Method for improving light load efficiency of gallium nitride interleaved converter

Abstract

The invention discloses a light load efficiency improving method of a gallium nitride interleaving converter, which comprises the following steps of: S1, selecting a gallium nitride power switch tube with low on-resistance, and reducing resistance loss in an on state; s2, a magnetic core of the transformer is made of a magnetic material with high magnetic conductivity, a winding structure is optimized to be in a multi-strand thin wire parallel winding or flat winding mode, and copper loss and magnetic core loss during light load are reduced; s3, the output current of the converter is monitored in real time through a current sampling circuit, and when the output current is lower than a preset light-load current threshold value, it is judged that the converter is in the light-load state, resistance loss and copper loss in the light-load state are greatly reduced by selecting a gallium nitride power switch tube with low on-resistance and combining an optimized transformer winding structure, and therefore the output current of the converter is effectively improved. The energy conversion efficiency is improved from the basic level, the switching frequency is reduced through an intelligent mode switching mechanism, meanwhile, the switching transition time is further shortened through dynamic optimization of driving parameters, and the switching loss is remarkably reduced.

Description

Technical Field

[0001] This invention belongs to the field of gallium nitride interleaved converter technology, and particularly relates to a method for improving the light-load efficiency of gallium nitride interleaved converters. Background Technology

[0002] Gallium nitride (GaN) interleaved converters are high-efficiency power conversion devices based on GaN power devices. They adopt a multi-phase interleaved parallel topology. The core of the design is to control multiple identical conversion units in a time-staggered manner, so that the input / output current ripple cancels each other out, reducing the size of the filter inductor and the capacitance. They are suitable for scenarios such as new energy vehicle OBCs, data center power supplies and photovoltaic inverters. Through interleaved control technology, they solve the problems of EMI interference and thermal management at high frequencies. They utilize the low parasitic parameters of GaN devices to achieve zero voltage / zero current switching, representing the cutting-edge technology direction of high-density power conversion.

[0003] When the converter is operating under light load, traditional design schemes face significant efficiency degradation. On the one hand, the on-resistance loss of traditional silicon-based power devices or low-performance gallium nitride devices increases significantly under light load. In addition, the copper loss and core loss caused by unreasonable transformer winding design remain high, resulting in a significant decrease in energy conversion efficiency. On the other hand, if the converter continues to operate in continuous conduction mode under light load conditions, the high-frequency switching action of the switching transistors will generate a large amount of switching losses. The parameters of traditional drive circuits cannot be adapted to the light load requirements, further aggravating the efficiency degradation. Therefore, a method for improving the light load efficiency of gallium nitride interleaved converters is proposed. Summary of the Invention

[0004] To overcome the aforementioned deficiencies of the prior art, embodiments of the present invention provide a method for improving the light-load efficiency of gallium nitride interleaved converters. This method addresses the significant increase in on-resistance losses in traditional silicon-based power devices or low-performance gallium nitride devices under light load conditions. Furthermore, the high copper and core losses caused by unreasonable transformer winding design lead to a substantial decrease in energy conversion efficiency. On the other hand, if the converter continues to operate in continuous conduction mode under light load conditions, the high-frequency switching action of the switching transistors will generate a large amount of switching losses. Since the parameters of traditional drive circuits cannot be adapted to the light-load requirements, this further exacerbates the problem of efficiency degradation.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for improving the light-load efficiency of a gallium nitride interleaved converter includes the following steps:

[0007] S1. Select gallium nitride power switches with low on-resistance to reduce resistance loss in the on-state.

[0008] S2. The transformer core is made of high permeability magnetic material, and the winding structure is optimized to be multi-strand fine wires wound in parallel or flat winding to reduce copper loss and core loss under light load.

[0009] S3. The converter output current is monitored in real time through the current sampling circuit. When the output current is lower than the preset light load current threshold, it is determined to be a light load state.

[0010] S4. Under light load conditions, switch the converter's operating mode from continuous conduction mode to discontinuous conduction mode, critical conduction mode, or reduce the switching frequency.

[0011] S5. Adjust the driving circuit parameters of the switching transistor, including the driving resistor, gate capacitance and driving voltage, to optimize the turn-on and turn-off speed of the switching transistor.

[0012] S6. The residual energy during the switching process is recovered and fed back to the input or output side through an additional inductor-capacitor resonant network or buffer circuit.

[0013] S7. Set hysteresis control near the light load current threshold, and adjust the working mode or drive parameters only when the current change exceeds the hysteresis width, and dynamically adjust the hysteresis width according to the ambient temperature.

[0014] Preferably, the optimization of the transformer winding structure includes adopting a multi-strand fine wire parallel winding or a flat winding method to reduce winding resistance. By selecting gallium nitride power switching transistors with low on-resistance and combining them with the optimized transformer winding structure, the resistance loss and copper loss under light load conditions are significantly reduced, thereby improving energy conversion efficiency from a fundamental level.

[0015] Preferably, the energy recovery and utilization step includes recovering the residual energy in the inductor and the residual charge in the capacitor through an inductor-capacitor resonant network. By reducing switching losses, recovering residual energy, and optimizing the drive waveform, the operating stress of the power device under light load conditions is reduced, and the service life of the device is extended.

[0016] Preferably, the hysteresis control strategy includes dynamically adjusting the hysteresis width according to the ambient temperature to compensate for the impact of temperature changes on circuit parameters. The temperature compensation stage dynamically adjusts the control parameters according to the ambient temperature, compensating for the impact of temperature changes on circuit performance and ensuring that the system can maintain efficient and stable operation under different temperature conditions. The introduction of the hysteresis control strategy means that the system only adjusts the operating mode or parameters when the load current changes beyond the set range, effectively avoiding frequent switching caused by load fluctuations and ensuring stable operation of the system in light load areas.

[0017] Preferably, the adjustment of the driving parameters includes optimizing the gate capacitance to adapt to the switching speed requirements under light load conditions.

[0018] Preferably, the adjustment of the drive circuit parameters also includes the introduction of an adaptive drive circuit, which adjusts the rising and falling edge slopes of the drive signal in real time according to the load current, and monitors the converter output current in real time through a current sampling circuit. When the output current is detected to be lower than the preset light load current threshold, the system determines that it has entered a light load state and triggers subsequent optimization measures. First, the operating mode is adjusted, switching from continuous conduction mode to discontinuous conduction mode, critical conduction mode, or reducing the switching frequency to reduce the number of switching transistors and reduce switching losses.

[0019] Preferably, in the operating mode switching step, when the output current is lower than the light load threshold, the switching frequency is first reduced. If the efficiency improvement still does not meet the requirements, the system switches to the discontinuous conduction mode or the critical conduction mode. Under light load conditions, the system further adjusts the driving circuit parameters of the switching transistor, including the driving resistor, gate capacitance, and driving voltage, to optimize the turn-on and turn-off speed of the switching transistor and reduce energy loss during the switching transition. At the same time, the residual energy during the switching process, including the residual energy in the inductor and the residual charge in the capacitor, is recovered through an additional inductor-capacitor resonant network or buffer circuit and fed back to the input or output side to achieve secondary utilization of energy.

[0020] Preferably, in the operating mode switching step, when recovering from low load to normal load, a gradual recovery strategy is adopted, gradually increasing the switching frequency or switching back to continuous conduction mode. The gradual recovery strategy adjusts the operating mode and parameters gradually when the load recovers from low to normal, avoiding voltage fluctuations and shocks, improving the dynamic response performance of the system, and is suitable for scenarios with frequent load changes. Hysteresis control is set near the light load current threshold, and the operating mode or drive parameters are adjusted only when the current change exceeds the hysteresis width, avoiding frequent switching caused by load fluctuations and ensuring stable system operation. In addition, a temperature compensation circuit is introduced to dynamically adjust the hysteresis width according to the ambient temperature to compensate for the impact of temperature changes on circuit parameters, further improving the stability and efficiency of the system under different environmental conditions.

[0021] Preferably, the resonant frequency of the inductor-capacitor resonant network is matched with the switching frequency to maximize energy recovery efficiency. Through the design of the inductor-capacitor resonant network or buffer circuit, the residual energy during the switching process is successfully recovered and fed back into the circuit for reuse, thereby maximizing energy utilization.

[0022] Preferably, the optimized design of the transformer also includes adopting a segmented winding structure to reduce leakage inductance between the primary and secondary windings, improve energy transmission efficiency, and reduce leakage inductance and electromagnetic interference.

[0023] The technical effects and advantages of the method for improving the light-load efficiency of a gallium nitride interleaved converter according to the present invention are as follows:

[0024] 1. This invention, by selecting gallium nitride power switching transistors with low on-resistance and combining them with an optimized transformer winding structure, significantly reduces resistance loss and copper loss under light load conditions, thereby improving energy conversion efficiency from a fundamental level.

[0025] 2. The invention's intelligent mode switching mechanism reduces the number of switching operations, while dynamically optimizing drive parameters further shortens the switching transition time, significantly reducing switching losses.

[0026] 3. This invention, through the design of an inductor-capacitor resonant network or a buffer circuit, successfully recovers the residual energy during the switching process and feeds it back into the circuit for reuse, thereby maximizing energy utilization.

[0027] 4. The invention introduces a hysteresis control strategy, which enables the system to adjust its operating mode or parameters only when the load current changes beyond the set range. This effectively avoids frequent switching caused by load fluctuations and ensures stable operation of the system in light load areas.

[0028] 5. In this invention, the temperature compensation stage dynamically adjusts the control parameters according to the ambient temperature, compensating for the impact of temperature changes on circuit performance and ensuring that the system can maintain efficient and stable operation under different temperature conditions.

[0029] 6. This invention reduces the operating stress of power devices under light load conditions and extends the service life of the devices by reducing switching losses, recovering residual energy and optimizing drive waveforms.

[0030] 7. This invention, with its optimized transformer winding structure, reduces leakage inductance and lowers electromagnetic interference.

[0031] 8. This invention, with its progressive recovery strategy, gradually adjusts the operating mode and parameters as the load recovers from low to normal, avoiding voltage fluctuations and shocks, improving the dynamic response performance of the system, and is suitable for scenarios with frequent load changes. Attached Figure Description

[0032] Figure 1 This is a flowchart of a method for improving the light-load efficiency of a gallium nitride interleaved converter proposed in this invention. Detailed Implementation

[0033] 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 embodiments of the present invention, and not all embodiments. 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.

[0034] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0035] refer to Figure 1 The method for improving the light-load efficiency of a gallium nitride interleaved converter, as shown, includes the following steps:

[0036] S1. Select gallium nitride power switches with low on-resistance to reduce resistance loss in the on-state.

[0037] S2. The transformer core is made of high permeability magnetic material, and the winding structure is optimized to be multi-strand fine wires wound in parallel or flat winding to reduce copper loss and core loss under light load.

[0038] S3. The converter output current is monitored in real time through the current sampling circuit. When the output current is lower than the preset light load current threshold, it is determined to be a light load state.

[0039] S4. Under light load conditions, switch the converter's operating mode from continuous conduction mode to discontinuous conduction mode, critical conduction mode, or reduce the switching frequency.

[0040] S5. Adjust the driving circuit parameters of the switching transistor, including the driving resistor, gate capacitance and driving voltage, to optimize the turn-on and turn-off speed of the switching transistor.

[0041] S6. The residual energy during the switching process is recovered and fed back to the input or output side through an additional inductor-capacitor resonant network or buffer circuit.

[0042] S7. Set hysteresis control near the light load current threshold, and adjust the working mode or drive parameters only when the current change exceeds the hysteresis width, and dynamically adjust the hysteresis width according to the ambient temperature.

[0043] Among them, the optimization of the transformer winding structure includes adopting multi-strand fine wire parallel winding or flat winding to reduce winding resistance. By selecting gallium nitride power switching tubes with low on-resistance and combining them with the optimized transformer winding structure, the resistance loss and copper loss under light load conditions are significantly reduced, thereby improving energy conversion efficiency from the fundamental level.

[0044] The energy recovery and utilization steps include recovering the residual energy in the inductor and the residual charge in the capacitor through an inductor-capacitor resonant network. By reducing switching losses, recovering residual energy, and optimizing the drive waveform, the operating stress of power devices under light load conditions is reduced, and the service life of the devices is extended.

[0045] The hysteresis control strategy includes dynamically adjusting the hysteresis width based on the ambient temperature to compensate for the impact of temperature changes on circuit parameters. The temperature compensation stage dynamically adjusts the control parameters based on the ambient temperature, compensating for the impact of temperature changes on circuit performance and ensuring that the system can maintain efficient and stable operation under different temperature conditions. The introduction of the hysteresis control strategy means that the system only adjusts the operating mode or parameters when the load current changes beyond the set range, effectively avoiding frequent switching caused by load fluctuations and ensuring stable operation of the system in light load areas.

[0046] The adjustment of drive parameters includes optimizing the gate capacitance to adapt to the switching speed requirements under light load conditions.

[0047] The adjustment of drive circuit parameters also includes the introduction of an adaptive drive circuit, which adjusts the rising and falling edge slopes of the drive signal in real time according to the load current. The current sampling circuit monitors the converter output current in real time. When the output current is detected to be lower than the preset light load current threshold, the system determines that it has entered a light load state and triggers subsequent optimization measures. First, the operating mode is adjusted, switching from continuous conduction mode to discontinuous conduction mode, critical conduction mode, or reducing the switching frequency to reduce the number of switching transistors and reduce switching losses.

[0048] In the working mode switching step, when the output current is lower than the light load threshold, the switching frequency is reduced first. If the efficiency improvement still does not meet the requirements, the system switches to discontinuous conduction mode or critical conduction mode. Under light load conditions, the system further adjusts the driving circuit parameters of the switching transistor, including the driving resistor, gate capacitance and driving voltage, to optimize the turn-on and turn-off speed of the switching transistor and reduce energy loss during the switching transition. At the same time, the residual energy during the switching process, including the residual energy in the inductor and the residual charge in the capacitor, is recovered through an additional inductor-capacitor resonant network or buffer circuit and fed back to the input or output side to achieve secondary utilization of energy.

[0049] In the working mode switching step, when recovering from low load to normal load, a gradual recovery strategy is adopted, gradually increasing the switching frequency or switching back to continuous conduction mode. The gradual recovery strategy adjusts the working mode and parameters gradually when the load recovers from low to normal, avoiding voltage fluctuations and shocks, improving the dynamic response performance of the system, and is suitable for scenarios with frequent load changes. Hysteresis control is set near the light load current threshold, and the working mode or drive parameters are adjusted only when the current change exceeds the hysteresis width, avoiding frequent switching caused by load fluctuations and ensuring stable system operation. In addition, a temperature compensation circuit is introduced to dynamically adjust the hysteresis width according to the ambient temperature to compensate for the impact of temperature changes on circuit parameters, further improving the stability and efficiency of the system under different environmental conditions.

[0050] In this system, the resonant frequency of the inductor-capacitor resonant network is matched with the switching frequency to maximize energy recovery efficiency. Through the design of the inductor-capacitor resonant network or buffer circuit, the residual energy during the switching process is successfully recovered and fed back into the circuit for reuse, thus maximizing energy utilization.

[0051] The optimized transformer design also includes adopting a segmented winding structure to reduce leakage inductance between the primary and secondary windings, improve energy transmission efficiency, and reduce leakage inductance and electromagnetic interference.

[0052] Working principle: The low on-resistance gallium nitride power switch is used to reduce the resistance loss of the device in the on state from the basic level. At the same time, the transformer uses a magnetic core made of high permeability magnetic material to reduce hysteresis loss. The winding structure is optimized to use multiple fine wires wound in parallel or flat winding to reduce winding resistance, thereby reducing copper loss and core loss under light load, laying the foundation for overall efficiency improvement.

[0053] The converter output current is monitored in real time by a current sampling circuit. When the output current is detected to be lower than the preset light load current threshold, the system determines that it has entered a light load state and triggers subsequent optimization measures. First, the operating mode is adjusted, switching from continuous conduction mode to discontinuous conduction mode, critical conduction mode or reducing the switching frequency to reduce the number of switching transistors and reduce switching losses.

[0054] Under light load conditions, the system further adjusts the driving circuit parameters of the switching transistor, including the driving resistor, gate capacitance and driving voltage, to optimize the turn-on and turn-off speed of the switching transistor and reduce energy loss during the switching transition. At the same time, through an additional inductor-capacitor resonant network or buffer circuit, the residual energy during the switching process is recovered, including the residual energy in the inductor and the residual charge in the capacitor, and fed back to the input or output side to achieve secondary utilization of energy.

[0055] Hysteresis control is set near the light load current threshold. The operating mode or drive parameters are only adjusted when the current change exceeds the hysteresis width to avoid frequent switching caused by load fluctuations and ensure stable system operation. In addition, a temperature compensation circuit is introduced to dynamically adjust the hysteresis width according to the ambient temperature to compensate for the impact of temperature changes on circuit parameters, thereby further improving the stability and efficiency of the system under different environmental conditions.

[0056] Low-loss materials and structural design provide the foundation for efficiency improvement, intelligent load sensing and mode switching enable dynamic response, dynamic parameter optimization and energy recovery further tap the energy-saving potential, and adaptive control ensures system stability. This multi-dimensional collaborative optimization strategy makes the method particularly suitable for application scenarios with a high proportion of light loads or large load fluctuations, such as server power supplies, communication base station power supplies and photovoltaic micro-inverters, effectively improving the system's operating efficiency and reliability across the entire load range.

[0057] The above embodiments can be implemented in whole or in part by software, hardware, firmware or other arbitrary combinations. When implemented by software, the above embodiments can be implemented in whole or in part in the form of a computer program product.

[0058] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims.

[0059] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for improving the light load efficiency of a gallium nitride interleaved converter, the method comprising: operating the interleaved converter in a first mode; and operating the interleaved converter in a second mode. The method comprises the following steps: S1. Selecting a gallium nitride power switch tube with low on-resistance to reduce resistance loss in the on state; S2. Using a high magnetic permeability magnetic material to make a transformer core, and optimizing the winding structure to a multi-strand thin wire and winding or flat winding mode to reduce copper loss and core loss at light load; S3. Real-time monitoring of the output current of the converter through a current sampling circuit, and determining the light load state when the output current is lower than the preset light load current threshold; S4. Switching the working mode of the converter from continuous conduction mode to discontinuous conduction mode, critical conduction mode or reducing the switching frequency in the light load state; S5. Adjusting the driving circuit parameters of the switch tube, including driving resistance, gate capacitance and driving voltage, to optimize the turn-on and turn-off speed of the switch tube; S6. Recovering residual energy in the switching process through an additional inductor-capacitor resonance network or buffer circuit and feeding back to the input side or output side; S7. Setting hysteresis control near the light load current threshold, adjusting the working mode or driving parameters only when the current change exceeds the hysteresis width, and dynamically adjusting the hysteresis width according to the ambient temperature.

2. The method of claim 1, wherein the method is applied to a gallium nitride interleaved converter. The optimization of the transformer winding structure includes using a multi-strand thin wire and winding or flat winding mode to reduce the winding resistance.

3. The method of claim 1, wherein the method further comprises: The energy recovery step includes recovering residual energy in the inductor and residual charge in the capacitor through an inductor-capacitor resonance network.

4. The method of claim 1, wherein the GaN interleaved converter is a GaN half bridge converter. The hysteresis control strategy includes dynamically adjusting the hysteresis width according to the ambient temperature to compensate for the influence of temperature changes on circuit parameters.

5. The method of claim 1, wherein the method further comprises: The adjustment of the driving parameters includes optimizing the gate capacitance to adapt to the switching speed requirement in light load working condition.

6. The method of claim 1, wherein the method further comprises: The adjustment of the driving circuit parameters also includes introducing an adaptive driving circuit to adjust the rising and falling slope of the driving signal in real time according to the load current.

7. The method of claim 1, wherein the method further comprises: In the working mode switching step, when the output current is lower than the light load threshold, the switching frequency is first reduced, and if the efficiency improvement still does not meet the requirements, the discontinuous conduction mode or critical conduction mode is switched to.

8. The method of claim 1, wherein the GaN interleaved converter is a GaN half bridge converter. In the working mode switching step, when recovering from low load to normal load, a gradual recovery strategy is adopted to gradually increase the switching frequency or switch back to continuous conduction mode.

9. The method of claim 1, wherein the method further comprises: determining a load of the GaN inverter; and adjusting the frequency of the GaN inverter based on the load of the GaN inverter. The resonance frequency of the inductor-capacitor resonance network matches the switching frequency to maximize the energy recovery efficiency.

10. The method of claim 1, wherein the GaN interleaved converter is a GaN half bridge converter. The optimization design of the transformer also includes using a segmented winding structure to reduce the leakage inductance between the primary and secondary windings and improve energy transmission efficiency.

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