TWI645659B - LLC resonant converter efficiency improvement method and structure thereof - Google Patents

Abstract

An efficiency improvement method for an LLC resonant converter and a structure thereof for optimizing energy conversion efficiency of a switched power supply device, wherein the plurality of first time points and the plurality of first time points after the first time point Reading the input power of the switched power supply device at two time points respectively to obtain a first power (first time point power) and a second power (power after the first time point), and comparing the first power with After the second power, when the second power is less than the first power, the operating voltage is adjusted by an adjustment value and a number of adjustments is calculated, and when the second power is greater than the first power, the adjustment value is used. Raising the working voltage and calculating the number of times of the increase, and determining the number of consecutive repetitions of the number of times of the adjustment or the number of times of the increase, and changing the number of times of the continuous repetition to a first tolerance value Change the working voltage.

Description

LLC resonant converter efficiency improvement method and structure thereof

The invention belongs to the technical field of switching power supply equipment, in particular to an efficiency improvement method of an LLC resonant converter and a structure thereof, so as to realize a stable switching frequency by adjusting the working voltage required by the LLC resonant converter. And improve the overall circuit efficiency.

Switched power supply equipment has been widely used to meet the requirements of high efficiency, lightness and shortness of various power supply equipment. It is often used to increase the switching frequency to achieve high power density (High Power Density). Conversion effect. Moreover, in order to reduce the switching loss caused by hard switching (Hard Switching), today's switching power supply equipment often uses Soft Switching technology to reduce the power switch by switching the voltage across the switch and the current product. The resulting switching loss means a circuit operation mode of Zero Voltage Switching (ZVS) or Zero Current Switching (ZCS), thereby achieving an overall conversion efficiency improvement.

In the switching power supply equipment, the Series Resonant Converter (SRC) has the characteristics of high switching frequency and zero voltage switching, and the series resonant converter has different circuit characteristics when operating in different operation intervals, so LLC is derived. Resonant converter. Moreover, the LLC resonant converter has the advantages of simple circuit structure, wide input voltage, high power density and high efficiency, but its original switching frequency will be light load, empty load, half load, heavy load or A sharp increase in full load causes an increase in loss, which in turn affects the switching frequency resulting in an optimum efficiency reduction. In view of this, as shown in FIG. 1, an rectifier 10, a power factor corrector 11, a working capacitor 12, an LLC resonant converter 13, a synchronous rectifier 14 and a resonant frequency regulator 15 are provided. 1 generally use a constant switching frequency to The efficiency is improved by adapting to the load change, and the resonant frequency regulator 15 monitors the instantaneous switching frequency of the LLC resonant converter 13 and compares the instantaneous switching frequency with a set frequency, for example, 100 kHz, and adjusts the power factor corrector 11 The magnitude of the output power, that is, the magnitude of the voltage across the working capacitor 12, thereby making the LLC resonant converter 13 constant at 100 kHz. However, because there are errors in the production of electronic components, this method has the problem of insufficient accuracy and affects the final efficiency improvement rate.

In view of this, how to adjust the working voltage of the power supply equipment to obtain the optimal frequency point, so that the power supply equipment can be stabilized even under light load, empty load, half load, heavy load or full load state. The switching frequency of the LLC resonant converter 13 further enhances the overall efficiency and eliminates the efficiency of the influence of electronic component errors, which is the subject of the present invention.

In view of the problems of the prior art, the object of the present invention is to provide an efficiency improvement method for an LLC resonant converter and a structure thereof, which can automatically adjust the operating voltage to achieve an increase in circuit efficiency under the premise of adapting to load fluctuations.

In accordance with the purpose of the present invention, the efficiency improvement method of the LLC resonant converter is to optimize the energy conversion efficiency of a switched power supply device, taking into account the energy loss and efficiency of the LLC resonant converter component, or, at the same time, to consider LLC. The energy loss and efficiency of the two converters of the resonant converter component and the power factor corrector control the operating voltage. The switching power supply device is provided with a rectifier, a power factor corrector and the LLC resonant converter, and the power factor corrector is electrically connected to the rectifier and the LLC resonant converter to provide an external power supply through the rectifier. The operating voltage is applied to the LLC resonant converter, comprising the steps of: reading the input power of the rectifier at a plurality of first time points, and calculating the input power to obtain a first power; after the first time Reading the input power of the rectifier at a plurality of second time points, and calculating the input power to obtain a second power; comparing the first power with the second power, and when the second power is less than the first power Adjusting the working voltage by an adjustment value and calculating a frequency adjustment number, and vice versa, when the second power is greater than the first power, raising the working voltage by the adjustment value and calculating a tone And the number of consecutive repetitions of the number of times of the adjustment or the number of times of the increase, and when the number of consecutive repetitions reaches a first tolerance value, the operation of lowering the operating voltage by the adjustment value is The adjustment value is increased by the operating voltage, and the operating voltage is increased by the adjustment value, and the operating voltage is adjusted by the adjustment value, and the number of counteracts is recorded, and the number of the reverse actions reaches a second tolerance. When the value is used, the adjustment value is replaced by a trimming number.

Wherein, when reading the input power, the method further comprises the steps of: reading the rectifier to receive an alternating voltage and an alternating current from the external power source, obtaining the input power by a product; and determining a difference between the alternating voltages And the ratio of the difference between each of the alternating currents, such that when the difference between the alternating voltages is greater than 5 volts or the difference ratio between the alternating currents is greater than 5%, the alternating voltage is re-read and the alternating current The current is recalculated to obtain the input power. Before reading the second power, the method further includes: reading the working voltage, and using a modulation coefficient and a voltage value of the working voltage when the working voltage is within a predetermined range The signal output period of the power factor corrector is output. When the second power is equal to the first power, the method further includes the step of: determining that the signal output period of the power factor corrector is less than an initial value, to adjust the operating voltage by using the adjusted value. Moreover, the adjustment value is 1-20 volts, and the fine adjustment number is 0.1-2 volts, and the first tolerance value and the second tolerance value are 5-100 times.

According to a second object of the present invention, the efficiency improvement structure of the LLC resonant converter is for optimizing the energy conversion efficiency of a switching power supply device, and the switching power supply device is provided with a rectifier, a power factor corrector and An LLC resonant converter electrically connected to the rectifier and the LLC resonant converter through the rectifier to provide an operating voltage to the LLC resonant converter using an external power supply, characterized in that the LLC resonant converter The efficiency improving structure is electrically connected to the rectifier and the power factor corrector and is provided with a detecting chip and a micro control unit. The detecting chip is electrically connected to the rectifier and the micro control unit and is provided with a plurality of counters. The micro control The unit is electrically connected to the power factor corrector, and the detecting chip reads the input power of the rectifier at a plurality of first time points and calculates a first power, and a plurality of seconds after the first time point Reading the input power of the rectifier at a time point and calculating a second power, comparing the first power with the second power, and causing the micro control unit to Power is less than the first When a power is used, the operating voltage is adjusted by an adjustment value, and one of the counters is used to calculate a frequency reduction number. Otherwise, when the second power is greater than the first power, the operating voltage is raised and utilized by the adjustment value. One of the counters calculates a number of upgrades, and the micro control unit determines the number of consecutive downs or the number of consecutive repetitions of the number of upgrades, so that the number of consecutive repetitions reaches a first tolerance value The operation of lowering the operating voltage by the adjustment value is used to adjust the operating voltage by the adjustment value, and the operating voltage is adjusted by the adjustment value, and the operating voltage is adjusted by the adjustment value, and the operating voltage is used. The next one of the counters records a number of counteracts such that when the number of counteracts reaches a second tolerance, the adjustment is replaced by a trimming number.

The detection chip is provided with a first register, a second register and a comparator, and the comparator is electrically connected to the first register, the second register, and the counters. At least one of the first control unit and the second control unit are respectively configured to store the input power between the AC voltage and the AC current from the external power source, and then store the first power and the second power in the first a temporary register and the second temporary register, at the same time, the detecting chip instantly determines the difference between the difference between the alternating current voltages and each of the alternating currents, so that the difference between the alternating current voltages is greater than When the ratio of the difference between 50 volts or each of the alternating currents is greater than 5%, the alternating voltage and the alternating current are re-read and recalculated to obtain the first power and the second power.

The detecting chip reads the working voltage before reading the second power, and when the voltage value of the working voltage is within a predetermined range, calculating the voltage value by using a modulation coefficient and the working voltage The signal output period of the power corrector.

After the comparator compares the first power and the second power to obtain the second power equal to the first power, the micro control unit determines the signal output period of the power factor corrector to correct the power factor. When the signal output period of the device is less than an initial value, the operating voltage is adjusted by the adjustment value. The adjustment value is 1-20 volts, and the fine adjustment number is 0.1-2 volts, and the first tolerance value and the second tolerance value are 5-100 times. In summary, the present invention uses the detecting unit to detect the variation of the input power at any time and obtain the amount of the operating voltage of the power supply device to obtain the optimal frequency point after learning the load variation. The power supply device can stabilize the switching frequency of the LLC resonant converter 13 even under light load, empty load, half load, heavy load or full load state, thereby improving overall efficiency and eliminating the influence of electronic component errors. Efficiency, that is, equivalent to using the micro control unit to regulate the input power, so that the switched power supply device can obtain the optimal efficiency by using the minimum input power under the current load, and stabilize the LLC resonant converter. The effect of switching frequencies.

Traditional skill

1‧‧‧LLC power supply equipment

10‧‧‧Rectifier

11‧‧‧Power factor corrector

12‧‧‧ working capacitor

13‧‧‧LLC resonant converter

14‧‧‧Synchronous rectifier

15‧‧‧Resonance Frequency Regulator

this invention

2‧‧‧Switching power supply equipment

20‧‧‧Rectifier

21‧‧‧Power factor corrector

22‧‧‧LLC resonant converter

23‧‧‧LLC resonant converter efficiency improvement structure

230‧‧‧Test wafer

2300‧‧‧ counter

2301‧‧‧First register

2302‧‧‧Second register

2303‧‧‧ Comparator

231‧‧‧Micro Control Unit

2310‧‧‧ adjustment value

24‧‧‧ working capacitor

3‧‧‧External power supply

S10~S13, S2~S90‧‧‧ steps

Figure 1 is a schematic diagram of the architecture of a conventional LLC power supply device.

Figure 2 is a block diagram showing a first embodiment of the preferred embodiment of the present invention.

Figure 3 is a flow chart of a method according to a first embodiment of the preferred embodiment of the present invention.

Figure 4 is a block diagram showing the structure of a second embodiment of the preferred embodiment of the present invention.

5A, 5B, and 5C are flowcharts of a method of the second embodiment of the preferred embodiment of the present invention.

In order for your review board to have a clear understanding of the contents of the present invention, please refer to the following description for matching drawings.

Please refer to FIG. 2 and FIG. 3, which are respectively a block diagram and a method flowchart of a first embodiment of the preferred embodiment of the present invention. As shown, a switching power supply device 2 is provided with a rectifier 20, a power factor corrector 21, an LLC resonant converter 22 and an efficiency boosting structure 23 of the LLC resonant converter, and the efficiency of the LLC resonant converter The lifting structure 23 is provided with a detection chip 230 and a micro control unit 231 for optimizing the energy conversion efficiency of the switching power supply device 2. The detection chip is provided with a plurality of counters 2300. The power factor corrector 21 is electrically connected to the rectifier 20 and the LLC resonant converter 22 to provide an operating voltage to the LLC resonant converter 22 through the rectifier 20 through an external power source 3. The efficiency improving structure 23 of the LLC resonant converter is electrically connected to the rectifier 20 and the power factor corrector 21, and the detecting chip 230 Electrically connecting the rectifier 20 and the micro control unit 231, the micro control unit 231 is electrically connected to the power factor corrector 21, and the method for operating the efficiency improvement structure of the LLC resonant converter can include at least the following steps: Step S10, The detecting chip 230 reads the input power of the rectifier 20 at a plurality of first time points and calculates a first power, and in step S11, reads the rectifier at a plurality of second time points after the first time point. The input power of 20 is calculated to obtain a second power. Next, in step S12, the detecting chip 230 compares the first power with the second power, so that the micro control unit 231 lowers the working voltage by an adjustment value 2310 when the second power is less than the first power and utilizes One of the counters 2300 calculates a number of down regulations, and vice versa, when the second power is greater than the first power, the operating voltage is raised by the adjustment value 2310 and one of the counters 2300 is used to calculate a rise. frequency.

At the same time, in step S13, the micro control unit 231 determines the number of consecutive repetitions or the number of consecutive repetitions of the number of adjustments, so that when the number of consecutive repetitions reaches a first tolerance value, the adjustment value 2310 is adjusted downward. The operating voltage is adjusted to increase the operating voltage by the adjustment value 2310, and the operating voltage is adjusted by the adjustment value 2310, and the operating voltage is adjusted by the adjustment value 2310, and the counter 2300 is utilized. The next one records the number of counteracts, and when the number of counteracts reaches a second tolerance, the adjustment value 2310 is replaced by a trimming number.

Please refer to FIG. 4, FIG. 5A, FIG. 5B and FIG. 5C, which are respectively a schematic structural diagram and a method flowchart of a second embodiment of the preferred embodiment of the present invention. As shown in the figure, a switching power supply device 2 is provided with a rectifier 20, a power factor corrector 21, an LLC resonant converter 22, an efficiency boosting structure 23 of the LLC resonant converter and a working capacitor 24, and the LLC The efficiency improvement structure 23 of the resonant converter is provided with a detection chip 230 and a micro-control unit 231 (MCU) for optimizing the energy conversion efficiency of the switching power supply 2 device. The rectifier 20 is electrically connected to an external power source 3 and the power factor corrector 21. The power factor corrector 21 is electrically connected to the efficiency boosting structure 23 of the LLC resonant converter and electrically connected to the LLC resonant converter through the working capacitor 24 . The detecting unit 230 is electrically connected to the rectifier 20 and the micro control unit 231. The micro control unit 231 is electrically connected to the power factor corrector 21. The rectifier 20 The rectified electric energy is rectified by the alternating current voltage of the external power source 3 to form a rectified electric energy, and then output to the power factor corrector 21 for correction by the power corrector 21, and then the working capacitor 24 is used to form an operating voltage for providing LLC resonant converter 22.

Moreover, the detecting chip 230 can be provided with at least a plurality of counters 2300, a first register 2301, a second register 2302 and a comparator 2303. The first register 2301 and the second register 2302 is electrically connected to the comparator 2303, and the comparator 2303 is electrically connected to at least one of the counters 2300. The method for operating the efficiency of the LLC resonant converter can at least include the following steps: enabling the switching After the power supply device 2, in step S2, the detecting chip 230 reads the alternating voltage and the alternating current from the external power source 3 at a plurality of first time points, and obtains a plurality of input powers of the rectifier 20 by a product. And in step S20, using the input power, for example, 10 sets of input power operations to obtain a first power, and treating the first power as a previous input power (P _in (n-1)) Stored in the first register 2301. In this embodiment, the detecting chip 230 utilizes one of the counters 2300, for example, a first counter counting operation to obtain the first power number, and at the beginning of the switching power supply device 2 starts operating. Since the previous input power is not stored in the first register, the first counter is reset to zero when the detection chip 230 obtains the initial first power.

At this time, in step S3, the detecting wafer 230 determines whether the difference between the alternating voltages is greater than 1-20V (for example, 10 volts <V>) or is the difference ratio between the alternating currents greater than 5%? If yes, step S30: re-reading the alternating voltage and the alternating current to recalculate the input power.

Step S4, the detecting wafer 230 reads the working voltage, and determines whether the pressure value of the working voltage is within a predetermined range. If yes, step S40: the micro control unit 231 calculates and adjusts the signal output period of the power factor corrector 21 by using a modulation coefficient and the voltage value of the working voltage, for example, the working period of the working voltage, and records the operation result. In the second of the counters 2300, for example, a second counter, and executing step S5. Moreover, the operating voltage (V _C ) read by the detecting wafer 230 when the switching power supply device 2 starts operating is a circuit preset voltage value.

Step S5, reading the AC voltage and the AC current of the external power source 3 at a plurality of second time points after the first time point, and obtaining a plurality of products by the product, for example, 10 sets of the input power of the rectifier 20, and then obtaining a calculation result. The second power is stored in the second temporary register 2302 as the instantaneous input power (P _in ), and the count of the first counter is incremented by one.

Next, in step S6, the comparator 2303 compares the first power with the second power, and determines whether the second power is less than the first power. If yes, in step S60, the micro control unit 231 will lower the operating voltage by an adjustment value 2310, for example, 10V, and step S7: one of the counters 2300, for example, a third counter, calculates a tone. The number of drops. On the other hand, if the second power is equal to the first power, in step S61, it is determined whether the count value of the first counter reaches an upper limit, for example, 10 times (5-100 times). If yes, it is further determined in step S610 whether the signal output period of the power factor corrector 21 in the second counter is less than an initial value, for example, 100%? Yes, step S60, otherwise step S62. Moreover, if the value of the first counter does not reach the upper limit, the process returns to step S5. In addition, if the second power is greater than the first power, step S62: the operating voltage is raised by the adjustment value 2310, and step S7: the third counter calculates a number of adjustments. Incidentally, after the comparison between the first power and the second power is completed, the current second power is regarded as the previous input power, that is, the first power (P _in (n-1)). And stored in the second register 2302.

In step S8, the micro control unit 231 determines whether the number of consecutive repetitions or the number of consecutive repetitions of the number of adjustments reaches a first tolerance value. If the number of consecutive repetitions reaches the first tolerance value, for example, 10 times (5-100 times), step S80: the micro control unit 231 forms a reverse actuation command, so that the adjustment value 2310 is lowered. The operating voltage is adjusted to increase the operating voltage by the adjustment value 2310. Similarly, the operating voltage is adjusted by the adjustment value 2310 to adjust the operating voltage by the adjustment value 2310. Then, the other of the counters 2300, for example, a fourth counter, calculates a number of counteracts, and then proceeds to step S9.

In step S9, the micro control unit 231 determines whether the number of counteracts reaches a certain level. Two tolerance values, for example 10 times (5-100 times)? If so, step S90: the adjustment value 2310 is replaced by a fine adjustment number, for example, 1V. It is noted that after the switching power supply device 2 is turned on for a period of time, the working voltage may not be within the preset range, and it is determined in step S41 whether the operating voltage is the LLC resonant converter. 22 Can one of the maximum limits or a minimum limit under normal operation? If so, the micro control unit 231 forms a reverse action command in step S42, so that the original action determined in step S6 is reversed, that is, the original adjustment of the working voltage is changed to the upshift operation, and vice versa. In this way, the switching power supply device 2 can adapt to each load fluctuation, and automatically adjusts to maintain the switching frequency of the LLC resonant converter 22 to stabilize the overall circuit efficiency when the minimum input power is used.

The above description is only illustrative of preferred embodiments and not limiting. For example, in another implementation manner in which the first embodiment and the second embodiment are extended, the optimal point of the operating voltage (VC) may be determined not only by the LLC resonant converter 22, but also It depends on the optimum operating voltage among the component characteristics of the power factor corrector 21. Generally, the power factor converter 21 has a lower energy conversion efficiency when the operating voltage of the component is higher, and the energy conversion efficiency of the LLC resonant converter 22 is lower when the operating voltage of the component is lower, so in order to optimize the switching. The overall circuit efficiency of the power supply device 2 can also be based on the average component operating voltage between the power factor corrector 21 and the LLC resonant converter 22 as its optimum point. Therefore, any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

Claims (10)

An efficiency improvement method for an LLC resonant converter for optimizing energy conversion efficiency of a switching power supply device, the switching power supply device being provided with a rectifier, a power factor corrector and the LLC resonant converter, and The power factor corrector is electrically connected to the rectifier and the LLC resonant converter to provide an operating voltage to the LLC resonant converter through the rectifier through an external power supply, comprising the steps of: reading the plurality of first time points An input power of the rectifier, and calculating the input power to obtain a first power; reading the input power of the rectifier at a plurality of second time points after the first time, and calculating the input power to obtain a first The second power is compared with the second power, and when the second power is less than the first power, the operating voltage is adjusted by an adjustment value and a number of adjustments is calculated, and vice versa At the first power, the operating voltage is increased by the adjustment value and a number of adjustments is calculated; and the number of consecutive repetitions or the number of consecutive repetitions of the number of adjustments is determined, and the continuous repetition is repeated. When the number reaches a first tolerance value, the operation of lowering the operating voltage by the adjustment value is used to increase the operating voltage by the adjustment value, and the adjustment of the operating voltage is adjusted by the adjustment value to the adjustment value. The operating voltage is lowered, and the number of reverse actions is recorded. When the number of the reverse actions reaches a second tolerance, the adjustment value is replaced by a trimming number. The method for improving the LLC resonant converter according to claim 1, wherein when the input power is read, the method further comprises the steps of: reading the rectifier to receive an alternating current voltage and an alternating current from the external power source. Obtaining the input power by a product; and determining a ratio of a difference between each of the alternating voltages and each of the alternating currents, so that a difference between each of the alternating voltages is greater than 5 volts or between the alternating currents When the difference ratio is greater than 5%, the AC voltages are re-read and the AC currents are recalculated to obtain the input powers. A method for improving the efficiency of an LLC resonant converter as described in claim 2, wherein Before reading the second power, the method further comprises the steps of: reading the working voltage, and calculating the voltage value of the working voltage by using a modulation coefficient when the working voltage is within a predetermined range This power is due to the signal output period of the corrector. The method for improving the LLC resonant converter according to claim 3, wherein when the second power is equal to the first power, the method further includes the following steps: determining a signal output period of the power corrector, When the signal output period of the power factor corrector is less than an initial value, the operating voltage is adjusted by using the adjusted value, and the adjusted value is 1-20 volts, and the fine tuning number is 0.1-2 volts, and the A tolerance value and the second tolerance value are 5-100 times. The efficiency improvement structure of the LLC resonant converter according to claim 4, wherein the operating voltage is the optimum component operating voltage of the power corrector and the optimal component operating voltage of the LLC resonant converter. Between the mean values. An efficiency improving structure of an LLC resonant converter for optimizing energy conversion efficiency of a switching power supply device, wherein the switching power supply device is provided with a rectifier, a power factor corrector and an LLC resonant converter, The power factor corrector is electrically connected to the rectifier and the LLC resonant converter through the rectifier to provide an operating voltage to the LLC resonant converter by using an external power source, wherein the LLC resonant converter improves the efficiency of the structure. Connecting the rectifier and the power factor corrector and providing a detecting chip and a micro control unit, the detecting chip is electrically connected to the rectifier and the micro control unit and is provided with a plurality of counters, and the micro control unit is electrically connected to the power factor a corrector, wherein the detecting chip reads the input power of the rectifier at a plurality of first time points and calculates a first power, and reads the input of the rectifier at a plurality of second time points after the first time point After the power is calculated to obtain a second power, the first power and the second power are compared, so that the micro control unit is less than the first power at the second power Wherein when one of a adjustment value to the lowered operating voltage and using a counter of calculation of such a cut number, contrary to the adjustment of the operating voltage value raised to the second power is greater than the first power And using one of the counters to calculate a number of upgrades, and the micro control unit determines the number of consecutive repetitions or the number of consecutive repetitions of the number of upgrades, so that the number of consecutive repetitions reaches a first tolerance When the value is adjusted, the operation voltage is adjusted by the adjustment value, and the operating voltage is raised by the adjustment value, and the operating voltage is adjusted by the adjustment value, and the operating voltage is adjusted by the adjustment value, and One of the counters is used to record a number of counteracts such that when the number of counteracts reaches a second tolerance, the adjustment is replaced by a trimming number. The efficiency improvement structure of the LLC resonant converter of claim 6, wherein the detecting chip is provided with a first register, a second register and a comparator, wherein the comparator is electrically connected to the comparator At least one of the first register, the second register, and the counters and the micro control unit, the detection chip reads the rectifier to receive an alternating voltage from the external power source and an alternating current to obtain the input After the power is stored, the first power and the second power are respectively stored in the first temporary register and the second temporary storage device, and at the same time, the detection chip instantly determines the difference between the alternating current voltages and each of the alternating currents. The ratio of the difference between the currents is such that when the difference between the alternating voltages is greater than 5 volts or the difference ratio between the alternating currents is greater than 5%, the alternating voltage and the alternating current are re-read and recalculated The first power and the second power are obtained. The efficiency improvement structure of the LLC resonant converter according to claim 7, wherein the detecting chip reads the working voltage before reading the second power, and the voltage value of the working voltage is between When the range is set, the signal output period of the power factor corrector is calculated by using a modulation coefficient and a voltage value of the working voltage. The efficiency improvement structure of the LLC resonant converter of claim 8, wherein the comparator compares the first power with the second power to obtain the second power equal to the first power, the micro control The unit will determine the signal output period of the power factor corrector, so that when the signal output period of the power factor corrector is less than an initial value, the operating voltage is adjusted by the adjustment value, and the adjustment value is 1-20 volts. And the trimming number is 0.1-2 volts, and the first tolerance value and the second tolerance value are 5-100 times. The efficiency improvement structure of the LLC resonant converter according to claim 9, wherein the operating voltage is the optimum component operating voltage of the power corrector and the optimal component operating voltage of the LLC resonant converter. Between the mean values.