with high requirements for high-voltage conversion performance. Attached Figure Description

[0044] The accompanying drawings are provided to further illustrate the invention and form part of this application. The illustrative embodiments and descriptions of the invention are used to understand the invention and do not constitute an undue limitation thereof. In the drawings:

[0045] Figure 1 This is a schematic diagram of the circuit structure of a coupled inductor ultra-high gain DC-DC converter provided in an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of the equivalent circuit of the coupled inductor ultra-high gain DC-DC converter in the first operating mode in an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of the equivalent circuit of the coupled inductor ultra-high gain DC-DC converter in the second operating mode in an embodiment of the present invention;

[0048] Figure 4 This is a three-dimensional characteristic curve of voltage gain as a function of duty cycle and the turns ratio of coupling inductor in an embodiment of the present invention;

[0049] Figure 5 This is a simulation waveform diagram of a key node of the coupled inductor ultra-high gain DC-DC converter in an embodiment of the present invention;

[0050] Figure 6 This is a schematic diagram of the control method of the coupled inductor ultra-high gain DC-DC converter in an embodiment of the present invention. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. It should be noted that the terms "first," "second," "third," "fourth," "fifth," and "sixth" in this invention are used to distinguish different objects, rather than to describe a specific order.

[0052] Figure 1 The diagram shown is a circuit schematic of a coupled inductor ultra-high gain DC-DC converter provided by an example of the present invention. (Refer to...) Figure 1 The DC-DC converter includes an input port, an output port, and an energy storage inductor. L 1. First power switching transistor S 1. Second power switching transistor S 2. First capacitor C 1. Second capacitor C 2. Third capacitor C 3. Fourth capacitor C 4. Fifth capacitor C 5. Sixth capacitor C 6. First diode D 1. Second diode D 2. Third diode D 3. Fourth diode D 4. Fifth diode D 5. Sixth diode D 6. A three-winding coupled inductor, wherein the input port is used to connect an input voltage source. V in The output port is used to connect the load. R L The three-winding coupled inductor includes a primary winding. N 1. First secondary winding N 2 and second auxiliary winding N 3; First power switching transistor S 1 and second power switching transistors S Both are power MOSFETs. The DC-DC converters are respectively connected to the input voltage source. V in and load R L Among them, the input voltage source V in The positive terminal and the energy storage inductor L The first terminal of 1 is connected to the input voltage source. V in The negative terminal and the first capacitor C The negative terminal of 1, the first power switch transistor S1 source, second diode D Cathode connection of 2; load R L The two ends are respectively connected to the fifth capacitor C 5's positive terminal and the sixth capacitor C The negative terminal of 6 is connected. The energy storage inductor... L The second terminal of 1 is connected to the first diode. D 1's anode, the first power switch transistor S 1's drain, second capacitor C 2. Positive terminal connection; First diode D Cathode of 1 and first capacitor C 1's positive terminal, the third diode D 3's anode, second power switch S 2. Drain connection; second capacitor C The negative terminal of 2 and the second diode D 2's anode and primary winding N Connect the opposite terminal of 1. The second power switch transistor. S 2 source and primary winding N 1's corresponding terminal, the third capacitor C 3. Negative terminal connection; third diode D Cathode of 3 and third capacitor C 3's positive terminal, fourth capacitor C 4's negative terminal, the fourth diode D 4. Anode connection; fourth capacitor C 4's positive terminal and the first secondary winding N 2. Connection of opposite terminals; fourth diode D 4's cathode and the fifth diode D 5's anode, second secondary winding N The opposite-named terminals of 3 are connected. The first secondary winding... N The same terminal of 2 and the fifth diode D 5 cathode, sixth diode D 6. Anode connection; sixth diode D Cathode of 6 and fifth capacitor C 5. Positive terminal connection; second secondary winding N The same terminal of 3 and the fifth capacitor C 5's negative terminal, the sixth capacitor C 6. Positive terminal connection; sixth capacitor C The negative terminal of 6 and the primary winding N 1 is a connection with a different name.

[0053] The primary winding N 1 is equivalent to the primary winding and magnetizing inductance of an ideal transformer. L m After parallel connection, then with leakage inductanceL k Series connection.

[0054] In this example, the first power switch transistor S 1 and second power switching transistors S 2. Simultaneous opening and closing, with completely consistent timing; the DC-DC converter, within one switching cycle, adjusts according to the first power switching transistor... S 1 and second power switching transistors S The on and off states of 2 are divided into the first working mode and the second working mode;

[0055] First operating mode: When the switch trigger pulse signal is at a high level, the DC-DC converter enters the first operating mode; in this current mode, the first power switch transistor... S 1 and second power switching transistors S 2 is turned on, the fourth diode D 4 and the sixth diode D 6 is turned on, the first diode D 1. Second diode D 2. Third diode D 3 and the fifth diode D 5. Shutdown;

[0056] Second operating mode: When the switch trigger pulse signal is at a low level, the DC-DC converter enters the second operating mode; in the current mode, the first power switch transistor... S 1 and second power switching transistors S 2. Turn off, the fourth diode D 4 and the sixth diode D 6. Turn off, the first diode D 1. Second diode D 2. Third diode D 3 and the fifth diode D 5. Conductive.

[0057] like Figure 2 As shown, Figure 2 The blue arrows indicate the current flow direction in the first operating mode. The specific operating mode of the first operating mode is as follows:

[0058] When the switch trigger pulse signal is at a high level, the first power switch transistor S 1 and second power switching transistors S 2. Simultaneously turned on, the input voltage source V in Through the first power switch S 1-way energy storage inductor L 1. Charging, energy storage inductor L The current of capacitor 1 increases linearly; the first capacitorC 1 and second capacitors C 2 in series, through the first power switch transistor S 1 and second power switching transistors S 2 together form the primary winding. N 1. Charging, magnetizing inductor L m The linear increase in current causes a change in the magnetic flux in the core, and the changing magnetic flux simultaneously passes through the first secondary winding. N 2 and second auxiliary winding N 3, thus in the first secondary winding N 2 and second auxiliary winding N A corresponding voltage is induced at both ends of the first capacitor; C 1. Second capacitor C 2. Third capacitor C 3 and second auxiliary winding N 3 in series, through the first power switch transistor S 1. Second power switching transistor S 2 and the fourth diode D 4 together form the sixth capacitor C 6. Charging; the first capacitor C 1. Second capacitor C 2. Third capacitor C 3. Fourth capacitor C 4 and the first secondary winding N 2 in series, through the first power switch transistor S 1. Second power switching transistor S 2 and the sixth diode D 6 together form the fifth capacitor C 5 and the sixth capacitor C 6. Charging; the fifth capacitor C 5 and the sixth capacitor C 6 together serve as load R L Provides energy.

[0059] Kirchhoff's Voltage Law (KVL) equation in the first operating mode is as follows:

[0060] ;

[0061] in, Indicates the input voltage source; , , , , and The first capacitor C 1. Second capacitor C 2. Third capacitor C3. Fourth capacitor C 4. Fifth capacitor C 5. Sixth capacitor C 6 voltage; , , and These are energy storage inductors L 1. Primary winding N 1. First secondary winding N 2 and second auxiliary winding N 3. Voltage in the first operating mode; and These are the turns ratios of the three-winding coupled inductors, where... For the first secondary winding N 2 with the primary winding N A turns ratio of 1; For the second secondary winding N 3 and primary winding N A turns ratio of 1.

[0062] like Figure 3 As shown, Figure 3 The blue arrow in the middle indicates the current flow direction in the second operating mode. The specific operating mode of the second operating mode is as follows:

[0063] When the switch trigger pulse signal is at a low level, the first power switch transistor S 1 and second power switching transistors S 2. Simultaneously turn off the output voltage source. V in and energy storage inductor L 1. Connected in series, through the first diode D 1 and second diodes D 2 are respectively the first capacitor C 1 and second capacitors C 2. Charging; the leakage inductance L k Energy is transmitted through the third diode D 3 by the third capacitor C 3. Absorption; the sixth capacitor C 6. Primary winding N 1. First secondary winding N 2 and second auxiliary winding N 3 in series, through the fifth diode D 5 together form the third capacitor C 3 and the fourth capacitor C 4. Charging; the fifth capacitor C 5 and the sixth capacitor C 6 together serve as load R L Provides energy.

[0064] Kirchhoff's Voltage Law (KVL) equation in the second operating mode is as follows:

[0065] ;

[0066] in, Indicates the input voltage source; , , , and The first capacitor C 1. Second capacitor C 2. Third capacitor C 3. Fourth capacitor C 4 and the sixth capacitor C 6 voltage; , , and These are energy storage inductors L 1. Primary winding N 1. First secondary winding N 2 and second auxiliary winding N 3. Voltage in the second operating mode; and These are the turns ratios of the three-winding coupled inductors, where... For the first secondary winding N 2 with the primary winding N A turns ratio of 1; For the second secondary winding N 3 and primary winding N A turns ratio of 1.

[0067] The voltage gain of the DC-DC converter Represented as:

[0068] ;

[0069] in, Indicates the input voltage source; This represents the output voltage of the DC-DC converter; Indicates the first power switch transistor S 1 and second power switching transistors S Duty cycle of 2; where For the first secondary winding N 2 with the primary winding N A turns ratio of 1; For the second secondary winding N 3 and primary winding N A turns ratio of 1.

[0070] Furthermore, the first capacitor C 1. Second capacitor C 2. Third capacitor C 3. Fourth capacitor C 4 and the sixth capacitor C The capacitance values ​​of 6 satisfy the following conditions:

[0071] ;

[0072] in, This represents the input current of the DC-DC converter; , , , , and These represent the first capacitor. C 1. Second capacitor C 2. Third capacitor C 3. Fourth capacitor C 4 and the sixth capacitor C 6. Permissible peak capacitor voltage ripple; Indicates the first power switch transistor S 1 and second power switching transistors S 2. Switching frequency; Indicates the first power switch transistor S 1 and second power switching transistors S Duty cycle of 2; This indicates the voltage gain of the DC-DC converter.

[0073] Furthermore, the energy storage inductor L 1 and the excitation inductance of the three-winding coupled inductor L m The sensitivity values ​​satisfy the following:

[0074] ;

[0075] in, and The energy storage inductors are respectively represented L 1 and the excitation inductor L m Permissible peak inductor current ripple; Indicates the first power switch transistor S 1 and second power switching transistors S 2. Switching frequency; Indicates the first power switch transistor S 1 and second power switching transistors S A duty cycle of 2.

[0076] Figure 4This diagram illustrates a three-dimensional characteristic curve of voltage gain as a function of duty cycle and the turns ratio of the coupling inductor in an embodiment of the present invention. Figure 4 As can be seen, the new structure enables the converter's voltage gain to be within the duty cycle. ratio of turns and It allows for flexible adjustment across three dimensions and can operate at a relatively small duty cycle. ratio of turns and Under certain conditions, extremely high voltage gain can be achieved. For example, when the duty cycle... The turns ratio is 0.5. and When both are 1, the theoretical voltage gain can reach 34 times, which is beneficial to improving the overall efficiency and power density of the system.

[0077] like Figure 5 As shown, this example uses PLECS simulation software (PLECS is a system-level power electronics simulation software developed by Plexim GmbH, Switzerland), where the converter parameters are set as follows:

[0078] Input voltage source V in The voltage is 24V, and the load is... R L The resistance is 2150Ω, the first capacitor C 1 and second capacitors C The capacitance of capacitor 2 is 20μF, and the third capacitor... C 3 and the fourth capacitor C The capacitance of capacitor 4 is 10μF, and the fifth capacitor... C 5 and the sixth capacitor C The capacitance of 6 is 50μF, and the energy storage inductor... L The inductance of 1 is 290μH, and the magnetizing inductance is... L m The sensing value is 290 μH, leakage inductance L k The inductance is 1μH, and the turns ratio of the three-winding coupled inductor is... First power switch S 1 and second power switching transistors S The switching frequency of component 2 is 50kHz, and the duty cycle is 0.45. The simulation waveform is as follows. Figure 5 As shown, Figure 5 The horizontal axis represents the time axis. Figure 5 The CCP contains 6 groups of waveforms, numbered from top to bottom as Group 1 to Group 6.

[0079] The first group consists of the first power switching transistors. S 1 and second power switching transistors SWaveform of the switch trigger pulse signal for step 2.

[0080] The second group consists of energy storage inductors. L The current waveform diagram for Figure 1 shows that the input current is continuous, and since the input terminal is directly connected to the energy storage inductor... L 1. The input energy has low input current ripple. Furthermore, during the parameter design phase, the energy storage inductor can be used to achieve this. L Calculate the appropriate energy storage inductor using the inductance relationship formula. L 1. Ensure the current ripple meets the requirements;

[0081] The third group consists of the first power switching transistor. S The voltage and current waveforms are shown in Figure 1. The drain-source voltage stress is only 44V, less than 7% of the output voltage.

[0082] The fourth group is the second power switch. S The voltage and current waveforms are shown in Figure 2. The drain-source voltage stress is 110V, which is one-sixth of the output voltage.

[0083] The fifth and sixth groups show the input and output voltage waveforms. It can be seen that the DC-DC converter outputs 658V with a 24V input, and the voltage gain is... The value was 27.4, which verifies that the DC-DC converter topology has a very strong boost capability.

[0084] Figure 6 The diagram shown is a schematic representation of the control method provided in an example of the present invention. Figure 6 As shown in the figure, an embodiment of the present invention provides a coupled inductor ultra-high gain DC-DC converter, comprising: a voltage sampling sensor, a controller, a PWM signal generator, a gate driver, and a DC-DC converter provided in the first aspect of the present invention; wherein: the positive and negative terminals of the voltage sampling sensor are respectively connected to the two ends of the load of the DC-DC converter; the input terminal of the controller is connected to the output terminal of the voltage sampling sensor; the output terminal of the controller is connected to the input terminal of the PWM signal generator; the output terminal of the PWM signal generator is connected to the gate driver; and the gate driver is connected to the first power switch. S 1 and second power switching transistors S 2. Gate connection.

[0085] This invention provides a control method for a coupled inductor ultra-high gain DC-DC converter, comprising:

[0086] The voltage sampling sensor is used to acquire the output voltage across the load terminals of the DC-DC converter.

[0087] The controller calculates the error value between the output voltage and the set reference voltage, and adjusts the first power switch transistor according to the error value. S 1 and second power switching transistors S 2. The required duty cycle is determined, and the adjusted required duty cycle is transmitted to the PWM signal generator;

[0088] The PWM signal generator transmits the required duty cycles PWM1 and PWM2 to the gate driver;

[0089] The gate driver will drive voltage V gs1 and V gs2 The power is transmitted to the first power switch respectively. S 1 and second power switching transistors S 2's gate.

[0090] In this example, the voltage sampling sensor is preferably a Hall voltage sampling sensor, which acquires the output voltage of the DC-DC converter at a fixed sampling frequency. The controller is preferably an incremental proportional-integral (PI) controller. As a preferred embodiment, the sampling frequency is set to 10kHz. The controller has a fixed control cycle internally, and in this embodiment, the control cycle is consistent with the sampling cycle. At the beginning of each control cycle, the controller reads the latest output voltage sample value, executes the control algorithm, and updates the duty cycle of the pulse width modulation (PWM) signal before the end of the cycle. The gate driver is preferably an SI8271AB-IS current-isolated gate driver.

[0091] To achieve precise control of the output voltage, the specific control steps in this embodiment are as follows:

[0092] 1. In each control cycle k, the controller calculates the current output voltage sample value. With the preset target voltage Error value between ; ;

[0093] It should be noted that the target voltage The specific application scenario will determine the appropriate voltage level. For example, when it is necessary to boost a low DC voltage to 650V for subsequent use, Set to 650V.

[0094] 2. The controller determines the error based on the current error. Error compared to the previous control cycle Calculate the increment of the duty cycle : ;

[0095] in, The proportionality coefficient determines the system's response speed to the current error; The integral coefficient determines the system's ability to eliminate accumulated errors. Employing an incremental algorithm avoids the integral saturation problem that may occur in traditional positional PI algorithms, thus improving the system's dynamic response performance.

[0096] 3. Calculate the increment Duty cycle compared to the previous control cycle Accumulate to obtain the duty cycle of the current period. : ;

[0097] To prevent the converter from malfunctioning due to an excessively low duty cycle, such as insufficient output voltage caused by an undersized duty cycle or magnetic saturation caused by an oversized duty cycle, the controller... Amplitude limiting is applied:

[0098] ;

[0099] In this embodiment, a minimum duty cycle is set based on the characteristics of the converter topology. The maximum duty cycle is 0.1. It is 0.9.

[0100] Duty cycle after bandwidth limiting The value is assigned to the controller's PWM compare register, and the controller generates a frequency of 100kHz and a duty cycle of [value missing]. The PWM wave is amplified by the gate driver and then sent to the first power switch. S 1 and second power switching transistors S The gate of 2 controls its on and off states.

[0101] Regarding the proportionality coefficient and integral coefficient For tuning, this embodiment adopts the trial-and-error method commonly used in engineering, and optimizes it in combination with the mathematical model of the converter.

[0102] Through the above control method, this embodiment forms a complete digital closed-loop control system. The voltage sampling sensor provides real-time feedback of the output voltage, and the controller rapidly calculates and adjusts the duty cycle in each control cycle, thereby stabilizing the output voltage of the high-gain DC-DC converter at the target value. This control strategy not only effectively suppresses input voltage fluctuations and load disturbances but also enhances the robustness and reliability of the system through protection mechanisms such as duty cycle limiting, ensuring the converter can operate safely and stably under various operating conditions.

Claims

1. A coupled inductor ultra-high gain DC-DC converter, characterized in that, include: The system includes an input port, an output port, an energy storage inductor, a first power switch, a second power switch, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a sixth diode, and a three-winding coupled inductor. The input port is used to connect to an input voltage source; the output port is used to connect to a load; the three-winding coupled inductor includes a primary winding, a first secondary winding, and a second secondary winding; wherein, the positive terminal of the input voltage source is connected to the first terminal of the energy storage inductor, and the negative terminal of the input voltage source is connected to the negative terminal of the first capacitor, the source of the first power switch, and the cathode of the second diode; the second terminal of the energy storage inductor is connected to the anode of the first diode, the drain of the first power switch, and the positive terminal of the second capacitor; the cathode of the first diode is connected to the positive terminal of the first capacitor, the anode of the third diode, and the second power switch. The drain of the second capacitor is connected to the anode of the second diode and the opposite terminal of the primary winding; the source of the second power switch is connected to the same terminal of the primary winding and the negative terminal of the third capacitor; the cathode of the third diode is connected to the positive terminal of the third capacitor, the negative terminal of the fourth capacitor, and the anode of the fourth diode; the positive terminal of the fourth capacitor is connected to the opposite terminal of the first secondary winding; the cathode of the fourth diode is connected to the anode of the fifth diode and the opposite terminal of the second secondary winding; the same terminal of the first secondary winding is connected to the cathode of the fifth diode and the anode of the sixth diode; the cathode of the sixth diode is connected to the positive terminal of the fifth capacitor; the same terminal of the second secondary winding is connected to the negative terminal of the fifth capacitor and the positive terminal of the sixth capacitor; the negative terminal of the sixth capacitor is connected to the opposite terminal of the primary winding; the positive and negative terminals of the output port are respectively connected to the positive terminal of the fifth capacitor and the negative terminal of the sixth capacitor.

2. The coupled inductor ultra-high gain DC-DC converter according to claim 1, characterized in that, The primary winding is equivalent to the magnetizing inductance connected in parallel with the primary winding of an ideal transformer, and then connected in series with the leakage inductance.

3. The coupled inductor ultra-high gain DC-DC converter according to claim 1, characterized in that, The control timing of the first power switch and the second power switch is the same. Within one switching cycle, the DC-DC converter includes: In the first operating mode, the first power switch and the second power switch are turned on, the fourth diode and the sixth diode are turned on, and the first diode, the second diode, the third diode and the fifth diode are turned off. In the second operating mode, the first power switch and the second power switch are turned off, the fourth diode and the sixth diode are turned off, and the first diode, the second diode, the third diode and the fifth diode are turned on.

4. The coupled inductor ultra-high gain DC-DC converter according to claim 3, characterized in that, In the first working mode: The input voltage source charges the energy storage inductor through the first power switch that is turned on; The first capacitor and the second capacitor connected in series charge the primary winding through the first power switch and the second power switch that are turned on. The first capacitor, the second capacitor, the third capacitor, and the second secondary winding connected in series charge the sixth capacitor through the first power switch, the second power switch, and the fourth diode; The first capacitor, the second capacitor, the third capacitor, the fourth capacitor, and the first secondary winding connected in series charge the fifth capacitor and the sixth capacitor through the first power switch, the second power switch, and the sixth diode; The fifth and sixth capacitors provide energy to the load; Kirchhoff's voltage law equation in the first operating mode is: ； in, Indicates the input voltage source; , , , , and These are the voltages of the first capacitor, the second capacitor, the third capacitor, the fourth capacitor, the fifth capacitor, and the sixth capacitor, respectively. , , and These are the voltages of the energy storage inductor, primary winding, first secondary winding, and second secondary winding under the first operating mode, respectively. and These are the turns ratios of the three-winding coupled inductors, where... This is the turns ratio of the first secondary winding to the primary winding; This is the turns ratio of the second secondary winding to the primary winding.

5. The coupled inductor ultra-high gain DC-DC converter according to claim 3, characterized in that, In the second working mode: The input voltage source is connected in series with the energy storage inductor, and charges the first capacitor and the second capacitor respectively through the conducting first diode and the second diode; The leakage inductance energy of the three-winding coupled inductor is released to the third capacitor through the conducting third diode; The sixth capacitor, the primary winding, the first secondary winding, and the second secondary winding, which are connected in series, charge the third capacitor and the fourth capacitor through the conducting fifth diode; The fifth and sixth capacitors provide energy to the load; Kirchhoff's voltage law equation in the second operating mode is: ； in, Indicates the input voltage source. , , , and These are the voltages of the first capacitor, the second capacitor, the third capacitor, the fourth capacitor, and the sixth capacitor, respectively. , , and These are the voltages of the energy storage inductor, primary winding, first secondary winding, and second secondary winding in the second operating mode, respectively. and These are the turns ratios of the three-winding coupled inductors, where... This is the turns ratio of the first secondary winding to the primary winding; This is the turns ratio of the second secondary winding to the primary winding.

6. The coupled inductor ultra-high gain DC-DC converter according to claim 1, characterized in that, The voltage gain of the DC-DC converter Represented as: ； in, Indicates the input voltage source; This represents the output voltage of the DC-DC converter; This indicates the duty cycle of the first power switch and the second power switch; This is the turns ratio of the first secondary winding to the primary winding; This is the turns ratio of the second secondary winding to the primary winding.

7. The coupled inductor ultra-high gain DC-DC converter according to claim 1, characterized in that, The capacitance values ​​of the first capacitor, the second capacitor, the third capacitor, the fourth capacitor, the fifth capacitor, and the sixth capacitor respectively satisfy the following: ； in, This represents the input current of the DC-DC converter; , , , , and These represent the allowable peak values ​​of capacitor voltage ripple for the first, second, third, fourth, fifth, and sixth capacitors, respectively. This indicates the switching frequency of the first power switch and the second power switch; This indicates the duty cycle of the first power switch and the second power switch; This is the turns ratio of the first secondary winding to the primary winding; This is the turns ratio of the second secondary winding to the primary winding; This indicates the voltage gain of the DC-DC converter.

8. The coupled inductor ultra-high gain DC-DC converter according to claim 1, characterized in that, The inductance values ​​of the energy storage inductor and the magnetizing inductor of the three-winding coupled inductor respectively satisfy: ； in, and These represent the allowable peak values ​​of the inductor current ripple for the energy storage inductor and the magnetizing inductor, respectively. This indicates the switching frequency of the first power switch and the second power switch; This indicates the duty cycle of the first power switch and the second power switch.

9. A coupled inductor ultra-high gain DC-DC converter, characterized in that, include: The invention comprises a voltage sampling sensor, a controller, a PWM signal generator, a gate driver, and a DC-DC converter according to any one of claims 1-8; wherein the positive and negative terminals of the voltage sampling sensor are respectively connected to the two ends of the load of the DC-DC converter; the input terminal of the controller is connected to the output terminal of the voltage sampling sensor; the output terminal of the controller is connected to the input terminal of the PWM signal generator; the output terminal of the PWM signal generator is connected to the gate driver; and the gate driver is connected to the gates of the first power switch and the second power switch.

10. A method for controlling the coupled inductor ultra-high gain DC-DC converter of claim 9, characterized in that, The method includes: The voltage sampling sensor is used to acquire the output voltage across the load terminals of the DC-DC converter. The controller calculates the error value between the output voltage and the set reference voltage, adjusts the required duty cycle of the first power switch and the second power switch according to the error value, and transmits the adjusted required duty cycle to the PWM signal generator. The PWM signal generator transmits the required duty cycle to the gates of the first power switch and the second power switch.

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