WO2018019095A1

WO2018019095A1 - Control method and device for resonant converter

Info

Publication number: WO2018019095A1
Application number: PCT/CN2017/091665
Authority: WO
Inventors: 冯宇; 李秋实; 王陶; 张南山
Original assignee: 中兴通讯股份有限公司
Priority date: 2016-07-29
Filing date: 2017-07-04
Publication date: 2018-02-01
Also published as: CN107666244B; CN107666244A

Abstract

A control method and device for a resonant converter. The control method comprises: acquiring a drive signal regulation quantity and a current output voltage for a resonant converter under a load condition at a current moment (S301, S501); according to the drive signal regulation quantity and the current output voltage, selecting a current drive state of the resonant converter (S302, S502); and regulating, under a current drive state, a duty cycle and an operation frequency of a drive signal for the resonant converter to a target duty cycle and a stable operation frequency, respectively (S303, S504). The control method and device can avoid the situation where an operation frequency of a drive signal for a resonant converter increases constantly or the resonant converter is in an unstable state when a load changes, thereby reducing the switching loss of the resonant converter.

Description

Control method and device for resonant converter

Technical field

Embodiments of the present invention relate to a resonant power conversion technique, and in particular, to a control method and apparatus for a resonant converter.

Background technique

With the advancement of power conversion technology, power supplies are moving toward high efficiency and high power density. Resonant converters are widely used in switching power supply technology due to their advantages of soft switching, high efficiency, high operating frequency and small size. Taking LLC (abbreviation of Lr, Lm, Cr, which respectively represent resonant inductance, magnetizing inductance and resonant capacitance in resonance parameters) as an example, when the resonant element on the converter operates in a sinusoidal resonance state, on the switch tube The voltage naturally crosses zero, and the zero voltage turn-on and turn-off of the primary side switching tube can be realized in the range of frequency conversion, so the power loss is small, and the application of the LLC resonant converter is more and more widely used.

As shown in Fig. 1, according to the basic operating characteristics of the LLC resonant converter, the LLC series resonant converter is near the resonant frequency point, and the operating frequency of the driving signal of the resonant converter is increased or decreased, and the current output voltage gain is lowered. As shown in Fig. 2, under normal circumstances, the LLC resonant converter is in the state of constant voltage loop. As the load increases, the LLC resonant converter enters the limited power state, the current limiting state and the retracted state, and the current output voltage. The set voltage value Vset is continuously decreased, and at this time, the operating frequency of the driving signal of the LLC resonant converter is continuously increased, thereby causing an increase in the switching loss of the LLC resonant converter.

It can be seen that the resonant converter has a large switching loss when the load is low.

Summary of the invention

An object of the embodiments of the present invention is to provide a control method and apparatus for a resonant converter, which solves the problem that a resonant converter has a large switching loss when a large load is low.

In order to achieve the above object, an embodiment of the present invention provides a control method for a resonant converter, including:

Acquiring a driving signal adjustment amount and a current output voltage of the resonant converter at a current time load state;

Selecting a current driving state of the resonant converter according to the driving signal adjustment amount and the current output voltage;

And adjusting a duty ratio and an operating frequency of the driving signal of the resonant converter to a target duty ratio and a stable operating frequency, respectively, in the current driving state.

Embodiments of the present invention provide a control device for a resonant converter, including:

a processing module, configured to acquire a driving signal adjustment amount and a current output voltage of the resonant converter under a current time load state;

Selecting a module, configured to select a current driving state of the resonant converter according to the driving signal adjustment amount and the current output voltage;

And an adjustment module configured to adjust a duty ratio and an operating frequency of the driving signal of the resonant converter to a target duty ratio and a stable operating frequency, respectively, in the current driving state.

The embodiment of the present invention further provides a computer storage medium, where the computer storage medium stores one or more programs executable by a computer, and when the one or more programs are executed by the computer, the computer is executed as described above. A control method for a resonant converter is provided.

According to still another embodiment of the present invention, there is also provided a storage medium comprising a stored program, wherein the program is executed to perform the method of any of the above.

One of the above technical solutions has the following advantages or benefits:

In the embodiment of the present invention, the driving signal adjustment amount and the current output voltage of the resonant converter are acquired in a current time load state; and the current current of the resonant converter is selected according to the driving signal adjustment amount and the current output voltage. a driving state; adjusting a duty ratio and an operating frequency of the driving signal of the resonant converter to a target duty ratio and a stable operating frequency, respectively, in the current driving state. It is possible to avoid an increase in the operating frequency of the drive signal of the resonant converter when the load changes or to make the resonant converter unstable, thereby reducing the switching loss of the resonant converter.

DRAWINGS

The drawings described herein are intended to provide a further understanding of the invention, and are intended to be a part of the invention. In the drawing:

1 is a topological structural diagram of a main circuit of a prior art half-bridge LLC series resonant converter;

2 is an output load characteristic curve of a prior art half bridge LLC resonant converter;

3 is a schematic flow chart of a method for controlling a resonant converter according to an embodiment of the present invention;

4 is a structural diagram of a control loop of a resonant converter according to an embodiment of the present invention;

FIG. 5 is a schematic flowchart diagram of another method for controlling a resonant converter according to an embodiment of the present disclosure;

6 is a diagram showing a correspondence relationship between a duty ratio of a driving signal of a resonant converter and an operating frequency according to an embodiment of the present invention;

FIG. 7 is a flowchart of an application example of a control method of a resonant converter when a load is increased according to an embodiment of the present invention; FIG.

FIG. 8 is a schematic structural diagram of a control device for a resonant converter according to an embodiment of the present invention; FIG.

FIG. 9 is a schematic structural diagram of a selection module according to an embodiment of the present invention;

FIG. 10 is a schematic structural diagram of a first selection unit according to an embodiment of the present disclosure;

FIG. 11 is a schematic structural diagram of another selection module according to an embodiment of the present disclosure;

FIG. 12 is a schematic structural diagram of a processing module according to an embodiment of the present invention.

detailed description

The invention will be described in detail below with reference to the drawings in conjunction with the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict.

It is to be understood that the terms "first", "second" and the like in the specification and claims of the present invention are used to distinguish similar objects, and are not necessarily used to describe a particular order or order.

In order to make the technical problems, technical solutions and advantages to be solved by the embodiments of the present invention more clear, The detailed description will be made in conjunction with the drawings and specific embodiments.

As shown in FIG. 3, the embodiment provides a schematic flowchart of a control method of a resonant converter, including the following steps:

Step S301: Acquire a driving signal adjustment amount and a current output voltage of the resonant converter in a current state load state.

In this embodiment, the driving signal adjustment amount of the resonant converter may be equivalent to one of the driving signal operating frequency value f and the driving signal working period value T, and the two satisfy the relationship f=1/T. If the driving signal adjustment amount is equivalent to the driving signal operating frequency, the driving signal adjustment amount is increased, that is, the driving signal operating frequency is increased at this time, and the driving signal working period is decreased, and vice versa.

Wherein, the current output voltage of the resonant converter and the adjustment amount of the driving signal may be obtained by data acquisition on the resonant converter, by extracting or calculating from the sampled data.

Step S302: Select a current driving state of the resonant converter according to the driving signal adjustment amount and the current output voltage.

Wherein, when the load changes, the driving signal adjustment amount of the resonant converter and the current output voltage may change correspondingly, which may cause the operating frequency of the driving signal of the resonant converter to change. For example, as shown in FIG. 2, under normal circumstances, the LLC resonant converter is in a state of constant voltage loop load, and as the load continues to increase, the LLC resonant converter sequentially enters a limited power state, a current limiting state, and a retracted state. The output voltage continues to drop, and the operating frequency of the drive signal of the LLC resonant converter increases.

In this embodiment, the resonant converters can respectively operate in a plurality of driving states, the plurality of driving states corresponding to different duty ratios, and different driving states have different adjustment intervals, voltage intervals, and operating frequency intervals. . When the load changes, the operating frequency of the drive signal of the resonant converter can be adjusted to a stable operating frequency by selecting the current driving state of the resonant converter even if it is operating in a driving state of a suitable duty cycle. For example, when the load is continuously increased, if the operating frequency of the driving signal of the resonant converter cannot be adjusted to a stable operating frequency in the operating frequency range of the current driving state of the resonant converter, it is necessary to adjust the The drive state flag of the resonant converter switches its drive state to make it at the duty cycle The operating frequency of the drive signal of the resonant converter is adjusted to be stable in the operating frequency range of the small driving state.

The selection of the current driving state of the resonant converter according to the driving signal adjustment amount and the current output voltage may be understood as the driving signal adjustment amount and the current output voltage and each of the resonant converters. Comparing the preset conditions of the driving state, selecting a driving state in which the operating frequency of the driving signal of the resonant converter is stable is the current driving state, that is, adjusting the driving state flag of the resonant converter to the driving of the current driving state. Status flag. For example, if the driving signal adjustment amount and the current output voltage reach a preset condition of a certain driving state, the driving state may be selected as the current driving state of the resonant converter. The preset condition may be a preset adjustment amount threshold and a voltage threshold, or may be a preset adjustment amount interval and a voltage interval.

Step S303, adjusting a duty ratio and an operating frequency of the driving signal of the resonant converter to a target duty ratio and a stable operating frequency, respectively, in the current driving state.

In this embodiment, the target duty ratio is a duty ratio corresponding to a current driving state of the resonant converter. The stable operating frequency is a target operating frequency of the driving signal of the resonant converter under the current load, and the stable operating frequency of the driving signal of the resonant converter is different under different loads. When the control loop of the resonant converter determines the current driving state, the driving signal operating frequency and duty ratio of the resonant converter may be adjusted in the current driving state to determine a stable operating frequency and a target duty ratio. Thus, the output drive signal drives the resonant converter to operate, causing the resonant converter to output a stable voltage and current.

In the present embodiment, the above control method of the resonant converter can be realized by the control loop of the resonant converter shown in FIG. As shown in FIG. 4, the current analog output signal of the resonant converter is collected by the signal collector as a feedback signal, such as a current output voltage signal and an output current signal, and the feedback signal is preset with a preset reference value such as a voltage set in the memory. The fixed value, the current limit value and the limited power value are compared, and the driving signal adjustment amount is calculated by the controller, and then the driving signal adjustment amount and the current output voltage are compared with the preset adjustment amount threshold value and the voltage threshold value to determine the current driving. State, adjusting the operating frequency and duty cycle of the resonant converter drive signal Pulse Frequency Modulation (PFM) and Pulse Width Modulation (PWM), the output drive signal drives the resonant converter to operate.

In this embodiment, the driving signal adjustment amount and the current output voltage of the resonant converter are acquired in a current time load state; and the current current of the resonant converter is selected according to the driving signal adjustment amount and the current output voltage. a driving state; adjusting a duty ratio and an operating frequency of the driving signal of the resonant converter to a target duty ratio and a stable operating frequency, respectively, in the current driving state. It is possible to avoid an increase in the operating frequency of the drive signal of the resonant converter when the load changes or to make the resonant converter unstable, thereby reducing the switching loss of the resonant converter.

As shown in FIG. 5, FIG. 5 is a schematic flowchart diagram of another method for controlling a resonant converter according to an embodiment of the present invention. The control method of the resonant converter includes:

Step S501: Acquire a driving signal adjustment amount and a current output voltage of the resonant converter in a current state load state.

Wherein, the current output voltage of the resonant converter and the adjustment amount of the driving signal may be obtained by data acquisition on the resonant converter, by extracting or calculating from the sampled data. For example, optionally, the foregoing step S501 may include:

Collecting an analog output signal of the resonant converter under a load state at a current time as a feedback signal;

Acquiring, by the feedback signal, a current output voltage of the resonant converter;

A drive signal adjustment amount of the resonant converter is calculated by the feedback signal and a preset reference value.

In this embodiment, the analog output signal may be an analog current signal or an analog voltage signal.

When the analog output signal is an analog voltage signal, the current output voltage is directly obtained by the analog output signal; when the analog output signal is an analog current signal, the analog output signal is calculated by current-voltage conversion The current output voltage is obtained.

The driving signal adjustment amount may be obtained by using the feedback signal and the preset reference value, where the calculation is performed by a control algorithm, and the control algorithm may be A nonlinear control algorithm such as a proportional-integral-derivative control algorithm or a nonlinear control algorithm such as a fuzzy control algorithm is used. For example, the analog output signal can be used as a feedback signal, and then the proportional-integral algorithm is used to integrate the absolute value of the difference between the feedback signal and the preset reference value, and then multiply by a certain ratio to obtain the adjustment amount of the driving signal. The above process may be: comparing the detected digital value of the current output voltage or the output current with a preset reference value, and performing a proportional-integral operation on the comparison result to obtain the driving signal adjustment amount. The preset reference value may include a defined voltage value, a limited current value, a defined power value, and the like.

Step S502, determining whether the driving signal adjustment amount and the current output voltage are located in an adjustment amount interval and a voltage interval of the first driving state, wherein the first driving state is the resonance transformation in a load state at a previous time The drive state of the device.

In this embodiment, the resonant converters can be respectively operated in a plurality of driving states, the plurality of driving states each having different duty ratios, and the adjustment range and the voltage interval of the driving states of different duty ratios are also It will be different. The adjustment amount interval in each driving state includes two driving signal adjustment amount thresholds, respectively corresponding to the driving signal adjustment amount upper limit threshold value and the driving signal adjustment amount lower limit threshold value in the driving state, and the driving signal adjustment amount of the adjacent driving state is adopted. The hysteresis method, that is, the lower limit threshold of the driving signal adjustment amount of the lower duty cycle driving state is slightly larger than the upper threshold of the driving signal adjustment amount of the higher duty driving state, for preventing the driving state from being switched back and forth; in each driving state The voltage range also includes two output voltage thresholds, which respectively correspond to the output voltage upper threshold and the voltage output lower threshold in the driving state, and the output voltage threshold of the adjacent driving state may adopt a hysteresis method, that is, a lower account. The upper limit of the output voltage of the space ratio driving state is slightly larger than the lower limit of the output voltage of the higher duty driving state, and is used to prevent the driving state from switching back and forth.

The current time and the last time are two adjacent time nodes of the control loop detecting the working state of the resonant converter. The first driving state is a driving state of the resonant converter in a load state at a last time. In a load state of the last time, the operating frequency of the driving signal of the resonant converter in the first driving state is stable, and the driving signal adjustment amount of the resonant converter and the current output voltage are respectively located at the moment The adjustment amount interval and the voltage interval of the first driving state.

Determining whether the driving signal adjustment amount and the current output voltage are located in an adjustment amount interval and a voltage interval of the first driving state, may be understood as that the driving signal adjustment amount and the current output voltage are respectively related to the The two adjustment amount thresholds of the first driving state are compared with two voltage thresholds, that is, whether the driving signal adjustment amount is greater than or equal to the driving signal adjustment amount lower limit threshold of the first driving state and less than or equal to the driving signal adjustment amount. An upper threshold, the current output voltage being greater than or equal to an output voltage lower threshold of the first driving state and less than or equal to an output voltage upper threshold.

Step S503, if the driving signal adjustment amount is not located in the adjustment amount interval of the first driving state or the current output voltage is not located in the voltage range of the first driving state, the selection and the first driving state have A second driving state of different duty ratios is used as the current driving state.

In this embodiment, the second driving state is a driving state different from the first driving state, and the driving signal adjustment amount and the current output voltage of the resonant converter are respectively located in the second driving state at the current time. Adjust the amount interval and voltage range.

Wherein, as shown in FIG. 2, as the load increases, the resonant converter changes along the trend of the constant voltage loop, the constant power loop, the current limiting loop, and the retracting loop, and the driving signal is occupied according to the resonant characteristics of the resonant converter. In the case where the ratio remains unchanged, the operating frequency of the resonant converter is continuously increased, that is, the adjustment amount of the driving signal of the resonant converter is continuously increased, and the current output voltage is also continuously decreased. And when the adjustment amount of the driving signal of the resonant converter exceeds the adjustment amount interval of the first driving state or the current output voltage of the resonant converter exceeds the voltage interval of the first driving state, the resonance is required The driving state of the converter is switched from the first driving state to the second driving state, that is, the second driving state is selected as the current driving state of the resonant converter, and the driving state of the resonant converter is The flag bit is changed from the first drive state flag position to the second drive status flag bit.

For example, when the driving signal adjustment amount of the resonant converter exceeds the driving signal adjustment amount upper limit threshold of the first driving state, the resonant converter may be switched from the first driving state to having a small duty Ratio of drive state, and the current output voltage is located at this has a small duty The voltage range of the drive state of the ratio, at which time the drive state having a smaller duty ratio is the second drive state.

Similarly, when the load continues to decrease, the amount of adjustment of the driving signal of the resonant converter is continuously reduced, and the current output voltage of the resonant converter is continuously increased, and when the amount of driving signal adjustment of the resonant converter exceeds When the preset adjustment interval minimum value of the first driving state is described, it is necessary to switch the driving state of the resonant converter to the second driving state of the higher duty ratio, and change the operating frequency of the driving signal so that it does not grow. The time is in an unstable state with a large load, low operating frequency, and low duty cycle.

Optionally, the step S503 may include the following steps:

Determining the second driving state, wherein the second driving state and the first driving state have different duty ratios, and the driving signal adjustment amount and the current output voltage of the resonant converter are respectively located at the current time The adjustment amount interval and the voltage interval of the second driving state;

The second driving state is taken as the current driving state.

In this embodiment, the determining the second driving state may be: when the driving signal adjustment amount is not located in the adjustment amount interval of the first driving state or the current output voltage is not located in the first driving state Comparing the driving signal adjustment amount and the output voltage with an adjustment amount interval and a voltage interval of each driving signal having a different duty ratio from the first driving state, respectively, in the voltage interval, if the driving The signal adjustment amount and the adjustment amount interval and the voltage interval of the drive signal in which the output voltage is located in a certain driving state determine that the driving state is the second driving state.

The second driving state may be determined according to a relationship between the driving signal adjustment amount and the current output voltage respectively, and a relationship between two driving signal adjustment amount thresholds and two output voltage thresholds of the first driving state. . For example, if the driving signal adjustment amount is greater than the driving signal adjustment amount upper limit threshold of the first driving state or the current output voltage is smaller than the output driving lower threshold value of the first driving state, the selection has a smaller than the first driving a driving state of the duty ratio of the state as the second driving state; if the driving signal adjustment amount is smaller than a driving signal adjustment amount lower limit threshold of the first driving state or the current output voltage is greater than the first The output voltage upper limit threshold of the driving state selects a driving state having a duty ratio greater than the first driving state as the second driving state.

In addition, if the driving signal adjustment amount of the resonant converter at the current time is greater than the upper limit threshold of the driving signal adjustment amount in all driving states or less than the upper limit threshold of the driving signal adjustment amount in all driving states, the driving of the resonant converter at this time The operating frequency of the signal cannot be adjusted to a stable operating frequency in each driving state. In order to avoid damage to the switching tube of the resonant converter due to excessive adjustment of the driving signal in this state, the driving wave is turned off, and the resonant converter is controlled. The switch tube is turned off.

In this embodiment, the using the second driving state as the current driving state may be understood to be that the driving state flag of the resonant converter is from the first driving state flag position to the second driving state. Sign bit.

Optionally, after the step S502, the method may further include:

And if the driving signal adjustment amount and the current output voltage are both located in the adjustment amount interval and the voltage interval of the first driving state, selecting the first driving state as the current driving state.

In this embodiment, if the load of the resonant converter at the current time is constant or does not change much compared to the load at the previous moment, the adjustment amount of the driving signal and the current output voltage are still within the adjustment amount interval of the first driving state. Within the voltage interval, the resonant converter maintains the current driving state as the first driving state, and adjusts the operating frequency of the driving signal of the resonant converter at the same duty ratio.

Step S504, adjusting a duty ratio and an operating frequency of the driving signal of the resonant converter to a target duty ratio and a stable operating frequency, respectively, in the current driving state.

In this embodiment, when the current driving state is switched from the first driving state to the second driving state, that is, the driving state flag of the resonant converter is switched from the first driving state flag to When the second driving state flag is set, the duty ratio of the driving signal of the resonant converter is adjusted from the duty ratio corresponding to the first driving state to the duty ratio corresponding to the second driving state, and Adjusting a drive signal adjustment amount of the resonant converter from the second drive The driving signal adjustment amount lower limit threshold of the state is changed to the driving signal adjustment amount upper limit threshold, and the operating frequency of the adjustment driving signal is changed from the minimum operating frequency of the second driving state to the maximum operating frequency.

Optionally, the operating frequency of the driving signal of the resonant converter is adjusted by using a fixed-width modulation mode in the current driving state.

Wherein, in the current driving state, the operating frequency of the driving signal of the resonant converter is adjusted by using a fixed-width frequency modulation mode, so that the operating frequency of the driving signal of the resonant converter can be quickly adjusted to a stable state, so that the The resonant converter outputs a stable output voltage.

The implementation process of the control method of the resonant converter can be exemplified by the application examples shown in FIG. 6 and FIG. 7. Of course, the application example only exemplifies a situation that can be implemented by the embodiment of the present invention. For the other embodiments, which are identical or similar to the implementation principles of the embodiments of the present invention, the scope of protection of the present invention is not limited herein.

As shown in FIG. 6, the driving state of the resonant converter is divided into five driving states of the driving state 1, the driving state 2, the driving state 3, the driving state 4, and the driving state 5 according to the duty ratio and the voltage interval. The duty ratios of the driving state 1, the driving state 2, the driving state 3, the driving state 4, and the driving state 5 are sequentially D1, D2, D3, D4, and D5, and may be preset to D1>D2>D3>D4> D5, wherein the driving state 1, the driving state 2, and the driving state 3 may be in a driving state of a constant voltage loop, a constant power loop, or a current limiting loop, and the voltage ranges of the three driving states are both [V ₀ min, V ₀ max], where V ₀ max corresponding output voltage upper-limit threshold value of the driving state, the maximum output voltage of the resonant converter, V ₀ min to correspond to a voltage lower threshold value in the driving state, a cycloalkyl stage a voltage limiting And the driving state 4 and the driving state 5 may be a driving state in a current limiting ring or a retracting ring, and the voltage ranges of the two driving states are [V ₄ min, V ₄ max] and [V ₅ min respectively , V ₅ max], which are limited to a certain voltage value of the phase rings or ring retracts, may generally V ₅ min 0V, and the driving state may be a predetermined upper limit voltage 4 V ₄ max threshold value is greater than the driving state 1, state 2 and the driving state of the driving voltage of the lower threshold of 3 V ₀ min, i.e., V ₄ min <V ₀ min < V ₄ max<V ₀ max, the upper voltage threshold V ₅ max of the driving state _{5 is} greater than the lower voltage threshold V ₄ min of the driving state 4, that is, V ₅ min<V ₄ min <V ₅ max<V ₀ min ; thus causing hysteresis between adjacent voltage intervals to prevent back and forth switching. The preset individual voltage thresholds can be based on the resonant converter circuit parameters and actual operation.

The operating frequency interval of the drive signal of the resonant converter is set to [f _min , f _max ], the resonance frequency point is f _r , and f _min <f _r . At the same time, according to the duty ratio and the operating frequency interval, the driving signal adjustment amount lower limit threshold value and the driving signal adjustment amount upper limit threshold value of the five driving states are respectively preset, that is, the adjustment amount intervals of the five driving states are set to [P ₁ min respectively]. , P ₁ max], [P ₂ min, P ₂ max], [P ₃ min, P ₃ max], [P ₄ min, P ₄ max], [P ₅ min, P ₅ max], the adjustment threshold is increasing Large, P ₁ min is the minimum of all the driving signal adjustment thresholds, P ₅ max is the maximum of all the driving signal adjustments, but there is a hysteresis between the adjacent state adjustment thresholds, such as the relationship between the driving states 1 and 2 P ₁ min<P ₂ min<P ₁ max<P ₂ max, that is, the lower limit threshold of the driving signal adjustment amount of the driving state 2 is larger than the upper limit threshold of the driving signal adjustment amount of the driving state 1, so that the resonant converter is in the driving states 1 and 2 The critical point between them switches back and forth. Wherein, the five driving states adopt a fixed-width frequency modulation mode.

As shown in FIG. 7, when the load is continuously increased, the driving signal adjustment amount P of the resonant converter is continuously increased at the present moment, and the control implementation process for the resonant converter is as follows:

When the first driving state is the driving state 1, if the adjustment amount P is less than or equal to the driving signal adjustment amount upper limit threshold P ₁ max of the driving state 1, and the current output voltage is in the voltage threshold range [V ₀ min, V ₀ max In the driving state 1, the driving state 1 is the current driving state, and in the driving state 1, the operating frequency fs of the driving signal of the resonant converter is changed from fmin to fmax, and the duty ratio of the driving signal is D1 to determine Stabilizing the operating frequency to cause the resonant converter to output a stable voltage; if the adjustment amount P is greater than the driving signal adjustment amount upper limit threshold P ₁ max, and the current output voltage is within the voltage threshold range [V ₀ min, V ₀ max], switching the said The current driving state is driving state 2, and the operating frequency fs of the driving signal of the resonant converter is adjusted from f ₁ to f ₂ in the driving state 2, and the duty ratio of the driving signal is D2, thereby avoiding the resonant converter operating frequency fs of the drive signal exceeds its allowable maximum value f _max; when the first driving state is the driving state 2, if the resonant converter drive signal adjustment amount P continues to increase, and the driving signal modulation The amount of P is greater than the driving state of the drive signal adjustment amount upper threshold 2 P ₂ max, and the current output voltage of the voltage interval _{_{[V 0 min, V 0 max}} ] within, switches the current driving state is the driving state 3, the driving state 3 The operating frequency fs of the driving signal for adjusting the resonant converter is changed from f ₁ to f ₃ ; when the first driving state is the driving state 3, if the driving signal adjustment amount P of the resonant converter continues to increase And when it is greater than the driving signal adjustment amount upper limit threshold P ₃ max of the driving state 3, at this time, if the current output voltage of the resonant converter satisfies V ₄ min ≤ Vout ≤ V ₄ max, the current driving state is switched as 4 driving state; if the current resonant converter if the output voltage satisfies V _₅ min≤Vout≤V ₅ max, the target driving state is switched to a driving state 5; 4 and 5, the driving state of the resonant converter regulator The subsequent driving signal operating frequency range is [f _min , f _max ], and when the driving signal adjustment amount P of the resonant converter continues to increase and is greater than P ₅ max, the driving wave is turned off. Of course, when the driving signal adjustment amount P of the resonant converter increases greatly, it is also possible to directly switch from the current driving state to any driving state in which the duty ratio is smaller than the duty ratio of the current driving state, such as by the driving state. 1 switches to the driving state 3, the driving state 4 or the driving state 5, and details are not described herein.

Similarly, when the load is reduced, the driving signal adjustment amount P of the resonant converter is continuously reduced, and the control implementation process for the resonant converter can be as follows:

When the first driving state is the driving state 5, the driving signal adjustment amount P decreases and is smaller than the driving signal adjustment amount lower limit threshold P ₅ min of the driving state 5, and the current output voltage is in the voltage threshold range [V ₀ min, V _{In the 0} max], the current driving state is switched to the driving state 3; when the first driving state is the driving state 3, the driving signal adjustment amount P is decreased and is smaller than the driving signal adjustment amount lower threshold P ₃ min of the driving state 3 And switching the current driving state to the driving state 2; when the first driving state is the driving state 2, the driving signal adjustment amount P is decreased and is smaller than the driving signal adjustment amount lower threshold P ₂ min of the driving state 2, switching The current driving state is driving state 1. When the drive signal adjustment amount P in the driving state of the resonant converter 1 continues to decrease to less than ₁ min P, the drive signal is adjusted so that an amount of P = P ₁ min, to achieve the capacity limit adjusting the resonant converter. In the above process, the driving signal operating frequency fs and the duty ratio D of the resonant converter may be adjusted in the current driving state to cause the resonant converter to output a stable voltage.

Of course, in this embodiment, the same can be applied to the embodiment shown in FIG. 3, and can be achieved. The same beneficial effect. In this embodiment, a plurality of optional implementation manners are added on the basis of the circuit shown in FIG. 3, and the first driving state is switched to have a different occupation according to the driving signal adjustment variable and the current output voltage of the current time resonant converter. The second driving state of the air ratio realizes that the operating frequency of the driving signal of the resonant converter is stabilized in the second driving state, thereby reducing the switching loss of the resonant converter.

As shown in FIG. 8, FIG. 8 is a schematic structural diagram of a control device for a resonant converter according to an embodiment of the present invention. The control device 80 of the resonant converter includes:

The processing module 81 is configured to acquire a driving signal adjustment amount and a current output voltage of the resonant converter in a current state load state;

The selecting module 82 is configured to select a current driving state of the resonant converter according to the driving signal adjustment amount and the current output voltage;

The adjustment module 83 is configured to adjust a duty ratio and an operating frequency of the driving signal of the resonant converter to a target duty ratio and a stable operating frequency, respectively, in the current driving state.

Optionally, as shown in FIG. 9, the selecting module 82 includes:

The determining unit 821 is configured to determine whether the driving signal adjustment amount and the current output voltage are located in an adjustment amount interval and a voltage interval of the first driving state, wherein the first driving state is a load state at a previous time The driving state of the resonant converter;

The first selecting unit 822 is configured to: if the driving signal adjustment amount is not located in the adjustment amount interval of the first driving state or the current output voltage is not located in the voltage range of the first driving state, The first driving state has a second driving state having a different duty ratio as the current driving state.

Optionally, as shown in FIG. 10, the first selecting unit 822 includes:

Determining the sub-unit 8221, configured to determine the second driving state, wherein the second driving state and the first driving state have different duty ratios, and the driving signal adjustment amount of the resonant converter at the current time And the current output voltage are respectively located in the adjustment amount interval and the voltage interval of the second driving state;

The selection subunit 8222 is arranged to use the second driving state as the current driving state.

Optionally, as shown in FIG. 11, the selecting module 82 further includes:

The second selection unit 823 is configured to select the first driving state as the current if the driving signal adjustment amount and the current output voltage are both located in the adjustment amount interval and the voltage interval of the first driving state. Drive status.

Optionally, as shown in FIG. 12, the processing module 81 includes:

The collecting unit 811 is configured to collect an analog output signal of the resonant converter under a load state at a current time as a feedback signal;

The voltage obtaining unit 812 is configured to acquire, by the feedback signal, a current output voltage of the resonant converter;

The adjustment amount calculation unit 813 is configured to calculate a drive signal adjustment amount of the resonance converter by the feedback signal and a preset reference value.

The control device 80 of the resonant converter can implement the various processes implemented by the resonant converter in the method embodiments of FIGS. 1 to 7 and achieve the same beneficial effects. To avoid repetition, details are not described herein again.

It will be understood by those skilled in the art that all or part of the steps of implementing the above embodiments may be performed by hardware associated with program instructions, which may be stored in a computer readable medium, including when executed, including The following steps:

Obtaining a driving signal adjustment amount and a current output voltage of the resonant converter in a load state at a current time;

Optionally, the selecting a current driving state of the resonant converter according to the driving signal adjustment amount and the current output voltage includes:

Determining whether the driving signal adjustment amount and the current output voltage are located in an adjustment amount interval and a voltage interval of the first driving state, wherein the first driving state is driving of the resonant converter in a load state at a previous time status;

If the driving signal adjustment amount is not located in the adjustment amount interval of the first driving state or the current output voltage is not located in the voltage range of the first driving state, selecting to have a different duty from the first driving state The second driving state of the ratio is taken as the current driving state.

Optionally, the selecting, as the current driving state, the second driving state that has a different duty ratio from the first driving state, includes:

The second driving state is taken as the current driving state.

Optionally, after the determining whether the driving signal adjustment amount and the current output voltage are located in the adjustment amount interval and the voltage interval of the first driving state, the method further includes:

Optionally, the obtaining the driving signal adjustment amount and the current output voltage of the resonant converter under the current time load state, including:

The storage medium is, for example, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

The above is a preferred embodiment of the present invention, and it should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the embodiments of the present invention. Retouching should also be considered as the scope of protection of the present invention.

Embodiments of the present invention also provide a storage medium including a stored program, wherein the program described above executes the method of any of the above.

Optionally, in the embodiment, the storage medium may be configured to store program code set to perform the following steps:

S1. Acquire a driving signal adjustment amount and a current output voltage of the resonant converter in a current state load state;

S2. Select a current driving state of the resonant converter according to the driving signal adjustment amount and the current output voltage.

S3. Adjust a duty ratio and an operating frequency of the driving signal of the resonant converter to a target duty ratio and a stable operating frequency, respectively, in the current driving state.

Optionally, the storage medium is further configured to store program code configured to perform the step of: selecting the current driving state of the resonant converter according to the driving signal adjustment amount and the current output voltage, comprising:

S1, determining whether the driving signal adjustment amount and the current output voltage are located in an adjustment amount interval and a voltage interval of the first driving state, wherein the first driving state is the resonant converter in a loading state at a last time Drive state

S2, if the driving signal adjustment amount is not located in the adjustment amount interval of the first driving state or the current output voltage is not located in the voltage range of the first driving state, the selection is different from the first driving state. The second driving state of the duty ratio is the current driving state.

Optionally, the storage medium is further configured to store program code configured to perform the step of: selecting the second driving state having a different duty ratio from the first driving state as the current driving state, comprising:

S1, determining the second driving state, wherein the second driving state and the first driving The dynamic state has different duty ratios, and the driving signal adjustment amount and the current output voltage of the resonant converter are respectively located in the adjustment amount interval and the voltage interval of the second driving state at the current time;

S2, the second driving state is taken as the current driving state.

Optionally, the storage medium is further configured to store program code set to perform the step of: determining whether the driving signal adjustment amount and the current output voltage are within an adjustment amount interval and a voltage interval of the first driving state ,Also includes:

S1. If the driving signal adjustment amount and the current output voltage are both located in the adjustment amount interval and the voltage interval of the first driving state, the first driving state is selected as the current driving state.

Optionally, the storage medium is further configured to store program code configured to perform the following steps: obtaining the driving signal adjustment amount and the current output voltage of the resonant converter under the current time load state, including:

S1, collecting an analog output signal of the resonant converter under a current load state as a feedback signal;

S2, obtaining, by the feedback signal, a current output voltage of the resonant converter;

S3. Calculate a driving signal adjustment amount of the resonant converter by using the feedback signal and a preset reference value.

Optionally, in the embodiment, the foregoing storage medium may include, but is not limited to, a USB flash drive, a Read-Only Memory (ROM), and a Random Access Memory (RAM). A variety of media that can store program code, such as a hard disk, a disk, or an optical disk.

Embodiments of the present invention also provide a processor configured to execute a program, wherein the program is operative to perform the steps of any of the above methods.

Optionally, in this embodiment, the foregoing program is configured to perform the following steps:

Optionally, in this embodiment, the foregoing program is configured to perform the following steps: selecting the current driving state of the resonant converter according to the driving signal adjustment amount and the current output voltage, including:

Optionally, in this embodiment, the foregoing program is configured to perform the following steps: the selecting, by using the second driving state that has a different duty ratio from the first driving state, as the current driving state, includes:

S1, determining the second driving state, wherein the second driving state and the first driving state have different duty ratios, and the driving signal adjustment amount and the current output voltage of the resonant converter at the current time are respectively Located in the adjustment amount interval and the voltage interval of the second driving state;

S2, the second driving state is taken as the current driving state.

Optionally, in this embodiment, the foregoing program is configured to perform the following steps: after determining whether the driving signal adjustment amount and the current output voltage are located in an adjustment amount interval and a voltage interval of the first driving state, include:

Optionally, in this embodiment, the foregoing program is configured to perform the following steps: The driving signal adjustment amount and the current output voltage of the resonant converter under the load state at the previous time include:

For example, the specific examples in this embodiment may refer to the examples described in the foregoing embodiments and the optional embodiments, and details are not described herein again.

It will be apparent to those skilled in the art that the various modules or steps of the present invention described above can be implemented by a general-purpose computing device that can be centralized on a single computing device or distributed across a network of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device such that they may be stored in the storage device by the computing device and, in some cases, may be different from the order herein. The steps shown or described are performed, or they are separately fabricated into individual integrated circuit modules, or a plurality of modules or steps thereof are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software.

The above description is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the scope of the present invention are intended to be included within the scope of the present invention.

Industrial applicability

In the embodiment of the present invention, the driving signal adjustment amount and the current output voltage of the resonant converter are acquired in a current time load state; and the current current of the resonant converter is selected according to the driving signal adjustment amount and the current output voltage. Drive state; adjusting the state in the current drive state The duty ratio and operating frequency of the drive signal of the resonant converter are respectively to the target duty ratio and the stable operating frequency. It is possible to avoid an increase in the operating frequency of the drive signal of the resonant converter when the load changes or to make the resonant converter unstable, thereby reducing the switching loss of the resonant converter.

Claims

A control method for a resonant converter, comprising:

Obtaining a driving signal adjustment amount and a current output voltage of the resonant converter in a load state at a current time;

Selecting a current driving state of the resonant converter according to the driving signal adjustment amount and the current output voltage;

And adjusting a duty ratio and an operating frequency of the driving signal of the resonant converter to a target duty ratio and a stable operating frequency, respectively, in the current driving state.
The control method according to claim 1, wherein said selecting a current driving state of said resonant converter according to said driving signal adjustment amount and said current output voltage comprises:

Determining whether the driving signal adjustment amount and the current output voltage are located in an adjustment amount interval and a voltage interval of the first driving state, wherein the first driving state is driving of the resonant converter in a load state at a previous time status;

If the driving signal adjustment amount is not located in the adjustment amount interval of the first driving state or the current output voltage is not located in the voltage range of the first driving state, selecting to have a different duty from the first driving state The second driving state of the ratio is taken as the current driving state.
The control method according to claim 2, wherein said selecting a second driving state having a different duty ratio from said first driving state as said current driving state comprises:

Determining the second driving state, wherein the second driving state and the first driving state have different duty ratios, and the driving signal adjustment amount and the current output voltage of the resonant converter are respectively located at the current time The adjustment range and the electric quantity of the second driving state Within the pressure interval;

The second driving state is taken as the current driving state.
The control method according to claim 2, wherein the determining whether the driving signal adjustment amount and the current output voltage are located in the adjustment amount interval and the voltage interval of the first driving state further comprises:

And if the driving signal adjustment amount and the current output voltage are both located in the adjustment amount interval and the voltage interval of the first driving state, the first driving state is selected as the current driving state.
The control method according to any one of claims 1 to 4, wherein the obtaining a driving signal adjustment amount and a current output voltage of the resonant converter in a current state load state includes:

Collecting an analog output signal of the resonant converter under a load state at a current time as a feedback signal;

Acquiring, by the feedback signal, a current output voltage of the resonant converter;

A drive signal adjustment amount of the resonant converter is calculated by the feedback signal and a preset reference value.
A control device for a resonant converter, comprising:

a processing module configured to obtain a driving signal adjustment amount and a current output voltage of the resonant converter in a current state of the load state;

Selecting a module, configured to select a current driving state of the resonant converter according to the driving signal adjustment amount and the current output voltage;

An adjustment module configured to adjust the resonant converter in the current driving state The duty cycle and operating frequency of the drive signal are respectively to the target duty cycle and the stable operating frequency.
The control device according to claim 6, wherein said selection module comprises:

a determining unit, configured to determine whether the driving signal adjustment amount and the current output voltage are located in an adjustment amount interval and a voltage interval of the first driving state, wherein the first driving state is the last time load state The driving state of the resonant converter;

The first selection unit is configured to select, if the driving signal adjustment amount is not located in the adjustment amount interval of the first driving state or the current output voltage is not located in the voltage range of the first driving state, A driving state has a second driving state having a different duty ratio as the current driving state.
The control device according to claim 7, wherein said first selection unit comprises:

Determining a subunit, configured to determine the second driving state, wherein the second driving state and the first driving state have different duty ratios, and a current driving signal adjustment amount of the resonant converter The current output voltage is respectively located in the adjustment amount interval and the voltage interval of the second driving state;

The subunit is selected to be set to use the second driving state as the current driving state.
The control device of claim 7, wherein the selection module further comprises:

a second selection unit, configured to select the first driving state as the current driving if the driving signal adjustment amount and the current output voltage are both located in an adjustment amount interval and a voltage interval of the first driving state status.
The control device according to any one of claims 6 to 9, wherein the processing module comprises:

An acquisition unit configured to collect a mode of the resonant converter under a load state at a current time The output signal is intended to be used as a feedback signal;

a voltage obtaining unit configured to acquire, by the feedback signal, a current output voltage of the resonant converter;

The adjustment amount calculation unit is configured to calculate a drive signal adjustment amount of the resonance converter by the feedback signal and a preset reference value.
A storage medium, the storage medium comprising a stored program, wherein the program is executed to perform the method of any one of claims 1 to 5.