WO2023020051A1

WO2023020051A1 - Resonant converter, control method for resonant converter, and power adapter

Info

Publication number: WO2023020051A1
Application number: PCT/CN2022/093685
Authority: WO
Inventors: 杨滚; 肖松; 伍梁
Original assignee: 华为数字能源技术有限公司
Priority date: 2021-08-17
Filing date: 2022-05-18
Publication date: 2023-02-23
Also published as: CN115706525A

Abstract

Provided in the present application are a resonant converter, a control method for a resonant converter, and a power adapter. The resonant converter comprises a direct-current power supply, a first switch, a second switch, a capacitor, a transformer, a resistance characteristic module, a capacitance characteristic module and a control module, wherein the control module can control the switching-on or switching-off of the first switch and the second switch on the basis of a drive signal, and the first switch and the second switch are switched on in a complementary manner; and further, the control module can detect voltages at both ends of the resistance characteristic module and/or durations of the voltages at the both ends of the resistance characteristic module after the second switch is switched off, so as to determine whether the first switch achieves zero voltage switching. On the basis of the present application, whether a first switch achieves zero voltage switching can be detected, the loss and size of a resonant converter are reduced, and the conversion efficiency and stability are improved. The present application has good applicability.

Description

Resonant converter, control method of resonant converter and power adapter

This application claims the priority of the Chinese patent application with the application number 202110944083.X and the application name "resonant converter, control method of resonant converter and power adapter" submitted to the China Patent Office on August 17, 2021, all of which The contents are incorporated by reference in this application.

technical field

The present application relates to the technical field of power electronics, and in particular to a resonant converter, a control method of the resonant converter, and a power adapter.

Background technique

With the development of adapter fast charging technology, adapters are also developing towards high power density at a high speed, so improving the power density of adapters has become a future technology development trend. Since the increase of the power density of the adapter will increase the loss, and the natural heat dissipation capacity per unit volume is limited, it is necessary to reduce the loss of the adapter to meet the heat dissipation requirements while increasing the power density. The loss of the power tube (that is, the loss of the adapter) can be reduced by realizing the zero voltage switching (ZVS) of the power tube in the adapter, so how to determine the zero voltage switching of the power tube is particularly important.

The inventor of the present application has found in the course of research and practice that an adapter (such as a power adapter) usually includes a transformer and a power tube. In the prior art, an auxiliary winding is arranged in the transformer of the adapter, and the voltage at both ends of the power tube is detected by the auxiliary winding. And when the voltage at both ends of the power transistor is lower than the voltage threshold, it is determined that the power transistor has not achieved zero-voltage conduction. On the contrary, when the voltage across the power transistor is greater than the above voltage threshold, it can be determined that the power transistor has achieved zero-voltage conduction. However, the zero-voltage conduction of the prior art requires an additional auxiliary winding in the transformer of the power adapter, which will lead to an increase in the size of the power adapter, low stability and poor applicability of the power adapter.

Contents of the invention

The present application provides a resonant converter, a control method of the resonant converter, and a power adapter, which can detect whether the first switch realizes zero-voltage conduction, reduce the loss and size of the resonant converter, and improve conversion efficiency and stability. Strong applicability.

In a first aspect, the present application provides a resonant converter, which includes a DC power supply, a first switch, a second switch, a capacitor, a transformer, a resistance characteristic module, a capacitance characteristic module and a control module. Here, the resistive characteristic module includes devices with resistive characteristics, and the capacitive characteristic module includes devices with capacitive characteristics. Wherein, the first switch is connected in parallel with the DC power supply after being connected in series with the second switch, the capacitor is connected in parallel with the second switch after being connected in series with the transformer, and the resistance characteristic module and the capacitance characteristic module are connected in parallel with the first switch after being connected in series, wherein the negative pole of the DC power supply can be grounded. The above-mentioned control module can be connected with the first switch, the second switch and the resistance characteristic module, and can be used to control the turn-on or turn-off of the first switch and the second switch based on the driving signal, where the first switch and the second switch are turned on complementary. Further, the control module is also used to detect the voltage across both ends of the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module after the second switch is turned off to determine whether the first switch realizes zero-voltage conduction (or called zero voltage turn-on). Wherein, the voltage at both ends of the resistance characteristic module and/or the duration of the voltage at both ends of the resistance characteristic module may include the voltage at both ends of the resistance characteristic module, the duration of the voltage at both ends of the resistance characteristic module, or the duration of the voltage at both ends of the resistance characteristic module The duration of the voltage across the voltage and resistance characteristic modules. Since the voltage at both ends of the resistance characteristic module can indicate the voltage slope of the voltage at both ends of the first switch, it can be used as a judgment basis to determine whether the first switch realizes zero-voltage conduction. The zero-voltage turn-on here can be understood as the state that the first switch is in when the voltage across the first switch is 0 during the turn-on process. In the present application, it may be determined based on the voltage across both ends of the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module whether the first switch realizes zero-voltage conduction, and may reduce the voltage when the first switch realizes zero-voltage conduction. The loss thereby reduces the loss of the resonant converter; in addition, there is no need to set an auxiliary winding in the transformer, thereby reducing the size of the resonant converter, improving the conversion efficiency and stability of the resonant converter, and having strong applicability.

With reference to the first aspect, in a first possible implementation manner, the above-mentioned control module is configured to detect the voltage across the two ends of the resistance characteristic module after a preset delay time when the second switch is turned off, and to detect the voltage across the two ends of the resistance characteristic module When it is greater than the first voltage threshold, it is determined that the first switch has achieved zero-voltage conduction, or when the voltage across the resistance characteristic module is less than or equal to the first voltage threshold, it is determined that the first switch has not achieved zero-voltage conduction. Here, the preset delay time and the first voltage threshold may be parameters set by the user, or parameters configured by the resonant converter. In the resonant converter provided by this application, it can be determined that the first switch has achieved zero-voltage conduction when the voltage across the resistance characteristic module is greater than the first voltage threshold, thereby reducing the loss of the first switch and further reducing the resonance The loss of the converter, while improving the conversion efficiency, the applicability is stronger.

With reference to the first aspect, in a second possible implementation manner, the above-mentioned resonant converter further includes a timing module, and the timing module can be connected to the control module. Optionally, the timing module can also be integrated in the control module, which can be determined according to actual application scenarios, and is not limited here. The above-mentioned control module can be used to detect the voltage across the two ends of the resistance characteristic module after the second switch is turned off, and control the timing module to start timing when the voltage across the resistance characteristic module is greater than the second voltage threshold, and the voltage across the resistance characteristic module When it is equal to the third voltage threshold, the timing module is controlled to stop timing to obtain the duration. Wherein, the above-mentioned second voltage threshold is smaller than the third voltage threshold, and both the second voltage threshold and the third voltage threshold here may be parameters set by the user, or parameters configured in the resonant converter. In the resonant converter provided in the present application, the voltage value of the voltage at both ends of the resistance characteristic module can be used as a basis to control the timing of the timing module, so as to obtain the duration.

With reference to the second possible implementation manner of the first aspect, in a third possible implementation manner, the above-mentioned control module can be used to determine that the first switch has achieved zero-voltage conduction when the duration is longer than a preset duration threshold, or When the duration is less than or equal to the preset duration threshold, it is determined that the first switch has not achieved zero-voltage conduction. Wherein, the preset duration threshold may be a parameter set by a user, or a parameter configured in the resonant converter. Optionally, after the first switch realizes zero-voltage conduction, the timing module may reset the duration to zero, so as to detect whether the first switch realizes zero-voltage conduction in the next cycle. In the resonant converter provided by the present application, it can be determined that the first switch has achieved zero-voltage conduction when the duration timed by the timing module is greater than the preset time threshold, and there is no need to set an auxiliary winding in the transformer, thereby reducing the resonance conversion The size of the converter is reduced, and the conversion efficiency and stability of the resonant converter are improved at the same time, and the applicability is strong.

With reference to the first aspect, in a fourth possible implementation manner, the above-mentioned resonant converter further includes a timing module, and the timing module is connected to the control module. Optionally, the timing module can also be integrated in the control module, which can be determined according to actual application scenarios, and is not limited here. The above-mentioned control module can be used to detect the voltage at both ends of the resistance characteristic module after the second switch is turned off, and control the timing module to start timing when the voltage at both ends of the resistance characteristic module is greater than the second voltage threshold, and detect the time counted by the timing module When the duration of the voltage at both ends of the resistance characteristic module is greater than the second voltage threshold is greater than the preset duration threshold, it is determined that the first switch has achieved zero voltage conduction, wherein the timing module can be when the voltage at both ends of the resistance characteristic module is equal to the third voltage threshold Stop the timer. In the case that the first switch has not achieved zero-voltage conduction before the timing module stops timing, the control module can obtain the duration when the timing module stops timing, and determine that the first switch has achieved when the duration is greater than the preset duration threshold Zero-voltage conduction, or determining that the first switch has not achieved zero-voltage conduction when the duration is less than or equal to the preset duration threshold. In the resonant converter provided by the present application, it can be determined that the first switch has achieved zero-voltage conduction when it is detected that the time counted by the timing module is greater than the preset time threshold, and there is no need to set an auxiliary winding in the transformer, thereby reducing resonance The size of the converter is reduced, and the conversion efficiency and stability of the resonant converter are improved at the same time, and the applicability is strong.

With reference to any one of the fourth possible implementation manners from the first aspect to the first aspect, in a fifth possible implementation manner, the above-mentioned control module is further configured to realize zero in the i-th cycle when the first switch is detected When the voltage is turned on, the conduction duration of the second switch in the i+1th period is adjusted to obtain the adjusted conduction duration. Wherein, the above-mentioned adjusted conduction duration is the difference between the conduction duration of the second switch in the i-th period and the preset conduction duration, and the period is the switching period in which the first switch and the second switch are complementary conduction . The preset on-time duration here may be a parameter set by the user, or a parameter configured in the resonant converter. In the resonant converter provided in the present application, the conduction duration of the second switch in the (i+1)th cycle can be adjusted, so that the first switch can realize zero-voltage conduction in the (i+1)th cycle.

With reference to any one of the fourth possible implementation manners from the first aspect to the first aspect, in a sixth possible implementation manner, the above-mentioned control module is further configured to detect that the first switch does not realize the During zero-voltage conduction, the conduction duration of the second switch in the i+1th period is adjusted to obtain an adjusted conduction duration. Wherein, the above-mentioned adjusted on-time length is an accumulated value between the on-time length of the second switch in the i-th cycle and the preset on-time length, and this cycle can be the complementary conduction time of the first switch and the second switch. switching cycle. In the resonant converter provided in the present application, the conduction duration of the second switch in the (i+1)th cycle can be adjusted, so that the first switch can realize zero-voltage conduction in the (i+1)th cycle.

In combination with any one of the first aspect to the sixth possible implementation manner of the first aspect, in the seventh possible implementation manner, the above-mentioned resistance characteristic module includes a resistor, a diode, a triode, an insulated gate bipolar transistor (insulated gate bipolar transistor, which may be referred to as IGBT), metal-oxide-semiconductor field-effect transistor (metal-oxide-semiconductor field-effect transistor, which may be referred to as MOSFET), gallium nitride tube and/or other devices with resistive characteristics. Since these resistive devices are small in size, it is possible to detect whether the first switch realizes zero-voltage conduction while reducing the size of the resonant converter.

In combination with any one of the first aspect to the seventh possible implementation manner of the first aspect, in the eighth possible implementation manner, the above-mentioned capacitance characteristic module includes a capacitor, a diode, a MOSFET, a gallium nitride (GaN) tube, a carbide Silicon (SiC) tubes and/or other devices exhibiting capacitive properties. Since these capacitive devices are small in size, it is possible to detect whether the first switch realizes zero-voltage conduction while reducing the size of the resonant converter.

In a second aspect, the present application provides a resonant converter, which includes a DC power supply, a first switch, a second switch, a capacitor, a transformer, a resistance characteristic module, a capacitance characteristic module and a control module. Wherein, the first pole of the first switch can be connected to the first pole of the DC power supply, the second pole of the first switch can be connected to one end of the transformer, and the other end of the transformer can be connected to the second pole of the DC power supply, and the capacitor and the second switch are connected in series Afterwards, it is connected in parallel with the transformer, and the resistance characteristic module and the capacitance characteristic module are connected in parallel with the first switch after being connected in series. The negative pole of the DC power supply is grounded. The above-mentioned control module can be connected with the first switch, the second switch and the resistance characteristic module, and can be used to control the turn-on or turn-off of the first switch and the second switch based on the driving signal. Further, the control module is further configured to detect the voltage across the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module after the second switch is turned off to determine whether the first switch realizes zero-voltage conduction. In the present application, it may be determined based on the voltage across both ends of the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module whether the first switch realizes zero-voltage conduction, and may reduce the voltage when the first switch realizes zero-voltage conduction. The loss thereby reduces the loss of the resonant converter; in addition, there is no need to set an auxiliary winding in the transformer, thereby reducing the size of the resonant converter, improving the conversion efficiency and stability of the resonant converter, and having strong applicability.

It should be noted that the above-mentioned first possible implementation manner of the first aspect to the eighth possible implementation manner of the first aspect are also applicable to the circuit topology of the resonant converter provided in the second aspect, and will not be described in detail below.

In a third aspect, the present application provides a resonant converter, which includes a DC power supply, a first switch, a second switch, a capacitor, a transformer, a resistance characteristic module, a capacitance characteristic module and a control module. Wherein, the first pole of the first switch can be connected to the first pole of the DC power supply, the second pole of the first switch can be connected to one end of the transformer, the other end of the transformer can be connected to the second pole of the DC power supply, and the first pole of the second switch can be connected to the second pole of the DC power supply. pole is connected to one end of the capacitor and then grounded, the other end of the capacitor can be connected to the second pole of the second switch through the auxiliary winding in the transformer, and the negative pole of the DC power supply is grounded, where the negative pole of the DC power supply can be the first pole of the DC power supply or second pole. The above-mentioned control module can be connected with the first switch, the second switch and the resistance characteristic module, and can be used to control the turn-on or turn-off of the first switch and the second switch based on the driving signal. Further, the control module is further configured to detect the voltage across the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module after the second switch is turned off to determine whether the first switch realizes zero-voltage conduction. In the present application, it may be determined based on the voltage across both ends of the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module whether the first switch realizes zero-voltage conduction, and may reduce the voltage when the first switch realizes zero-voltage conduction. The loss further reduces the loss of the resonant converter; in addition, the size of the resonant converter can be reduced, and the conversion efficiency and stability of the resonant converter are improved, and the applicability is strong.

It should be noted that the above-mentioned first possible implementation manner of the first aspect to the eighth possible implementation manner of the first aspect are also applicable to the circuit topology of the resonant converter provided in the third aspect, and will not be described in detail below.

In a fourth aspect, the present application provides a method for controlling a resonant converter, the method is suitable for a resonant converter, and the resonant converter includes a DC power supply, a first switch, a second switch, a capacitor, a transformer, a resistance characteristic module, Capacitance characteristic module and control module. Wherein, the first switch is connected in parallel with the DC power supply after being connected in series with the second switch, the capacitor is connected in parallel with the second switch after being connected in series with the transformer, the resistance characteristic module and the capacitance characteristic module are connected in parallel with the first switch after being connected in series, the negative pole of the DC power supply is grounded, and the control module Connect the first switch, the second switch and the resistance characteristic module. In this method, the control module may control the first switch and the second switch to be turned on or off based on the driving signal. Further, the control module can detect the voltage across the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module after the second switch is turned off to determine whether the first switch realizes zero-voltage conduction. In the present application, it may be determined based on the voltage across both ends of the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module whether the first switch realizes zero-voltage conduction, and may reduce the voltage when the first switch realizes zero-voltage conduction. The loss of the first switch is reduced, thereby reducing the loss of the resonant converter, and improving the conversion efficiency and stability of the resonant converter, and has strong applicability.

With reference to the fourth aspect, in a first possible implementation manner, the above-mentioned control module can detect the voltage at both ends of the resistance characteristic module after a preset delay time when the second switch is turned off, and when the voltage at both ends of the resistance characteristic module is greater than When the first voltage threshold is reached, it is determined that the first switch has achieved zero-voltage conduction. Alternatively, the control module may determine that the first switch has not achieved zero-voltage conduction when the voltage across the resistance characteristic module is less than or equal to the first voltage threshold.

With reference to the fourth aspect, in a second possible implementation manner, the above-mentioned resonant converter further includes a timing module, and the timing module can be connected to the control module. The above-mentioned control module can detect the voltage at both ends of the resistance characteristic module after the second switch is turned off, and control the timing module to start timing when the voltage at both ends of the resistance characteristic module is greater than the second voltage threshold, and when the voltage at both ends of the resistance characteristic module is equal to When the third voltage threshold is reached, the timing module is controlled to stop timing to obtain the duration of the voltage across the resistance characteristic module. Wherein, the second voltage threshold is smaller than the third voltage threshold. After obtaining the duration, the control module may determine that the first switch has achieved zero voltage conduction when the duration is greater than the preset duration threshold, or determine that the first switch has not achieved zero voltage when the duration is less than or equal to the preset duration threshold conduction.

With reference to the fourth aspect, in a third possible implementation manner, the above-mentioned resonant converter further includes a timing module, and the timing module can be connected to the control module. The above-mentioned control module can detect the voltage at both ends of the resistance characteristic module after the second switch is turned off, and control the timing module to start timing when the voltage at both ends of the resistance characteristic module is greater than the second voltage threshold, and when the resistance measured by the timing module is detected It is determined that the first switch has achieved zero-voltage conduction when the duration for which the voltage across the characteristic module is greater than the second voltage threshold is greater than the preset duration threshold. Wherein, the timing module can stop timing when the voltage across the resistance characteristic module is equal to the third voltage threshold.

With reference to any one of the fourth aspect to the third possible implementation manner of the fourth aspect, in the fourth possible implementation manner, the above-mentioned control module can realize zero-voltage conduction of the first switch in the i-th period after detecting that When turning on, the conduction duration of the second switch in the i+1th period is adjusted to obtain the adjusted conduction duration. Wherein, the above-mentioned adjusted conduction duration is the difference between the conduction duration of the second switch in the i-th cycle and the preset conduction duration, and this cycle is a switch in which the first switch and the second switch are complementary conduction cycle.

With reference to any one of the fourth aspect to the third possible implementation manner of the fourth aspect, in the fifth possible implementation manner, the above-mentioned control module may detect that the first switch does not achieve zero voltage in the i-th cycle When conducting, the conduction duration of the second switch in the i+1th cycle is adjusted to obtain the adjusted conduction duration. Wherein, the above-mentioned adjusted conduction duration is an accumulated value between the conduction duration of the second switch in the i-th cycle and the preset conduction duration, and this cycle can be understood as the complementary conduction of the first switch and the second switch switching cycle.

In a fifth aspect, the present application provides a method for controlling a resonant converter, the method is suitable for a resonant converter, and the resonant converter includes a DC power supply, a first switch, a second switch, a capacitor, a transformer, a resistance characteristic module, Capacitance characteristic module and control module, wherein, the first pole of the first switch is connected to the first pole of the DC power supply, the second pole of the first switch is connected to one end of the transformer, and the other end of the transformer is connected to the second pole of the DC power supply, the capacitor and The second switch is connected in parallel with the transformer after being connected in series, and the resistance characteristic module and the capacitance characteristic module are connected in parallel with the first switch after being connected in series. The first switch, the second switch and the resistance characteristic module can be connected. In this method, the control module may control the first switch and the second switch to be turned on or off based on the driving signal. Further, the control module can detect the voltage across the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module after the second switch is turned off to determine whether the first switch realizes zero-voltage conduction. In the present application, it may be determined based on the voltage across both ends of the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module whether the first switch realizes zero-voltage conduction, and may reduce the voltage when the first switch realizes zero-voltage conduction. The loss of the first switch is reduced, thereby reducing the loss of the resonant converter, and improving the conversion efficiency and stability of the resonant converter, and has strong applicability.

It should be noted that the above-mentioned first possible implementation manner of the fourth aspect to the fifth possible implementation manner of the fourth aspect are also applicable to the method for controlling the resonant converter provided in the fifth aspect, which will not be described in detail below.

In a sixth aspect, the present application provides a control method for a resonant converter, the method is suitable for a resonant converter, and the resonant converter includes a DC power supply, a first switch, a second switch, a capacitor, a transformer, a resistance characteristic module, a capacitor The characteristic module and the control module, wherein the first pole of the first switch can be connected to the first pole of the DC power supply, the second pole of the first switch can be connected to one end of the transformer, and the other end of the transformer can be connected to the second pole of the DC power supply, The first pole of the second switch is connected to one end of the capacitor and grounded, and the other end of the capacitor is connected to the second pole of the second switch through the auxiliary winding in the transformer. The negative pole of the DC power supply is grounded, and the negative pole of the DC power supply can be The first pole or the second pole, the control module can be connected with the first switch, the second switch and the resistance characteristic module. In this method, the control module may control the first switch and the second switch to be turned on or off based on the driving signal. Further, the control module can detect the voltage across the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module after the second switch is turned off to determine whether the first switch realizes zero-voltage conduction. In the present application, it may be determined based on the voltage across both ends of the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module whether the first switch realizes zero-voltage conduction, and may reduce the voltage when the first switch realizes zero-voltage conduction. The loss of the first switch is reduced, thereby reducing the loss of the resonant converter, and improving the conversion efficiency and stability of the resonant converter, and has strong applicability.

It should be noted that the above-mentioned first possible implementation manner of the fourth aspect to the fifth possible implementation manner of the fourth aspect are also applicable to the method for controlling the resonant converter provided in the sixth aspect, which will not be described in detail below.

Optionally, the control method of the above-mentioned resonant converter can also be applied to a quasi resonant flyback (quasi resonant flyback) circuit topology. In this method, the control module can control the conduction of the first switch and the second switch based on the driving signal or off. Further, the control module can detect the voltage across the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module after the second switch is turned off to determine whether the first switch realizes zero-voltage conduction. In the present application, it may be determined based on the voltage across both ends of the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module whether the first switch realizes zero-voltage conduction, and may reduce the voltage when the first switch realizes zero-voltage conduction. The loss of the first switch is reduced, thereby reducing the loss of the resonant converter, and improving the conversion efficiency and stability of the resonant converter, and has strong applicability.

In a seventh aspect, the present application provides a power adapter, which includes an alternating current (AC)/direct current (DC) conversion module and the AC/DC conversion module as described in the first aspect to the above-mentioned The resonant converter provided in any one of the third aspects. Wherein, the input end of the AC/DC conversion module can be connected to the power grid, and the output end of the resonant converter can be connected to a load (such as an electronic device). The aforementioned AC/DC conversion module can be used to output the first DC voltage to the resonant converter based on the AC voltage provided by the power grid. At this time, the resonant converter can be used to convert the first DC voltage into the second DC voltage to supply power to the load. In the present application, the size of the power adapter can be reduced, and the stability, power supply efficiency, and heat dissipation capability of the power adapter are improved at the same time, and the applicability is strong.

In the present application, it may be determined based on the voltage across both ends of the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module whether the first switch realizes zero-voltage conduction, and may reduce the voltage when the first switch realizes zero-voltage conduction. The loss thereby reduces the loss of the resonant converter; in addition, there is no need to set an auxiliary winding in the transformer, thereby reducing the size of the resonant converter, improving the conversion efficiency and stability of the resonant converter, and having strong applicability.

Description of drawings

FIG. 1 is a schematic diagram of an application scenario of a power adapter provided by the present application;

Fig. 2 is a structural schematic diagram of the resonant converter provided by the present application;

Fig. 3 is another structural schematic diagram of the resonant converter provided by the present application;

Fig. 4 is another structural schematic diagram of the resonant converter provided by the present application;

Fig. 5 is another structural schematic diagram of the resonant converter provided by the present application;

Fig. 6 is another structural schematic diagram of the resonant converter provided by the present application;

Fig. 7 is another structural schematic diagram of the resonant converter provided by the present application;

FIG. 8 is a schematic waveform diagram of the voltage across the first switch and the voltage across the resistance characteristic module provided by the present application;

9 is another schematic waveform diagram of the voltage across the first switch and the voltage across the resistance characteristic module provided by the present application;

FIG. 10 is a schematic flowchart of a control method for a resonant converter provided by the present application;

Fig. 11 is a schematic flow chart of detecting whether the first switch realizes zero-voltage conduction provided by the present application;

FIG. 12 is another schematic flowchart of detecting whether the first switch realizes zero-voltage conduction provided by the present application.

Detailed ways

The resonant converter provided by this application can be applied to power adapters of different types of electronic devices such as smart phones, tablet computers, laptops, desktop computers, smart speakers, smart watches, and wearable devices, so as to convert 220V household electricity into different The voltage and current applicable to the type of electronic equipment can be applied to the field of electronic equipment, laser field (such as laser power adapter) and other fields. The resonant converter provided by this application is suitable for power adapters, which can be adapted to the power supply application scenarios of different types of electronic devices. The electronic devices here may include but are not limited to smartphones, tablet computers, notebook computers, desktop computers, Smart speakers, smart watches, and wearables. The following will take an electronic device power supply scenario as an example for description, and details will not be repeated below.

Please also refer to FIG. 1 . FIG. 1 is a schematic diagram of an application scenario of the power adapter provided in this application. In the power supply scenario for electronic equipment, as shown in Figure 1, the power adapter includes an AC/DC conversion module and a resonant converter connected to the AC/DC conversion module, wherein the input end of the AC/DC conversion module can be connected to the power grid (such as AC power grid), the output end of the AC/DC conversion module can be connected to the input end of the resonant converter, and the output end of the resonant converter can be connected to a load (such as an electronic device). When the electronic equipment needs to be powered, the AC/DC conversion module can convert the AC voltage (such as 220V AC) provided by the grid into the first DC voltage, and output the first DC voltage to the resonant converter. At this time, the resonant converter can convert the first DC voltage into a second DC voltage, and supply power to the electronic device based on the second DC voltage. Optionally, the above-mentioned power adapter may further include a filter module (not shown in the figure), and the filter module is respectively connected with the AC/DC conversion module and the resonant converter, and the filter module can filter out noise in the resonant converter. In the application scenario shown in Figure 1, since the power adapter cannot effectively dissipate heat due to the excessive loss of the resonant converter, it is particularly important to reduce the loss of the resonant converter. The switch in the resonant converter provided by the present application can reduce the loss of the resonant converter and further reduce the loss of the power adapter when realizing zero-voltage conduction, thereby improving the heat dissipation capability and power supply efficiency of the power adapter, and has strong applicability.

The resonant converter provided by the present application includes a DC power supply, a first switch, a second switch, a capacitor, a transformer, a resistance characteristic module, a capacitance characteristic module and a control module, wherein the first switch is connected in parallel with the DC power supply after being connected in series with the second switch , the capacitor is connected in parallel with the second switch after being connected in series with the transformer, the resistance characteristic module and the capacitance characteristic module are connected in parallel with the first switch after being connected in series, wherein the negative pole of the DC power supply can be grounded. The above-mentioned control module can be connected with the first switch, the second switch and the resistance characteristic module, and can control the turn-on or turn-off of the first switch and the second switch based on the driving signal, where the first switch and the second switch are turned on complementary. Further, the control module can also detect the voltage across the two terminals of the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module after the second switch is turned off, and can quickly determine whether the first switch realizes zero-voltage conduction, thereby The low loss of the resonant converter can be guaranteed when the first switch achieves zero-voltage conduction, and corresponding measures (such as increasing the conduction time of the second switch) are taken when the first switch does not achieve zero-voltage conduction to ensure the first The switch realizes zero-voltage conduction, and the resonant converter has a simple structure, high stability, and strong applicability. The resonant converter provided by the present application and its working principle will be illustrated below with reference to FIG. 2 to FIG. 9 .

Referring to FIG. 2 , FIG. 2 is a schematic structural diagram of the resonant converter provided by the present application. As shown in Figure 2, the resonant converter 1 includes a DC power supply 10, a first switch S1 (also called a main switch tube), a second switch S2 (also called an auxiliary switch tube), a capacitor C1, and a transformer T1 , a resistance characteristic module 20 , a capacitance characteristic module 30 and a control module 40 . Wherein, the first switch S1 and the second switch S2 can be connected in parallel with the DC power supply 10 after being connected in series, the capacitor C1 and the transformer T1 can be connected in parallel with the second switch S2 after being connected in series, and the resistance characteristic module 20 and the capacitance characteristic module 30 can be connected in series with the first The switches S1 are connected in parallel, wherein the negative pole of the DC power supply 10 can be grounded. Wherein, the first switch S1 and the second switch S2 can be made of silicon semiconductor material (silicon, Si), or silicon carbide (silicon carbide, SiC) of the third generation wide bandgap semiconductor material, or gallium nitride (gallium nitride, GaN), or diamond (diamond), or zinc oxide (zinc oxide, ZnO), or MOSFETs, IGBTs, or diodes made of other materials, which can be determined according to actual application scenarios, and are not limited here. The resistance characteristic module 20 here includes devices with resistance characteristics, which may include but not limited to resistors, diodes, triodes, IGBTs, MOSFETs and/or gallium nitride tubes. The capacitive characteristic module 30 here includes devices with capacitive characteristics, and the devices with capacitive characteristics may include but not limited to capacitors, diodes, MOSFETs, gallium nitride tubes and/or silicon carbide tubes. The above-mentioned resistance characteristic module 20 and capacitance characteristic module 30 can form a detection circuit, and the detection circuit can be used to detect the voltage at both ends of the first switch S1, and the voltage at both ends of the resistance characteristic module 20 can be obtained to indicate the two ends of the first switch S1 Therefore, it can be used as a judgment basis to determine whether the first switch S1 realizes zero-voltage conduction.

In some feasible implementation manners, the circuit topology of the resonant converter 1 may be an asymmetrical half bridge flyback (asymmetrical half bridge flyback, may be referred to as AHB flyback) circuit topology and an asymmetrical half bridge forward (asymmetrical half bridge forward, It can be referred to as AHB forward) circuit topology for short. Please also refer to FIG. 3 . FIG. 3 is another schematic structural diagram of the resonant converter provided in the present application. In the case that the circuit topology of the above-mentioned resonant converter 1 is an asymmetrical half-bridge flyback circuit topology, as shown in 3a in FIG. 3, the resistance characteristic module 20 shown in FIG. 30 may include a capacitor C0, and the transformer T1 may include a leakage inductance Lr, an excitation inductance Lm, a primary winding and a secondary winding, and the turns ratio between the primary winding and the secondary winding may be n:1, where n is positive integer. Wherein, since the magnetic field lines generated on the primary side of the transformer T1 cannot all pass through the secondary winding, the inductance that generates magnetic flux leakage in the transformer T1 can be called leakage inductance Lr (leakage inductance). The excitation inductance Lm (magnetic inductance) is the primary side inductance of the transformer T1, the current on it will not be conducted to the secondary, its function is to excite the iron core of the transformer T1, so that the ferromagnetic molecules in the iron core can be used To conduct magnetism. For the convenience of description, the description below will take the first switch and the second switch as MOSFETs as an example, and details will not be repeated below. The source of the first switch S1 is connected to the negative pole of the DC power supply 10 and one end of the capacitor C0, and the drain of the first switch S1 is connected to the source of the second switch S2, one end of the exciting inductor Lm, one end of the resistor R0 and the primary winding The drain of the second switch S2 is connected to the positive pole of the DC power supply 10 and one end of the capacitor C1, and the other end of the capacitor C1 can be connected to the other end of the excitation inductance Lm and the end of the same name of the primary winding through the leakage inductance Lr. The other end of the resistor R0 is connected to the other end of the capacitor C0, wherein the negative pole of the DC power supply 10 is grounded, and the terminal with the same name of the secondary winding is grounded. Wherein, the DC voltage provided by the DC power supply 10 can be expressed as Vin (namely the input voltage of the resonant converter 1), and the resistor R0 and the capacitor C0 can form a detection circuit to detect the voltage across the first switch S1 (which can be expressed as Vdssw). Optionally, the resonant converter 1 shown in FIG. 2 also includes a capacitor C3 and a rectification module 50, the capacitor C3 is connected in parallel with the DC power supply 10, the rectification module 50 includes a switch S3 and a capacitor C2, and the switch S3 and the capacitor C2 are connected in series to the The secondary windings are connected in parallel, and both ends of the capacitor C2 can be used as the output terminal of the rectifier module 50 and connected to a load RL (such as the electronic device in FIG. 2 ) to supply power to the load RL based on the output voltage Vo.

In some feasible implementation manners, when the circuit topology of the above-mentioned resonant converter 1 is an asymmetrical half-bridge forward circuit topology, as shown in 3b in FIG. 3 , in the resistance characteristic module 20 shown in FIG. 2 Including the resistor R0, the capacitance characteristic module 30 may include the capacitor C0, the transformer T1 includes the leakage inductance Lr, the excitation inductance Lm, the primary winding and the secondary winding, wherein the turns ratio between the primary winding and the secondary winding is Can be n:1, n is a positive integer. For the convenience of description, the description below will take the first switch and the second switch as MOSFETs as an example, and details will not be repeated below. The drain of the first switch S1 is connected to the positive pole of the DC power supply 10, the source of the first switch S1 is connected to the drain of the second switch S2 and one end of the capacitor C1, and the source of the second switch S2 is connected to the negative pole of the DC power supply 10, the excitation One end of the inductance Lm is connected to the opposite end of the primary winding, and the other end of the capacitor C1 is connected to the other end of the exciting inductance Lm and the same end of the primary winding through the leakage inductance Lr. The resistor R0 and the capacitor C0 can be connected in series to the first switch S1 is connected in parallel, wherein the negative pole of the DC power supply 10 is grounded, and the opposite end of the secondary winding is grounded. Wherein, the DC voltage provided by the DC power supply 10 can be expressed as Vin (ie, the input voltage of the resonant converter 1 ). Optionally, the resonant converter 1 shown in FIG. 2 also includes a capacitor C3 and a rectification module 50, the capacitor C3 is connected in parallel with the DC power supply 10, the rectification module 50 includes a switch S3 and a capacitor C2, and the switch S3 and the capacitor C2 are connected in series to the The secondary windings are connected in parallel, and both ends of the capacitor C2 can be used as the output terminal of the rectifier module 50 and connected to a load RL (such as the electronic device in FIG. 2 ) to supply power to the load RL based on the output voltage Vo.

Further, please refer to FIG. 4 , which is another schematic structural diagram of the resonant converter provided by the present application. As shown in Fig. 4, the resonant converter 2 includes a DC power supply 10, a first switch S1 (also called a main switch tube), a second switch S2 (also called an auxiliary switch tube), a capacitor C1, a transformer T1, a resistor A characteristic module 20 , a capacitance characteristic module 30 and a control module 40 . Wherein, the first pole of the first switch S1 can be connected to the first pole of the DC power supply 10, the second pole of the first switch S1 can be connected to one end of the transformer T1, and the other end of the transformer T1 can be connected to the second pole of the DC power supply 10, The capacitor C1 and the second switch S2 are connected in parallel with the transformer T1 after being connected in series, the resistance characteristic module 20 and the capacitance characteristic module 30 are connected in parallel with the first switch S1 after being connected in series, the negative pole of the DC power supply 10 is grounded, and the negative pole of the DC power supply 10 here can be DC The first pole of the power supply 10 or the second pole of the DC power supply 10 . The resistance characteristic module 20 here includes devices with resistance characteristics, which may include but not limited to resistors, diodes, triodes, IGBTs, MOSFETs and/or gallium nitride tubes. The capacitive characteristic module 30 here includes devices with capacitive characteristics, and the devices with capacitive characteristics may include but not limited to capacitors, diodes, MOSFETs, gallium nitride (GaN) tubes and/or silicon carbide (SiC) tubes. When the first pole of the DC power supply 10 is negative, the second pole of the DC power supply 10 is positive, and the circuit topology of the resonant converter 2 is an active clamp flyback (ACF flyback) circuit for short. topology; when the first pole of the DC power supply 10 is positive, the second pole of the DC power supply 10 is negative, and at this time the circuit topology of the resonant converter 2 is active clamp forward (active clamp forward, which may be referred to as ACF forward for short) ) circuit topology.

In some feasible implementation manners, when the circuit topology of the above-mentioned resonant converter 2 is an active clamp flyback circuit topology, please refer to FIG. 5 , which is another structural schematic diagram of the resonant converter provided by the present application. . As shown in FIG. 5, the resistance characteristic module 20 shown in FIG. 4 includes a resistor R0, the capacitance characteristic module 30 may include a capacitor C0, and the transformer T1 includes a magnetic leakage inductance Lr, a primary winding and a secondary winding, and the primary The turns ratio between the side winding and the secondary winding may be n:1, where n is a positive integer. For the convenience of description, the description below will take the first switch and the second switch as MOSFETs as an example, and details will not be repeated below. At this time, the first pole of the first switch S1 is the source, and the second pole of the first switch S1 is the drain; the first pole of the DC power supply 10 is negative, and the second pole of the DC power supply 10 is positive. The source of the first switch S1 can be connected to the negative pole of the DC power supply 10, the drain of the first switch S1 can be connected to the opposite end of the primary winding (that is, one end of the transformer T1) and the source of the second switch S2, the second The drain of the switch S2 is connected to one end of the capacitor C1, and the other end of the capacitor C1 can be connected to the positive pole of the DC power supply 10 and one end of the leakage inductance Lr (that is, the other end of the transformer T1), and the other end of the leakage inductance Lr is connected to the primary winding The capacitor C1 and the second switch S2 are connected in parallel with the transformer T1 in series, the resistor R0 and the capacitor C0 are connected in parallel with the first switch S1 in series, the negative pole of the DC power supply 10 is grounded, and the terminal with the same name of the secondary winding is grounded. Optionally, as shown in FIG. 5, the resonant converter 2 shown in FIG. 4 above may further include a capacitor C3 and a rectification module 50, the capacitor C3 is connected in parallel with the DC power supply 10, and the rectification module 50 includes a switch S3 and a capacitor C2, The switch S3 is connected in series with the capacitor C2 in parallel with the secondary winding, and the two ends of the capacitor C2 can be used as the output terminal of the rectifier module 50 and connected to the load RL (such as the electronic device in FIG. 2 above) to supply power to the load RL based on the output voltage Vo .

Optionally, in some feasible implementation manners, when the circuit topology of the above-mentioned resonant converter 2 is an active clamp forward circuit topology, the first pole of the first switch S1 is drain, and the first switch S1 The second pole of the DC power supply is the source pole; the first pole of the DC power supply 10 is the positive pole, and the second pole of the DC power supply 10 is the negative pole. Wherein, the drain of the first switch S1 can be connected to the positive pole of the DC power supply 10, the source of the first switch S1 can be connected to one end of the transformer T1, the other end of the transformer T1 can be connected to the negative pole of the DC power supply 10, the capacitor C1 and the second switch S2 can be connected in parallel with the transformer T1 after being connected in series, the resistance characteristic module 20 and the capacitance characteristic module 30 can be connected in parallel with the first switch S1 after being connected in series, and the negative pole of the DC power supply 10 is grounded. For the internal structure of the transformer T1 here, reference may be made to the internal structure of the transformer T1 shown in 3b in FIG. 3 above, which will not be repeated here.

Further, please refer to FIG. 6 , which is another schematic structural diagram of the resonant converter provided by the present application. As shown in FIG. 6, the resonant converter 3 includes a DC power supply 10, a first switch S1 (also called a main switch tube), a second switch S2 (also called an auxiliary switch tube), a capacitor C1, a transformer T1, A resistance characteristic module 20 , a capacitance characteristic module 30 and a control module 40 . Wherein, the first pole of the first switch S1 can be connected to the first pole of the DC power supply 10, the second pole of the first switch S1 can be connected to one end of the transformer T1, and the other end of the transformer T1 can be connected to the second pole of the DC power supply 10, The first pole of the second switch S2 is connected to one end of the capacitor C1 and then grounded. The other end of the capacitor C1 can be connected to the second pole of the second switch S2 through the auxiliary winding in the transformer T1. The negative pole of the DC power supply 10 is grounded. Here, the negative pole of the DC power supply 10 can be the first pole of the DC power supply 10 or the second pole of the DC power supply 10 , which can be determined according to actual application scenarios, and is not limited here. The resistance characteristic module 20 here includes devices with resistance characteristics, which may include but not limited to resistors, diodes, triodes, IGBTs, MOSFETs and/or gallium nitride tubes. The capacitive characteristic module 30 here includes devices with capacitive characteristics, and the devices with capacitive characteristics may include but not limited to capacitors, diodes, MOSFETs, gallium nitride (GaN) tubes and/or silicon carbide (SiC) tubes. Wherein, when the first pole of the DC power supply 10 is positive, the second pole of the DC power supply 10 is negative; when the first pole of the DC power supply 10 is negative, the second pole of the DC power supply 10 is positive.

In some feasible implementation manners, the circuit topology of the resonant converter 3 may be an AZVS circuit topology, please also refer to FIG. 7 , which is another schematic structural diagram of the resonant converter provided in the present application. As shown in FIG. 7, the resistance characteristic module 20 shown in FIG. 6 includes a resistor R0, the capacitance characteristic module 30 may include a capacitor C0, and the transformer T1 includes a leakage inductance Lr, an excitation inductance Lm, a primary winding, and a secondary winding. winding and auxiliary winding, and the turns ratio between the primary winding and the secondary winding can be n:1, where n is a positive integer. For the convenience of description, the description below will take the first switch and the second switch as MOSFETs as an example, and details will not be repeated below. At this time, the first pole of the first switch S1 is the source, and the second pole of the first switch S1 is the drain; the first pole of the second switch S2 is the source, and the second pole of the second switch S2 is the drain; DC power supply The first pole of 10 is the negative pole, and the second pole of the DC power supply 10 is the positive pole. The source of the first switch S1 is connected to the negative pole of the DC power supply 10, the drain of the first switch S1 is connected to the opposite end of the primary winding (that is, one end of the transformer T1), the excitation inductance Lm is connected in parallel with the primary winding, and the leakage inductance One end of Lr can be used as the other end of the transformer T1 to connect the positive pole of the DC power supply 10, the other end of the leakage inductance Lr is connected to the same-named end of the primary winding, the resistor R0 and the capacitor C0 are connected in parallel with the first switch S1 after being connected in series, and the second switch The source of S2 is connected to one end of capacitor C1 and then grounded, and the other end of capacitor C1 can be connected to the drain of the second switch S2 through the auxiliary winding, wherein the negative pole of DC power supply 10 is grounded, and the terminal with the same name of the secondary winding is grounded. Optionally, the resonant converter 3 shown in FIG. 6 also includes a resistor R1, a capacitor C4, a diode D1, and a rectifier module 50, wherein the primary winding is connected to one end of the resistor R1 and one end of the capacitor C4 through the diode D1, and the resistor R1 The other end of the capacitor C4 and the other end of the capacitor C4 are connected in parallel to the positive pole of the DC power supply 10. The rectifier module 50 includes a switch S3 and a capacitor C2. The switch S3 is connected in series with the capacitor C2 and connected in parallel with the secondary winding. The output end of the rectification module 50 is connected to a load RL (such as the electronic device in FIG. 2 ) to supply power to the load RL based on the output voltage Vo.

In some feasible implementation manners, the above-mentioned control module 40 (such as the control module 40 in the above-mentioned FIGS. As shown, the control module 40 can connect the gate of the first switch S1 and the gate of the second switch S2 to control the first switch S1 and the second switch S2. The control module 40 can control the first switch S1 and the second switch S2 to be turned on or off based on the driving signal, where S1 and the second switch S2 are turned on complementary. The driving signal here may be a pulse width modulation (pulse width modulation, PWM) signal of the first switch S1 and the second switch S2, which may be referred to as a PWM signal for short. Further, the control module 40 can also detect the voltage across the resistance characteristic module 20 and/or the duration of the voltage across the resistance characteristic module 30 after the second switch S2 is turned off to determine whether the first switch S1 realizes zero-voltage conduction. Pass. Since the voltage across the resistance characteristic module 20 can be used to indicate the voltage slope (ie RC slope) of the voltage across the first switch S1 , it can be used as a judgment basis to determine whether the first switch S1 achieves zero-voltage conduction.

In some feasible implementation manners, please refer to FIG. 8 , which is a schematic waveform diagram of the voltage across the first switch and the voltage across the resistance characteristic module provided in the present application. As shown in FIG. 8, from the driving signal of the first switch S1 and the driving signal of the second switch S2, it can be obtained that: the first switch S1 and the second switch S2 are turned on complementary (that is, the first switch S1 and the second switch S2 are complementary switch), the second switch S2 is turned off when the first switch S1 is turned on, or the second switch S2 is turned on when the first switch S1 is turned off. For the first switch S1 and the second switch S2 as complementary switches, in order to prevent the first switch S1 and the second switch S2 from being turned on at the same time, it is necessary to add a dead time between the first switch S1 and the second switch S2, Such as t _D1 or t _D2 , where t _D1 may be the dead time from the moment when the first switch S1 is turned off to the moment when the second switch S2 is turned on, and t _D2 may be the time from when the second switch S2 is turned off to the moment when the second switch S2 is turned on. A dead time between switch S1 conduction moments. The above control module 40 can control the first switch S1 and the second switch S2 to be turned on or off based on the driving signal of the first switch S1 and the driving signal of the second switch S2 as shown in FIG. 8 . Further, the above-mentioned control module 40 can detect the voltage across the two terminals of the resistance characteristic module 20 after the preset delay time when the second switch S2 is turned off, wherein the preset delay time can be a parameter set by the user, or a parameter configured by the resonant converter. parameter. At this time, the voltage waveform corresponding to the voltage across the two ends of the resistance characteristic module 20 (may be expressed as Vdec) can be shown in FIG. Denoted as Vdssw) with respect to the voltage slope (ie Vdec∝dVdssw/dt) obtained after derivation of time t, so based on the voltage Vdec across the resistance characteristic module 20, it can be determined whether the first switch S1 achieves zero-voltage conduction, wherein the time t_detect1 The sum time t_detect1 may represent the duration of detecting zero-voltage conduction in different periods, and the period is a switching period in which the first switch S1 and the second switch S2 are complementary conducted. At this time, the control module 40 may determine that the first switch S1 achieves zero-voltage conduction when the voltage across the resistance characteristic module 20 is greater than the first voltage threshold. The first voltage threshold here can be a parameter set by the user, or a parameter configured by the resonant converter. For example, as shown in FIG. 8, the first voltage threshold can be a voltage threshold V1 or a voltage threshold V2, and the voltage threshold V1 is greater than the voltage Threshold V2. Optionally, the control module 40 may also determine that the first switch S1 has not achieved zero-voltage conduction when the voltage across the resistance characteristic module 20 is less than or equal to the first voltage threshold.

In some feasible implementation manners, please refer to FIG. 9 , which is another schematic waveform diagram of the voltage across the first switch and the voltage across the resistance characteristic module provided in the present application. As shown in FIG. 9, from the driving signal of the first switch S1 and the driving signal of the second switch S2, it can be obtained that: the first switch S1 and the second switch S2 are turned on complementary (that is, the first switch S1 and the second switch S2 are complementary switch), the second switch S2 is turned off when the first switch S1 is turned on, or the second switch S2 is turned on when the first switch S1 is turned off. For the first switch S1 and the second switch S2 as complementary switches, in order to prevent the first switch S1 and the second switch S2 from being turned on at the same time, it is necessary to add a dead time between the first switch S1 and the second switch S2, Such as t _D1 or t _D2 , where t _D1 may be the dead time from the moment when the first switch S1 is turned off to the moment when the second switch S2 is turned on, and t _D2 may be the time from when the second switch S2 is turned off to the moment when the second switch S2 is turned on. A dead time between switch S1 conduction moments. The above control module 40 can control the first switch S1 and the second switch S2 to be turned on or off based on the driving signal of the first switch S1 and the driving signal of the second switch S2 as shown in FIG. 9 . Further, the control module 40 can start to detect the voltage across the resistance characteristic module 20 after the second switch S2 is turned off. At this time, the voltage waveform corresponding to the voltage across the resistance characteristic module 20 (which can be expressed as Vdec) can be as follows: As shown in FIG. 9 , the voltage Vdec at both ends of the resistance characteristic module 20 can be used to indicate the voltage slope (that is, Vdec∝dVdssw/dt) obtained after deriving the voltage at both ends of the first switch S1 (which can be expressed as Vdssw) with respect to time t, Therefore, based on the voltage Vdec at both ends of the resistance characteristic module 20, it can be determined whether the first switch S1 achieves zero-voltage conduction, wherein the time t_detect1 and time t_detect1 can represent the duration of detecting zero-voltage conduction in different cycles, and this cycle is the first switch S1. and the switching cycle of the complementary conduction of the second switch S2.

In some feasible implementation manners, the above-mentioned

resonant converter

1 , 2 or 3 further includes a timing module (such as a timer), and the timing module can be connected to the control module 40 . Optionally, the timing module can also be integrated into the control module 40, which can be determined according to actual application scenarios, and is not limited here. In the process of detecting the voltage across the resistance characteristic module 20, the above-mentioned control module 40 can control the timing module to start timing when the voltage across the resistance characteristic module 20 is greater than the second voltage threshold, and the voltage across the resistance characteristic module 20 When it is equal to the third voltage threshold, the timing module is controlled to stop timing, so as to obtain the duration of the voltage across the resistance characteristic module 20 (the duration t _hold shown in FIG. 9 ). Wherein, the above-mentioned second voltage threshold (voltage threshold V3 as shown in FIG. 9 ) is smaller than the third voltage threshold (voltage threshold V4 as shown in FIG. 9 ), where both the second voltage threshold and the third voltage threshold can be user Parameters set, or parameters configured in the resonant converter. After obtaining the duration, the control module 40 determines that the first switch S1 has achieved zero-voltage conduction when the duration is greater than the preset duration threshold, and controls the timing module to reset the duration to zero, so as to detect the first switch in the next cycle Whether S1 achieves zero voltage conduction. Wherein, the preset duration threshold may be a parameter set by a user, or a parameter configured in the resonant converter. Conversely, the above-mentioned control module 40 determines that the first switch S1 has achieved zero-voltage conduction when the duration is less than or equal to the preset duration threshold, and controls the timing module to reset the duration, so as to detect the first switch S1 in the next cycle. Whether to achieve zero voltage conduction.

Optionally, in some feasible implementation manners, the above-mentioned control module 40 can control the timing module to start timing when the voltage across the resistance characteristic module 20 is greater than the second voltage threshold, and detect that the resistance characteristic module timed by the timing module When the duration of the voltage at both ends of 20 is greater than the second voltage threshold is greater than the preset duration threshold, it is determined that the first switch S1 has achieved zero voltage conduction, wherein the timing module can stop when the voltage at both ends of the resistance characteristic module is equal to the third voltage threshold timing. In the case that the first switch S1 does not achieve zero-voltage conduction before the timing module stops timing, the above-mentioned control module 40 can obtain the duration when the timing module stops timing, and determine the duration of the first switch when the duration is greater than the preset duration threshold. S1 has achieved zero-voltage conduction, and controls the timing module to reset the duration to zero, so as to detect whether the first switch S1 achieves zero-voltage conduction in the next cycle. Conversely, the above-mentioned control module 40 determines that the first switch S1 has not achieved zero-voltage conduction when the duration is less than or equal to the preset duration threshold, and controls the timing module to reset the duration, so as to detect the first switch S1 in the next cycle. Whether to achieve zero voltage conduction.

In some feasible implementation manners, the above-mentioned control module 40 may, when it is detected that the first switch S1 realizes zero-voltage conduction in the i-th period, determine the conduction duration of the second switch S2 in the i+1-th period Adjust to obtain the adjusted conduction period (such as reducing the conduction period of the second switch S2 in the i+1th period), so that the first switch S1 realizes zero-voltage conduction in the i+1th period Pass. Wherein, i can be a positive integer. At this time, the adjusted conduction duration can be the difference between the conduction duration of the second switch S2 in the i-th cycle and the preset conduction duration. This cycle can be understood as A switching cycle in which the first switch S1 and the second switch S2 are turned on complementary. The preset on-time duration here may be a parameter set by the user, or a parameter configured in the resonant converter. Optionally, the control module 40 may also adjust the conduction duration of the second switch S2 in the i+1 period when it detects that the first switch S1 has not achieved zero-voltage conduction in the i period. In order to obtain an adjusted conduction period (for example, increase the conduction period of the second switch S2 in the i+1th period), so that the first switch S1 realizes zero-voltage conduction in the i+1th period. Wherein, i is a positive integer. At this time, the adjusted on-time length is the cumulative value between the on-time length of the second switch S2 in the i-th cycle and the preset on-time length. This cycle can be the first switch S1 and the switching cycle of the complementary conduction of the second switch S2. After adjusting the conduction duration of the second switch S2 in the (i+1)th period, the above-mentioned control module 40 can detect in real time whether the first switch S1 realizes zero-voltage conduction in the (i+1)th period, thereby improving the resonance The conversion efficiency and stability of the converter are stronger.

Referring to FIG. 10 , FIG. 10 is a schematic flowchart of a method for controlling a resonant converter provided in the present application. The control method of the resonant converter provided by the present application is applicable to the control modules (such as the above-mentioned control Module 40), optionally, the control method of the resonant converter may also be applicable to quasi-resonant flyback circuit topology, as shown in FIG. 10, the method may include the following steps S101-step S102:

Step S101 , controlling the first switch and the second switch to be turned on or off based on a driving signal.

In some feasible implementation manners, the control module can generate a driving signal for controlling the turn-on or turn-off of the first switch and the second switch, and control the turn-on or turn-off of the first switch and the second switch based on the drive signal off, wherein the first switch and the second switch are complementary turned on. The driving signal here may be a pulse width modulation signal (that is, a PWM signal) of the first switch and the second switch. For example, the driving signal may be (10), wherein 1 is used to indicate that the first switch is turned on, and 0 is used to indicate that the second switch is turned off.

Step S102 , after the second switch is turned off, detect the voltage across the two terminals of the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module to determine whether the first switch realizes zero-voltage conduction.

In some feasible implementation manners, please refer to FIG. 11 . FIG. 11 is a schematic flowchart of detecting whether the first switch realizes zero-voltage conduction provided by the present application. As shown in FIG. 11 , the above control module can detect the voltage across the two ends of the resistance characteristic module after the preset delay time when the second switch is turned off, and determine the first switch when the voltage across the resistance characteristic module is greater than the first voltage threshold. Realize zero voltage conduction. At this time, the control module can also adjust the conduction duration of the second switch in the next cycle, and continue to detect whether the first switch realizes zero-voltage conduction in the next cycle. Alternatively, the control module may determine that the first switch has not achieved zero-voltage conduction when the voltage across the resistance characteristic module is less than or equal to the first voltage threshold, adjust the conduction duration of the second switch in the next cycle, and continue to detect the first switch. Whether the switch achieves zero voltage conduction in the next cycle.

In some feasible implementation manners, the above-mentioned resonant converter also includes a timing module, which can be connected to the control module. Optionally, the timing module can also be integrated in the control module, which can be determined according to actual application scenarios, and will not be described here. limit. Please refer to FIG. 12 . FIG. 12 is another schematic flowchart of detecting whether the first switch realizes zero-voltage conduction provided by the present application. As shown in Figure 12, the above-mentioned control module can detect the voltage across the two ends of the resistance characteristic module after the second switch is turned off, and control the timing module to start timing when the voltage across the resistance characteristic module is greater than the second voltage threshold, and when the resistance characteristic module When the voltage across the module is equal to the third voltage threshold, the timing module is controlled to stop timing to obtain the duration. Wherein, the second voltage threshold is smaller than the third voltage threshold. After obtaining the duration, the above control module can determine that the first switch has achieved zero-voltage conduction when the duration is greater than the preset duration threshold, adjust the conduction duration of the second switch in the next cycle, and continue to detect the first switch in the next cycle. Whether the cycle achieves zero voltage conduction. Alternatively, the control module may determine that the first switch has not achieved zero-voltage conduction when the duration is less than or equal to the preset duration threshold, and the control timing module resets the duration to zero, adjusts the conduction duration of the second switch in the next cycle, and continues Detecting whether the first switch realizes zero-voltage conduction in the next period.

Optionally, in some feasible implementation manners, the above-mentioned resonant converter further includes a timing module, and the timing module can be connected to the control module. The above-mentioned control module can detect the voltage at both ends of the resistance characteristic module after the second switch is turned off, and control the timing module to start timing when the voltage at both ends of the resistance characteristic module is greater than the second voltage threshold, and when the resistance measured by the timing module is detected It is determined that the first switch has achieved zero-voltage conduction when the duration for which the voltage across the characteristic module is greater than the second voltage threshold is greater than the preset duration threshold. Wherein, the timing module may stop timing when the voltage across the resistance characteristic module is equal to the third voltage threshold. In the case that the first switch has not achieved zero-voltage conduction before the timing module stops timing, the control module can obtain the duration when the timing module stops timing, and determine that the first switch has achieved when the duration is greater than the preset duration threshold Zero-voltage conduction, or determining that the first switch has not achieved zero-voltage conduction when the duration is less than or equal to the preset duration threshold. Further, the control module can also control the timing module to reset the duration to zero, so as to detect whether the first switch realizes zero-voltage conduction in the next period.

In some feasible implementation manners, the above-mentioned control module may adjust the conduction duration of the second switch in the i+1 period when it detects that the first switch achieves zero-voltage conduction in the i period. The adjusted conduction period is obtained (for example, reducing the conduction period of the second switch in the i+1th period). Wherein, i can be a positive integer, and the adjusted conduction duration here is the difference between the conduction duration of the second switch in the i-th cycle and the preset conduction duration, and the cycle can be the first switch and The switching period during which the second switch is complementary turned on. Optionally, the above control module may adjust the conduction duration of the second switch in the i+1 period to obtain the adjusted The conduction period of the second switch (for example, increasing the conduction period of the second switch in the i+1th cycle). Wherein, i is a positive integer, and the adjusted on-time length here is the accumulated value between the on-time length of the second switch in the i-th cycle and the preset on-time length. This cycle can be understood as the first switch and The switching period during which the second switch is complementary turned on. After adjusting the turn-on duration of the second switch in the i+1th cycle, the control module can detect in real time whether the first switch realizes zero-voltage conduction in the i+1th cycle, thereby improving the performance of the resonant converter. Transformation efficiency and stability, stronger applicability.

In the specific implementation, more operations performed by the control module in the control method of the resonant converter provided in this application can refer to the implementation performed by the control module in the resonant converter and its working principle shown in Fig. 2 to Fig. 9 , which will not be repeated here.

The above is only a specific implementation of the application, but the scope of protection of the application is not limited thereto. Anyone familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the application. Should be covered within the protection scope of this application. Therefore, the protection scope of the present application should be determined by the protection scope of the claims.

Claims

A resonant converter, characterized in that the resonant converter includes a DC power supply, a first switch, a second switch, a capacitor, a transformer, a resistance characteristic module, a capacitance characteristic module, and a control module, wherein the first switch and The second switch is connected in parallel with the DC power supply after being connected in series, the capacitor is connected in parallel with the second switch after being connected in series with the transformer, and the resistance characteristic module and the capacitance characteristic module are connected in series with the first switch connected in parallel, the negative pole of the DC power supply is grounded;

The control module is connected to the first switch, the second switch and the resistance characteristic module, and is used to control the turn-on or turn-off of the first switch and the second switch based on a driving signal;

The control module is further configured to detect the voltage across the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module after the second switch is turned off.
The resonant converter according to claim 1, wherein the control module is configured to detect the voltage across the two terminals of the resistance characteristic module after a preset delay time when the second switch is turned off, and When the voltage across the resistance characteristic module is greater than the first voltage threshold, it is determined that the first switch has achieved zero-voltage conduction.
The resonant converter according to claim 1, wherein the resonant converter further comprises a timing module, and the timing module is connected to the control module;

The control module is configured to detect the voltage across the resistance characteristic module after the second switch is turned off, and control the timing module to start timing when the voltage across the resistance characteristic module is greater than a second voltage threshold, and controlling the timing module to stop timing to obtain the duration when the voltage across the resistance characteristic module is equal to a third voltage threshold, wherein the second voltage threshold is smaller than the third voltage threshold.
The resonant converter according to claim 3, wherein the control module is configured to determine that the first switch has achieved zero-voltage conduction when the duration is greater than a preset duration threshold.
The resonant converter according to claim 1, wherein the resonant converter further comprises a timing module, and the timing module is connected to the control module;

The control module is configured to detect the voltage across the resistance characteristic module after the second switch is turned off, and control the timing module to start timing when the voltage across the resistance characteristic module is greater than a second voltage threshold, and determining that the first switch has achieved zero-voltage conduction when it is detected that the voltage across the resistance characteristic module timed by the timing module is greater than the second voltage threshold for a duration longer than the preset duration threshold, wherein the The timing module stops timing when the voltage across the resistance characteristic module is equal to the third voltage threshold.
The resonant converter according to any one of claims 1-5, wherein the control module is further configured to, when it is detected that the first switch achieves zero-voltage Adjusting the conduction duration of the second switch in the i+1th period to obtain the adjusted conduction duration;

Wherein, the adjusted conduction duration is the difference between the conduction duration of the second switch in the ith period and the preset conduction duration, and the period is the first switch and the preset conduction duration. The switching period during which the second switch is turned on complementary.
The resonant converter according to any one of claims 1-5, wherein the control module is further configured to: Adjusting the conduction duration of the second switch in the i+1th period to obtain the adjusted conduction duration;

Wherein, the adjusted conduction duration is an accumulated value between the conduction duration of the second switch in the ith period and a preset conduction duration, and the period is the first switch and the preset conduction duration. The switching period during which the second switch is turned on complementary.
The resonant converter according to any one of claims 1-7, wherein the resistance characteristic module includes resistors, diodes, triodes, insulated gate bipolar transistors (IGBTs), metal oxide semiconductor field effect transistors (MOSFETs) and/or or GaN tubes.
The resonant converter according to any one of claims 1-8, wherein the capacitive characteristic module includes capacitors, diodes, MOSFETs, gallium nitride tubes and/or silicon carbide tubes.
A resonant converter, characterized in that the resonant converter includes a DC power supply, a first switch, a second switch, a capacitor, a transformer, a resistance characteristic module, a capacitance characteristic module, and a control module, wherein the first switch The first pole is connected to the first pole of the DC power supply, the second pole of the first switch is connected to one end of the transformer, the other end of the transformer is connected to the second pole of the DC power supply, the capacitor and the The second switch is connected in parallel with the transformer after being connected in series, the resistance characteristic module and the capacitance characteristic module are connected in parallel with the first switch after being connected in series, the negative pole of the DC power supply is grounded, and the negative pole of the DC power supply is the The first pole or the second pole of the DC power supply;

The control module is connected to the first switch, the second switch and the resistance characteristic module, and is used to control the turn-on or turn-off of the first switch and the second switch based on a driving signal;

The control module is further configured to detect the voltage across the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module after the second switch is turned off.
A resonant converter, characterized in that the resonant converter includes a DC power supply, a first switch, a second switch, a capacitor, a transformer, a resistance characteristic module, a capacitance characteristic module, and a control module, wherein the first switch The first pole is connected to the first pole of the DC power supply, the second pole of the first switch is connected to one end of the transformer, the other end of the transformer is connected to the second pole of the DC power supply, and the second switch The first pole of the capacitor is connected to one end of the capacitor and then grounded, the other end of the capacitor is connected to the second pole of the second switch through the auxiliary winding in the transformer, the negative pole of the DC power supply is grounded, and the DC The negative pole of the power supply is the first pole or the second pole of the DC power supply;

The control module is connected to the first switch, the second switch and the resistance characteristic module, and is used to control the turn-on or turn-off of the first switch and the second switch based on a driving signal;

The control module is further configured to detect the voltage across the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module after the second switch is turned off.
A control method for a resonant converter, characterized in that the method is suitable for a resonant converter, and the resonant converter includes a DC power supply, a first switch, a second switch, a capacitor, a transformer, a resistance characteristic module, and a capacitance characteristic module and a control module, wherein the first switch is connected in parallel with the DC power supply after being connected in series with the second switch, the capacitor is connected in parallel with the second switch after being connected in series with the transformer, and the resistance characteristic module and the The capacitance characteristic module is connected in parallel with the first switch after being connected in series, the negative pole of the DC power supply is grounded, and the control module is connected to the first switch, the second switch and the resistance characteristic module; the method includes:

controlling the first switch and the second switch to be turned on or off based on a driving signal;

Detecting the voltage across both ends of the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module after the second switch is turned off.
The method according to claim 12, wherein the detecting the voltage across the resistance characteristic module after the second switch is turned off comprises:

Detecting the voltage across the resistance characteristic module after a preset delay period for turning off the second switch, and determining that the first switch has been implemented when the voltage across the resistance characteristic module is greater than a first voltage threshold Zero voltage conduction.
The method according to claim 12, wherein the resonant converter further includes a timing module, the timing module is connected to the control module; the module for detecting the resistance characteristic after the second switch is turned off The voltage at both ends of the resistance characteristic module and the duration of the voltage at both ends of the module include:

After the second switch is turned off, the voltage at both ends of the resistance characteristic module is detected, and when the voltage at both ends of the resistance characteristic module is greater than the second voltage threshold, the timing module is controlled to start counting, and when the resistance characteristic module When the voltage across the module is equal to a third voltage threshold, control the timing module to stop timing to obtain the duration of the voltage across the resistance characteristic module, wherein the second voltage threshold is smaller than the third voltage threshold;

It is determined that the first switch has achieved zero-voltage conduction when the duration is greater than a preset duration threshold.
The method according to claim 12, wherein the resonant converter further includes a timing module, the timing module is connected to the control module; the module for detecting the resistance characteristic after the second switch is turned off The voltage at both ends of the resistance characteristic module and the duration of the voltage at both ends of the module include:

Detecting the voltage across the resistance characteristic module after the second switch is turned off, and controlling the timing module to start timing when the voltage across the resistance characteristic module is greater than a second voltage threshold;

It is determined that the first switch has achieved zero-voltage conduction when it is detected that the voltage across the resistance characteristic module timed by the timing module is greater than the second voltage threshold for a duration greater than the preset duration threshold, wherein the timing The module stops timing when the voltage across the resistance characteristic module is equal to the third voltage threshold.
The method according to any one of claims 12-15, wherein the method further comprises:

When it is detected that the first switch realizes zero-voltage conduction in the i-th period, adjusting the conduction duration of the second switch in the i+1 period to obtain an adjusted conduction duration;

Wherein, the adjusted conduction duration is the difference between the conduction duration of the second switch in the ith period and the preset conduction duration, and the period is the first switch and the preset conduction duration. The switching period during which the second switch is turned on complementary.
The method according to any one of claims 12-15, wherein the method further comprises:

When it is detected that the first switch does not achieve zero-voltage conduction in the i-th period, adjusting the conduction period of the second switch in the i+1 period to obtain an adjusted conduction period ;

Wherein, the adjusted conduction duration is an accumulated value between the conduction duration of the second switch in the ith period and a preset conduction duration, and the period is the first switch and the preset conduction duration. The switching period during which the second switch is turned on complementary.
A control method for a resonant converter, characterized in that the method is suitable for a resonant converter, and the resonant converter includes a DC power supply, a first switch, a second switch, a capacitor, a transformer, a resistance characteristic module, and a capacitance characteristic module and the control module, wherein the first pole of the first switch is connected to the first pole of the DC power supply, the second pole of the first switch is connected to one end of the transformer, and the other end of the transformer is connected to the The second pole of the DC power supply, the capacitor and the second switch are connected in parallel to the transformer after being connected in series, the resistance characteristic module and the capacitance characteristic module are connected in parallel to the first switch after being connected in series, and the DC power supply The negative pole is grounded, the negative pole of the DC power supply is the first pole or the second pole of the DC power supply, and the control module is connected to the first switch, the second switch and the resistance characteristic module;

The methods include:

controlling the first switch and the second switch to be turned on or off based on a driving signal;

Detecting the voltage across the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module after the second switch is turned off.
A control method for a resonant converter, characterized in that the method is suitable for a resonant converter, and the resonant converter includes a DC power supply, a first switch, a second switch, a capacitor, a transformer, a resistance characteristic module, and a capacitance characteristic module and the control module, wherein the first pole of the first switch is connected to the first pole of the DC power supply, the second pole of the first switch is connected to one end of the transformer, and the other end of the transformer is connected to the The second pole of the DC power supply, the first pole of the second switch is connected to one end of the capacitor and then grounded, and the other end of the capacitor is connected to the second pole of the second switch through the auxiliary winding in the transformer , the negative pole of the DC power supply is grounded, the negative pole of the DC power supply is the first pole or the second pole of the DC power supply, and the control module is connected to the first switch, the second switch and the resistance characteristic module; the method comprising:

controlling the first switch and the second switch to be turned on or off based on a driving signal;

Detecting the voltage across the resistance characteristic module and/or the duration of the voltage across the resistance characteristic module after the second switch is turned off.
A power adapter, characterized in that the power adapter includes an AC/DC conversion module and the resonant converter according to any one of claims 1-11 connected to the AC/DC conversion module;

The AC/DC conversion module is configured to output a first DC voltage to the resonant converter based on the AC voltage provided by the power grid;

The resonant converter is used to convert the first DC voltage into a second DC voltage to supply power to a load.