Power module control method and system based on three-phase SEPIC isolation topology

Abstract

The invention provides a power module control method based on a three-phase SEPIC isolation topology, and the method comprises the steps: calculating an output voltage modulation value according to an output voltage sampling value, an output voltage target value and an output current sampling value of a power module; according to the output voltage modulation value, the duty ratio or the switching frequency of a switching tube of each single-phase converter unit in the power module is calculated; and generating a PWM driving signal for the switching tube of each single-phase converter unit in combination with SPWM modulation according to the duty ratio or the switching frequency. According to the control method of the power module based on the three-phase SEPIC isolation topology, output voltage is used as an outer loop, output current is used as an inner loop, the duty ratio or frequency of a switching tube in the power module is calculated through obtained loop output, and then the power module is controlled in an SPWM mode; therefore, input current is not needed, control is simple, and cost can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of charging pile power modules, and more particularly, to a control method and system for a power module based on a three-phase SEPIC isolation topology. Background Art

[0002] The core of a charging pile is the power module. Currently, most power modules use a two-stage topology. Using a one-stage topology eliminates the need for intermediate decoupling capacitors, reducing costs. Typical first-stage topologies for charging pile power modules include SWISS full-bridge isolation, three-phase SEPIC isolation, and simplified matrix converters.

[0003] The three-phase SEPIC isolation topology uses two control methods: using the output voltage and output current competition loop as the outer loop, the input current as the inner loop, and SPWM modulation to control the power module; and using the output voltage as the outer loop, the output current as the inner loop, and the input current as the innermost loop, and SPWM modulation to control the power module. All of these control methods require sampling of the output voltage, output current, and input current, resulting in higher power module costs and complex control methods.

[0004] Based on this, a new solution is needed. Summary of the Invention

[0005] The purpose of the present invention is to provide a control method and system for a power module based on a three-phase SEPIC isolation topology, so as to reduce the cost of the power module and simplify the control method.

[0006] According to one aspect of the present invention, a control method for a power module based on a three-phase SEPIC isolation topology is provided, wherein the power module includes three identical single-phase converter units, and the method is characterized in that the method comprises the following steps:

[0007] Calculating an output voltage modulation value according to an output voltage sampling value, an output voltage target value, and an output current sampling value of the power module;

[0008] Calculating the duty cycle or switching frequency of the switch tube of each of the single-phase converter units in the power module according to the output voltage modulation value; and

[0009] According to the duty cycle or the switching frequency, a PWM driving signal is generated for the switching tube of each single-phase converter unit in combination with SPWM modulation.

[0010] In the control method of a power module based on a three-phase SEPIC isolation topology provided by the present invention, the step of calculating the output voltage modulation value according to the output voltage sampling value, the output voltage target value, and the output current sampling value of the power module includes:

[0011] Subtracting the output voltage sample value from the output voltage target value to obtain an output voltage error value;

[0012] Using an output voltage controller to adjust the output voltage error value to obtain an output current target value;

[0013] Obtaining an output current error value by subtracting the output current sampling value from the output current target value; and

[0014] The output current controller is used to adjust the output current error value to obtain the output voltage modulation value.

[0015] In the control method of a power module based on a three-phase SEPIC isolation topology provided by the present invention, the step of calculating the duty cycle of the switch tube of each single-phase converter unit in the power module according to the output voltage modulation value includes:

[0016] Calculating a duty cycle modulation coefficient based on the output voltage target value and the input line voltage peak value;

[0017] The duty cycle of the switch tube is obtained based on the product of the output voltage modulation value and the duty cycle modulation coefficient.

[0018] In the control method of a power module based on a three-phase SEPIC isolation topology provided by the present invention, the step of calculating the switching frequency of the switch tube of each single-phase converter unit in the power module according to the output voltage modulation value includes:

[0019] Calculating a switching frequency modulation coefficient based on the output voltage target value;

[0020] The switching frequency of the switching tube is obtained based on the product of the output voltage modulation value and the switching frequency modulation coefficient.

[0021] According to another aspect of the present invention, a control system for a power module based on a three-phase SEPIC isolation topology is provided, wherein the power module includes three identical single-phase converter units and is characterized in that it includes:

[0022] A first calculation module is used to calculate an output voltage modulation value according to an output voltage sampling value, an output voltage target value and an output current sampling value of the power module;

[0023] a second calculation module, configured to calculate a duty cycle or a switching frequency of a switch tube of each of the single-phase converter units in the power module according to the output voltage modulation value; and

[0024] A signal generating module is used to generate a PWM driving signal for the switching tube of each single-phase converter unit according to the duty cycle or the switching frequency in combination with SPWM modulation.

[0025] In the control system of the power module based on the three-phase SEPIC isolation topology provided by the present invention, the first calculation module includes:

[0026] an output voltage error value calculation unit, configured to obtain an output voltage error value by subtracting the output voltage sampling value from the output voltage target value;

[0027] an output current target value calculation unit, configured to adjust the output voltage error value using an output voltage controller to obtain an output current target value;

[0028] an output current error value calculation unit, configured to obtain an output current error value by subtracting the output current sampling value from the output current target value; and

[0029] The output voltage modulation value calculation unit is used to adjust the output current error value by using an output current controller to obtain the output voltage modulation value.

[0030] In the control system of the power module based on the three-phase SEPIC isolation topology provided by the present invention, the second calculation module includes:

[0031] a duty cycle modulation coefficient calculation unit, configured to calculate a duty cycle modulation coefficient based on the output voltage target value and the input line voltage peak value;

[0032] A duty cycle calculation unit is used to obtain the duty cycle of the switch tube based on the product of the output voltage modulation value and the duty cycle modulation coefficient.

[0033] In the control system of the power module based on the three-phase SEPIC isolation topology provided by the present invention, the second calculation module includes:

[0034] a switching frequency modulation coefficient calculation unit, configured to calculate a switching frequency modulation coefficient based on the output voltage target value;

[0035] A switching frequency calculation unit is used to obtain the switching frequency of the switching tube based on the product of the output voltage modulation value and the switching frequency modulation coefficient.

[0036] Implementing the control method and system for a power module based on a three-phase SEPIC isolation topology of the present invention has the following beneficial effects: The control method for a power module based on a three-phase SEPIC isolation topology provided by the present invention uses the output voltage as the outer loop and the output current as the inner loop. The resulting loop output is used to calculate the duty cycle or frequency of the switching transistors in the power module, and then uses SPWM modulation to control the power module. Thus, the duty cycle or switching frequency of the switching transistors in each single-phase converter unit is directly calculated based on the output voltage sampled value, output voltage target value, output current sampled value of the power module, and the duty cycle modulation coefficient or switching frequency modulation coefficient, simplifying control. Furthermore, no input current is required, further reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only embodiments of the present invention. Those skilled in the art can also derive other drawings based on the provided drawings without inventive work.

[0038] Figure 1 Shown is a diagram of a three-phase isolation topology structure based on SEPIC used in the present invention;

[0039] Figure 2 FIG2 is a flow chart of a control method for a power module based on a three-phase SEPIC isolation topology provided by the present invention. DETAILED DESCRIPTION

[0040] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The drawings illustrate exemplary embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present invention.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0042] Figure 1 Shown is a diagram of a three-phase isolation topology structure based on SEPIC used in the present invention; Figure 2 FIG. 1 is a flow chart of a control method for a power module based on a three-phase SEPIC isolation topology provided by the present invention. Figure 1As shown, the control method of the power module based on the three-phase SEPIC isolation topology provided by the present invention includes the following steps:

[0043] Step S1, calculating an output voltage modulation value according to an output voltage sampling value, an output voltage target value, and an output current sampling value of the power module;

[0044] Specifically, in one embodiment of the present invention, an output voltage outer loop and an input current inner loop control method are used to generate an output voltage modulation value. First, the output voltage of the power module is sampled to obtain an output voltage sampling value Vo; then, the output voltage sampling value Vo is subtracted from the output voltage target value VoRef to obtain an output voltage error value, wherein the output voltage target value VoRef in the output voltage outer loop is set according to the operating conditions required for the power module to operate; the output voltage controller uses a voltage regulator to adjust the output voltage error value through a feedback adjustment algorithm to obtain the output voltage controller output value, namely, the output current target value IoRef. Secondly, the output current of the power module is sampled to obtain an output current sampling value Io; then, the output current sampling value is subtracted from the output current target value IoRef to obtain an output current error value; and the output current controller uses a current regulator to adjust the output current error value through a feedback adjustment algorithm to obtain the output current controller output value, which is the output voltage modulation value Vo_Mod.

[0045] Therefore, step S1 includes: subtracting the output voltage sampling value from the output voltage target value to obtain an output voltage error value; adjusting the output voltage error value using an output voltage controller to obtain an output current target value; subtracting the output current sampling value from the output current target value to obtain an output current error value; and adjusting the output current error value using an output current controller to obtain the output voltage modulation value.

[0046] In this embodiment, voltage and current stabilization control is achieved by using an output voltage outer loop and an output current inner loop. Thus, the system output is regulated by a feedback mechanism without the need for direct sampling of the input current. The output voltage outer loop is used to achieve a stable output voltage through feedback control, and static and dynamic regulation of the output voltage is adopted; the output current inner loop is used to achieve a stable output current through feedback control, and static and dynamic regulation of the output current is adopted. Thus, the power module can be controlled based on the output voltage, output current, and input voltage without sampling the input current. Through this control method, the power module can be effectively and accurately controlled based on the feedback of the output voltage, output current, and input voltage to achieve stable output voltage and current without the need for complex input current sampling.

[0047] Step S2: calculating the duty cycle or switching frequency of the switch tube of each of the single-phase converter units in the power module according to the output voltage modulation value;

[0048] Specifically, in one embodiment of the present invention, the duty cycle of the input three-phase switching transistor is calculated using the output voltage modulation value. Specifically, the output voltage modulation value is multiplied by the coefficient K_Vo2Duty to obtain the duty cycle for each single-phase converter unit, where K_Vo2Duty is equal to VoRef / (Voref+uinPeak), and uinPeak is the peak value of the input line voltage. Therefore, in one embodiment of the present invention, step S2 includes: calculating the duty cycle modulation coefficient based on the output voltage target value and the peak value of the input line voltage; and obtaining the duty cycle of the switching transistor based on the product of the output voltage modulation value and the duty cycle modulation coefficient.

[0049] Specifically, in another embodiment of the present invention, the output voltage modulation value is used to calculate the frequency of the input three-phase switching transistors. Specifically, the output voltage modulation value is multiplied by the coefficient K_Vo2Fs to obtain the switching frequency for each single-phase converter unit, where K_Vo2Fs is equal to 500,000 / Voref. Therefore, in one embodiment of the present invention, step S2 includes: calculating the switching frequency modulation coefficient based on the output voltage target value; and obtaining the switching frequency of the switching transistor based on the product of the output voltage modulation value and the switching frequency modulation coefficient.

[0050] In input current control, the input current is controlled using the phase and amplitude of the input current target value to ensure that Thdi meets the requirements. In non-input current control, the duty cycle or frequency is directly determined through loop control. In this topology, energy transfer occurs when the switch is off. Due to the DC blocking capacitor and input inductor energy storage elements, the energy transferred backward by the switch varies at different input voltages while the duty cycle remains constant. The input current changes with the input voltage, causing it to follow the input voltage phase, ensuring that Thdi meets the requirements.

[0051] Step S3: Generate a PWM drive signal for the switch tube of each single-phase converter unit according to the duty cycle or the switching frequency in combination with SPWM modulation.

[0052] Specifically, in one embodiment of the present invention, the SPWM principle is used to obtain the PWM drive signal required by the switch. The duty cycle of each single-phase converter unit is input, and according to the SPWM modulation principle, the input A-phase PWM is obtained. The input A-phase PWM serves as the input A-phase switch drive signal. The B-phase duty cycle is input, and according to the SPWM modulation principle, the input B-phase PWM is obtained. The input B-phase PWM serves as the input B-phase switch drive signal. The C-phase duty cycle is input, and according to the SPWM modulation principle, the input C-phase PWM serves as the input C-phase switch drive signal.

[0053] Specifically, in another embodiment of the present invention, the SPWM principle is used to obtain the PWM drive signal required by the switch. Specifically, the A-phase switching frequency is input, a fixed duty cycle is given, and the SPWM modulation principle is used to obtain the input A-phase PWM, which serves as the input A-phase switch drive signal. The B-phase switching frequency is input, a fixed duty cycle is given, and the SPWM modulation principle is used to obtain the input B-phase PWM, which serves as the input B-phase switch drive signal. The C-phase switching frequency is input, a fixed duty cycle is given, and the SPWM modulation principle is used to obtain the input C-phase PWM, which serves as the input C-phase switch drive signal.

[0054] The present invention provides a control method for a power module based on a three-phase SEPIC isolation topology. This method uses the output voltage as the outer loop and the output current as the inner loop. The resulting loop output is used to calculate the duty cycle or frequency of the power module's switches, and then uses SPWM modulation to control the power module. This method directly calculates the duty cycle or switching frequency of each single-phase converter unit's switch based on the power module's output voltage sampled value, output voltage target value, output current sampled value, and duty cycle modulation coefficient or switching frequency modulation coefficient, simplifying control. Furthermore, the method eliminates the need for input current, further reducing costs.

[0055] Accordingly, the present invention also provides a control system for a power module based on a three-phase SEPIC isolation topology, wherein the power module includes three identical single-phase converter units, including: a first calculation module, used to calculate an output voltage modulation value based on an output voltage sampling value, an output voltage target value, and an output current sampling value of the power module; a second calculation module, used to calculate the duty cycle or switching frequency of the switching tube of each single-phase converter unit in the power module based on the output voltage modulation value; and a signal generation module, used to generate a PWM drive signal for the switching tube of each single-phase converter unit based on the duty cycle or the switching frequency in combination with SPWM modulation.

[0056] Furthermore, in one embodiment of the present invention, the first calculation module includes: an output voltage error value calculation unit, used to subtract the output voltage sampling value from the output voltage target value to obtain an output voltage error value; an output current target value calculation unit, used to adjust the output voltage error value using an output voltage controller to obtain an output current target value; an output current error value calculation unit, used to subtract the output current sampling value from the output current target value to obtain an output current error value; and an output voltage modulation value calculation unit, used to adjust the output current error value using an output current controller to obtain the output voltage modulation value.

[0057] Furthermore, in one embodiment of the present invention, the second calculation module includes: a duty cycle modulation coefficient calculation unit, used to calculate the duty cycle modulation coefficient based on the output voltage target value and the input line voltage peak value; a duty cycle calculation unit, used to obtain the duty cycle of the switching tube based on the product of the output voltage modulation value and the duty cycle modulation coefficient; a switching frequency modulation coefficient calculation unit, used to calculate the switching frequency modulation coefficient based on the output voltage target value; and a switching frequency calculation unit, used to obtain the switching frequency of the switching tube based on the product of the output voltage modulation value and the switching frequency modulation coefficient.

[0058] An embodiment of the present invention further provides a control device for a power module based on a three-phase SEPIC isolation topology, which may include:

[0059] memory for storing computer programs;

[0060] The processor, when used to execute the computer program stored in the above-mentioned memory, can implement the following steps:

[0061] An output voltage modulation value is calculated based on the output voltage sampling value, the output voltage target value and the output current sampling value of the power module; a duty cycle or a switching frequency of the switching tube of each single-phase converter unit in the power module is calculated based on the output voltage modulation value; and a PWM drive signal is generated for the switching tube of each single-phase converter unit based on the duty cycle or the switching frequency in combination with SPWM modulation.

[0062] An embodiment of the present invention further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the following steps can be implemented:

[0063] An output voltage modulation value is calculated based on the output voltage sampling value, the output voltage target value and the output current sampling value of the power module; a duty cycle or a switching frequency of the switching tube of each single-phase converter unit in the power module is calculated based on the output voltage modulation value; and a PWM drive signal is generated for the switching tube of each single-phase converter unit based on the duty cycle or the switching frequency in combination with SPWM modulation.

[0064] The computer-readable storage medium may include: a USB flash drive, a mobile hard disk, a read-only memory (ROM)> a random access memory (RAM), a magnetic disk or an optical disk, and other media that can store program codes.

[0065] In the description provided herein, numerous specific details are described. However, it is understood that embodiments of the present invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0066] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the claims below, inventive aspects lie in less than all the features of the individual embodiments disclosed above. Accordingly, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of the invention.

[0067] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and in addition may be divided into multiple submodules or subunits or subcomponents. All features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed herein may be combined in any combination, except that at least some of such features and / or processes or units are mutually exclusive. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature providing the same, equivalent or similar purpose.

[0068] Furthermore, those skilled in the art will appreciate that although some embodiments herein include certain features included in other embodiments but not other features, combinations of features from different embodiments are intended to be within the scope of the present invention and to form different embodiments. For example, in the claims below, any of the claimed embodiments may be used in any combination.

[0069] The various component embodiments of the present invention can be implemented in hardware, or in software modules running on one or more processors, or in a combination thereof. It will be appreciated by those skilled in the art that a microprocessor or digital signal processor (DSP) can be used in practice to implement some or all of the functions of some or all of the components in accordance with the embodiments of the present invention. The present invention can also be implemented as a device or apparatus program (e.g., a computer program and a computer program product) for executing a portion or all of the methods described herein. Such a program implementing the present invention can be stored on a computer-readable medium, or can have the form of one or more signals. Such a signal can be downloaded from an Internet website, or provided on a carrier signal, or provided in any other form.

[0070] It should be noted that the above embodiments illustrate rather than limit the invention, and that those skilled in the art may devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between brackets should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention may be implemented by means of hardware comprising several different elements and by means of appropriately programmed computers. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third etc. does not indicate any order. These words may be interpreted as names.

Claims

1. A control method for a power module based on a three-phase SEPIC isolation topology, wherein the power module comprises three identical single-phase converter units, characterized in that: The following steps are involved: Calculating an output voltage modulation value according to an output voltage sampling value, an output voltage target value, and an output current sampling value of the power module; Calculating the duty cycle or switching frequency of the switch tube of each of the single-phase converter units in the power module according to the output voltage modulation value; and According to the duty cycle or the switching frequency, a PWM driving signal is generated for the switching tube of each single-phase converter unit in combination with SPWM modulation.

2. The control method of a power module based on a three-phase SEPIC isolation topology according to claim 1, characterized in that: The step of calculating the output voltage modulation value according to the output voltage sampling value, the output voltage target value and the output current sampling value of the power module includes: Subtracting the output voltage sample value from the output voltage target value to obtain an output voltage error value; Using an output voltage controller to adjust the output voltage error value to obtain an output current target value; Obtaining an output current error value by subtracting the output current sampling value from the output current target value; and The output current controller is used to adjust the output current error value to obtain the output voltage modulation value.

3. The control method of a power module based on a three-phase SEPIC isolation topology according to claim 1, characterized in that: The step of calculating the duty cycle of the switch tube of each of the single-phase converter units in the power module according to the output voltage modulation value includes: Calculating a duty cycle modulation coefficient based on the output voltage target value and the input line voltage peak value; The duty cycle of the switch tube is obtained based on the product of the output voltage modulation value and the duty cycle modulation coefficient.

4. The control method of a power module based on a three-phase SEPIC isolation topology according to claim 1, characterized in that: The step of calculating the switching frequency of the switch tube of each of the single-phase converter units in the power module according to the output voltage modulation value includes: Calculating a switching frequency modulation coefficient based on the output voltage target value; The switching frequency of the switching tube is obtained based on the product of the output voltage modulation value and the switching frequency modulation coefficient.

5. A control system for a power module based on a three-phase SEPIC isolation topology, wherein the power module comprises three identical single-phase converter units, characterized in that: include: A first calculation module is used to calculate an output voltage modulation value according to an output voltage sampling value, an output voltage target value and an output current sampling value of the power module; a second calculation module, configured to calculate a duty cycle or a switching frequency of a switch tube of each of the single-phase converter units in the power module according to the output voltage modulation value; and A signal generating module is used to generate a PWM driving signal for the switching tube of each single-phase converter unit according to the duty cycle or the switching frequency in combination with SPWM modulation.

6. The control system of the power module based on the three-phase SEPIC isolation topology according to claim 5, characterized in that: The first calculation module includes: an output voltage error value calculation unit, configured to obtain an output voltage error value by subtracting the output voltage sampling value from the output voltage target value; an output current target value calculation unit, configured to adjust the output voltage error value using an output voltage controller to obtain an output current target value; an output current error value calculation unit, configured to obtain an output current error value by subtracting the output current sampling value from the output current target value; and The output voltage modulation value calculation unit is used to adjust the output current error value by using an output current controller to obtain the output voltage modulation value.

7. The control method of a power module based on a three-phase SEPIC isolation topology according to claim 5, characterized in that: The second calculation module includes: a duty cycle modulation coefficient calculation unit, configured to calculate a duty cycle modulation coefficient based on the output voltage target value and the input line voltage peak value; A duty cycle calculation unit is used to obtain the duty cycle of the switch tube based on the product of the output voltage modulation value and the duty cycle modulation coefficient.

8. The control method of a power module based on a three-phase SEPIC isolation topology according to claim 5, characterized in that: The second calculation module includes: a switching frequency modulation coefficient calculation unit, configured to calculate a switching frequency modulation coefficient based on the output voltage target value; A switching frequency calculation unit is used to obtain the switching frequency of the switching tube based on the product of the output voltage modulation value and the switching frequency modulation coefficient.

9. A control device for a power module based on a three-phase SEPIC isolation topology, characterized in that: The method comprises a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the steps of the control method of a power module based on a three-phase SEPIC isolation topology are implemented as described in any one of claims 1 to 4.

10. A computer-readable storage medium storing a computer program, wherein: When the computer program is executed by a processor, the method according to any one of claims 1 to 4 is implemented.

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