TWI411204B - Resonance conversion device and control module of a resonance converter and method thereof - Google Patents

Abstract

A control method of a resonance converter for a control module is provided. The control module is coupled to the resonance converter to form a closed loop. The control module is configured to generate a driving signal, which is used for driving on-off of a power switch of the resonance converter. The control method detects a load, which is coupled to the resonance converter, and determines whether it is in a work loading range, if yes, directs the control module to generate the driving signal according to an output voltage Vo of the resonance converter, if no, directs the control module to generate the driving signal according to an output current Io of the resonance converter, thereby permitting the resonance converter to achieve a better output voltage linearity at the start-up time and the output current to remain constant when an over-loading or an output-short is happened.

Description

Control module and method for resonant converter and resonant converter

The present invention relates to a control method, and more particularly to a control method for a resonant converter.

Since the LLC resonant converter has the advantages of high efficiency, high power density, etc., it has been frequently used in recent years to generate power sources for various electronic devices (for example, communication devices).

1 is a conventional half-bridge LLC resonant converter 900. The LLC resonant converter 900 is switched between a first power switch Q1 and a second power switch Q2 to control the LLC resonant converter 900. There is a stable output voltage Vo.

However, when the load RL coupled to the conventional half bridge LLC resonant converter 900 is too large, or the output of the LLC resonant converter 900 is shorted, the LLC resonant converter 900 may output excessive current, which is easy. Causes damage to the back-end electronics. Moreover, when the LLC resonant converter 900 is just started, the linearity of its output voltage is not high, making it not suitable for certain applications (eg, servos).

Referring to FIG. 2, an LLC resonant converter 900' using a current limiting circuit 910 is known in which a current limiting circuit 910 is used to limit the voltage of a resonant capacitor Cr in the LLC resonant converter 900' to limit the LLC resonant converter. 900's output current purpose. However, in practice, the energy of the resonant capacitor Cr can still be transferred to the output by the current limiting circuit 910, so that the current cannot be accurately limited in the LLC resonant converter 900', and the increase of the current limiting circuit 910 does not improve the LLC resonant conversion. The linearity of the output voltage Vo when the device 900' is activated.

Accordingly, it is an object of the present invention to provide a control method for a resonant converter that can accurately limit current when the resonant converter is overloaded or the output is shorted.

Therefore, the control method of the resonant converter of the present invention is applied to a control module, which is coupled to the resonant converter to form a closed loop, and the control module is configured to generate a driving signal-driven resonant converter. The power switch is turned on and off, the control method includes the following steps: (A) determining whether a load coupled to the resonant converter is within a working load range, and if so, performing step (B), otherwise performing step (C); (B) causing the control module to generate the driving signal according to an output voltage Vo of the resonant converter; and (C) causing the control module to generate the driving signal according to an output current Io of the resonant converter.

Preferably, the step (A) comprises the substeps: (A-1) sampling the output voltage Vo of the resonant converter and the output current Io; (A-2) respectively comparing a reference voltage Vref and a reference current Iref with the output voltage Vo The output current Io is subtracted to obtain an error voltage Ver and an error current Ier; (A-3) generating a voltage frequency signal V _VF related to the frequency of the driving signal according to the error voltage Ver, and generating a voltage according to the error current Ier The current frequency signal V _IF associated with the frequency of the driving signal; and (A-4) comparing the voltage frequency signal V _VF with the current frequency signal V _IF , if the voltage frequency signal V _{VF is} smaller than the current frequency signal V _IF , performing the step ( B) If the voltage frequency signal V _{VF is} greater than the current frequency signal V _IF , then step (C) is performed.

Preferably, the step (B) so that the system control module generates the frequency corresponding to the frequency of the voltage signal V of _{the VF} signal according to driving voltage signal V the frequency of _{the VF;} step (C) in accordance with a current-based control module Order-frequency signal V _{The IF} generates a drive signal corresponding to the frequency of the current frequency signal V _IF .

Preferably, the step (C) comprises the following sub-steps: (C-1) determining whether the frequency of the driving signal is a highest limiting frequency, and if so, performing step (C-2), otherwise performing step (C-3); (C-2) causes the control module to adjust the duty cycle of the drive signal according to the output current Io; and (C-3) causes the control module to adjust the frequency of the drive signal according to the output current Io.

Further, another object of the present invention is to provide a control method of a resonant converter which can increase the linearity of an output voltage when a resonant converter is started, and accurately limit the current when an overload occurs or an output short circuit occurs.

Therefore, the control method of the resonant converter of the present invention is applied to a control module, which is coupled with the resonant converter to form a closed loop, and the control method comprises the following steps: (A) making the control module according to A trigger signal generates a driving signal to drive the opening and closing of a power switch of the resonant converter to generate an output voltage Vo, and the driving signal has an initial duty cycle and an initial frequency; (B) the control module is converted according to the resonance Output voltage Vo adjustment drive The duty cycle of the signal; (C) in the process of adjusting the duty cycle, if the duty cycle of the driving signal has reached 50%, and the output voltage Vo of the resonant converter does not reach a predetermined operating voltage Vref, then the step (D) is performed. And (D) causing the control module to adjust the frequency of the driving signal according to the output voltage Vo such that the output voltage Vo generated by the resonant converter reaches the operating voltage.

Preferably, after the step (D), the control method further comprises the following steps: (E) determining whether a load coupled to the resonant converter is within a working load range, and if yes, performing step (F), otherwise executing Step (G); (F) causing the control module to generate a driving signal according to the output voltage Vo of the resonant converter; and (G) causing the control module to generate a driving signal according to an output current Io of the resonant converter.

Preferably, the step (E) comprises the sub-steps: (E-1) sampling the output voltage Vo of the resonant converter and the output current Io; (E-2) respectively separating a reference voltage Vref and a reference current Iref from the output voltage Vo The output current Io is subtracted to obtain an error voltage Ver and an error current Ier; (E-3) generating a voltage frequency signal V _VF related to the frequency of the driving signal according to the error voltage Ver, and generating a voltage according to the error current Ier The current frequency signal V _IF associated with the frequency of the driving signal; and (E-4) comparing the voltage frequency signal V _VF with the current frequency signal V _IF , if the voltage frequency signal V _{VF is} smaller than the current frequency signal V _IF , the steps are performed ( F), if the voltage frequency signal V _{VF is} greater than the current frequency signal V _IF , then step (G) is performed.

Preferably, the step (F) in the system control module generates the voltage command signal V _VF frequency of driving signal to be frequency of the voltage-frequency signal V _VF; the step (G) in accordance with a current-based control module Order frequency signal The V _IF generates a drive signal corresponding to the frequency of the current frequency signal V _IF .

Preferably, the step (G) comprises the following substeps: (G-1) determining whether the frequency of the driving signal is a highest limiting frequency, and if so, performing step (G-2), otherwise performing step (G-3); (G-2) causes the control module to adjust the duty cycle of the drive signal according to the output current Io; and (G-3) causes the control module to adjust the frequency of the drive signal according to the output current Io.

Furthermore, it is another object of the present invention to provide a control module that increases the linearity of the output voltage at the start of the resonant converter.

Therefore, the control module of the resonant converter of the present invention is coupled to a resonant converter to form a closed loop, and the control module is configured to generate a power switch for driving the signal-driven resonant converter to open and close to generate an output voltage. Vo and an output current Io, the control module comprises: a sampling circuit, a voltage subtractor, a current subtractor, a voltage regulator, a current regulator, a comparator, a control circuit and a driving circuit.

The sampling circuit samples the output voltage Vo of the resonant converter and the output current Io; the voltage subtractor subtracts a reference voltage Vref from the output voltage Vo to obtain an error voltage Ver; the current subtractor subtracts a reference current Iref from the output current Io And an error current Ier; the voltage regulator generates a voltage frequency signal V _VF related to the frequency of the driving signal according to the error voltage Ver; the current regulator generates a current frequency signal V _IF related to the frequency of the driving signal according to the error current Ier The comparator is used to compare the voltage frequency signal V _VF with the current frequency signal V _IF ; the driving circuit is used to generate the driving signal.

When the comparator compares the voltage frequency signal V _{VF to the} current frequency signal V _IF , the control circuit controls the driving circuit to generate the driving signal according to the output voltage Vo; when the comparator compares the voltage frequency signal V _{VF to be} greater than the current frequency signal V _IF , the control The circuit control drive circuit generates a drive signal based on the output current Io.

Further, another object of the present invention is to provide a resonance converting device which can accurately limit current when an overload occurs or an output short circuit occurs.

Thus, the resonant converter of the present invention comprises: a resonant converter and a control circuit. The resonant converter has a power switch, and the control circuit is configured to generate a driving signal to drive the power switch to open and close to generate an output voltage Vo and an output current Io, including a sampling circuit, a voltage subtractor, a current subtractor, and a A voltage regulator, a current regulator, a comparator, a control circuit and a drive circuit.

The sampling circuit samples the output voltage Vo of the resonant converter and the output current Io; the voltage subtractor subtracts a reference voltage Vref from the output voltage Vo to obtain an error voltage Ver; the current subtractor subtracts a reference current Iref from the output current Io And an error current Ier; the voltage regulator generates a voltage frequency signal V _VF related to the frequency of the driving signal according to the error voltage Ver; the current regulator generates a current frequency signal V _IF related to the frequency of the driving signal according to the error current Ier The comparator is used to compare the voltage frequency signal V _VF with the current frequency signal V _IF ; the driving circuit is used to generate the driving signal.

When the comparator compares the voltage frequency signal V _{VF to the} current frequency signal V _IF , the control circuit controls the driving circuit to generate the driving signal according to the output voltage Vo; when the comparator compares the voltage frequency signal V _{VF to be} greater than the current frequency signal V _IF , the control The circuit control drive circuit generates a drive signal based on the output current Io.

The effect of the invention is that the resonant converter can have better output voltage linearity at startup, and its output current can be maintained at a certain value when an overload or an output short circuit occurs.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments.

Referring to FIG. 3, FIG. 4 and FIG. 5, FIG. 4 is a preferred embodiment of a method for controlling a resonant converter according to the present invention. The control method is applied to a resonant converter device 100, and the resonant converter device 100 includes a resonant converter 1 And a control module 2 coupled to the resonant converter 1 to form a closed loop. In this embodiment, the resonance conversion device 100 can be applied to provide power supplies such as a server, a workstation, a communication device, a desktop computer, a game machine, a flat panel television, etc., and the resonant converter 1 is a half bridge LLC resonant converter, but not The resonant converter 1 includes a first power switch Q1 and a second power switch Q2. The control module 2 is configured to generate a first driving signal HVG and a second driving signal LVG to respectively drive the first The opening and closing of a power switch Q1 and the second power switch Q2 enables the resonant converter 1 to have a better linearity of the output voltage Vo in a startup mode, and when the load R _{L is} overcurrent or the resonant converter 1 When the output is short-circuited, the output current Io of the resonant converter 1 can be limited.

The control module 2 includes a sampling circuit 3, a voltage subtractor 41, a current subtractor 42, a voltage regulator 51, a current regulator 52, a comparator 6, a control circuit 7, and a driving circuit 8. In this embodiment, the voltage regulator 51 and the current regulator 52 are both Proportional Integral (PI) controllers, and the drive circuit 8 can be a PWM module and a Voltage Controlled Oscillator (VCO). One of them is not limited to this embodiment.

The following describes in detail how the control module 2 generates the first driving signal HVG and the second driving signal LVG to drive the opening and closing of the first power switch Q1 and the second power switch Q2 to adjust the output voltage Vo of the resonant converter 1 respectively. And output current Io. It is worth mentioning that the first driving signal HVG and the second driving signal LVG are complementary signals, and therefore, only the first driving signal HVG will be described below.

Referring to FIG. 6(a), it is assumed that the resonant converter 1 is initially in the startup mode, and the startup mode described herein refers to the period during which the output voltage Vo of the resonant converter 1 rises from zero to an operating voltage, that is, During t0~t2. It is worth mentioning that when the resonant converter 1 is in the startup mode, it is assumed that the load R _L to which it is coupled maintains a certain value. In this embodiment, the load R _L is a test device that can operate in a certain current mode, but is not limited thereto.

Therefore, as shown in step 11 of FIG. 3, the control circuit 7 generates an initial voltage signal according to a trigger signal, the initial voltage signal having a preset duty cycle and an initial frequency.

Step 12, the driving circuit 8 generates one according to the initial voltage signal The initial duty cycle and the first drive signal HVG of the initial frequency. In this embodiment, the initial duty cycle of the first driving signal HVG is 0%. In contrast, the initial duty cycle of the second driving signal LVG is 100%, and the initial frequency is set to the first driving signal HVG and the second. A maximum limit frequency Fmax that the drive signal LVG can tolerate.

In step 13, the control circuit 7 adjusts the duty cycle of the first driving signal HVG generated by the driving circuit 8 according to an output voltage Vo of the resonant converter 1. As shown in FIG. 6, in order to make the output voltage Vo of the resonant converter 1 reach the operating voltage, the control circuit 7 of the embodiment controls the duty cycle of the first driving signal HVG to gradually increase from 0% (initial duty cycle) to 50. %, so that the output voltage Vo of the resonant converter 1 can rise steadily. It is particularly noted that during the duty cycle of adjusting the first driving signal HVG, the control circuit 7 maintains the frequency of the first driving signal HVG at the highest limiting frequency Fmax as shown in FIG. 6(c). When the resonant converter 1 is started, its back-end device will be in a constant current mode, so the output current Io of the resonant converter 1 will maintain a certain value, as shown in Fig. 6(b).

In step 14, the control circuit 7 detects whether the duty cycle of the first driving signal HVG has reached 50% when the output voltage Vo of the resonant converter 1 has not reached the operating voltage. If yes, step 15 is performed, and the control circuit 7 is based on the output voltage Vo. The frequency of the first driving signal HVG is adjusted to control the output voltage Vo of the resonant converter 1 to reach the operating voltage, otherwise step 13 is repeated.

In other words, when the duty cycle of the first driving signal HVG has risen to 50%, but the output voltage Vo of the resonant converter 1 does not reach the operating voltage, that is, the time t1 of FIG. 5, since the duty cycle of the first driving signal HVG has been no The method is further increased. Therefore, the control circuit 7 is modified to reduce the frequency of the first driving signal HVG and the second driving signal LVG to maintain the output current Io and exchange for a higher output voltage Vo, so that the output voltage Vo can reach the operating voltage. . It should also be noted that during the adjustment of the frequencies of the first driving signal HVG and the second driving signal LVG, the control circuit 7 maintains the duty cycle of the first driving signal HVG at 50%.

The above steps 11 to 15 are the control of the resonant converter 1 in the startup mode, and after the output voltage Vo of the resonant converter 1 reaches the operating voltage, the resonant converter 1 enters an operational mode.

Therefore, in step 20, the control module 2 determines whether the load R _L coupled to the resonant converter 1 is within a working load range, and if so, the control circuit 7 controls the driving circuit 8 to generate the first according to the output voltage Vo of the resonant converter 1 A driving signal HVG and a second driving signal LVG are as shown in step 25. Referring to FIG. 7 , the horizontal axis is the ratio of the load R _L coupled to the resonant converter 1 and a rated load. In this embodiment, the working range of the load R _L is greater than zero (short circuit) and less than 120% of the rated load, that is, when the load R _{L to} which the resonant converter 1 is coupled is in the range of the working load, the resonant converter 1 is in the operating mode. In addition, in the embodiment, the method of determining whether the load R _L is in the working load range is described by taking the steps 21 to 24 as an example, but is not limited thereto.

In step 21, the sampling circuit 3 samples the output voltage Vo of the resonant converter 1 and the output current Io, and transmits the two to the voltage subtractor 41 and the current subtractor 42, respectively.

Step 22, the voltage subtractor 41 sets a reference voltage Vref and the output power The voltage Vo is subtracted to obtain an error voltage Ver, and the current subtractor 42 subtracts a reference current Iref from the output current Io to obtain an error current Ier. In the present embodiment, the reference current Iref is set to a maximum output current Imax that the resonant converter 1 can tolerate.

In step 23, the voltage regulator 51 amplifies and integrates the error voltage Ver by a certain degree to generate a voltage frequency signal V _VF related to the frequency of the first driving signal HVG, and the current regulator 52 passes the error current Ier through a certain period. After the proportional amplification and integration, a current frequency signal V _IF related to the frequency of the first driving signal HVG is generated.

In this embodiment, when the resonant converter 1 is in the operating mode, its output current Io is lower than the reference current Iref (maximum output current Imax), and the "change amount" between the output current Io and the reference current Iref is greater than The "change amount" between the output voltage Vo and the reference voltage Vref causes the current frequency signal V _IF generated by the current regulator 52 to be greater than the voltage frequency signal V _VF generated by the voltage regulator 51.

Therefore, in step 24, the comparator 6 compares the magnitudes of the voltage frequency signal V _VF and the current frequency signal V _IF , and if the voltage frequency signal V _{VF is} less than or equal to the current frequency signal V _IF , it indicates that the resonant converter 1 is in the operating mode. Therefore, the control circuit 7 controls the driving circuit 8 to generate the first driving signal HVG and the second driving signal LVG according to the voltage frequency signal V _VF , and the control module 2 repeats step 20 .

However, in this embodiment, the voltage frequency signal V _VF is inversely proportional to the frequencies of the first driving signal HVG and the second driving signal LVG, that is, the smaller the voltage frequency signal V _{VF is} , the first driving signal HVG and the second driving The frequency of the signal LVG will be higher. Therefore, when the resonant converter 1 is in the operating mode, when the output voltage Vo rises, the reference voltage Vref is subtracted from the output voltage Vo, and the error voltage Ver is lowered, and the corresponding voltage frequency signal V _VF is also lowered, so that the first When the frequency of a driving signal HVG and the second driving signal LVG is increased, the output voltage Vo is thus lowered, so that the output voltage Vo can be stabilized at a certain value.

Referring to FIG. 7, with the different applications of the resonant converter device 100, when the load R _L coupled to the resonant converter 1 exceeds a rated load of 120%, or the output of the resonant converter 1 is short-circuited (the load R _L is zero), When the load R _L exceeds the workload range, the resonant converter 1 enters an overcurrent mode.

Taking the rated load of the load R _L exceeding 120% as an example, the output current Io of the resonant converter 1 starts to rise to reach the maximum output current Imax, so that the error current Ier is reduced by subtracting from the reference current Iref (step 22) The current frequency signal V _IF generated by the current regulator 52 is also smaller than the voltage frequency signal V _VF generated by the voltage regulator 51 (step 23). At this time, the comparator 6 compares the voltage frequency signal V _{VF to the} current frequency signal V _IF (step 24), and then performs step 26, the control circuit 7 controls the driving circuit 8 to generate the first driving according to the output current Io of the resonant converter 1. Signal HVG and second drive signal LVG.

In order to prevent the resonant converter 1 from outputting excessive current in the overcurrent mode, the back-end electrical equipment (not shown) is damaged. Therefore, when the output current Io is too large, a too small current frequency signal V _IF is generated. In this embodiment, the current frequency signal V _{IF is} also inversely proportional to the frequencies of the first driving signal HVG and the second driving signal LVG, so the frequency-increasing first driving signal HVG and the second driving signal LVG will be controlled. The output current Io of the resonant converter 1 is lowered so that the output current Io is limited to the maximum output current Imax as shown in Figs. 6(a) and (c).

Step 26 includes sub-steps: Step 261, the control circuit 7 determines whether the frequency of the first driving signal HVG and the second driving signal LVG is the highest limiting frequency Fmax, and if so, executing step 262, the control circuit 7 will according to the current frequency signal V _IF The frequency of the first driving signal HVG and the second driving signal LVG is fixed at the highest limiting frequency Fmax, and the duty cycle of the first driving signal HVG and the second driving signal LVG is adjusted; otherwise, step 263 is performed, and the control circuit 7 is based on the current frequency signal V. _{The IF} adjusts the frequencies of the first driving signal HVG and the second driving signal LVG.

In the design of this embodiment, when the output current Io of the resonant converter 1 rises to the maximum output current Imax, and the reference current Iref is also set to the maximum output current Imax, the error current Ier generated by the current subtractor 42 will be Zero (or close to zero), the current frequency signal V _IF generated by the current regulator 52 causes the frequencies of the first driving signal HVG and the second driving signal LVG to reach the highest limiting frequency Fmax, that is, when the output current Io rises to When the maximum output current Imax, the frequency of the first driving signal HVG and the second driving signal LVG generated by the driving circuit 8 will be the highest limiting frequency Fmax.

Therefore, when the frequencies of the first driving signal HVG and the second driving signal LVG have reached the maximum limiting frequency Fmax, it indicates that the frequency can no longer rise, and the control circuit 7 reduces the duty cycle of the first driving signal HVG (second driving) The duty cycle of the signal LVG is increased to control the output current Io of the resonant converter 1 to be limited to the maximum output current Imax. Conversely, if the frequencies of the first driving signal HVG and the second driving signal LVG do not reach the maximum limiting frequency Fmax, the control circuit 7 increases the first driving signal HVG and the second driving signal LVG as the output current Io increases. The frequency, as in step 263, is to achieve the purpose of stabilizing the output current Io.

In addition, the control method of the resonant converter 1 can also be implemented in the software and programmed in the control module 2, so that the control module 2 can perform the above steps 20 to 26 to achieve the output voltage Vo and output of the resonant converter 1. Control of current Io.

In summary, the control method of the resonant converter 1 of the present invention determines the mode of the resonant converter 1 by the load RL coupled to the resonant converter 1, and performs corresponding control for different modes. In the startup mode, the control module 2 controls the duty cycle of the first driving signal HVG and the second driving signal LVG first, and if the duty cycle reaches 50%, the first driving signal HVG and the second driving signal are controlled. The frequency of the LVG to increase the linearity of the output voltage Vo at the start of the resonant converter 1. In addition, when the resonant converter 1 is in the overcurrent mode, the control module 2 first increases the frequencies of the first driving signal HVG and the second driving signal LVG, and if the frequency reaches the highest limiting frequency Fmax, the first driving is controlled. The duty cycle of the signal HVG and the second driving signal LVG can limit the output current Io of the resonant converter 1 to a certain value.

However, the above is only the preferred embodiment of the present invention, and the scope of the present invention cannot be limited thereto, that is, the patent application according to the present invention The scope of the invention and the equivalent equivalents and modifications of the invention are still within the scope of the invention.

11~15‧‧‧Steps

20~26‧‧‧Steps

261~263‧‧‧Steps

100‧‧‧Resonance converter

1‧‧‧Resonant converter

2‧‧‧Control Module

3‧‧‧Sampling circuit

41‧‧‧Voltage subtractor

42‧‧‧ current subtractor

51‧‧‧Voltage regulator

52‧‧‧ Current Regulator

6‧‧‧ comparator

7‧‧‧Control circuit

8‧‧‧Drive circuit

1 is a circuit diagram illustrating a basic topology of a conventional half-bridge LLC resonant converter; FIG. 2 is a circuit diagram illustrating a conventional LLC resonant converter topology using a current limiting circuit; FIGS. 3 and 4 are a flow chart, respectively. A preferred embodiment of the control method of the resonant converter of the present invention is shown; FIG. 5 is a circuit block diagram illustrating the resonant converter of the present embodiment; and FIG. 6 is a waveform diagram illustrating (a) the output voltage of the resonant converter and (b) the relationship between the output current of the resonant converter and the time; (c) the relationship between the switching frequency of the first power switch and the second power switch in the resonant converter and time; and FIG. 7 is a Waveform diagram illustrating (a) the relationship between the output current of the resonant converter and the load; (b) the relationship between the output voltage of the resonant converter and the load; (c) the first power switch and the second power switch in the resonant converter The switching frequency is related to the load.

20~26. . . step

261~263. . . step

Claims (19)

A control method for a resonant converter is applied to a control module, and the control module is coupled to the resonant converter to form a closed loop, and the control module is configured to generate a driving signal to drive the resonant converter. The power switch is turned on and off. The control method includes the following steps: (A) determining whether a load coupled to the resonant converter is within a working load range, and if yes, performing step (B), otherwise performing step (C) (B) causing the control module to generate the driving signal according to an output voltage of the resonant converter; and (C) causing the control module to generate the driving signal according to an output current of the resonant converter; wherein, the step (A) comprising the sub-steps: (A-1) sampling the output voltage and the output current of the resonant converter; (A-2) subtracting a reference voltage and a reference current from the output voltage and the output current respectively An error voltage and an error current; (A-3) generating a voltage frequency signal related to the frequency of the driving signal according to the error voltage, and generating a current frequency signal related to the frequency of the driving signal according to the error current; and( A-4) comparing the voltage frequency signal with the current frequency signal, if the voltage frequency signal is less than or equal to the current frequency signal, performing step (B), if the voltage frequency signal is greater than the current frequency signal, performing the step ( C). According to the control side of the resonant converter described in claim 1 The method, wherein the step (B) causes the control module to generate the driving signal corresponding to the frequency of the voltage frequency signal according to the voltage frequency signal. The control method of the resonant converter according to claim 1, wherein the step (C) causes the control module to generate the driving signal corresponding to the frequency of the current frequency signal according to the current frequency signal. The control method of the resonant converter according to any one of claims 1 to 3, wherein the step (C) comprises the following substeps: (C-1) determining whether the frequency of the driving signal is the highest Limiting the frequency, if yes, executing step (C-2), otherwise performing step (C-3); (C-2) causing the control module to adjust the duty cycle of the driving signal according to the output current; and (C-3 And causing the control module to adjust the frequency of the driving signal according to the output current. A computer-accessible recording medium, wherein a control program of a resonant converter is recorded, and the control program can be placed in a control module, so that the control module performs the method as claimed in claim 1 step. A control method for a resonant converter is applied to a control module, and the control module is coupled to the resonant converter to form a closed loop. The control method comprises the following steps: (A) making the control module according to a The trigger signal generates a driving signal to drive the opening and closing of a power switch of the resonant converter to generate an output voltage, and the driving signal has an initial duty cycle and an initial frequency; (B) causing the control module to adjust the duty cycle of the driving signal according to the output voltage of the resonant converter; (C) in the process of adjusting the duty cycle, if the duty cycle of the driving signal has reached 50%, and the resonance If the output voltage of the converter does not reach a predetermined operating voltage, step (D) is performed; and (D), the control module adjusts the frequency of the driving signal according to the output voltage, so that the resonant converter generates the The output voltage reaches the operating voltage; wherein, after the step (D), the control method further comprises the following steps: (E) determining whether a load coupled to the resonant converter is within a working load range, and if so, Performing step (F), otherwise performing step (G); (F) causing the control module to generate the driving signal according to the output voltage of the resonant converter; and (G) causing the control module to be based on one of the resonant converters The output current generates the driving signal; wherein the step (E) comprises the sub-steps: (E-1) sampling the output voltage and the output current of the resonant converter; (E-2) respectively, respectively, a reference voltage and a reference current The output voltage and the output current are subtracted And obtaining an error voltage and an error current; (E-3) generating a voltage frequency signal related to the frequency of the driving signal according to the error voltage, and generating a current frequency related to the frequency of the driving signal according to the error current Signal; and (E-4) comparing the voltage frequency signal with the current frequency signal, if the voltage frequency signal is less than or equal to the current frequency signal, performing step (F), if the voltage frequency signal is greater than the current frequency signal, performing the step (G). The control method of the resonant converter according to claim 6, wherein the initial frequency is a maximum limit frequency that the driving signal can tolerate. The control method of the resonant converter according to claim 6, wherein the step (F) causes the control module to generate the driving signal corresponding to the frequency of the voltage frequency signal according to the voltage frequency signal. The control method of the resonant converter according to claim 6, wherein the step (G) causes the control module to generate a driving signal corresponding to the frequency of the current frequency signal according to the current frequency signal. The control method of the resonant converter according to any one of claims 6 to 9, wherein the step (G) comprises the following substep: (G-1) determining whether the frequency of the driving signal is the highest Limiting the frequency, if yes, executing step (G-2), otherwise performing step (G-3); (G-2) causing the control module to adjust the duty cycle of the driving signal according to the output current; and (G-3) And causing the control module to adjust the frequency of the driving signal according to the output current. A computer-accessible recording medium, wherein a control program of a resonant converter is recorded, and the control program can be placed in a control module, so that the control module performs the method as described in claim 6 step Step. A control module of a resonant converter is coupled to a resonant converter to form a closed loop, and the control module is configured to generate a driving signal to drive a power switch of the resonant converter to open and close to generate an output voltage and An output current, the control module includes: a sampling circuit that samples an output voltage and an output current of the resonant converter; a voltage subtractor that subtracts a reference voltage from the output voltage to obtain an error voltage; a current subtraction method And subtracting a reference current from the output current to obtain an error current; a voltage regulator generating a voltage frequency signal related to the frequency of the driving signal according to the error voltage; and a current regulator according to the error current Generating a current frequency signal related to the frequency of the driving signal; a comparator for comparing the voltage frequency signal with the current frequency signal; a driving circuit for generating the driving signal; and a control circuit for comparing the voltage at the comparator When the frequency signal is smaller than the current frequency signal, the driving circuit is controlled to generate the driving signal according to the output voltage, in the ratio When comparing the frequency of the voltage signal is larger than the current frequency signal, the driving control circuit generates the drive signal based on the output current. Control mode of the resonant converter according to claim 12 of the patent application scope The control circuit determines whether the frequency of the driving signal is a highest limiting frequency, and if so, the control circuit adjusts the driving signal according to the output current. The duty cycle, if not, the control circuit adjusts the frequency of the drive signal based on the output current. The control module of the resonant converter according to claim 12, wherein the comparator compares the voltage frequency signal to be less than or equal to the current frequency signal, and the control circuit generates a corresponding voltage frequency according to the voltage frequency signal. The drive signal of the frequency of the signal. The control module of the resonant converter according to claim 12, wherein the comparator compares the voltage frequency signal to be greater than the current frequency signal, and the control circuit generates a corresponding current frequency signal according to the current frequency signal. Frequency drive signal. A resonant converter includes: a resonant converter having a power switch; and a control module for generating a driving signal to drive the power switch to open and close to generate an output voltage and an output current, the control module Include a sampling circuit for sampling the output voltage and output current of the resonant converter, a voltage subtractor, subtracting a reference voltage from the output voltage to obtain an error voltage, a current subtractor, a reference current and the output The current is subtracted to obtain an error current. a voltage regulator generates a voltage frequency signal related to the frequency of the driving signal according to the error voltage, and a current regulator generates a current frequency signal related to the frequency of the driving signal according to the error current, a comparator, Comparing the voltage frequency signal with the current frequency signal, a driving circuit, generating the driving signal, and a control circuit, when the comparator compares the voltage frequency signal to be smaller than the current frequency signal, controlling the driving circuit to generate according to the output voltage The driving signal is controlled to generate the driving signal according to the output current when the comparator compares the voltage frequency signal to the current frequency signal. According to the resonance conversion device of claim 16, wherein the comparator compares the voltage frequency signal to be greater than the current frequency signal, and the control circuit determines whether the frequency of the driving signal is a highest limit frequency, and if so, The control circuit adjusts the duty cycle of the driving signal according to the output current. If not, the control circuit adjusts the frequency of the driving signal according to the output current. The resonance conversion device of claim 16, wherein the comparator compares the voltage frequency signal to be less than or equal to the current frequency signal, and the control circuit generates a frequency corresponding to the voltage frequency signal according to the voltage frequency signal. The drive signal. The resonance conversion device of claim 16, wherein the comparator compares the voltage frequency signal to be greater than the current frequency signal, The control circuit generates a driving signal corresponding to the frequency of the current frequency signal according to the current frequency signal.