Power conversion device and conversion method thereof

Abstract

The invention provides a power conversion device and a conversion method thereof. The power conversion device comprises a transformer circuit and a bridge rectifier switching circuit coupled with an input side circuit of the transformer circuit, and the switching frequency control circuit generates compensation frequency according to input voltage of the bridge rectifier switching circuit and adjusts switching frequency of the bridge rectifier switching circuit according to the compensation frequency.

Description

Technical Field

[0001] This invention relates to a power supply device, and more particularly to a power conversion device and conversion method thereof. Background Technology

[0002] Power conversion devices are indispensable components in modern electronic devices. In power conversion devices employing power factor correction (PFC) circuits and full-bridge CLLC resonant converters, the front-end PFC circuit improves the power factor value and provides DC voltage to the subsequent CLLC resonant converter circuit, thereby providing charging current. The DC voltage provided by the PFC circuit includes ripple components; for example, in the case of a 60Hz sine wave AC mains voltage, the DC voltage provided by the PFC circuit may carry a 120Hz ripple component. Due to the poor line regulation capability of the CLLC resonant converter circuit, the ripple component in the DC voltage will be reflected at the output of the CLLC resonant converter circuit, thus affecting the stability of the charging current. Furthermore, the larger the ripple amplitude, the greater the stress on the CLLC resonant converter circuit, which will shorten the lifespan of electronic components (such as capacitors). Summary of the Invention

[0003] This invention provides a power conversion device and conversion method that can effectively reduce the influence of ripple components in DC voltage, provide stable output current, and extend the service life of the power conversion device.

[0004] The power conversion device of the present invention includes a first bridge rectifier switch circuit, a transformer circuit, and a switching frequency control circuit. The input terminal of the first bridge rectifier switch circuit receives an input voltage. The transformer circuit includes an input-side circuit and an output-side circuit, with the input-side circuit coupled to the first bridge rectifier switch circuit. The switching frequency control circuit generates a compensation frequency based on the input voltage and adjusts the switching frequency of the first bridge rectifier switch circuit according to the compensation frequency.

[0005] In one embodiment of the present invention, the power conversion device further includes a power factor correction circuit, which is coupled to a first bridge rectifier switch circuit and a switching frequency control circuit, and provides a DC voltage as the input voltage based on the input AC signal.

[0006] In one embodiment of the present invention, the power conversion device further includes a second bridge rectifier switch circuit, which is coupled to the output side circuit of the transformer and generates an output voltage according to the voltage provided by the transformer circuit. The switching frequency control circuit adjusts the switching frequency of the first bridge rectifier switch circuit and the second bridge rectifier switch circuit according to the compensation frequency.

[0007] In one embodiment of the present invention, the output-side circuit includes a secondary winding, a resonant capacitor, and a resonant inductor. The secondary winding is coupled to a second bridge rectifier switching circuit. The resonant inductor and the resonant capacitor are connected in series between the secondary winding and the second bridge rectifier switching circuit.

[0008] In one embodiment of the present invention, the switching frequency control circuit includes a charging control circuit, a frequency compensation circuit, and an adder circuit. The charging control circuit generates an initial switching frequency based on the target output current, the target output voltage, the output current of the second bridge rectifier switch circuit, and the output voltage. The frequency compensation circuit generates a compensation frequency based on the DC voltage and the frequency of the input AC signal. The adder circuit adds the initial switching frequency to the compensation frequency to generate a control frequency, which serves as the switching frequency between the first and second bridge rectifier switch circuits.

[0009] In one embodiment of the present invention, the power conversion device further includes a frequency range limiting circuit coupled to an adder circuit to limit the control frequency to a default frequency range.

[0010] In one embodiment of the present invention, within a default frequency range, the voltage gain of the power conversion device decreases as the control frequency increases.

[0011] In one embodiment of the present invention, the switching frequency control circuit described above performs bandpass filtering on the DC voltage according to the frequency of the input AC signal to generate a ripple signal with a frequency doubling ripple frequency, and generates a compensation frequency based on the relationship between the ripple signal and the voltage gain of the power conversion device and the control frequency.

[0012] In one embodiment of the present invention, the frequency of the frequency doubling ripple is twice the frequency of the input AC signal.

[0013] In one embodiment of the present invention, the input-side circuit includes a primary winding, a resonant capacitor, a resonant inductor, and a magnetizing inductor. The primary winding is coupled to a first bridge rectifier switching circuit. The resonant inductor and the resonant capacitor are connected in series between the primary winding and the first bridge rectifier switching circuit. The magnetizing inductor is coupled between the two ends of the primary winding.

[0014] In one embodiment of the present invention, the switching frequency control circuit described above is a digital signal processor.

[0015] This invention also provides a conversion method for a power conversion device, wherein the power conversion device includes a first bridge rectifier switch circuit and a transformer circuit, wherein the input terminal of the first bridge rectifier switch circuit receives an input voltage, and the transformer circuit includes an input side circuit and an output side circuit, the input side circuit being coupled to the first bridge rectifier switch circuit. The conversion method of the power conversion device includes the following steps: generating a compensation frequency based on the input voltage; adjusting the switching frequency of the first bridge rectifier switch circuit based on the compensation frequency.

[0016] In one embodiment of the present invention, the conversion method of the power conversion device further includes providing a power factor correction circuit to provide a DC voltage as the input voltage based on the input AC signal.

[0017] In one embodiment of the present invention, the power conversion device further includes a second bridge rectifier switch circuit, which generates an output voltage based on the voltage provided by the transformer circuit. The conversion method of the power conversion device includes adjusting the switching frequency of the first bridge rectifier switch circuit and the second bridge rectifier switch circuit according to the compensation frequency.

[0018] In one embodiment of the present invention, the output-side circuit includes a secondary winding, a resonant capacitor, and a resonant inductor. The secondary winding is coupled to a second bridge rectifier switching circuit. The resonant inductor and the resonant capacitor are connected in series between the secondary winding and the second bridge rectifier switching circuit.

[0019] In one embodiment of the present invention, the conversion method of the power conversion device described above includes the following steps: Generating an initial switching frequency based on the target output current, target output voltage, output current of the second bridge rectifier switch circuit, and output voltage. Generating a compensation frequency based on the DC voltage and the frequency of the input AC signal. Adding the initial switching frequency to the compensation frequency to generate a control frequency, which is used as the switching frequency between the first bridge rectifier switch circuit and the second bridge rectifier switch circuit.

[0020] In one embodiment of the present invention, the conversion method of the power conversion device described above includes limiting the control frequency to a default frequency range.

[0021] In one embodiment of the present invention, within a default frequency range, the voltage gain of the power conversion device decreases as the control frequency increases.

[0022] In one embodiment of the present invention, the conversion method of the power conversion device described above includes the following steps: Bandpass filtering of the DC voltage based on the frequency of the input AC signal to generate a ripple signal with a harmonic ripple frequency; Generating a compensation frequency based on the relationship between the ripple signal and the voltage gain of the power conversion device and the control frequency.

[0023] In one embodiment of the present invention, the frequency of the frequency doubling ripple is twice the frequency of the input AC signal.

[0024] In one embodiment of the present invention, the input-side circuit includes a primary winding, a resonant capacitor, a resonant inductor, and a magnetizing inductor. The primary winding is coupled to a first bridge rectifier switching circuit. The resonant inductor and the resonant capacitor are connected in series between the primary winding and the first bridge rectifier switching circuit. The magnetizing inductor is coupled between the two ends of the primary winding.

[0025] Based on the above, the power conversion device of this embodiment includes a transformer circuit and a bridge rectifier switch circuit coupled to the input side circuit of the transformer circuit. The switching frequency control circuit can generate a compensation frequency according to the input voltage of the bridge rectifier switch circuit, and adjust the switching frequency of the bridge rectifier switch circuit according to the compensation frequency. This can effectively reduce the influence of ripple components in the DC voltage received by the bridge rectifier switch circuit, provide stable output current and output voltage, and extend the service life of the power conversion device.

[0026] To make the above features and advantages of the present invention more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a power conversion device according to an embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram showing the relationship between the voltage gain of the power conversion device and the control frequency of the bridge rectifier circuit according to an embodiment of the present invention.

[0029] Figure 3 This is a schematic diagram of a switching frequency control circuit according to an embodiment of the present invention.

[0030] Figures 4-6 This is an operation timing diagram of the power conversion device according to an embodiment of the present invention.

[0031] Figures 7-9 This is a flowchart of a power conversion method according to an embodiment of the present invention. Detailed Implementation

[0032] To make the content of this invention more readily apparent, the following specific embodiments are provided as examples on which this invention can indeed be practiced. Furthermore, wherever possible, components / members referred to by the same reference numerals in the drawings and embodiments represent the same or similar parts.

[0033] Please refer to the following: Figure 1 , Figure 1This is a schematic diagram of a power conversion device according to an embodiment of the present invention. The power conversion device 100 may include a power factor correction circuit 102, bridge rectifier switch circuits 104 and 106, a transformer circuit 108, and a switching frequency control circuit 110. The power factor correction circuit 102 is coupled to an AC power supply AC1 and a bridge rectifier switch circuit 104. The transformer circuit 106 is coupled to a bridge rectifier switch circuit 104 and a bridge rectifier switch circuit 106. The output terminal of the bridge rectifier switch circuit 106 is coupled to a battery BAT1. In addition, the switching frequency control circuit 110 is coupled to the output terminal of the power factor correction circuit 102, the bridge rectifier switch circuit 104, and the bridge rectifier switch circuit 106, wherein the bridge rectifier switch circuit 104 and the bridge rectifier switch circuit 106 may be, for example, full-bridge rectifier switch circuits.

[0034] Furthermore, the transformer circuit 108 may include an input-side circuit 114 and an output-side circuit 116. The input-side circuit 114 may include a primary winding Np, a resonant inductor Lrp, a resonant capacitor Crp, and a magnetizing inductor Lm. The resonant inductor Lrp and the resonant capacitor Crp are connected in series between the bridge rectifier switching circuit 104 and one end of the primary winding Np. The other end of the primary winding Np is coupled to the bridge rectifier switching circuit 104. The magnetizing inductor Lm is coupled between the two ends of the primary winding Np. Additionally, the output-side circuit 116 may include a secondary winding Ns, a resonant inductor Lrs, and a resonant capacitor Crs. The resonant inductor Lrs and the resonant capacitor Crs are connected in series between the bridge rectifier switching circuit 106 and one end of the secondary winding Ns. The other end of the secondary winding Ns is coupled to the bridge rectifier switching circuit 106.

[0035] The power factor correction circuit 102 receives an input AC signal (such as AC current Iac and AC voltage Vac) from the AC power supply AC1, and provides a DC voltage Vbus as the input voltage of the bridge rectifier switching circuit 104 based on the input AC signal, and provides the DC voltage Vbus to the switching frequency control circuit 110. Furthermore, the power factor correction circuit 102 can adjust the waveform of the received AC current to improve the power factor value and reduce power consumption. The switching frequency control circuit 110 controls the switching operation of the bridge rectifier switching circuits 104 and 106, and the transformer circuit 108 performs voltage conversion on the voltage provided by the bridge rectifier switching circuit 104, thereby generating an output voltage Vo and an output current Io at the output terminal of the bridge rectifier switching circuit 106. The switching frequency control circuit 110 generates a compensation frequency based on the DC voltage Vbus and adjusts the switching frequency of the bridge rectifier switch circuits 104 and 106 according to the compensation frequency. This reduces the impact of the ripple component of the DC voltage Vbus on the stability of the output current Io and the output voltage Vo, thereby extending the service life of the power conversion device 100. It is worth noting that in some embodiments, the power conversion device 100 may include only one bridge rectifier switch circuit 104. In this case, the switching frequency control circuit 110 can also generate a compensation frequency based on the DC voltage Vbus and adjust the switching frequency of the bridge rectifier switch circuit 104 according to the compensation frequency, thereby providing stable output current Io and output voltage Vo.

[0036] Furthermore, the switching frequency control circuit 110 can bandpass filter the DC voltage Vbus according to the frequency of the input AC signal to generate a ripple signal with a frequency doubling of the ripple frequency, and generate a compensation frequency based on the relationship between the ripple signal and the voltage gain of the power conversion device 100 and the control frequency of the bridge rectifier switching circuits 104 and 106 (i.e., the switching frequency of the bridge rectifier switching circuits 104 and 106). For example, if the input AC signal is a sine wave with a frequency of 60Hz, the frequency doubling of the ripple frequency can be, for example, 120Hz, which is twice the frequency of the input AC signal, but is not limited to this. The voltage gain of the power conversion device 100 is equal to the output voltage Vo of the bridge rectifier switching circuit 106 divided by the input voltage (DC voltage Vbus) of the bridge rectifier switching circuit.

[0037] Figure 2 This is a schematic diagram illustrating the relationship between the voltage gain of the power conversion device and the control frequency of the bridge rectifier circuit according to an embodiment of the present invention. Figure 2 The voltage gain versus control frequency relationship shown is obtained when the power conversion device 100 uses specific circuit parameters and is connected to a specific load. The voltage gain of the power conversion device 100 versus the control frequency relationship can be as follows: Figure 2As shown, when the control frequency is greater than f1, the voltage gain decreases as the control frequency increases. Therefore, the switching frequency control circuit 110 can adjust the voltage gain by adjusting the control frequency, thereby controlling the output voltage Vo. For example, when the DC voltage Vbus increases, increasing the control frequency can suppress the output voltage Vo from increasing with the DC voltage Vbus, while decreasing the control frequency can suppress the output voltage Vo from decreasing with the DC voltage Vbus. Similarly, the switching frequency control circuit 110 can adjust the control frequency of the bridge rectifier switching circuits 104 and 106 according to the ripple signal to suppress the influence of the ripple component in the DC voltage Vbus on the output voltage Vo and the output current Io, thereby providing a stable output current and extending the service life of the power conversion device 110.

[0038] In detail, the implementation of the switching frequency control circuit 110 can be as follows: Figure 3 As shown, the circuit includes a charging control circuit 302, an adder circuit 304, a frequency compensation circuit 306, and a frequency range limiting circuit 308. The adder circuit 304 is coupled to the charging control circuit 302, the frequency compensation circuit 306, and the frequency range limiting circuit 308. The charging control circuit 302 can generate an initial switching frequency fsw based on the target output current Iotar, the target output voltage Votar, the output current Io, and the output voltage Vo. The initial switching frequency fsw is used to control the output current Io and the output voltage Vo to be close to or equal to the target output current Iotar and the target output voltage Votar. The frequency compensation circuit 306 can generate a compensation frequency fcps based on the DC voltage Vbus and the frequency fac of the input AC signal (such as AC current Iac and AC voltage Vac). Figure 4As shown in the diagram, the compensation frequency fcps can be a digital signal. More specifically, some signals (such as output current Io, output voltage Vo, and DC voltage Vbus) have already been converted into digital signals from the original detected signals (e.g., by an analog-to-digital converter). The switching frequency control circuit 110 is a digital signal processor, and the target output current Iotar, target output voltage Votar, output current Io, output voltage Vo, DC voltage Vbus, and the frequency fac of the input AC signal are all digital signals. Compared to analog circuits, digital signal processors offer greater flexibility in subsequent adjustments. For example, when adjusting parameters (AC signal frequency fac, filter parameters, or other parameters), passive components do not need to be modified, and space can be saved. For instance, the frequency compensation circuit 306 can determine the center frequency for bandpass filtering of the DC voltage Vbus based on the frequency fac of the input AC signal. For example, if the frequency fac of the input AC signal is 60Hz, the center frequency for bandpass filtering of the DC voltage Vbus can be set to 120Hz, but this is not a limitation. The frequency compensation circuit 306 can bandpass filter the DC voltage Vbus to generate a ripple signal with a frequency doubling of the ripple frequency, and generate a compensation frequency fcps based on the relationship between the ripple signal and the voltage gain of the power conversion device 100 and the control frequency. The adder circuit 304 can add the original switching frequency fsw and the compensation frequency fcps to generate a control frequency fctrl, which is used as the switching frequency between the bridge rectifier switch circuit 104 and the bridge rectifier switch circuit 106.

[0039] like Figure 2 As described in the embodiment, when the control frequency is greater than f1, the voltage gain decreases as the control frequency increases. When the ripple signal voltage increases, increasing the control frequency can suppress the output voltage Vo from increasing with the ripple signal voltage; conversely, when the ripple signal voltage decreases, decreasing the control frequency can suppress the output voltage Vo from decreasing with the ripple signal voltage. Therefore, as... Figure 4 As shown, by adding the compensation frequency fcps, which changes according to the voltage gain, to the original switching frequency fsw to adjust the control frequency fctrl, the voltage gain of the power conversion device 100 can be adjusted according to the voltage change of the ripple signal, thereby suppressing the influence of the ripple component in the DC voltage Vbus on the output voltage Vo and the output current Io, thus providing a stable output current Io and output voltage Vo, and extending the service life of the power conversion device 110.

[0040] For example Figure 5 , Figure 6 As shown, in Figure 5 In this embodiment, the compensation frequency fcps is 0, meaning that the frequency compensation circuit 306 does not provide a compensation frequency, while... Figure 6In this embodiment, the frequency compensation circuit 306 provides the compensation frequency. Figure 5 , Figure 6 As can be seen from the embodiment, after the frequency compensation circuit 306 provides a compensation frequency to adjust the control frequency fctrl, the fluctuations of the output current Io and the output voltage Vo are significantly reduced. In other words, the influence of the ripple component in the DC voltage Vbus on the output voltage Vo and the output current Io has been effectively suppressed, thus providing a stable output current Io and output voltage Vo.

[0041] Furthermore, to ensure that the control frequency fctrl falls within an appropriate frequency range, the frequency range limiting circuit 308 can limit the control frequency fctrl to a default frequency range, wherein within the default frequency range, the voltage gain of the power conversion device 100 decreases as the control frequency fctrl increases. The default frequency range can be, for example, [missing information]. Figure 2 The frequency range is greater than frequency f1, but is not limited to this.

[0042] Figure 7 This is a flowchart illustrating a power conversion method of a power conversion device according to an embodiment of the present invention. The power conversion device includes a first bridge rectifier switch circuit and a transformer circuit. The input terminal of the first bridge rectifier switch circuit receives an input voltage. The transformer circuit includes an input side circuit and an output side circuit. The input side circuit is coupled to the first bridge rectifier switch circuit, and the output side circuit provides output voltage and output current. As can be seen from the above embodiment, the power conversion method of the power conversion device may include at least the following steps: First, a compensation frequency is generated based on the input voltage (step S702). Then, the switching frequency of the first bridge rectifier switch circuit is adjusted based on the compensation frequency (step S704) to reduce the influence of ripple components in the DC voltage on the output current and output voltage.

[0043] In other embodiments, the power conversion device may further include a power factor correction circuit and a second bridge rectifier switching circuit. The input side circuit of the transformer circuit may include a primary winding, a resonant inductor, a resonant capacitor, and a magnetizing inductor. The resonant inductor and resonant capacitor are connected in series between the first bridge rectifier switching circuit and one end of the primary winding. The other end of the primary winding is coupled to the first bridge rectifier switching circuit, and the magnetizing inductor is coupled between the two ends of the primary winding. Furthermore, the output side circuit may include a secondary winding, a resonant inductor, and a resonant capacitor. The resonant inductor and resonant capacitor are connected in series between the second bridge rectifier switching circuit and one end of the secondary winding. The other end of the secondary winding is coupled to the second bridge rectifier switching circuit, and the output terminal of the second bridge rectifier switching circuit is used to provide output voltage and output current. Figure 8As shown, the conversion method of the power conversion device may include providing a power factor correction circuit to provide a DC voltage as the input voltage of the first bridge rectifier switch circuit based on the input AC signal provided by the AC power supply (step S802). Then, a compensation frequency is generated based on the DC voltage output by the first bridge rectifier switch circuit and the frequency of the input AC signal provided by the AC power supply (step S804), and the switching frequency of the first bridge rectifier switch circuit and the second bridge rectifier switch circuit is adjusted based on the compensation frequency (step S806).

[0044] Furthermore, the method for adjusting the switching frequency of the first bridge rectifier switch circuit and the second bridge rectifier switch circuit can be as follows: Figure 9 As shown. First, an initial switching frequency is generated based on the target output current, target output voltage, output current of the second bridge rectifier switch circuit, and output voltage (step S902). This initial switching frequency is used to control the output current and output voltage of the second bridge rectifier switch circuit to be close to or equal to the target output current and target output voltage. Next, the DC voltage output from the first bridge rectifier switch circuit is bandpass filtered based on the frequency of the input AC signal to generate a ripple signal with a frequency doubling the ripple frequency (step S904). This ripple frequency is, for example, twice the frequency of the input AC signal, but not limited thereto. Then, a compensation frequency is generated based on the relationship between the ripple signal and the voltage gain of the power conversion device and the control frequency (step S906). Finally, the initial switching frequency and the compensation frequency are added together to generate a control frequency, which serves as the switching frequency between the first and second bridge rectifier switch circuits (step S908). In this embodiment, the control frequency can also be limited to a default frequency range (step S910) to ensure that the influence of ripple components in the DC voltage on the output current and output voltage is suppressed, wherein within the default frequency range, the voltage gain of the power conversion device decreases as the control frequency increases.

[0045] In summary, the power conversion device of this invention includes a transformer circuit and a bridge rectifier switch circuit coupled to the input side circuit of the transformer circuit. The switching frequency control circuit can generate a compensation frequency based on the input voltage of the bridge rectifier switch circuit and adjust the switching frequency of the bridge rectifier switch circuit according to the compensation frequency. This can effectively reduce the influence of ripple components in the DC voltage received by the bridge rectifier switch circuit, provide stable output current and output voltage, and extend the service life of the power conversion device. In some embodiments, the power conversion device may further include a bridge rectifier switch circuit coupled to the output side circuit of the transformer circuit. Adjusting the switching frequency of the bridge rectifier switch circuit coupled to both the input and output side circuits according to the compensation frequency can also effectively reduce the influence of ripple components in the DC voltage.

[0046] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A power conversion device, characterized by, comprising: a first bridge rectifier switching circuit having an input receiving an input voltage; a transformer circuit including an input side circuit and an output side circuit, the input side circuit coupled to the first bridge rectifier switching circuit; and a switching frequency control circuit generating a compensation frequency based on the input voltage and adjusting a switching frequency of the first bridge rectifier switching circuit based on the compensation frequency. further comprising:

2. The power conversion device of claim 1, wherein a power factor correction circuit coupled to the first bridge rectifier switching circuit and the switching frequency control circuit, providing a DC voltage based on an input AC signal as the input voltage. further comprising:

3. The power conversion device of claim 2, wherein, a second bridge rectifier switching circuit coupled to the output side circuit of the transformer, generating an output voltage based on a voltage provided by the transformer circuit, the switching frequency control circuit adjusting the switching frequency of the first bridge rectifier switching circuit and the second bridge rectifier switching circuit based on the compensation frequency. the output side circuit comprising:

4. The power conversion device of claim 3, wherein a secondary winding coupled to the second bridge rectifier switching circuit; a resonant capacitor; and a resonant inductor connected in series with the resonant capacitor between the secondary winding and the second bridge rectifier switching circuit. the switching frequency control circuit comprising:

5. The power conversion device of claim 3, wherein a charge control circuit generating an original switching frequency based on a target output current, a target output voltage, an output current of the second bridge rectifier switching circuit, and an output voltage of the second bridge rectifier switching circuit; a frequency compensation circuit generating the compensation frequency based on the DC voltage and a frequency of the input AC signal; and an adder circuit adding the original switching frequency and the compensation frequency to generate a control frequency as the switching frequency of the first bridge rectifier switching circuit and the second bridge rectifier switching circuit. further comprising:

6. The power conversion device of claim 5, wherein, a frequency range limiting circuit coupled to the adder circuit, limiting the control frequency within a default frequency range. within the default frequency range, a voltage gain of the power conversion device decreases as the control frequency increases.

7. The power conversion device of claim 6, wherein the switching frequency control circuit band-pass filters the DC voltage based on the frequency of the input AC signal to generate a ripple signal having a frequency that is a multiple of the frequency of the input AC signal, and generates the compensation frequency based on the ripple signal and a relationship between the voltage gain of the power conversion device and the control frequency.

8. The power conversion device of claim 3, wherein, the frequency that is a multiple of the frequency of the input AC signal is twice the frequency of the input AC signal.

9. The power conversion device of claim 8, wherein, the input side circuit comprising:

10. The power conversion device of claim 1, wherein, a primary winding coupled to the first bridge rectifier switching circuit; a resonant capacitor; a resonant inductor connected in series with the resonant capacitor between the primary winding and the first bridge rectifier switching circuit; and a magnetizing inductor coupled between two ends of the primary winding. the switching frequency control circuit is a digital signal processor.

11. The power conversion device of claim 1, wherein, the power conversion device comprising a first bridge rectifier switching circuit having an input receiving an input voltage and a transformer circuit including an input side circuit and an output side circuit, the input side circuit coupled to the first bridge rectifier switching circuit, a method of converting power by the power conversion device comprising:

12. A conversion method of a power conversion device, characterized by, generating a compensation frequency based on the input voltage; and ​ The switching frequency of the first bridge rectifier switching circuit is adjusted according to the compensation frequency.

13. The conversion method of the power conversion device according to claim 12, characterized by, Further comprising: A power factor correction circuit is provided to provide a DC voltage according to an input AC signal as the input voltage.

14. The conversion method of the power conversion device according to claim 13, characterized by, The power conversion device further comprises a second bridge rectifier switching circuit which generates an output voltage according to a voltage provided by the transformer circuit, and the conversion method of the power conversion device comprises: The switching frequency of the first bridge rectifier switching circuit and the second bridge rectifier switching circuit is adjusted according to the compensation frequency.

15. The conversion method of the power conversion device according to claim 14, characterized by, The output side circuit comprises: A secondary winding coupled to the second bridge rectifier switching circuit; A resonance capacitor; and A resonance inductor connected in series with the resonance capacitor between the secondary winding and the second bridge rectifier switching circuit.

16. The conversion method of the power conversion device according to claim 14, wherein Comprising: An original switching frequency is generated according to a target output current, a target output voltage, an output current of the second bridge rectifier switching circuit, and an output voltage; The compensation frequency is generated according to the DC voltage and the frequency of the input AC signal; and The original switching frequency and the compensation frequency are added to generate a control frequency as the switching frequency of the first bridge rectifier switching circuit and the second bridge rectifier switching circuit.

17. The conversion method of the power conversion device according to claim 16, wherein Comprising: The control frequency is limited within a default frequency range.

18. The conversion method of the power conversion device according to claim 17, wherein, Within the default frequency range, the voltage gain of the power conversion device decreases with the increase of the control frequency.

19. The conversion method of the power conversion device according to claim 14, wherein Comprising: The DC voltage is band-pass filtered according to the frequency of the input AC signal to generate a ripple signal having a frequency which is a multiple of the frequency of the input AC signal; and The compensation frequency is generated according to the ripple signal and the relationship between the voltage gain of the power conversion device and the control frequency. The multiple of the frequency of the input AC signal is 2.

20. The conversion method of the power conversion device according to claim 19, wherein, The input side circuit comprises:

21. The conversion method of the power conversion device according to claim 12, wherein, A primary winding coupled to the first bridge rectifier switching circuit; A resonance capacitor; A resonance inductor connected in series with the resonance capacitor between the primary winding and the first bridge rectifier switching circuit; and An excitation inductor coupled between two ends of the primary winding. ​

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