Bidirectional DC-DC control method, control system and readable storage medium

Abstract

The invention relates to the technical field of circuit control, in particular to a bidirectional DC-DC control method which comprises the following steps: setting forward and reverse modes of a bidirectional phase-shifted full bridge, and after a mode selection instruction is acquired, selecting a mode flag bit according to data analysis to perform mode selection; wherein the forward mode is a Buck mode, that is, a primary side current peak value is automatically limited through a peak current control mode; and the reverse mode is a Boost mode, that is, phase shift control is realized through a voltage control mode, and the output PWM duty ratio signal is controlled through the two modes, so that a peak current control mode and a cycle-by-cycle current limiting function can be realized more easily.

Description

Technical Field

[0001] The present invention relates to the field of circuit control technology, and in particular to a bidirectional DC-DC control method, a control system and a readable storage medium. Background Art

[0002] With the development and update of materials for making power electronic devices, the operating frequencies that switching tubes can adapt to are getting higher and higher, making DC / DC converters also develop towards high frequency. The current soft switching technology application circuit topology mostly adopts a simple structure of LLC, and the mainstream control method is PFM. The frequency modulation control is difficult to control, and it is not easy to quickly respond and control the switching of the peak current control mode with high precision, resulting in the inability to achieve the cycle-by-cycle current limiting function.

[0003] Therefore, how to quickly respond and control the switching of the peak current control mode with high precision, which leads to the inability to achieve the cycle-by-cycle current limiting function, is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0004] The invention provides a bidirectional DC-DC control method, a control system and a readable storage medium.

[0005] In order to solve the above technical problems, the present invention provides a bidirectional DC-DC control method comprising: A forward and reverse mode of a bidirectional phase-shifted full bridge is provided, and after obtaining a mode selection instruction, a mode flag is selected according to data analysis to select a mode; wherein The forward mode is Buck mode, which automatically limits the primary current peak through the peak current control mode; and The reverse mode is the Boost mode, that is, phase shift control is achieved through the voltage control mode.

[0006] When executing Buck mode, the methods for automatically limiting the primary current peak through peak current control mode include: Initialize the EPWM module to respond; By sampling the primary peak current signal into an analog comparator, the output voltage corresponding to the primary peak current signal is calculated by the PI controller and then assigned to the maximum given value of the analog comparator; When the maximum given value of the analog comparator is greater than the fixed output value of the voltage loop, the direction of the counter is determined through the interrupt processing of the EPWM module, thereby generating a corresponding PWM duty cycle signal.

[0007] The method for determining the direction of the counter and then generating a corresponding PWM duty cycle signal includes: If the counter is counting upward, EPWM2A is pulled low and EPWM2B is pulled high; or If the counter is counting down, EPWM2A is pulled high and EPWM2B is pulled low.

[0008] When executing the Boost mode, the method of implementing phase shift control through the voltage control mode includes: Configure to turn off the interrupt signal triggered by the analog comparator; By collecting the feedback signal of the output voltage, the output PWM duty cycle signal is controlled through the PI controller, and the two time base signals EPWM3B and EPWM5B are configured to be 180 degrees out of phase. Through the Up-Down counter mode, the two waveforms are output once every cycle to control the full-bridge inverter.

[0009] The beneficial effect of the present invention is that the present invention is provided with a forward and reverse mode of a bidirectional phase-shifted full-bridge, and a mode is selected according to a mode flag bit selected by data analysis. In the two modes, the output voltage is collected and processed by a PI controller to control the output PWM duty cycle signal, making it easier to realize the peak current control mode and the cycle-by-cycle current limiting function.

[0010] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description and the drawings.

[0011] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0013] Figure 1 A flow chart showing a bidirectional DC-DC control method according to some embodiments; Figure 2 A flowchart of the Buck mode involved in some embodiments is shown; Figure 3 A flowchart of the Boost mode involved in some embodiments is shown; Figure 4 A circuit schematic diagram of a bidirectional DC-DC control system according to some embodiments is shown. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] like Figure 1 As shown, at least one embodiment provides a bidirectional DC-DC control method, including forward and reverse modes provided with a bidirectional phase-shifted full-bridge, and after obtaining a mode selection instruction, selecting a mode according to a mode flag bit through data analysis; wherein the forward mode is a Buck mode, that is, the primary current peak is automatically limited through a peak current control mode; and the reverse mode is a Boost mode, that is, phase shift control is achieved through a voltage control mode.

[0016] Specifically, MOD Select is a variable or control bit used to select the operating mode of the converter. If "MOD Select" is set to 1 (Yes), the power converter will be configured in Buck mode; if "MOD Select" is set to 0 (No), the power converter will be configured in Boost mode.

[0017] like Figure 2 As shown, when executing Buck mode, the method of automatically limiting the primary current peak through the peak current control mode includes: initializing the EPWM module (referring to the enhanced pulse width modulation module in the digital signal processor) that responds; in some embodiments, it is necessary to configure parameters of the GPIO module (also called General Purpose Input / Output Module, which provides a series of programmable digital input and output pins that can be configured as input or output modes), the ADC module (also called Analog-to-Digital Converter Module), etc.

[0018] By sampling the primary peak current signal into an analog comparator, the output voltage corresponding to the primary peak current signal is calculated by the PI controller and then assigned to the maximum given value of the analog comparator; when the maximum given value of the analog comparator is greater than the fixed output value of the voltage loop, In some embodiments, the voltage loop output entering the comparator is first judged whether it is greater than the peak current sampling signal. If it is judged to be less than or equal to the peak current sampling signal, the primary peak current signal continues to be collected; if it is greater than the peak current sampling signal, the interrupt processing of the EPWM module (referring to the interrupt of the control period event in the digital signal processor) is used to judge the direction of the counter, and then generate a corresponding PWM duty cycle signal.

[0019] Specifically, the method for determining the direction of the counter and then generating a corresponding PWM duty cycle signal includes: if the counter is counting upward, EPWM2A (referring to an output channel in the enhanced pulse width modulation module) is pulled low and EPWM2B (referring to the second output channel in the enhanced pulse width modulation module) is pulled high; if the counter is counting downward, EPWM2A is pulled high and EPWM2B is pulled low.

[0020] like Figure 3 As shown, when executing the Boost mode, the method for realizing phase shift control through the voltage control mode includes: configuring to turn off the interrupt signal triggered by the analog comparator; controlling the output PWM duty cycle signal through the PI controller by collecting the feedback signal of the output voltage, configuring the two time base signals EPWM3B (referring to the third output channel in the enhanced pulse width modulation module) and EPWM5B (referring to the fifth output channel in the enhanced pulse width modulation module) to be 180 degrees out of phase, and through the Up-Down counter mode (in some embodiments, the "Up-Down counter mode" refers to the counter counting down after reaching the maximum value, or counting up after reaching the minimum value, forming a periodic counting mode), so that the two waveforms are output once a cycle to control the full-bridge inverter.

[0021] like Figure 4 As shown, in some embodiments, a bidirectional DC-DC control system is provided, including: a full-bridge inverter module; a synchronous rectifier module, the synchronous rectifier module is electrically connected to the full-bridge inverter module through a transformer; and a control module, which is electrically connected to the full-bridge inverter module and the synchronous rectifier module respectively: wherein the control module is configured to collect a feedback signal of the output voltage of the synchronous rectifier module, and output a corresponding control PWM control signal to the full-bridge inverter module according to a mode selection.

[0022] Furthermore, the control module is configured to output a corresponding control PWM control signal to the full-bridge inverter module according to the mode selection, including a forward and reverse mode of a bidirectional phase-shifted full-bridge, and after obtaining the mode selection instruction, select the mode flag according to data analysis to perform mode selection; wherein the forward mode is the Buck mode, that is, the primary current peak is automatically limited through the peak current control mode; and the reverse mode is the Boost mode, that is, phase shift control is achieved through the voltage control mode.

[0023] Specifically, when executing the Buck mode, the primary current peak is automatically limited through the peak current control mode; that is, the EPWM module that responds is initialized; the primary peak current signal is sampled into an analog comparator, and the output voltage corresponding to the collected primary peak current signal is calculated by the PI controller, and then assigned to the maximum given value of the analog comparator; when the maximum given value of the analog comparator is greater than the fixed output value of the voltage loop, the interrupt processing of the EPWM module is used to determine the direction of the counter, and then generate a corresponding PWM duty cycle signal.

[0024] Specifically, the method for determining the direction of the counter and then generating the corresponding PWM duty cycle signal includes: if the counter is counting upward, EPWM2A is pulled low and EPWM2B is pulled high. If the counter is counting downward, EPWM2A is pulled high and EPWM2B is pulled low.

[0025] Furthermore, when executing the Boost mode, phase shift control is achieved through the voltage control mode, that is, the interrupt signal triggered by the analog comparator is configured to be turned off; the output PWM duty cycle signal is controlled by the PI controller through the collected output voltage feedback signal, and the two time base signals EPWM3B and EPWM5B are configured to be 180 degrees apart in phase, and through the Up-Down counter mode, the two waveforms are made to output a PWM waveform once every cycle to control the full-bridge inverter.

[0026] In some embodiments, a readable storage medium is provided, which stores readable instructions, and when the readable instructions are executed by at least one control module, the bidirectional DC-DC control method as described above is executed.

[0027] Some embodiments provide a program product, including a program or an instruction, wherein when the program or the instruction is executed on a control module, the control module is enabled to perform the bidirectional DC-DC control method as described above.

[0028] In some embodiments, the control module is implemented using a control module such as, but not limited to, a DSP.

[0029] In summary, the present invention is provided with a forward and reverse mode of a bidirectional phase-shifted full bridge, and the mode is selected according to the mode flag bit of data analysis. In the two modes, the output voltage is collected and processed by the PI controller to control the output PWM duty cycle signal, making it easier to realize the peak current control mode and the cycle-by-cycle current limiting function. In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0031] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. With the above-mentioned ideal embodiments of the present invention as inspiration, through the above-mentioned description, relevant staff can make various changes and modifications without departing from the scope of the technical idea of ​​the present invention. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A bidirectional DC-DC control method, characterized in that: include: A forward and reverse mode of a bidirectional phase-shifted full bridge is provided, and after obtaining a mode selection instruction, a mode selection is performed according to a mode flag bit selected by data analysis; in The forward mode is Buck mode, which automatically limits the primary current peak through the peak current control mode; and The reverse mode is the Boost mode, that is, phase shift control is achieved through the voltage control mode.

2. The bidirectional DC-DC control method according to claim 1, characterized in that: When executing Buck mode, the methods for automatically limiting the primary current peak through peak current control mode include: Initialize the EPWM module to respond; By sampling the primary peak current signal into an analog comparator, the output voltage corresponding to the primary peak current signal is calculated by the PI controller and then assigned to the maximum given value of the analog comparator; When the maximum given value of the analog comparator is greater than the fixed output value of the voltage loop, the direction of the counter is determined through the interrupt processing of the EPWM module, thereby generating a corresponding PWM duty cycle signal.

3. The bidirectional DC-DC control method according to claim 2, characterized in that: The method for determining the direction of the counter and then generating a corresponding PWM duty cycle signal includes: If the counter is counting upward, EPWM2A is pulled low and EPWM2B is pulled high; or If the counter is counting down, EPWM2A is pulled high and EPWM2B is pulled low.

4. The bidirectional DC-DC control method according to claim 1, characterized in that: When executing the Boost mode, the method of implementing phase shift control through the voltage control mode includes: Configure to turn off the interrupt signal triggered by the analog comparator; By collecting the feedback signal of the output voltage, the output PWM duty cycle signal is controlled through the PI controller, and the two time base signals EPWM3B and EPWM5B are configured to be 180 degrees out of phase. Through the Up-Down counter mode, the two waveforms are output once every cycle to control the full-bridge inverter.

5. A bidirectional DC-DC control system, characterized in that: include: Full-bridge inverter module; A synchronous rectification module, wherein the synchronous rectification module is electrically connected to the full-bridge inverter module via a transformer; as well as A control module is electrically connected to the full-bridge inverter module and the synchronous rectification module respectively: The control module is configured to collect a feedback signal of the output voltage of the synchronous rectification module, and output a corresponding control PWM control signal to the full-bridge inverter module according to the mode selection.

6. The bidirectional DC-DC control system according to claim 5, characterized in that: The control module is configured to output a corresponding control PWM control signal to the full-bridge inverter module according to the mode selection, including: A forward and reverse mode of a bidirectional phase-shifted full bridge is provided, and after obtaining a mode selection instruction, a mode flag is selected according to data analysis to select a mode; wherein The forward mode is Buck mode, which automatically limits the primary current peak through the peak current control mode; and The reverse mode is the Boost mode, that is, phase shift control is achieved through the voltage control mode.

7. The bidirectional DC-DC control system according to claim 6, characterized in that: When executing Buck mode, the peak current control mode is used to automatically limit the primary current peak value; that is, Initialize the EPWM module to respond; By sampling the primary peak current signal into an analog comparator, the output voltage corresponding to the primary peak current signal is calculated by the PI controller and then assigned to the maximum given value of the analog comparator; When the maximum given value of the analog comparator is greater than the fixed output value of the voltage loop, the direction of the counter is determined through the interrupt processing of the EPWM module, thereby generating a corresponding PWM duty cycle signal.

8. The bidirectional DC-DC control system according to claim 7, characterized in that: The method for determining the direction of the counter and then generating a corresponding PWM duty cycle signal includes: If the counter is counting upward, EPWM2A is pulled low and EPWM2B is pulled high; or If the counter is counting down, EPWM2A is pulled high and EPWM2B is pulled low.

9. The bidirectional DC-DC control system according to claim 8, characterized in that: When executing the Boost mode, phase shift control is achieved through the voltage control mode, that is, Configure to turn off the interrupt signal triggered by the analog comparator; By collecting the feedback signal of the output voltage, the output PWM duty cycle signal is controlled through the PI controller, and the two time base signals EPWM3B and EPWM5B are configured to be 180 degrees out of phase. Through the Up-Down counter mode, the two waveforms are output once every cycle to control the full-bridge inverter.

10. A readable storage medium storing readable instructions, which, when executed by at least one control module, enables the bidirectional DC-DC control method according to any one of claims 1 to 4 to be executed.

11. A program product, comprising a program or an instruction, wherein when the program or the instruction is executed on a control module, the control module is enabled to execute the bidirectional DC-DC control method according to any one of claims 1 to 4.

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