Primary AC / AC conversion system, high and low voltage management system

Abstract

The present invention provides a one-level AC / AC conversion system and a high and low voltage management system, and relates to the technical field of power distribution networks. The present invention uses one-level energy conversion to realize AC / AC conversion, replacing the mainstream AC / DC+DC / AC two-level architecture, which not only allows bidirectional energy flow and bidirectional circuit operation, but also uses a series-connected energy storage capacitor architecture to realize a transformer-free structure, does not require the busbar capacitor of the traditional two-level solution, and the architecture capacitor conversion branch has a small power, achieving low cost, high efficiency, and long life.

Description

Technical Field

[0001] The present invention relates to the technical field of power distribution network, and in particular to a primary AC / AC conversion system and a high and low voltage management system. Background Art

[0002] The power quality of the distribution network substation directly affects the power supply quality. Low-quality power supply may lead to increased grid line losses, equipment failures, and power outages, and affect users' production and life. In some power supply areas, seasonal and intermittent load fluctuations will reduce the transformer outlet voltage and aggravate voltage fluctuations; the heavy load at the end of the line will also cause the terminal voltage to decrease. Especially in mountainous and remote areas, the power supply radius of some substations is long, the terminal power quality is poor, and the power supply reliability is low. In addition, the access to new energy may cause high voltage problems, causing the power supply voltage to deviate from the standard voltage (220V). Too high or too low voltage will make the user's electrical equipment unable to work normally.

[0003] The existing treatment scheme generally adopts UPQC devices based on series and parallel connection of transformers, such as Figure 1 As shown, the device adopts a parallel side compensation current and a series transformer to achieve a compensation voltage method to achieve partial power power electronic conversion, but it adopts AC / DC+DC / AC two-stage energy conversion and has low efficiency. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the deficiencies in the prior art, the present invention provides a primary AC / AC conversion system and a high and low voltage management system, which solves the technical problem of low efficiency of the existing management solutions.

[0006] (II) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] In a first aspect, the present invention provides a primary AC / AC conversion system, comprising a jumper capacitor, an energy storage capacitor, a first inductor, a second inductor, a first switch group satisfying a bidirectional current path, and a second switch group satisfying a bidirectional current path;

[0009] The primary AC / AC conversion system includes four ports; wherein the first port is connected to the third port of the primary AC / AC conversion system via the first inductor, the energy storage capacitor and the second switch group satisfying the bidirectional current path; the second port is connected to the fourth port through the power supply line, and the A connection terminal and the B connection terminal are connected in sequence on the power supply line; the first port and the second port are respectively connected to the two ends of the input AC power supply, and the third port and the fourth port are respectively connected to the two ends of the load or the two ends of the charging power supply; or the first port and the second port are respectively connected to the two ends of the load or the two ends of the charging power supply, and the third port and the fourth port are respectively connected to the two ends of the AC input power supply;

[0010] Two ends of the jumper capacitor are respectively connected to a first port and a third port of a primary AC / AC conversion system;

[0011] A first end of the first switch group satisfying the bidirectional current path is connected to a common end of the first inductor and the energy storage capacitor; a second end of the first switch group satisfying the bidirectional current path is connected to the A connection end;

[0012] A first end of the second inductor is connected to a common end of the energy storage capacitor and a second switch group satisfying a bidirectional current path; and a second end is connected to the B connection terminal;

[0013] By controlling the duty ratio of the switches in two switch groups satisfying the bidirectional current path, the voltage of the input AC power source can be increased or decreased.

[0014] Preferably, a filter capacitor is further included, and the filter capacitor is connected to both ends of the input AC power supply.

[0015] Preferably, when the input alternating current power source connected is a power grid, the primary AC / AC conversion system further comprises a bypass switch, and two ends of the bypass switch are respectively connected to the first port and the third port of the primary AC / AC conversion system;

[0016] When the bypass switch is closed, the switches in the first switch group satisfying the bidirectional current path and the second switch group satisfying the bidirectional current path are both turned off.

[0017] Preferably, the first switch group satisfying the bidirectional current path and the second switch group satisfying the bidirectional current path both include two switch tubes with freewheeling diodes.

[0018] Preferably, the voltage of the input AC power source is increased or decreased by controlling the duty ratio of the switches in the two switch groups satisfying the bidirectional current path to be turned off and on, including:

[0019] The duty ratio of the two switch tubes in the first switch group that satisfies the bidirectional current path is D, 0≤D≤1, then the duty ratio of the second switch group that satisfies the bidirectional current path is 1-D, the voltage of the first port and the second port is represented by V1, the voltage of the third port and the fourth port is represented by V2, then the input and output voltage relationship is:

[0020]

[0021] By modifying the duty cycle of the switch tube and adjusting the output voltage, the voltage of the input AC power supply can be increased or decreased.

[0022] Preferably, when the primary AC / AC conversion system is used in a three-phase power grid, each phase of the three-phase power grid is respectively connected to an independent primary AC / AC conversion system.

[0023] In a second aspect, the present invention provides a high and low voltage management system, including a detection module, a control generation module and a primary AC / AC conversion system as described above;

[0024] Wherein, the detection module is used to detect whether the supply voltage is higher or lower than the threshold of the normal voltage range;

[0025] The control generation module is used to generate a control signal according to the output of the detection module, and the control signal is used to control the conduction or disconnection of the switches in the first switch group that satisfies the bidirectional current path and the second switch group that satisfies the bidirectional current path in the primary AC / AC conversion system.

[0026] Preferably, when the detection module detects that the supply voltage is higher than the threshold of the normal voltage range, a signal indicating that the voltage is too high is transmitted to the control generation module, and the control generation module generates a control signal to control the duty cycle of the switch in the primary AC / AC conversion system to reduce the voltage.

[0027] Preferably, when the detection module detects that the power supply voltage is lower than the threshold of the normal voltage range, a low voltage signal is transmitted to the control generation module, and the control generation module generates a control signal to control the duty cycle of the disconnection and conduction of the switch in the primary AC / AC conversion system, so that the voltage increases.

[0028] Preferably, when it is detected that the power supply voltage is within the normal voltage range, the control generation module generates a signal to disconnect all switches of the primary AC / AC conversion system, so that the primary AC / AC conversion system does not work.

[0029] (III) Beneficial effects

[0030] The present invention provides a primary AC / AC conversion system and a high and low voltage management system. Compared with the prior art, it has the following beneficial effects:

[0031] The present invention uses a one-stage energy conversion to achieve AC / AC conversion, replacing the mainstream AC / DC+DC / AC two-stage architecture. It not only allows bidirectional energy flow and bidirectional circuit operation, but also uses a series energy storage capacitor architecture to achieve a transformerless structure. The bus capacitor of the traditional two-stage solution is not required, and the power of the architecture capacitor conversion branch is relatively small, achieving low cost, high efficiency and long life. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 It is a structural diagram of the existing UPQC device;

[0034] Figure 2 This is the structural diagram of the transformer on-load voltage regulation scheme;

[0035] Figure 3 This is the structural diagram of the switched capacitor method;

[0036] Figure 4 This is the structural diagram of the bidirectional AC / DC+DC / AC governance solution;

[0037] Figure 5 It is the structural diagram of AC / AC governance plan;

[0038] Figure 6 for Figure 1 An architectural diagram of a UPQC device is shown;

[0039] Figure 7 is a structural diagram of a primary AC / AC conversion system in Example 1;

[0040] Figure 8 is a structural diagram of another primary AC / AC conversion system in Example 1;

[0041] Fig. 9 for Figure 7 The specific circuit diagram of the structure diagram shown;

[0042] Fig.10 for Fig. 9 The circuit diagram shown is the circuit diagram with bypass switch;

[0043] Fig.11 for Fig. 9A schematic diagram of the working mode 1 of the circuit diagram shown;

[0044] Fig.12 for Fig. 9 A schematic diagram of the working mode 2 of the circuit diagram shown;

[0045] Fig.13 for Fig. 9 A schematic diagram of the working mode 3 of the circuit diagram shown;

[0046] Fig.14 for Fig. 9 A schematic diagram of the working mode 4 of the circuit diagram shown;

[0047] Fig.15 This is an architecture diagram of a primary AC / AC conversion system applied to a three-phase system. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described. 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.

[0049] It should be noted that, for the convenience of description, the switch IGBT is used to represent the controllable (on and off) switch tube in the embodiment of the present invention, but the switch tube in the present invention is not limited to IGBT. Take IGBT as an example for explanation. The first end of the IGBT refers to the collector, the second end is the emitter, and the control end refers to the gate. A driving control signal is applied to the control end of each switch tube in the embodiment of the present invention. For the sake of brevity, it will not be repeated later. The power switch tube in the embodiment of the present invention can also be implemented by other controllable switch tube devices other than IGBT, such as MOSFET. At the same time, in order to ensure the normal operation of each switch device in the embodiment of the present invention, a freewheeling diode needs to be connected in parallel to each switch device. The parallel connection direction of the freewheeling diode is related to the type of the switch device. The technician can set it according to the type of the switch device, which is not limited here. If not specified, the switch device defaults to including a freewheeling diode, which will be pointed out in this embodiment in special cases.

[0050] The embodiments of the present application solve the technical problem of low efficiency of existing management solutions by providing a one-level AC / AC conversion system and a high and low voltage management system, and realize AC / AC conversion by adopting a one-level energy conversion, replacing the mainstream AC / DC+DC / AC two-level architecture, effectively improving efficiency and reducing costs.

[0051] The technical solution in the embodiment of the present application is to solve the above technical problems, and the overall idea is as follows:

[0052] In order to solve the problem of too low power supply voltage at the distribution transformer or the end of the line, the traditional treatment solutions mainly include passive treatment solutions and active treatment solutions. Among them, the traditional passive treatment solutions include transformer on-load voltage regulation and capacitor switching method. Figure 2 As shown in the figure, the transformer on-load voltage regulation scheme adjusts the output voltage through the transformer turns ratio, with limited adjustment range, poor flexibility and reliability. Figure 3 As shown in the figure, the capacitor switching method uses the capacitor method to achieve reactive support for line inductance to improve low voltage, but it cannot be adjusted seamlessly, and has poor flexibility and real-time performance. Active governance solutions are based on power electronics technology solutions, and commonly used ones are as follows Figure 4 or Figure 5 The bidirectional AC / DC+DC / AC, or AC / AC solution shown in FIG. 1 is a solution in which all power passes through the power electronic converter, which has disadvantages such as low efficiency and high cost. From the above description, it can be seen that the traditional passive control solution and active control solution can not only only solve the problem of too low power supply voltage, but also have many defects. In order to make up for these defects, the existing control solutions generally adopt the following Figure 1 The UPQC device shown, Figure 6 As shown, the device first connects a rectifier in parallel at the grid end to generate a DC voltage, and then inverts the DC voltage into AC through an inverter. This AC is added to the grid through a coupling transformer connected in series to the grid, so that the load side voltage is superimposed on the grid voltage by an AC voltage generated by the inverter, thereby adjusting the grid voltage. When the grid voltage is too low, the UPQC can be used to add a voltage in phase with the grid voltage to achieve voltage boost, so that the load voltage returns to the standard voltage (220V).

[0053] From the above analysis, it can be seen that the architecture of the UPQC device is relatively complex. It adopts a two-stage structure of rectification followed by inversion, and requires a coupling transformer to be connected in series with the power grid, which leads to complex control of the device, low efficiency, large size and high cost.

[0054] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0055] It should be noted that in the following embodiments, the capacitors involved, such as jumper capacitors, energy storage capacitors, etc., can be a capacitor group composed of multiple capacitors. In the embodiments of the present application, one capacitor is used as a representative for description, and the same applies to inductors.

[0056] Embodiment 1:

[0057] The embodiment of the present invention proposes a primary AC / AC conversion system, such as Figure 7 As shown, the primary AC / AC conversion system includes a cross-over capacitor C1, an energy storage capacitor C2, a first inductor L1, a second inductor L2, a first switch group satisfying a bidirectional current path, and a second switch group satisfying a bidirectional current path;

[0058] The primary AC / AC conversion system includes four ports; wherein the first port is connected to the third port of the primary AC / AC conversion system via the first inductor L1, the energy storage capacitor C2 and the second switch group satisfying the bidirectional current path; the second port is connected to the fourth port through the power supply line, and the A connection terminal and the B connection terminal are connected in sequence on the power supply line; the first port and the second port are respectively connected to the two ends of the input AC power supply, and the third port and the fourth port are respectively connected to the two ends of the load or the two ends of the charging power supply; or the first port and the second port are respectively connected to the two ends of the load or the two ends of the charging power supply, and the third port and the fourth port are respectively connected to the two ends of the AC input power supply;

[0059] Two ends of the cross-over capacitor C1 are respectively connected to the first port and the third port of the primary AC / AC conversion system;

[0060] A first end of the first switch group satisfying the bidirectional current path is connected to a common end of the first inductor L1 and the energy storage capacitor C2; a second end of the first switch group satisfying the bidirectional current path is connected to the A connection end;

[0061] A first end of the second inductor L2 is connected to a common end of the energy storage capacitor C2 and a second switch group satisfying a bidirectional current path; and a second end is connected to the B connection terminal;

[0062] By controlling the duty ratio of the switches in two switch groups satisfying the bidirectional current path, the voltage of the input AC power source can be increased or decreased.

[0063] The embodiment of the present invention adopts a one-stage energy conversion to realize AC / AC conversion, replacing the mainstream AC / DC+DC / AC two-stage architecture. It not only allows bidirectional energy flow and bidirectional circuit operation, but also adopts a series energy storage capacitor architecture to realize a transformer-free structure, does not require the bus capacitor of the traditional two-stage solution, and the power of the architecture capacitor conversion branch is relatively small, achieving low cost, high efficiency and long life.

[0064] The present invention can operate bidirectionally. In the following specific analysis process, the mode in which the first port and the second port are connected to the input AC power supply and the third port and the fourth port are connected to the load is mainly analyzed.

[0065] In the specific implementation process, in order to stabilize the current, a filter capacitor C can be connected at both ends of the input AC power supply, such as Figure 8 shown.

[0066] In the following, the input AC power source connected to the first port and the second port is the power grid, and the third port and the fourth port are connected to the load. Fig. 9 , the primary AC / AC conversion system of this embodiment is described in detail.

[0067] It should be noted that the switch group that satisfies the bidirectional current path can be a switch group consisting of two switch tubes with freewheeling diodes, or can be implemented by a single-pole switch, or other switch structures that can satisfy the bidirectional current path. In the embodiment of the present invention, it is composed of two IGBTs with freewheeling diodes, and the emitters of the two IGBTs are connected. Fig. 9 In the switch group that satisfies the bidirectional current path, the two groups of switches T1 and T2, T3 and T4 constitute a bidirectional energy path, which can realize bidirectional energy operation. A cross-over capacitor is connected between the power supply and the load to form a constant closed-loop path, in which no switching device performs switching action, thereby reducing the impact of grid fluctuations on the load and will not damage the power carrier communication between the distribution network and the user. At the same time, when the grid is normal, this circuit is not needed to raise the grid voltage, and the primary AC / AC conversion system needs to be cut off from the grid and the load to avoid unnecessary losses (that is, when the grid voltage is at the rated value, the bypass switch is closed, and the circuit exits the grid at this time, which is to connect the grid directly to the load). Therefore, it is necessary to connect a bypass switch in parallel on the basis of the circuit shown in 9, as shown in detail. Fig.10 After the bypass switch is closed, T1, T2, T3, and T4 are all turned off, and the circuit can be cut off from the grid side.

[0068] Below Fig. 9 Taking the circuit shown in FIG. 1 as an example, the working mode of the primary AC / AC conversion system in this embodiment is analyzed. The system has two modes in each of the positive and negative half cycles of the input voltage. When the input voltage is positive, the state of the switch device in each mode is as follows: Fig.11 , Fig.12 shown.

[0069] Working mode 1: Fig.11 As shown, the switch tubes T1 and T2 are turned on, and the other switch tubes are turned off. The current flow path is power grid → L1 → T1 → T2 and C2 → T1 → T2 → L2. At this time, the power grid charges the inductors L1 and L2 and stores energy, and supplies power to the load through the jumper capacitor C1.

[0070] Working mode 2: Fig.12 As shown, switch tubes T3 and T4 are turned on, and other switch tubes are turned off. The current flow path is grid → L1 → C2 → T3 → T4 → load and L2 → T3 → T4 → load. At this time, inductors L1 and L2 release energy to power the load and charge capacitors C1 and C2.

[0071] When the input voltage is negative, the state of the switch device in each mode is as follows: Fig.13 , Fig.14 shown.

[0072] Working mode 3: Fig.13 As shown, switch tubes T1 and T2 are turned on, and other switch tubes are turned off. The current flow path is grid → T2 → T1 → L1 and C2 → L2 → T2 → T1. At this time, the grid charges the inductors L1 and L2 and supplies power to the load through the capacitor C1.

[0073] Working mode 4: Fig.14 As shown, switch tubes T3 and T4 are turned on, and other switch tubes are turned off. The current flow path is grid → load → T4 → T3 → C2 → L1 and L2 → load → T4 → T3. At this time, inductors L1 and L2 release energy to supply power to the load and charge capacitors C1 and C2.

[0074] From the circuit principle, we can know that the relationship between the input and output voltages is related to the duty cycle of the switch under the condition that the circuit parameters are determined: if the duty cycle of switches T1 and T2 is D (0≤D≤1), then the duty cycle of switches T3 and T4 is (1-D), and the input voltage is represented by the symbol V in Indicates that the output voltage is V out The relationship between input and output voltage is:

[0075]

[0076] Therefore, by modifying the duty cycle of the switch tube, the voltage can be increased or decreased, achieving high and low voltage management.

[0077] It should be noted that, in the specific implementation process, the primary AC / AC conversion system of the embodiment of the present invention can be applied to a three-phase system. The innovative topology architecture shown is as follows: Fig.15 , of which the AC / AC part is Figure 7 or Figure 8 In the primary AC / AC conversion system shown, the operating mode of each phase in the three-phase circuit is consistent with the mode described above for the single phase, and will not be repeated here.

[0078] Embodiment 2:

[0079] This embodiment provides a high and low voltage management system, which includes a detection module, a control generation module and a primary AC / AC conversion system as described in embodiment 1;

[0080] The detection module is used to detect whether the power supply voltage is higher or lower than the threshold of the normal voltage range. When the voltage is higher than the threshold of the normal voltage range, it means that the voltage is too high, and a signal indicating that the voltage is too high is transmitted to the control generation module, and the control generation module generates a control signal to control the duty cycle of disconnection and conduction of switches in the primary AC / AC conversion system, so that the voltage is reduced; when the voltage is lower than the threshold of the normal voltage range, it means that the voltage is too low, and a signal indicating that the voltage is too low is transmitted to the control generation module, and the control generation module generates a control signal to control the duty cycle of disconnection and conduction of switches in the primary AC / AC conversion system, so that the voltage is increased; when the voltage is detected to be normal, a signal to disconnect all switches of the primary AC / AC conversion system is generated by the control generation module, so that the primary AC / AC conversion system does not work.

[0081] In summary, compared with the prior art, the present invention has the following beneficial effects:

[0082] The embodiment of the present invention uses a one-stage energy conversion to achieve AC / AC conversion, replacing the mainstream AC / DC+DC / AC two-stage architecture. At the same time, the energy storage capacitor series architecture is used to achieve a transformer-free structure, which does not require the bus capacitor of the traditional two-stage solution. The architecture capacitor conversion branch power is small, achieving low cost, high efficiency and long life. In addition, the three-phase circuit is decoupled in structure, each phase can be controlled separately, and the control method is simple.

[0083] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0084] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A primary AC / AC conversion system, characterized in that: It includes a jumper capacitor, an energy storage capacitor, a first inductor, a second inductor, a first switch group satisfying a bidirectional current path, and a second switch group satisfying a bidirectional current path; The primary AC / AC conversion system includes four ports; wherein the first port is connected to the third port of the primary AC / AC conversion system via the first inductor, the energy storage capacitor and the second switch group satisfying the bidirectional current path; the second port is connected to the fourth port through the power supply line, and the A connection terminal and the B connection terminal are connected in sequence on the power supply line; the first port and the second port are respectively connected to the two ends of the input AC power supply, and the third port and the fourth port are respectively connected to the two ends of the load or the two ends of the charging power supply; or the first port and the second port are respectively connected to the two ends of the load or the two ends of the charging power supply, and the third port and the fourth port are respectively connected to the two ends of the AC input power supply; Two ends of the jumper capacitor are respectively connected to a first port and a third port of a primary AC / AC conversion system; A first end of the first switch group satisfying the bidirectional current path is connected to a common end of the first inductor and the energy storage capacitor; a second end of the first switch group satisfying the bidirectional current path is connected to the A connection end; A first end of the second inductor is connected to a common end of the energy storage capacitor and a second switch group satisfying a bidirectional current path; and a second end is connected to the B connection terminal; By controlling the duty ratio of the switches in two switch groups satisfying the bidirectional current path, the voltage of the input AC power source can be increased or decreased.

2. The primary AC / AC conversion system according to claim 1, characterized in that: The device also includes a filter capacitor connected to both ends of the input AC power supply.

3. The primary AC / AC conversion system according to claim 1, characterized in that: When the input alternating current power source connected is a power grid, the primary AC / AC conversion system further comprises a bypass switch, and two ends of the bypass switch are respectively connected to the first port and the third port of the primary AC / AC conversion system; When the bypass switch is closed, the switches in the first switch group satisfying the bidirectional current path and the second switch group satisfying the bidirectional current path are both turned off.

4. The primary AC / AC conversion system according to claim 1, characterized in that: The first switch group satisfying the bidirectional current path and the second switch group satisfying the bidirectional current path both include two switch tubes with freewheeling diodes.

5. The primary AC / AC conversion system according to claim 4, characterized in that: By controlling the duty cycle of the switches in two switch groups satisfying the bidirectional current path, the voltage of the input AC power source can be increased or decreased, including: The duty ratio of the two switch tubes in the first switch group that satisfies the bidirectional current path is D, 0≤D≤1, then the duty ratio of the second switch group that satisfies the bidirectional current path is 1-D, the voltage of the first port and the second port is represented by V1, the voltage of the third port and the fourth port is represented by V2, then the input and output voltage relationship is: By modifying the duty cycle of the switch tube and adjusting the output voltage, the voltage of the input AC power supply can be increased or decreased.

6. The primary AC / AC conversion system according to any one of claims 1 to 5, characterized in that: When the primary AC / AC conversion system is used in a three-phase power grid, each phase of the three-phase power grid is respectively connected to an independent primary AC / AC conversion system.

7. A high and low voltage management system, characterized in that: It comprises a detection module, a control generation module and a primary AC / AC conversion system as claimed in any one of claims 1 to 6; Wherein, the detection module is used to detect whether the supply voltage is higher or lower than the threshold of the normal voltage range; The control generation module is used to generate a control signal according to the output of the detection module, and the control signal is used to control the conduction or disconnection of the switches in the first switch group that satisfies the bidirectional current path and the second switch group that satisfies the bidirectional current path in the primary AC / AC conversion system.

8. The high and low voltage management system according to claim 7, characterized in that: When the detection module detects that the supply voltage is higher than the threshold of the normal voltage range, a signal indicating that the voltage is too high is transmitted to the control generation module, and the control generation module generates a control signal to control the duty cycle of the switch in the primary AC / AC conversion system to reduce the voltage.

9. The high and low voltage management system according to claim 7, characterized in that: When the detection module detects that the power supply voltage is lower than the threshold of the normal voltage range, a signal indicating that the voltage is too low is transmitted to the control generation module, and the control generation module generates a control signal to control the duty cycle of the switch in the primary AC / AC conversion system to increase the voltage.

10. The high and low voltage management system according to claim 7, characterized in that: When it is detected that the power supply voltage is within the normal voltage range, the control generation module generates a signal to disconnect all switches of the primary AC / AC conversion system, so that the primary AC / AC conversion system does not work.

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