Resonant conversion control method and device, power conversion module and charging equipment

Abstract

The invention provides a resonant conversion control method and device, a power conversion module and charging equipment, and belongs to the technical field of power electronics. The method comprises the following steps: acquiring the output voltage of the resonant conversion circuit in real time; according to a first voltage difference value between the output voltage at the current moment and a preset reference voltage, determining a target switching frequency corresponding to a switching module in the resonant conversion circuit at the current moment; and controlling the output voltage of the resonant conversion circuit according to the first voltage difference value, the target switching frequency and a second voltage difference value between the output voltage at the previous moment and a preset reference voltage so as to reduce the rising speed of the output voltage of the resonant conversion circuit. According to the invention, the effects of inhibiting the current of the resonant cavity from being too large and reducing the jitter of the voltage waveform of the output voltage can be achieved.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a resonant conversion control method, device, power conversion module and charging equipment. Background Art

[0002] Resonant converters (LLC circuits for short) are resonant circuits that achieve a constant output voltage by controlling the switching frequency. They have the advantages of high output stability, flexible design, wide output voltage range, and strong anti-interference. Therefore, LLC circuits are widely used in computer, communication, medical and other fields. However, during the sudden loading process of the LLC circuit, the resonant cavity current changes greatly, which has a great impact on the electronic devices in the circuit and will seriously affect the life of the electronic devices. Therefore, a method is urgently needed to suppress the excessive sudden change of the resonant cavity current during the sudden loading process of the LLC circuit to ensure the normal operation of the LLC circuit.

[0003] In the related art, the magnitude of the resonant cavity current in the LLC circuit can generally be detected by a mutual inductor, and the current signal can be converted into a corresponding voltage signal VLr and output to a comparator. The comparator compares the voltage signal VLr with a reference voltage. If the voltage signal VLr is greater than the reference voltage, the comparator flips to trigger the clipping strategy of the digital signal processor (Digital Signal Processing, DSP for short); conversely, if the voltage signal VLr is less than or equal to the reference voltage, the DSP will re-transmit the wave.

[0004] However, when using relevant technologies to suppress the sudden change of the resonant cavity current during the sudden loading of the LLC circuit, the output signal of the comparator needs to be input into the DSP, and the DSP needs to be configured in cycle-by-cycle protection mode (CBC mode for short). When the DSP triggers the CBC mode, the LLC output voltage waveform will have obvious jitter. Summary of the invention

[0005] The purpose of the present application is to provide a resonant conversion control method, device, power conversion module and charging equipment, which can suppress excessive current in the resonant cavity and reduce the jitter of the voltage waveform of the output voltage.

[0006] The embodiment of the present application is implemented as follows:

[0007] In a first aspect of an embodiment of the present application, a resonant conversion control method is provided, the method comprising:

[0008] Obtain the output voltage of the resonant conversion circuit in real time;

[0009] Determine a target switching frequency corresponding to a switch module in the resonant conversion circuit at the current moment according to a first voltage difference between an output voltage at the current moment and a preset reference voltage;

[0010] The output voltage of the resonant conversion circuit is controlled according to the first voltage difference, the target switching frequency, and a second voltage difference between the output voltage at the previous moment and a preset reference voltage to reduce the recovery speed of the output voltage of the resonant conversion circuit.

[0011] As a possible implementation, controlling the output voltage of the resonant conversion circuit according to the first voltage difference, the target switching frequency, and the second voltage difference between the output voltage at the previous moment and the preset reference voltage includes:

[0012] If the first voltage difference is smaller than the second voltage difference, and the target switching frequency is smaller than the preset switching frequency, the output voltage of the resonant conversion circuit is controlled to reduce the recovery speed of the output voltage of the resonant conversion circuit.

[0013] As a possible implementation method, controlling the output voltage of the resonant conversion circuit includes:

[0014] calculating a difference between the first voltage difference and the second voltage difference;

[0015] Determining whether the output voltage of the resonant conversion circuit is in a voltage recovery stage according to the difference between the first voltage difference and the second voltage difference;

[0016] If so, a target voltage adjustment amplitude of the resonant conversion circuit is determined according to the first voltage difference and the preset voltage amplitude, and the output voltage of the resonant conversion circuit is controlled according to the target voltage adjustment amplitude.

[0017] As a possible implementation manner, determining a target voltage adjustment amplitude of the resonant conversion circuit according to the first voltage difference and a preset voltage amplitude includes:

[0018] If the first voltage difference is greater than or equal to a preset voltage amplitude, determining the target voltage adjustment amplitude of the resonant conversion circuit to be the preset voltage amplitude;

[0019] If the first voltage difference is smaller than the preset voltage amplitude, the target voltage adjustment amplitude of the resonant conversion circuit is determined to be the first voltage difference.

[0020] As a possible implementation, after the output voltage of the resonant conversion circuit is controlled according to the target voltage adjustment amplitude, it includes:

[0021] If the output voltage of the resonant conversion circuit reaches a preset reference voltage, the output voltage of the resonant conversion circuit is stopped from being controlled.

[0022] As a possible implementation manner, the above-mentioned resonant conversion control method further includes:

[0023] If the first voltage difference is greater than a preset voltage threshold and the target switching frequency is greater than or equal to a preset switching frequency, the switching frequency of the switching module in the resonant conversion circuit is controlled according to the preset switching frequency to reduce the resonant cavity current of the resonant conversion circuit, wherein the first voltage gain corresponding to the preset switching frequency is greater than the second voltage gain corresponding to the target switching frequency.

[0024] As a possible implementation manner, after controlling the switching frequency of the switch module in the resonant conversion circuit according to the preset switching frequency, the method includes:

[0025] If the target switching frequency is less than the preset switching frequency, the switching frequency of the switch module in the resonant conversion circuit is stopped from being controlled.

[0026] According to a second aspect of the embodiments of the present application, a resonant conversion control device is provided, the device comprising:

[0027] An acquisition module, used for acquiring the output voltage of the resonant conversion circuit in real time;

[0028] A determination module, used to determine a target switching frequency corresponding to a switch module in the resonant conversion circuit at a current moment according to a first voltage difference between an output voltage at a current moment and a preset reference voltage;

[0029] The control module is used to control the output voltage of the resonant conversion circuit according to the first voltage difference, the target switching frequency and the second voltage difference between the output voltage at the previous moment and the preset reference voltage to reduce the recovery speed of the output voltage of the resonant conversion circuit.

[0030] According to a third aspect of an embodiment of the present application, a power conversion module is provided. The power conversion module includes: a resonant conversion circuit and a controller. The controller is used to execute the steps of the resonant conversion control method described in the first aspect.

[0031] According to a fourth aspect of an embodiment of the present application, a charging device is provided, which includes the power conversion module described in the third aspect.

[0032] The beneficial effects of the embodiments of the present application include:

[0033] The embodiment of the present application provides a resonant conversion control method, which samples the output voltage of the resonant conversion circuit in real time; calculates the first voltage difference between the output voltage of the resonant conversion circuit at the current moment and the preset reference voltage; determines the target switching frequency corresponding to the switch module in the resonant conversion circuit at the current moment according to the first voltage difference; calculates the second voltage difference between the output voltage of the resonant conversion circuit at the previous moment and the preset reference voltage, and controls the output voltage of the resonant conversion circuit and the switching frequency of the switch module in the resonant conversion circuit according to the first voltage difference, the second voltage difference and the target switching frequency, so that the resonant cavity current in the resonant conversion circuit can be suppressed from being too large, and the recovery speed of the output voltage of the resonant conversion circuit can be reduced, thereby eliminating the jitter of the output voltage of the resonant conversion circuit. In this way, the effect of suppressing the excessive current of the resonant cavity and reducing the jitter of the voltage waveform of the output voltage can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 It is a main circuit diagram of an existing resonant conversion circuit;

[0036] Figure 2 A block diagram of a voltage loop provided in an embodiment of the present application;

[0037] Figure 3 A flow chart of a first resonant conversion control method provided in an embodiment of the present application;

[0038] Figure 4 A flow chart of a second resonant conversion control method provided in an embodiment of the present application;

[0039] Figure 5 A flow chart of a third resonant conversion control method provided in an embodiment of the present application;

[0040] Figure 6 A resonant cavity current waveform diagram without frequency limiting provided in an embodiment of the present application;

[0041] Figure 7 A resonant cavity current waveform diagram of the first frequency-limiting treatment provided in an embodiment of the present application;

[0042] Figure 8 A resonant cavity current waveform diagram of the second frequency limiting process provided in an embodiment of the present application;

[0043] Fig. 9 A schematic diagram of the structure of a resonant conversion control device provided in an embodiment of the present application;

[0044] Fig.10 A schematic diagram of the structure of a power conversion module provided in an embodiment of the present application;

[0045] Fig.11 A schematic diagram of the structure of a charging device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0047] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0048] At present, a mutual inductor is often used to detect the magnitude of the resonant cavity current in the resonant conversion circuit, and the detected resonant cavity current is converted into a corresponding voltage signal and sent to the comparator. The comparator triggers the digital signal processor based on the comparison result between the received voltage signal and the preset comparator reference voltage. Among them, if the received voltage signal is greater than the comparator reference voltage, the comparator flips to trigger the clipping function of the digital signal processor; if the received voltage signal is less than or equal to the comparator reference voltage, the comparator triggers the digital signal processor to re-transmit the wave. However, although this solution can solve the problem of excessive resonant cavity current in the resonant conversion circuit during sudden loading, the digital signal processor in this solution needs to receive the signal output by the comparator, so the digital signal processor needs to be configured in a cycle-by-cycle protection mode, which causes the voltage waveform output by the resonant conversion circuit to have obvious jitter.

[0049] To this end, the embodiment of the present application provides a resonant conversion control method, which obtains the output current of the resonant conversion circuit in real time, and determines the target switching frequency corresponding to the switch module in the resonant conversion circuit at the current moment according to the first voltage difference between the output voltage of the resonant conversion circuit at the current moment and the preset reference voltage; according to the first voltage difference, the second voltage difference between the output voltage of the resonant conversion circuit at the previous moment and the preset reference voltage, and the target switching frequency, controls the output voltage of the resonant conversion circuit, so that the output voltage of the resonant conversion circuit recovers slowly, thereby eliminating the problem of obvious jitter of the output voltage of the resonant conversion circuit. In this way, the effect of suppressing excessive current in the resonant cavity and reducing the jitter of the voltage waveform of the output voltage can be achieved.

[0050] Figure 1 This is a main circuit diagram of an existing resonant conversion circuit, see Figure 1 , Vbus is used as the bus voltage of the resonant conversion circuit 101, and the bus voltage can be provided by the power grid or by the collector box; C1 is used as the bus capacitor of the resonant conversion circuit 101, and the bus capacitor can be used to store the power grid charge output by the power grid to the resonant conversion circuit 101 through the bus. When the power grid stops supplying power, the bus capacitor can release the charge to provide the bus voltage for the resonant conversion circuit 101; Q1~Q4 are used as the switch module of the main power circuit of the resonant conversion circuit 101, and Q1~Q4 are all realized by transistors, and the external drive circuit controls the switching frequency of the transistor through the gate of each transistor; Lr and Cr are used as the resonant devices of the resonant conversion circuit 101, and I Lr is the resonant cavity current in the resonant conversion circuit 101; D1~D4 are used as the rectifier diodes at the output end of the resonant conversion circuit 101 as output rectifier diodes, Co is used as the filter capacitor at the output end of the resonant conversion circuit 101, and is used to filter out the harmonics in the output voltage signal of the resonant conversion circuit 101, and Ro is used as the load resistor of the resonant conversion circuit 101, and the terminal voltage of the load circuit is the output voltage of the resonant conversion circuit 101.

[0051] Among them, when the resonant conversion circuit 101 is in a large dynamic change scenario, the resonant conversion circuit 101 switches to a no-load state, and the output voltage of the resonant conversion circuit 101 when the output voltage Vo reaches a high voltage of 1000V, the resistance of the load resistor Ro can be regarded as infinite. If the resistance of the load resistor Ro suddenly changes from infinity to 25Ω, the output current of the resonant conversion circuit 101 suddenly changes from 0A to 40A, and the load pulling speed of the load resistor Ro is relatively fast, but the voltage loop of the power supply requires a certain response time, which leads to a drop in the output voltage of the resonant conversion circuit 101. The increase in the output voltage of the voltage loop of the power supply will cause the switching frequency of the switch module in the resonant conversion circuit 101 to decrease rapidly, and the resonant cavity current I Lr in the resonant conversion circuit 101 will suddenly increase to a large value in several switching cycles to meet the load demand. However, the excessive resonant cavity current I Lr will damage other electronic devices in the resonant conversion circuit 101 and cause problems such as overcurrent protection of the resonant conversion circuit 101.

[0052] The resonant conversion control method provided in the embodiment of the present application is explained in detail below with reference to the accompanying drawings.

[0053] Figure 2 A voltage loop block diagram provided for this application, see Figure 2 , Vo* is used to characterize a preset reference voltage, which is a reference voltage pre-set for the output voltage Vo of the resonant conversion circuit; the sampling voltage Vdc is used to indicate the real-time output voltage Vo across the load resistor RoI of the resonant conversion circuit; Verr is used to indicate the voltage difference between the preset reference voltage Vo* and the sampling voltage Vdc, and the voltage error signal Verr is input into the PI controller; the PI controller sends a control signal to the digital signal processor DSP based on the received voltage error signal Verr, and the digital signal processor DSP stores the received control signal into the period register Fs, and the period register Fs can directly convert the control signal into the frequency Fs output of the pulse width modulation signal PWM.

[0054] Among them, if the output voltage of the resonant switching circuit undergoes large dynamic switching, such as when suddenly loaded to full load, no load, etc., the output voltage Vo of the resonant switching circuit will suddenly drop, that is, the sampling voltage Vdc corresponding to the output voltage Vo of the resonant switching circuit will suddenly drop, causing the voltage difference Verr between the preset reference voltage Vo* and the sampling voltage Vdc to suddenly increase significantly, and the switching frequency of the switch module in the resonant conversion circuit will drop rapidly to improve the voltage gain of the resonant conversion circuit. However, this will cause the resonant cavity current ILr in the resonant conversion circuit to be too large.

[0055] It is worth noting that the voltage loop connects the control signal output by the voltage loop to the gates of Q1~Q4 via an external driving circuit. The voltage loop controls the switching frequency of the switching module in the resonant conversion circuit to suppress the problem of excessive current in the resonant cavity during sudden loading of the resonant conversion circuit, and eliminates the jitter problem of the output voltage of the resonant conversion circuit by controlling the output voltage of the resonant conversion circuit.

[0056] Figure 3 This is a flow chart of a resonant conversion control method provided by the present application, which can be applied to computer equipment, see Figure 3 , the embodiment of the present application provides a resonant conversion control method, comprising:

[0057] S301 , obtaining the output voltage of the resonant conversion circuit in real time.

[0058] Optionally, the terminal voltage of the load resistor at the output end of the resonant conversion circuit is collected in real time by a computer device or an external voltage collection circuit to obtain the real-time output voltage of the resonant conversion circuit. According to the real-time output voltage of the resonant conversion circuit, the switching state of the resonant conversion circuit can be determined, and the switching state of the resonant conversion circuit includes: normal state, no-load state, full-load state, etc.

[0059] S302: Determine a target switching frequency corresponding to a switch module in the resonant conversion circuit at the current moment according to a first voltage difference between an output voltage at the current moment and a preset reference voltage.

[0060] Optionally, the preset reference voltage is a voltage reference value set in advance by the user based on the output voltage of the normal operation of the resonant conversion circuit, the output voltage at the current moment is used to indicate the real-time output voltage of the resonant conversion circuit, and the first voltage difference is used to indicate the voltage error between the output voltage of the resonant conversion circuit at the current moment and the preset reference voltage.

[0061] Optionally, the target switching frequency is a switching control frequency calculated in real time by a PI controller in the voltage loop based on a first voltage difference. Based on the first voltage difference between the output voltage of the resonant conversion circuit at the current moment and a preset reference voltage, the switching control frequency corresponding to the switching module in the resonant conversion circuit at the current moment can be output.

[0062] S303, controlling the output voltage of the resonant conversion circuit according to the first voltage difference, the target switching frequency, and a second voltage difference between the output voltage at the previous moment and a preset reference voltage to reduce a recovery speed of the output voltage of the resonant conversion circuit.

[0063] Optionally, the previous moment refers to the time point closest to the current moment in the historical period, the output voltage at the previous moment is used to indicate the output voltage of the resonant conversion circuit collected at the previous moment, and the second voltage difference is used to indicate the voltage error between the output voltage of the resonant conversion circuit at the previous moment and a preset reference voltage.

[0064] It is worth noting that when the voltage loop controls the output voltage of the resonant conversion circuit, it is not a one-way voltage control, but a cyclic iterative control, so that the voltage change slope of the output voltage of the resonant conversion circuit is gentle, and the recovery speed of the resonant conversion circuit is reduced. The recovery speed is used to indicate the rise and fall speed of the output voltage of the resonant conversion circuit.

[0065] Optionally, after calculating a first voltage difference between the output voltage of the resonant conversion circuit at a current moment and a preset reference voltage, the voltage loop will assign the first voltage difference to the voltage difference calculation process of the voltage loop at the next moment. The voltage loop can determine whether the resonant conversion circuit is in a voltage recovery stage based on the first voltage difference and the second voltage difference, and when the resonant conversion circuit is in the voltage recovery stage, the output voltage of the resonant conversion circuit is limited and regulated so that the output voltage of the resonant conversion circuit changes slowly, thereby reducing the switching frequency of the switching module in the resonant conversion circuit, and the resonant cavity current in the resonant conversion circuit will not suddenly increase, thereby avoiding the resonant conversion circuit triggering overcurrent protection.

[0066] It is worth noting that during the voltage recovery stage of the output voltage of the resonant conversion circuit, the voltage waveform of the output voltage of the resonant conversion circuit will show obvious jitter. The jitter of the voltage waveform is caused by the burrs generated by the voltage sampling circuit, that is, the difference between the two voltage differences when the voltage loop enters or exits the limiting strategy to control the output voltage of the resonant conversion circuit is too large. When the voltage loop exits and enters the limiting strategy to control the output voltage of the resonant conversion circuit, the second voltage difference calculated before exiting the limiting strategy or entering the limiting strategy must be assigned to the first voltage difference calculated at the current moment, and the output voltage of the resonant conversion circuit must be regulated based on the first voltage difference and the second voltage difference, which can effectively avoid the jitter problem in the voltage recovery stage of the resonant conversion circuit.

[0067] In the embodiment of the present application, by real-time sampling of the output voltage of the resonant conversion circuit; calculating the first voltage difference between the output voltage of the resonant conversion circuit at the current moment and the preset reference voltage; determining the target switching frequency corresponding to the switch module in the resonant conversion circuit at the current moment according to the first voltage difference; calculating the second voltage difference between the output voltage of the resonant conversion circuit at the previous moment and the preset reference voltage, and controlling the output voltage of the resonant conversion circuit and the switching frequency of the switch module in the resonant conversion circuit according to the first voltage difference, the second voltage difference and the target switching frequency, the resonant conversion circuit can be suppressed from being excessively large in the resonant cavity current in the resonant conversion circuit, and the recovery speed of the output voltage of the resonant conversion circuit can be reduced, thereby eliminating the jitter of the output voltage of the resonant conversion circuit. In this way, the effect of suppressing the excessive current of the resonant cavity and reducing the jitter of the voltage waveform of the output voltage can be achieved.

[0068] In a possible implementation, the operation of step S301 may specifically be:

[0069] If the first voltage difference is smaller than the second voltage difference, and the target switching frequency is smaller than the preset switching frequency, the output voltage of the resonant conversion circuit is controlled to reduce the recovery speed of the output voltage of the resonant conversion circuit.

[0070] Optionally, the preset switching frequency is a limited frequency switching frequency set in advance by the user, and the preset switching frequency may be 120kHz, 130kHz, 150kHz, 180kHz, etc., and this application does not make any specific limitation on this.

[0071] Optionally, when the first voltage difference is less than the second voltage difference, that is, the output voltage of the resonant conversion circuit at the current moment is greater than the output voltage of the resonant conversion circuit at the previous moment, it indicates that the output voltage of the resonant conversion circuit is in the voltage recovery stage.

[0072] Optionally, the target switching frequency is less than the preset switching frequency, that is, the switching control frequency calculated in real time by the voltage loop is less than the preset switching control frequency, indicating that the output voltage of the resonant conversion circuit will not drop rapidly, and the actual switching frequency of the switching module in the resonant conversion circuit will not cause a large resonant cavity current.

[0073] Optionally, the target switching frequency being less than the preset switching frequency serves as a prerequisite for the voltage loop to enter the limiting strategy, and the first voltage difference being less than the second voltage difference serves as a decisive condition for the voltage loop to enter the limiting strategy. If the target switching frequency is less than the preset switching frequency, the first voltage difference is less than the second voltage difference, that is, when the output voltage of the resonant conversion circuit is in the voltage recovery stage, the output voltage of the resonant conversion circuit is not controlled, which will cause a large resonant cavity current to be generated in the resonant conversion circuit. Excessive resonant cavity current will damage other electronic devices in the resonant conversion circuit.

[0074] For a possible implementation, see Figure 4 , controlling the output voltage of the resonant conversion circuit, including:

[0075] S401, calculating a difference between a first voltage difference and a second voltage difference.

[0076] Optionally, a difference between the first voltage difference and the second voltage difference is calculated, and whether the resonant conversion circuit is in the voltage recovery stage is determined according to whether the difference between the first voltage difference and the second voltage difference is positive or negative.

[0077] S402: Determine whether the output voltage of the resonant conversion circuit is in a voltage recovery stage according to the difference between the first voltage difference and the second voltage difference.

[0078] Optionally, if the difference between the first voltage difference and the second voltage difference is a negative number, that is, the output voltage of the resonant conversion circuit at the current moment is greater than the output voltage of the resonant conversion circuit at the previous moment, the resonant conversion circuit is in a voltage recovery stage; if the difference between the first voltage difference and the second voltage difference is a positive number, that is, the output voltage of the resonant conversion circuit at the current moment is less than the output voltage of the resonant conversion circuit at the previous moment, the output voltage of the resonant conversion circuit is still falling.

[0079] Exemplarily, the output voltage of the resonant conversion circuit A at the current moment is U1, the output voltage of the resonant conversion circuit A at the previous moment is U0, the preset reference voltage is set to U, the first voltage difference Verr1 between the output voltage of the resonant conversion circuit A at the current moment and the preset reference voltage is U-U1, and the second voltage difference Verr2 between the output voltage of the resonant conversion circuit A at the current moment and the preset reference voltage is U-U0. If the difference between the first voltage difference and the second voltage difference is less than 0, that is, Verr1-Verr2<0, U-U1-U+U0=U0-U1<0, U1>U0, then the output voltage of the resonant conversion circuit A is in the voltage recovery stage.

[0080] S403: Determine a target voltage adjustment amplitude of the resonant conversion circuit according to the first voltage difference and a preset voltage amplitude, and control the output voltage of the resonant conversion circuit according to the target voltage adjustment amplitude.

[0081] Optionally, the preset voltage amplitude is a voltage limit set in advance by the user, and the preset voltage amplitude may be 3V, 5V, 7V, etc. The smaller the preset voltage amplitude, the slower the voltage recovery speed of the resonant conversion circuit. This application does not make any specific limitation on this.

[0082] Optionally, the target voltage regulation amplitude is a target voltage limit determined by the voltage loop according to a comparison result between the first voltage difference and a preset voltage amplitude, and the voltage loop iteratively adjusts the output voltage of the resonant conversion circuit according to the target voltage limit.

[0083] For a possible implementation, see Figure 5 , the above step S402 may specifically be:

[0084] S501: If the first voltage difference is greater than or equal to a preset voltage amplitude, determine that the target voltage adjustment amplitude of the resonant conversion circuit is the preset voltage amplitude.

[0085] Optionally, when the first voltage difference is greater than or equal to a preset voltage amplitude, that is, the voltage regulation amplitude corresponding to the first voltage difference is greater than the voltage regulation amplitude indicated by the preset voltage amplitude, the voltage loop uses the voltage regulation amplitude indicated by the preset voltage amplitude as the target voltage regulation amplitude, and the voltage loop adjusts the output voltage of the resonant conversion circuit according to the preset voltage amplitude so that the output voltage of the resonant conversion circuit slowly recovers.

[0086] S502: If the voltage amplitude is smaller than the preset voltage amplitude, determine the target voltage adjustment amplitude of the resonant conversion circuit to be the first voltage difference.

[0087] Optionally, when the first voltage difference is less than a preset voltage amplitude, that is, the voltage regulation amplitude corresponding to the first voltage difference is less than the voltage regulation amplitude indicated by the preset voltage amplitude, the voltage loop takes the voltage regulation amplitude indicated by the first voltage difference as the target voltage regulation amplitude, and the voltage loop adjusts the output voltage of the resonant conversion circuit according to the first voltage difference so that the output voltage of the resonant conversion circuit slowly recovers.

[0088] Exemplarily, the output voltage of the resonant conversion circuit A at the current moment is U1, the preset reference voltage is set to U, the first voltage difference Verr1 between the output voltage of the resonant conversion circuit A at the current moment and the preset reference voltage is =U-U1, and the preset voltage amplitude is 5V. If the first voltage difference Verr1 between the output voltage of the resonant conversion circuit A at the current moment and the preset reference voltage is greater than 5V, the voltage loop B uses the preset voltage amplitude of 5V as the target voltage adjustment amplitude, and adjusts the output voltage of the resonant conversion circuit A according to the voltage limit of 5V, so that the output voltage of the resonant conversion circuit A slowly recovers; if the first voltage difference Verr1 between the output voltage of the resonant conversion circuit A at the current moment and the preset reference voltage is less than 5V, the voltage loop B uses the first voltage difference Verr1 as the target voltage adjustment amplitude, and adjusts the output voltage of the resonant conversion circuit A according to the voltage limit of Verr1, so that the output voltage of the resonant conversion circuit A slowly recovers.

[0089] In a possible implementation, after the output voltage of the resonant conversion circuit is controlled according to the target voltage adjustment amplitude, the method includes:

[0090] If the output voltage of the resonant conversion circuit reaches a preset reference voltage, the output voltage of the resonant conversion circuit is stopped from being controlled.

[0091] Optionally, when the output voltage of the resonant conversion circuit at the current moment reaches a preset reference voltage, that is, the first voltage difference between the output voltage of the resonant conversion circuit at the current moment and the preset voltage is 0, the voltage loop exits the limiting strategy, and the resonant conversion circuit enters a normal operating state. The voltage loop will no longer control the output voltage of the resonant conversion circuit, and the voltage waveform of the output voltage of the resonant conversion circuit changes with the normal operating state of the resonant conversion circuit.

[0092] Exemplarily, the output voltage of the resonant conversion circuit A at the current moment is U1, and the preset reference voltage is set to U. If the output voltage U1 of the resonant conversion circuit A at the current moment = U, that is, the output voltage of the resonant conversion circuit A at the current moment reaches the preset reference voltage, then the voltage loop B exits the limiting control of the output voltage of the resonant conversion circuit A, and the resonant conversion circuit A returns to a normal operating state.

[0093] In a possible implementation, the above-mentioned resonant conversion control method further includes:

[0094] If the first voltage difference is greater than a preset voltage threshold and the target switching frequency is greater than or equal to a preset switching frequency, the switching frequency of the switching module in the resonant conversion circuit is controlled according to the preset switching frequency to reduce the resonant cavity current of the resonant conversion circuit, wherein the first voltage gain corresponding to the preset switching frequency is greater than the second voltage gain corresponding to the target switching frequency.

[0095] Optionally, the preset voltage threshold is a voltage limit corresponding to the first voltage difference set in advance by the user. The preset voltage threshold may be 5V, 10V, 15V, etc., and this application does not make any specific limitation on this.

[0096] Optionally, when a first voltage difference between the output voltage of the resonant conversion circuit at the current moment and a preset reference voltage is greater than a voltage limit indicated by a preset voltage threshold, the voltage loop will enter a frequency limiting strategy. After the voltage loop enters the frequency limiting strategy, the switching frequency of the switching module in the resonant conversion circuit is controlled according to the switching frequency indicated by a preset switching frequency.

[0097] Optionally, a first voltage difference between the output voltage of the resonant conversion circuit at the current moment and a preset reference voltage is greater than a preset voltage threshold as a trigger condition for the voltage loop to enter a frequency limiting strategy; a target switching frequency calculated by the voltage loop based on the first voltage difference is less than a preset switching frequency as a trigger condition for the voltage loop to exit the frequency limiting strategy.

[0098] Optionally, when a first voltage difference between the output voltage of the resonant conversion circuit at the current moment and a preset reference voltage is greater than a preset voltage threshold, the voltage loop triggers a frequency limiting strategy, and the voltage loop applies corresponding control signals to the gates of Q1 to Q4 in the switch module in the resonant conversion circuit according to a preset switching frequency to regulate the switching frequency of the switch module in the resonant conversion circuit, thereby preventing the output voltage of the resonant conversion circuit from dropping and suppressing the resonant cavity current in the resonant conversion circuit.

[0099] It is worth noting that the higher the switching frequency of the switch module in the resonant conversion circuit, the lower the voltage gain of the resonant conversion circuit; conversely, the lower the switching frequency of the switch module in the resonant conversion circuit, the higher the voltage gain of the resonant conversion circuit.

[0100] Optionally, the first voltage gain is used to indicate the voltage gain corresponding to the resonant conversion circuit when the switching frequency of the switching module in the resonant conversion circuit is the target switching frequency; the second voltage gain is used to indicate the voltage gain corresponding to the resonant conversion circuit when the switching frequency of the switching module in the resonant conversion circuit is the preset switching frequency.

[0101] Optionally, when the target switching frequency is greater than or equal to a preset switching frequency, a first voltage gain corresponding to the target switching frequency is less than a second voltage gain corresponding to the preset switching frequency.

[0102] Exemplarily, the output voltage of the resonant conversion circuit A at the current moment is U2, the preset reference voltage is set to U, the first voltage difference Verr1 between the output voltage of the resonant conversion circuit A at the current moment and the preset reference voltage is U-U2, and the preset voltage threshold is 10V. If the first voltage difference Verr1 is greater than the preset voltage threshold 10V, the voltage loop B enters the frequency limiting strategy, and the preset switching frequency is 150kHz. The voltage loop B controls the switching frequency of the switching module in the resonant conversion circuit A at 150kHz, wherein the voltage gain M corresponding to the switching frequency of 150kHz is greater than the voltage gain N corresponding to the switching frequency of 200kHz when the resonant conversion circuit is unloaded.

[0103] In a possible implementation, after controlling the switching frequency of the switch module in the resonant conversion circuit according to a preset switching frequency, the method includes:

[0104] If the target switching frequency is less than the preset switching frequency, the switching frequency of the switch module in the resonant conversion circuit is stopped from being controlled.

[0105] Optionally, when the target switching frequency calculated in real time by the voltage loop is lower than the switching control frequency indicated by the preset switching frequency, the voltage loop exits the frequency limiting strategy, and the voltage loop no longer controls the switching frequency of the switching module in the resonant conversion circuit.

[0106] Exemplarily, the voltage loop B calculates the first voltage difference Verr1 between the output voltage U2 of the resonant conversion circuit A at the current moment and the preset reference voltage U, and generates a target switching frequency K based on the first voltage difference Verr1. The preset switching frequency is 150kHz. If the target switching frequency K corresponding to the first voltage difference Verr1 is lower than the preset switching frequency of 150kHz, the voltage loop B exits the frequency limiting strategy, and the voltage loop B controls the switching frequency of the switching module in the resonant conversion circuit A according to the target switching frequency K.

[0107] Figure 6 This is a resonant cavity current waveform diagram without frequency limiting provided in this application, see Figure 6 In the current waveform diagram of the resonant cavity without frequency limiting provided in the present application, after the output voltage at the load end suddenly increases during the sudden loading process of the resonant conversion circuit, the output voltage of the resonant conversion circuit is rapidly pulled down by the load resistance, and the current in the resonant cavity increases rapidly, eventually causing the protection to be triggered by excessive current.

[0108] Figure 7 For the first frequency-limited resonant cavity current waveform diagram provided in this application, see Figure 7 The resonant cavity current waveform diagram with frequency limiting provided in the present application is used to indicate that the output voltage of the resonant conversion circuit is 1000V, and the resonant conversion circuit is in a large dynamic switching from no-load to full-load. After the voltage loop increases the frequency limiting, when the output voltage of the resonant conversion circuit drops, the voltage loop will control the switching frequency of the switching module in the resonant conversion circuit so that the output voltage of the resonant conversion circuit recovers smoothly, and the resonant cavity current of the resonant conversion circuit has basically no overcurrent shock.

[0109] Figure 8 For the resonant cavity current waveform diagram of the second frequency limiting treatment provided by this application, see Figure 8 The resonant cavity current waveform diagram with frequency limiting provided in the present application is used to indicate that the output voltage of the resonant conversion circuit is 510V, and the resonant conversion circuit is in a large dynamic switching from no-load to full-load. After the voltage loop increases the frequency limiting, when the output voltage of the resonant conversion circuit drops, the voltage loop will control the switching frequency of the switching module in the resonant conversion circuit so that the output voltage of the resonant conversion circuit recovers smoothly, and the resonant cavity current of the resonant conversion circuit has basically no overcurrent shock.

[0110] The specific implementation process and technical effects of the device, power conversion module and charging device used to execute the resonant conversion control method provided by the present application are as mentioned above and will not be repeated below.

[0111] Fig. 9 is a schematic diagram of a resonant conversion control device provided in an embodiment of the present application, see Fig. 9 , the device comprises:

[0112] An acquisition module 901 is used to acquire the output voltage of the resonant conversion circuit in real time;

[0113] A determination module 902 is used to determine a target switching frequency corresponding to a switch module in the resonant conversion circuit at the current moment according to a first voltage difference between an output voltage at the current moment and a preset reference voltage;

[0114] The control module 903 is used to control the output voltage of the resonant conversion circuit according to the first voltage difference, the target switching frequency and the second voltage difference between the output voltage at the previous moment and the preset reference voltage to reduce the recovery speed of the output voltage of the resonant conversion circuit.

[0115] In a possible implementation, the control module 903 is specifically used to:

[0116] If the first voltage difference is smaller than the second voltage difference, and the target switching frequency is smaller than the preset switching frequency, the output voltage of the resonant conversion circuit is controlled to reduce the recovery speed of the output voltage of the resonant conversion circuit.

[0117] In a possible implementation, the control module 903 is specifically used to:

[0118] calculating a difference between the first voltage difference and the second voltage difference;

[0119] Determining whether the output voltage of the resonant conversion circuit is in a voltage recovery stage according to the difference between the first voltage difference and the second voltage difference;

[0120] If so, a target voltage adjustment amplitude of the resonant conversion circuit is determined according to the first voltage difference and the preset voltage amplitude, and the output voltage of the resonant conversion circuit is controlled according to the target voltage adjustment amplitude.

[0121] In a possible implementation, the control module 903 is specifically used to:

[0122] If the first voltage difference is greater than or equal to a preset voltage amplitude, determining the target voltage adjustment amplitude of the resonant conversion circuit to be the preset voltage amplitude;

[0123] If the first voltage difference is smaller than the preset voltage amplitude, the target voltage adjustment amplitude of the resonant conversion circuit is determined to be the first voltage difference.

[0124] In a possible implementation, after the output voltage of the resonant conversion circuit is controlled according to the target voltage adjustment amplitude, the control module 903 is specifically used to:

[0125] If the output voltage of the resonant conversion circuit reaches a preset reference voltage, the output voltage of the resonant conversion circuit is stopped from being controlled.

[0126] In a possible implementation, the control module 903 is further configured to:

[0127] If the first voltage difference is greater than a preset voltage threshold and the target switching frequency is greater than or equal to a preset switching frequency, the switching frequency of the switching module in the resonant conversion circuit is controlled according to the preset switching frequency to reduce the resonant cavity current of the resonant conversion circuit, wherein the first voltage gain corresponding to the preset switching frequency is greater than the second voltage gain corresponding to the target switching frequency.

[0128] In a possible implementation, after controlling the switching frequency of the switch module in the resonant conversion circuit according to a preset switching frequency, the control module 903 is specifically used to:

[0129] If the target switching frequency is less than the preset switching frequency, the switching frequency of the switch module in the resonant conversion circuit is stopped from being controlled.

[0130] The above-mentioned device is used to execute the method provided by the aforementioned embodiment, and its implementation principle and technical effect are similar, which will not be repeated here.

[0131] The above modules may be one or more integrated circuits configured to implement the above methods, such as one or more application specific integrated circuits (ASICs), or one or more microprocessors, or one or more field programmable gate arrays (FPGAs). For another example, when a module is implemented in the form of a processing element scheduling program code, the processing element may be a general-purpose processor, such as a central processing unit (CPU) or other processor that can call program code. For another example, these modules may be integrated together and implemented in the form of a system-on-a-chip (SOC).

[0132] Fig.10 is a schematic diagram of a power conversion module provided in an embodiment of the present application, see Fig.10 The power conversion module 10 provided in the present application includes: a resonant conversion circuit 101 and a controller 102. The controller 102 is used to implement the steps in any of the above method embodiments when executing a computer program.

[0133] Fig.11 is a schematic diagram of a charging device provided in an embodiment of the present application, see Fig.11 The charging device 20 provided in the present application includes the above-mentioned power conversion module 10.

[0134] In the several embodiments provided by the present invention, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0135] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0136] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0137] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A resonant conversion control method, characterized in that: The method comprises: Obtain the output voltage of the resonant conversion circuit in real time; Determine a target switching frequency corresponding to a switch module in the resonant conversion circuit at the current moment according to a first voltage difference between an output voltage at the current moment and a preset reference voltage; The output voltage of the resonant conversion circuit is controlled according to the first voltage difference, the target switching frequency, and a second voltage difference between the output voltage at a previous moment and a preset reference voltage to reduce a recovery speed of the output voltage of the resonant conversion circuit.

2. The resonant conversion control method according to claim 1, characterized in that: The controlling the output voltage of the resonant conversion circuit according to the first voltage difference, the target switching frequency, and a second voltage difference between the output voltage at a previous moment and a preset reference voltage includes: If the first voltage difference is smaller than the second voltage difference, and the target switching frequency is smaller than a preset switching frequency, the output voltage of the resonant conversion circuit is controlled to reduce a recovery speed of the output voltage of the resonant conversion circuit.

3. The resonant conversion control method according to claim 2, characterized in that: The controlling the output voltage of the resonant conversion circuit comprises: calculating a difference between the first voltage difference and the second voltage difference; determining, according to a difference between the first voltage difference and the second voltage difference, whether the output voltage of the resonant conversion circuit is in a voltage recovery stage; If so, a target voltage adjustment amplitude of the resonant conversion circuit is determined according to the first voltage difference and a preset voltage amplitude, and the output voltage of the resonant conversion circuit is controlled according to the target voltage adjustment amplitude.

4. The resonant conversion control method according to claim 3, characterized in that: Determining a target voltage adjustment amplitude of the resonant conversion circuit according to the first voltage difference and a preset voltage amplitude includes: If the first voltage difference is greater than or equal to a preset voltage amplitude, determining the target voltage adjustment amplitude of the resonant conversion circuit to be the preset voltage amplitude; If the first voltage difference is less than the preset voltage amplitude, the target voltage adjustment amplitude of the resonant conversion circuit is determined to be the first voltage difference.

5. The resonant conversion control method according to claim 3, characterized in that: After the output voltage of the resonant conversion circuit is controlled by adjusting the amplitude according to the target voltage, the method includes: If the output voltage of the resonant conversion circuit reaches a preset reference voltage, the output voltage of the resonant conversion circuit is stopped from being controlled.

6. The resonant conversion control method according to claim 1, characterized in that: The method further comprises: If the first voltage difference is greater than a preset voltage threshold and the target switching frequency is greater than or equal to a preset switching frequency, the switching frequency of the switching module in the resonant conversion circuit is controlled according to the preset switching frequency to reduce the resonant cavity current of the resonant conversion circuit, wherein the first voltage gain corresponding to the preset switching frequency is greater than the second voltage gain corresponding to the target switching frequency.

7. The resonant conversion control method according to claim 6, characterized in that: After the switching frequency of the switch module in the resonant conversion circuit is controlled according to the preset switching frequency, the method further comprises: If the target switching frequency is less than the preset switching frequency, the switching frequency of the switch module in the resonant conversion circuit is stopped from being controlled.

8. A resonant conversion control device, characterized in that: The device comprises: An acquisition module, used for acquiring the output voltage of the resonant conversion circuit in real time; A determination module, used to determine a target switching frequency corresponding to a switch module in the resonant conversion circuit at a current moment according to a first voltage difference between an output voltage at a current moment and a preset reference voltage; A control module is used to control the output voltage of the resonant conversion circuit according to the first voltage difference, the target switching frequency, and a second voltage difference between the output voltage at a previous moment and a preset reference voltage, so as to reduce the recovery speed of the output voltage of the resonant conversion circuit.

9. A power conversion module, characterized in that: The power conversion module comprises: a resonant conversion circuit and a controller, wherein the controller is used to execute the steps of the resonant conversion control method according to any one of claims 1 to 7.

10. A charging device, characterized in that: The charging device comprises the power conversion module according to claim 9.

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