Switch tube reset control method and power conversion circuit

Abstract

The present application discloses a reset control method for a switch tube and a power conversion circuit. The reset control method for the switch tube includes: obtaining the on-time, off-time and transmitted current reference value of the switch tube; obtaining a first reset current value and a second reset current value according to the current reference value, wherein the second reset current value is a first preset multiple of the first reset current value; calculating a shielding window time according to the on-time and the off-time; driving the switch tube to reset according to the first reset current value or the second reset current value; after the switch tube is reset, stopping the reset control of the switch tube and continuing the shielding window time. The present application can reduce the interval where the switch tube is falsely reset, so that the switch tube can work stably, and thus the power conversion circuit can operate stably.

Description

Technical Field

[0001] The present application relates to the field of circuit control technology, and in particular to a reset control method of a switch tube and a power conversion circuit. Background Art

[0002] In the existing power conversion circuit, the reset control of the switch tube generally adopts the critical current control method, that is, in one switching cycle of the switch tube, if the switch tube works in the positive half sector of the AC voltage, it will reset once when its current is lower than the constant reset current value, and if the switch tube works in the negative half sector of the AC voltage, it will reset once when its current exceeds the constant reset current value. However, due to the influence of the interference current in the power conversion circuit, the above control method may cause the switch tube to reset incorrectly, thereby affecting the normal operation of the power conversion circuit. Summary of the invention

[0003] In view of this, the present application provides a reset control method of a switch tube and a power conversion circuit, which are used to reduce the interval where the switch tube is falsely reset, so that the switch tube can work stably, and thus the power conversion circuit can operate stably. The technical solution of the present application is as follows:

[0004] The first aspect of the present application provides a reset control method for a switch tube, comprising: obtaining the on time, off time and transmitted current reference value of the switch tube; obtaining a first reset current value and a second reset current value according to the current reference value, wherein the second reset current value is a first preset multiple of the first reset current value; calculating a shielding window time according to the on time and the off time; driving the switch tube to reset according to the first reset current value or the second reset current value; after the switch tube is reset, stopping the reset control of the switch tube and continuing the shielding window time.

[0005] In one embodiment of the present application, obtaining the first reset current value and the second reset current value according to the current reference value includes: when determining that the current reference value is greater than zero, determining that a negative preset current value is the first reset current value; when determining that the current reference value is less than zero, determining that the positive preset current value is the first reset current value; and determining that the preset current value of the first preset multiple is the second reset current value.

[0006] In one embodiment of the present application, the calculation of the shielding window time based on the on-time and the off-time includes: obtaining the switching cycle of the switching tube based on the on-time and the off-time; and determining the switching cycle of the second preset multiple as the shielding window time.

[0007] In one embodiment of the present application, driving the switch tube to reset according to the first reset current value or the second reset current value includes: obtaining a real-time current value transmitted by the switch tube; and driving the switch tube to reset when determining that the real-time current value reaches the first reset current value or the second reset current value.

[0008] In an embodiment of the present application, the method further includes: after the shielding window time has passed, returning to the step of obtaining the on-time, off-time and transmitted current reference value of the switch tube.

[0009] A second aspect of the present application provides a power conversion circuit, including a controller, and n switching tubes connected to the controller, where n is a positive integer greater than or equal to 2; the controller is used to: obtain the on-time, off-time and transmitted current reference value of the switching tube; obtain a first reset current value and a second reset current value according to the current reference value, wherein the second reset current value is a first preset multiple of the first reset current value; calculate a shielding window time according to the on-time and the off-time; drive the switching tube to reset according to the first reset current value or the second reset current value; after the switching tube is reset, stop the reset control of the switching tube and continue the shielding window time.

[0010] In one embodiment of the present application, the controller is also used to determine that when the current reference value is greater than zero, the negative preset current value is determined to be the first reset current value, when the current reference value is less than zero, the positive preset current value is determined to be the first reset current value, and the preset current value of the first preset multiple is determined to be the second reset current value.

[0011] In one embodiment of the present application, the controller is further used to obtain a switching period of the switch tube according to the on-time and the off-time, and determine a switching period of a second preset multiple as the shielding window time.

[0012] In one embodiment of the present application, the controller is further used to obtain a real-time current value transmitted by the switch tube, and when it is determined that the real-time current value reaches the first reset current value or the second reset current value, drive the switch tube to reset.

[0013] In one embodiment of the present application, the controller is further configured to return to the step of obtaining the on-time, off-time and transmitted current reference value of the switch tube after the shielding window time has passed.

[0014] The present application calculates the shielding window time through the on-time and off-time of the switch tube, and stops the reset control of the switch tube within the shielding window time after the switch tube is reset, which can reduce the interval in which the interference current causes the false reset of the switch tube, and sets the first reset current value and the second reset current value. When the real-time current of the switch tube reaches the first reset current value, the reset control of the switch tube is performed. Alternatively, when the reset control is not performed in response to the real-time current reaching the first reset current value due to the influence of the shielding window time of the previous switching cycle, the reset control can also be performed in response to the real-time current reaching the second reset current value, thereby avoiding affecting the reset control of the switch tube due to the large shielding window time, so that the switch tube can work stably. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a circuit diagram of a power conversion circuit provided in an embodiment of the present application.

[0016] Figure 2 It is a flow chart of a reset control method of a switch tube provided in an embodiment of the present application.

[0017] Figure 3 It is a flow chart of a reset current value acquisition method provided in an embodiment of the present application.

[0018] Figure 4 It is a flow chart of a shielding window time acquisition method provided in an embodiment of the present application.

[0019] Figure 5 It is a flow chart of a method for resetting a switch tube provided in an embodiment of the present application.

[0020] Figure 6 It is a flow chart of a second method for resetting a switch tube provided in an embodiment of the present application.

[0021] Figure 7 It is a schematic block diagram of a power conversion circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] It should be noted that in the embodiments of the present application, "at least one" refers to one or more, and "more than one" refers to two or more than two. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. The terms "first", "second", "third", "fourth", etc. (if any) in the specification, claims and drawings of this application are used to distinguish similar objects, rather than to describe a specific order or sequence.

[0023] It should also be noted that the method disclosed in the embodiments of the present application or the method shown in the flowchart includes one or more steps for implementing the method. Without departing from the scope of the claims, the execution order of multiple steps can be interchangeable with each other, and some of the steps can also be deleted.

[0024] In the existing power conversion circuit, the reset control of the switch tube generally adopts the critical current control method, that is, in one switching cycle of the switch tube, if the switch tube works in the positive half sector of the AC voltage, it will reset once when its current is lower than the constant reset current value, and if the switch tube works in the negative half sector of the AC voltage, it will reset once when its current exceeds the constant reset current value. However, due to the influence of the interference current in the power conversion circuit, the above control method may cause the switch tube to reset incorrectly, thereby affecting the normal operation of the power conversion circuit.

[0025] The present application provides a reset control method of a switch tube and a power conversion circuit, which are used to avoid erroneous resetting of the switch tube, so that the switch tube can work stably, and further the power conversion circuit can operate stably.

[0026] Please refer to Figure 1 , Figure 1 The power conversion circuit 100 includes a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4, a first inductor L f , the second inductor L o And the capacitor C o .

[0027] In the embodiment of the present application, the first end of the first switch tube Q1 is used to connect the DC power supply V in The second end of the first switch tube Q1 is connected to the first end of the third switch tube Q3, the first end of the second switch tube Q2 is connected to the first end of the first switch tube Q1, the second end of the second switch tube Q2 is connected to the first end of the fourth switch tube Q4, and the second end of the third switch tube is connected to the DC power supply V in The negative electrode of the fourth switch tube Q4 is connected to the second end of the third switch tube Q3. f The first end of the first inductor L is connected to the second end of the first switch tube Q1. f The second end of the second inductor L o The first end of the second inductor L o The second end is connected to the AC power supply V g The first end of the second switch tube Q2 is connected to the AC power supply V g The second end of the capacitor C o The first end of the first inductor L f The second end of the capacitor C oThe second end of is connected to the second end of the second switch tube Q2. It can be understood that the power conversion circuit 100 is a full-bridge inverter circuit.

[0028] In some embodiments, the power conversion circuit 100 also includes a controller, and the control ends of the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 are respectively connected to the controller, and the controller controls the conduction of the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 to convert the DC voltage into an AC voltage.

[0029] Please refer to Figure 2 , Figure 2 A schematic flow chart of a reset control method of a switch tube provided in an embodiment of the present application specifically includes the following steps:

[0030] Step S21: Obtain the on-time, off-time and transmitted current reference value of the switch tube.

[0031] In an embodiment of the present application, the controller in the power conversion circuit is connected to the control end of each switch tube to control the conduction and shutdown of the switch tube, thereby realizing the function of the power conversion circuit to convert voltage. At the same time, the controller can also obtain the conduction time, shutdown time and transmitted current reference value of the switch tube.

[0032] In some embodiments, the controller modulates the switching frequency of each switch tube in the power conversion circuit to realize the function of converting the DC voltage into the AC voltage, and after modulating the switching frequency, the controller can also obtain the on-time and off-time corresponding to the above-mentioned switch tube according to the switching frequency. At the same time, after modulating the switching frequency, the current reference value transmitted by the above-mentioned switch tube can also be obtained according to the switching frequency, the DC voltage and the power balance principle of the input and output of the power conversion circuit. Alternatively, a current acquisition circuit can also be provided in the power conversion circuit, and the current transmitted by the switch tube is collected by the current acquisition circuit, and the above-mentioned current reference value is obtained according to the power balance principle of the input and output of the power conversion circuit. In some embodiments, if the power conversion circuit is connected to a DC power supply, and receives the electric energy input by the DC power supply and converts it to output the supply voltage, the current reference value can also be obtained according to the input power of the DC power supply and the output voltage of the power conversion circuit, wherein the DC power supply includes clean energy such as photovoltaic panels.

[0033] Step S22: obtaining a first reset current value and a second reset current value according to the current reference value, wherein the second reset current value is a first preset multiple of the first reset current value.

[0034] In the embodiment of the present application, after obtaining the current reference value, the controller will obtain the first reset current and the second reset current according to the current reference value. It can be understood that when the power conversion circuit converts the DC voltage into the AC voltage, the direction of the current transmitted by the switch tube will change, that is, the transmission will switch between the forward current and the reverse current. Therefore, when the switch tube transmits the forward current, the current reference value obtained by the controller is a positive value, and when the switch tube transmits the reverse current, the current reference value obtained by the controller is a negative value.

[0035] It can be understood that after obtaining the current reference value, the controller can determine the direction of the current currently transmitted by the switch tube according to the positive or negative current reference value, thereby determining the direction of the reset current. The direction of the reset current is opposite to the direction of the current currently transmitted by the switch tube, that is, when the current reference value is positive, the first reset current value and the second reset current value obtained by the controller are negative values, and when the current reference value is negative, the first reset current value and the second reset current value obtained by the controller are positive values.

[0036] In some embodiments, the positive first reset current value and the second reset current value, and the negative first reset current value and the second reset current value, may be pre-stored in the controller.

[0037] Step S23: Calculate the shielding window time according to the on-time and the off-time.

[0038] In the embodiment of the present application, the above-mentioned shielding window time is the time for shielding the reset control of the switch tube. During the shielding window time, the controller does not respond to the current of the switch tube for reset control, so as to avoid the controller responding to the interference current in the switch tube for resetting again within a short time after resetting the switch tube.

[0039] Step S24: driving the switch tube to reset according to the first reset current value or the second reset current value.

[0040] In the embodiment of the present application, the controller further obtains the real-time current of the switch tube, performs reset control on the switch tube according to the real-time current and the first reset current value, or performs reset control on the switch tube according to the real-time current and the second reset current value. For example, the controller performs reset control on the switch tube in response to the real-time current reaching the first reset current value. Alternatively, when the controller does not perform reset control in response to the real-time current reaching the first reset current value due to the shielding window time of the previous switching cycle, the controller may also perform reset control in response to the real-time current reaching the second reset current value.

[0041] Step S25: After the switch tube is reset, the reset control of the switch tube is stopped and the shielding window time is continued.

[0042] In an embodiment of the present application, after the controller resets the switch tube in the current switching cycle, it will stop the reset control of the switch tube and continue the shielding window time. Among them, if part of the time in the next switching cycle is in the shielding window time, the controller will not reset the switch tube to avoid false reset caused by interference.

[0043] It can be understood that the present application calculates the shielding window time through the on-time and off-time of the switch tube, and stops the reset control of the switch tube within the shielding window time after the switch tube is reset, which can reduce the interval in which the interference current causes the switch tube to be reset incorrectly, and sets the first reset current value and the second reset current value. When the real-time current of the switch tube reaches the first reset current value, the switch tube is reset controlled. Alternatively, when the reset control is not performed in response to the real-time current reaching the first reset current value due to the influence of the shielding window time of the previous switching cycle, the reset control can also be performed in response to the real-time current reaching the second reset current value, thereby avoiding the reset control of the switch tube being affected by the large shielding window time, so that the switch tube can work stably, and then the power conversion circuit can operate stably.

[0044] In some embodiments, Figure 3 As shown, the above step of obtaining the first reset current value and the second reset current value according to the current reference value may specifically include the following steps:

[0045] Step S31: when it is determined that the current reference value is greater than zero, a negative preset current value is determined as a first reset current value.

[0046] In the embodiment of the present application, a preset current value may be pre-stored in the controller. When it is determined that the current reference value is greater than zero, the reset current is determined to be a negative value, that is, the negative preset current value is determined to be the first reset current value.

[0047] Step S32: when it is determined that the current reference value is less than zero, a positive preset current value is determined as a first reset current value.

[0048] Similarly, when the current reference value is less than zero, the reset current is determined to be a positive value, that is, the positive preset current value is determined to be the first reset current value.

[0049] Step S33: Determine the preset current value of the first preset multiple as the second reset current value.

[0050] In the embodiment of the present application, after determining the first reset current value, the controller determines the second reset current value of the first preset multiple. The first reset current value and the second reset current value are set, and when the real-time current of the switch tube reaches the first reset current value, the switch tube is reset controlled, or, when the controller does not perform reset control in response to the real-time current reaching the first reset current value due to the influence of the shielding window time of the previous switching cycle, the controller can also perform reset control in response to the real-time current reaching the second reset current value, thereby avoiding affecting the reset control of the switch tube due to the large shielding window time.

[0051] In some embodiments, Figure 4 As shown, the above step of calculating the shielding window time according to the on-time and the off-time may specifically include the following steps:

[0052] Step S41: Obtain the switching cycle of the switch tube according to the on-time and the off-time.

[0053] Step S42: Determine a switching cycle of a second preset multiple as the shielding window time.

[0054] In an embodiment of the present application, the above-mentioned second preset multiple can be greater than 0 and less than 1, for example, the second preset multiple can be 0.8, so as to ensure that a larger shielding window time can be calculated to avoid false reset caused by interference current, and at the same time make the shielding window time shorter than the switching cycle of the switching tube to avoid the shielding window time of the current switching cycle affecting the reset control of the next switching cycle.

[0055] In some embodiments, Figure 5 As shown, the above step of driving the switch tube to reset according to the first reset current value or the second reset current value may specifically include the following steps:

[0056] Step S51: obtaining the real-time current value transmitted by the switch tube.

[0057] Step S52: When it is determined that the real-time current value reaches the first reset current value or the second reset current value, the switch tube is driven to reset.

[0058] In an embodiment of the present application, a current sampling circuit may be provided in the power conversion circuit. The current sampling circuit is respectively connected to the switch tube and the controller. The current sampling circuit is used to collect the real-time current value of the switch tube and transmit it to the controller.

[0059] In some embodiments, the above real-time current value can also be Figure 1The current value outputted from the second end of the first inductor Lf, that is, a current sampling circuit can be provided in the power conversion circuit, the current sampling circuit is respectively connected to the second end of the first inductor Lf and the controller, and the current sampling circuit is used to collect the current value outputted from the second end of the first inductor Lf and transmit it to the controller.

[0060] Please refer to Figure 6 , Figure 6 This is a flow chart of a second method for resetting a switch tube provided in an embodiment of the present application. Figure 6 The reset control method shown includes steps S61 to S65, and Figure 1 The steps S21 to S25 shown are the same and will not be repeated here. Figure 5 The reset control method shown is similar to Figure 2 Compared with the reset control method shown in the figure, the difference is that it also includes:

[0061] Step S66: after the masking window time has passed, return to step S61 of obtaining the on-time, off-time and transmitted current reference value of the switch tube.

[0062] Please refer to Figure 7 , Figure 7 A schematic block diagram of a power conversion circuit provided in an embodiment of the present application, wherein the power conversion circuit 700 includes a controller 710 and n switch tubes 720 (four in the example in the figure) connected to the controller 710, where n is a positive integer greater than or equal to 2.

[0063] In an embodiment of the present application, the controller 710 is used to: obtain the on-time, off-time and transmitted current reference value of the switch tube 720, obtain a first reset current value and a second reset current value according to the current reference value, wherein the second reset current value is a first preset multiple of the first reset current value, obtain a shielding window time according to the on-time and the off-time, drive the switch tube 720 to reset according to the first reset current value or the second reset current value, and after the switch tube 720 is reset, stop the reset control of the switch tube 720 and continue the shielding window time.

[0064] In some embodiments, the controller 710 is also used to determine that when the current reference value is greater than zero, the negative preset current value is determined to be the first reset current value, when the current reference value is less than zero, the positive preset current value is determined to be the first reset current value, and the preset current value of the first preset multiple is determined to be the second reset current value.

[0065] In some embodiments, the controller 710 is further configured to obtain a switching period of the switch tube 720 according to the on-time and the off-time, and determine a switching period of a second preset multiple as the shielding window time.

[0066] In some embodiments, the controller 710 is further configured to obtain a real-time current value transmitted by the switch tube 720 , and when it is determined that the real-time current value reaches a first reset current value or a second reset current value, drive the switch tube 720 to reset.

[0067] In some embodiments, the controller 710 is further configured to return to the step of obtaining the on-time, off-time and transmitted current reference value of the switch tube 720 after the masking window time has passed.

[0068] It can be understood that the beneficial effects that can be achieved by the above-mentioned power conversion circuit 700 can refer to the beneficial effects of the reset control method of the switch tube 720 in the above-mentioned embodiment, which will not be repeated here.

[0069] An embodiment of the present application further provides a computer storage medium, which stores a computer program. When the computer program is executed by a processor, the processor executes the above-mentioned reset control method of the switch tube.

[0070] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer storage medium or transmitted through the computer storage medium. The computer instructions may be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a digital versatile disc (DVD)), or a semiconductor medium (eg, a solid state disk (SSD)).

[0071] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. The aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other media that can store program codes. In the absence of conflict, the technical features in this embodiment and the implementation scheme can be combined arbitrarily.

[0072] The embodiments described above are merely preferred embodiments of the present application and are not intended to limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements made to the technical solutions of the present application by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present application.

Claims

1. A reset control method for a switch tube, characterized in that: include: Obtaining the on-time, off-time and transmitted current reference value of the switch tube, wherein the current reference value is obtained according to the power balance principle of the input and output of the power conversion circuit; Obtaining a first reset current value and a second reset current value according to the current reference value, wherein the second reset current value is a first preset multiple of the first reset current value; Calculate the shielding window time according to the on-time and the off-time; The switch tube is driven to reset according to the first reset current value or the second reset current value; wherein, when the switch tube does not perform reset control in response to the first reset current value, the switch tube is reset controlled according to the second reset current value; After the switch tube is reset, the reset control of the switch tube is stopped and the shielding window time is continued.

2. The reset control method according to claim 1, characterized in that: The obtaining of the first reset current value and the second reset current value according to the current reference value comprises: When it is determined that the current reference value is greater than zero, determining a negative preset current value as the first reset current value; When it is determined that the current reference value is less than zero, determining the positive preset current value as a first reset current value; The preset current value of the first preset multiple is determined to be the second reset current value.

3. The reset control method according to claim 1, characterized in that: The calculating the shielding window time according to the on-time and the off-time includes: Obtaining a switching cycle of the switch tube according to the on-time and the off-time; A switching period of a second preset multiple is determined as the shielding window time.

4. The reset control method according to claim 1, wherein: The step of driving the switch tube to reset according to the first reset current value or the second reset current value includes: Get the real-time current value transmitted by the switch tube; When it is determined that the real-time current value reaches the first reset current value or the second reset current value, the switch tube is driven to reset.

5. The reset control method according to claim 1, characterized in that: Also includes: After the shielding window time has passed, return to the step of obtaining the on-time, off-time and transmitted current reference value of the switch tube.

6. A power conversion circuit, characterized in that: It includes a controller and n switch tubes connected to the controller, where n is a positive integer greater than or equal to 2; The controller is used to: Obtaining the on-time, off-time and transmitted current reference value of the switch tube, wherein the current reference value is obtained according to the power balance principle of the input and output of the power conversion circuit; Obtaining a first reset current value and a second reset current value according to the current reference value, wherein the second reset current value is a first preset multiple of the first reset current value; Calculate the shielding window time according to the on-time and the off-time; The switch tube is driven to reset according to the first reset current value or the second reset current value; wherein, when the switch tube does not perform reset control in response to the first reset current value, the switch tube is reset controlled according to the second reset current value; After the switch tube is reset, the reset control of the switch tube is stopped and the shielding window time is continued.

7. The power conversion circuit according to claim 6, characterized in that: The controller is also used to determine that when the current reference value is greater than zero, a negative preset current value is determined to be the first reset current value, when the current reference value is less than zero, a positive preset current value is determined to be the first reset current value, and a preset current value of the first preset multiple is determined to be the second reset current value.

8. The power conversion circuit according to claim 6, characterized in that: The controller is further used to obtain a switching cycle of the switch tube according to the on-time and the off-time, and determine a switching cycle of a second preset multiple as the shielding window time.

9. The power conversion circuit according to claim 6, characterized in that: The controller is further configured to obtain a real-time current value transmitted by the switch tube, and drive the switch tube to reset when it is determined that the real-time current value reaches the first reset current value or the second reset current value.

10. The power conversion circuit according to claim 6, characterized in that: The controller is also used to return to the step of obtaining the on-time, off-time and transmitted current reference value of the switch tube after the shielding window time has passed.

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