Unified electric energy controller

Abstract

The utility model discloses a unified electric energy controller, which belongs to the technical field of electric energy quality control and intelligent micro-grids in a power distribution network area, and comprises a series coupling transformer, a parallel side rectifier and a series side inverter, the input end of the series coupling transformer is connected with alternating current, and the output end of the series coupling transformer is connected with a load; the input end of the parallel-side rectifier is connected with alternating current; the input end of the series-side inverter is connected with the output end of the parallel-side rectifier, and the output end is connected with the secondary side of the series coupling transformer. The unified electric energy controller provided by the utility model is simple and flexible in installation scheme and safe and convenient to maintain, realizes comprehensive treatment of various electric energy quality problems, improves the electric energy quality of a transformer area, reduces line loss, prolongs the service life of equipment, and can be expanded to be applied to the fields of light storage direct-current flexible, flexible interconnection, alternating-current and direct-current micro-grids and the like.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of distribution network area electric energy quality management and intelligent microgrid, and particularly relates to a unified electric energy controller. BACKGROUND

[0002] In modern power systems, distribution network area electric energy quality faces many challenges. With the large-scale access of distributed generation (such as photovoltaic) and charging piles, and the increase of power electronic equipment load, voltage fluctuation, three-phase imbalance, harmonic and other problems occur frequently. At the same time, users have increasingly high requirements for power supply quality and reliability, especially in places like hospitals and high-speed rail stations. In addition, in remote areas, the long power supply radius affects the electric energy quality. Therefore, a device is needed to comprehensively solve the problem of distribution network area electric energy quality in order to improve power supply quality and reliability and meet the needs of different users and scenarios. SUMMARY

[0003] The present application aims to overcome the defects of the prior art and provide a unified electric energy controller.

[0004] To achieve the above-mentioned purpose, the present application provides a unified electric energy controller, comprising:

[0005] A first transformer, the input end is connected with the first alternating current, and the output end is connected with the load;

[0006] A first parallel side rectifier, the input end is connected with the first alternating current;

[0007] A first series side inverter, the input end is connected with the output end of the first parallel side rectifier, and the output end is connected with the secondary side of the first transformer.

[0008] Optionally, the unified electric energy controller further comprises a first capacitor and a first bypass switch. The first capacitor is connected in parallel with the input end of the first series side inverter, the first end of the first bypass switch is connected with the secondary side of the first transformer, and the second end is connected with the output end of the first series side inverter.

[0009] Optionally, the first parallel side rectifier comprises a first switch tube, a second switch tube, a third switch tube and a fourth switch tube. The first end of the first switch tube is connected to the first alternating current, and the second end is connected to the second end of the first capacitor; the first end of the second switch tube is connected to the first end of the first capacitor, and the second end is connected to the first end of the first switch tube; the first end of the third switch tube is connected to the first alternating current, and the second end is connected to the second end of the first capacitor; the first end of the fourth switch tube is connected to the first end of the second switch tube, and the second end is connected to the first end of the third switch tube. The parallel side rectifier adjusts the load side current, thereby effectively solving the three-phase imbalance problem and ensuring that the three-phase current tends to be balanced and stable; it can realize reactive power compensation, improve the power factor, and reduce the adverse effects of reactive power on the power grid; it also has low harmonic compensation capability, reducing the interference of harmonic current on the power grid and load.

[0010] Optionally, the first series side inverter comprises a fifth switch tube, a sixth switch tube, a seventh switch tube and an eighth switch tube. The first end of the fifth switch tube is connected to the second end of the secondary side of the first transformer, and the second end is connected to the second end of the first capacitor; the first end of the sixth switch tube is connected to the first end of the first capacitor, and the second end is connected to the first end of the fifth switch tube; the first end of the seventh switch tube is connected to the first end of the secondary side of the first transformer, and the second end is connected to the second end of the fifth switch tube; the first end of the eighth switch tube is connected to the first end of the sixth switch tube, and the second end is connected to the first end of the seventh switch tube. The series side inverter adjusts the voltage of the secondary side of the first transformer to realize the adjustment and closed-loop control of the load side voltage, so as to ensure that the load side voltage is stable at the set value and eliminate the voltage quality problem of the load power supply side.

[0011] Optionally, the load comprises a second alternating current.

[0012] Optionally, the unified power controller further comprises a second transformer, a direct current bus, energy storage and photovoltaic. The input end of the second transformer is connected to the first alternating current, and the output end is connected to the input end of the first parallel side rectifier; the direct current bus is connected in parallel across the first capacitor; the energy storage is connected to the direct current bus; and the output end of the photovoltaic is connected to the direct current bus.

[0013] Optionally, the unified power controller further comprises a ninth switch tube, a tenth switch tube and an eleventh switch tube. The first end of the ninth switch tube is connected to the first alternating current, and the second end is connected to the primary side of the second transformer; the tenth switch tube is connected in series at the output end of the first transformer; the first end of the eleventh switch tube is connected to the first end of the ninth switch tube, and the second end is connected to the second end of the tenth switch tube.

[0014] Optionally, the unified power controller further comprises a twelfth switch tube and a thirteenth switch tube, wherein a first end of the twelfth switch tube is connected to a second end of the first capacitor, and a second end of the twelfth switch tube is connected to a positive end of the DC bus; a first end of the thirteenth switch tube is connected to a first end of the first capacitor, and a second end of the thirteenth switch tube is connected to a negative end of the DC bus.

[0015] Optionally, the unified power controller further comprises a third transformer, a second parallel-side rectifier, a second series-side inverter, a second bypass switch, a fourth transformer, a fourteenth switch tube, a fifteenth switch tube, a sixteenth switch tube, a second capacitor, a seventeenth switch tube and an eighteenth switch tube, wherein an input end of the third transformer is connected to the third AC power, and an output end of the third transformer is connected to the fourth AC power; an input end of the second parallel-side rectifier is connected to the third AC power; an input end of the second series-side inverter is connected to an output end of the second parallel-side rectifier, and an output end of the second series-side inverter is connected to a secondary side of the third transformer; a first end of the second bypass switch is connected to the secondary side of the third transformer, and a second end of the second bypass switch is connected to the output end of the second series-side inverter; an input end of the fourth transformer is connected to the third AC power, and an output end of the fourth transformer is connected to an input end of the second parallel-side rectifier; a first end of the fourteenth switch tube is connected to the third AC power, and a second end of the fourteenth switch tube is connected to a primary side of the fourth transformer; the fifteenth switch tube is connected in series between the third transformer and the third AC power; a first end of the fifteenth switch tube is connected to the output end of the third transformer, and a second end of the fifteenth switch tube is connected to the third AC power; the sixteenth switch tube has a first end connected to the first end of the fourteenth switch tube, and a second end connected to the second end of the fifteenth switch tube; the second capacitor is connected in parallel to the output end of the second series-side inverter; a first end of the seventeenth switch tube is connected to a second end of the second capacitor, and a second end of the seventeenth switch tube is connected to a positive end of the DC bus; a first end of the eighteenth switch tube is connected to a first end of the second capacitor, and a second end of the eighteenth switch tube is connected to a negative end of the DC bus.

[0016] Optionally, the DC bus is connected with a DC load.

[0017] In the technical scheme, the first transformer and the series-side inverter work cooperatively to effectively regulate the input voltage; the parallel-side rectifier regulates the load-side current to ensure that the three-phase current tends to be balanced and stable; the series-side inverter regulates and closed-loop controls the load-side voltage by regulating the secondary side voltage of the transformer, thereby ensuring that the load-side voltage is stable at the set value.

[0018] In summary, the unified electric energy controller realizes comprehensive management of various power quality problems, improves the power quality of the transformer area, reduces line loss, and prolongs the service life of equipment; can quickly respond and timely cope with dynamic changes in the power grid, effectively improve the influence of voltage fluctuation, harmonic and other problems on the power grid and user equipment; the fault bypass and non-power maintenance function ensures the reliability of power supply, reduces the power outage time caused by equipment failure and maintenance, and improves user satisfaction.

[0019] In order to make the above features and advantages of the utility model more obvious and easy to understand, the following specific examples are described in detail below, and the accompanying drawings are as follows. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the following will briefly introduce the drawings needed to be used in the embodiment or related art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0021] Figure 1 The structure block diagram of the unified electric energy controller provided by the utility model.

[0022] Figure 2 The first specific embodiment of the utility model.

[0023] Figure 3 The second specific embodiment of the utility model.

[0024] Figure 4 The third specific embodiment of the utility model.

[0025] Figure 5 The fourth specific embodiment of the utility model.

[0026] In the drawings, similar reference numerals refer to similar elements. DETAILED DESCRIPTION

[0027] In order to make the purpose and technical scheme of the embodiments of the present application more clear, the technical scheme of the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all. Based on the described embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0028] Figure 1The utility model relates to a structure block diagram of unified electric energy controller, and provide a kind of unified electric energy controller, comprising: alternating current 11, load 12, bypass switch Q1, parallel side rectifier 13, series side inverter 14, transformer T1 and capacitor C1.It is connected alternating current 11 at the input of transformer T1, and output is connected load 12;The input of parallel side rectifier 13 is connected alternating current 11, and output is connected the input of series side inverter 14;The input of series side inverter 14 is connected in the output of parallel side rectifier 13, and output is connected the secondary side of transformer T1;Bypass switch Q1 is connected between the secondary side winding of transformer T1 and the output of series side inverter 14;Capacitor C1 is connected in the input of series side inverter 14.

[0029] As an example, series side inverter 14 realizes the regulation and closed-loop control of load side voltage by adjusting the secondary side voltage of transformer T1, guarantees that load side voltage is stable on set value, and can also be used to eliminate voltage quality problems of load power supply side, for example, voltage harmonic exceeds the standard, voltage three-phase imbalance, low power factor and the like.

[0030] As an example, parallel side rectifier 13 accurately regulates load side current, thereby solving three-phase imbalance problem, and ensuring that three-phase current tends to be balanced and stable;It can realize reactive power compensation, improve power factor, and reduce adverse effects of reactive power on power grid;It also has low harmonic compensation capability, reduces interference of harmonic current on power grid and load. Through cooperation of parallel side rectifier 13 and series side inverter 14, comprehensive optimization and treatment of power quality of distribution network area can be realized.

[0031] As an example, when voltage rises, capacitor C1 can store excess electric energy, and release electric energy when voltage decreases, thereby smoothing fluctuation of DC bus voltage, and providing stable DC power supply for subsequent series side inverter 14 and entire system. Meanwhile, capacitor C1 has low impedance characteristic to high frequency harmonic, can bypass high frequency harmonic on DC bus to ground, thereby reducing influence of harmonic on system.

[0032] As an example, transformer T1 can be series coupling transformer.

[0033] In one embodiment, referring to Figure 2 Load 12 can include alternating current 22, to realize electric energy exchange and regulation between two alternating currents. When there is electric energy quality problem (such as voltage fluctuation, harmonic, etc.) in power grid where alternating current 21 is located, electric energy is transmitted from relatively stable alternating current 22 to compensate through the action of unified electric energy controller. Conversely, if alternating current 22 has excess electric energy or better electric energy quality, electric energy can also be transmitted to network where alternating current 21 is located, to balance electric energy supply and demand and quality of two power grids.

[0034] In one embodiment, please refer to Figure 3 For some medium and low voltage areas with high proportion of new energy access, an interface can be reserved on the DC side of the unified power quality controller to access distributed power sources such as wind power, photovoltaic, energy storage, and charging piles, DC street lamps, etc., thereby solving the problems of difficult capacity expansion and high cost of capacity expansion in the area. The embodiment more specifically includes a transformer T2, a DC bus 35, an energy storage 36, and a photovoltaic 37. The input end of the transformer T2 is connected to an alternating current 31, and the output end is connected to the input end of a parallel side rectifier 33. The transformer T2 transmits the alternating current 31 on the grid side after transformation to the parallel side rectifier 33, ensuring that the parallel side rectifier 33 can obtain appropriate voltage input, and also plays a certain isolation role for the grid side and the rectifier side, reducing the influence of grid interference on the rectifier; the output end of the parallel side rectifier 33 is connected to the DC bus 35, and the DC bus 35 is connected with the energy storage 36 and the photovoltaic 37.

[0035] As an example, the photovoltaic 37 converts solar energy into DC power and outputs to the DC bus 35 when the light is sufficient. According to the load demand and the energy storage state, the photovoltaic power is reasonably distributed. If the load demand is large and the energy storage is not full, the photovoltaic power is preferentially supplied to the load; if the load demand is small and the energy storage is not full, the excess photovoltaic power will be stored in the energy storage 36, improving energy utilization efficiency.

[0036] As an example, the transformer T2 can be an isolation transformer.

[0037] In one embodiment, please refer to Figure 4 It also includes a switch tube Q 11 , a switch tube Q 12 , a switch tube Q 13 , a switch tube Q 101 , and a switch tube Q 102 . The first end of the switch tube Q 11 is connected to an alternating current 41, and the second end of the switch tube Q 11 is connected to the primary side of the transformer T2; the first end of the switch tube Q 12 is connected to the output end of the transformer T1, and the second end of the switch tube Q 12 is connected to an alternating current 42; the first end of the switch tube Q 13 is connected to the alternating current 41, and the second end is connected to the alternating current 42; the first end of the switch tube Q 101 is connected to the second end of the capacitor C1, and the second end is connected to the positive end of the DC bus 45; the first end of the switch tube Q 102 is connected to the first end of the capacitor C1, and the second end is connected to the negative end of the DC bus 45; the switch tube Q 101 and the switch tube Q 102 control the access of the DC side load, for example, when it is needed to supply power to the DC load 46, the switch tube Q 101and switch tube Q 102 The DC load 46 is connected to the circuit, and the electric energy is transmitted from the DC bus 45 to the DC load 46 through the corresponding path to provide the required DC electric energy. When the DC load 46 causes the current to increase sharply due to internal short circuit, the protection device in the circuit detects the overcurrent signal and triggers the switch tube Q 101 and switch tube Q 102 The switch tube Q

[0038] As an example, the switch tube Q 13 is always on, and when the circuit fails, the switch tube Q 13 is closed, and the switch tube Q 11 and switch tube Q 12 is disconnected, the unified electric energy controller is disconnected, the fault bypass and non-power maintenance are realized, the reliability of power supply is ensured, the power outage time caused by equipment failure and maintenance is reduced, and the user satisfaction is improved.

[0039] As an example, the parallel side rectifier 43 includes switch tubes Q2, Q3, Q4 and Q5. The first end of the switch tube Q2 is connected to the second end of the secondary side of the transformer T2, and the second end is connected to the second end of the capacitor C1; the first end of the switch tube Q3 is connected to the first end of the capacitor C1, and the second end is connected to the first end of the switch tube Q2; the first end of the switch tube Q4 is connected to the first end of the secondary side of the transformer T2, and the second end is connected to the second end of the capacitor C1; the first end of the switch tube Q5 is connected to the first end of the switch tube Q3, and the second end is connected to the first end of the switch tube Q4.

[0040] As an example, the series side inverter 44 includes switch tubes Q6, Q7, Q8 and Q9. The first end of the switch tube Q6 is connected to the second end of the secondary side of the transformer T1, and the second end is connected to the second end of the capacitor C1; the first end of the switch tube Q7 is connected to the first end of the capacitor C1, and the second end is connected to the first end of the switch tube Q6; the first end of the switch tube Q8 is connected to the first end of the secondary side of the transformer T1, and the second end is connected to the second end of the switch tube Q6; the first end of the switch tube Q9 is connected to the first end of the switch tube Q7, and the second end is connected to the first end of the switch tube Q8.

[0041] As an example, when the AC 41 input voltage is in the positive half cycle, the switch tube Q2 is closed, the switch tube Q3 is open, the switch tube Q4 is open, the switch tube Q5 is closed, the positive current of the AC 41 output reaches the positive pole of the capacitor C1 through the switch tube Q2, and the negative current of the AC 41 reaches the negative pole of the capacitor C1 through the switch tube Q5; when the AC 41 input voltage is in the negative half cycle, the switch tube Q2 is open, the switch tube Q3 is closed, the switch tube Q4 is closed, the switch tube Q5 is open, the negative current of the AC 41 output reaches the negative pole of the capacitor C1 through the switch tube Q3, and the positive current of the AC 41 reaches the positive pole of the capacitor C1 through the switch tube Q4.

[0042] As an example, the series side inverter 44 converts the power on the DC bus 45 into an alternating voltage and controls the output through different conduction combinations of the switch tube Q6, the switch tube Q7, the switch tube Q8 and the switch tube Q9. The transformer T1 adjusts the secondary side voltage according to the control voltage input by the series side inverter 44, so as to stabilize the load side voltage within a set value range.

[0043] As an example, the interface reserved on the DC bus 45 is connected to the DC load 46, which can access charging piles, wind power, photovoltaic, energy storage, DC street lamps, etc., to solve the problems of difficult capacity expansion and high capacity expansion cost in the transformer area.

[0044] As an example, the series unified power controller between the 10kV / 35kV two-way interval in the distribution network substation can realize flexible power supply in case of line fault, and can also realize online power flow transfer control, fault rapid exit and flexible power supply. The AC interconnection control between the 10kV or 35kV lines of adjacent transformer areas or the 400V transformer area lines can realize balanced power supply of adjacent transformer area lines, power supply to each other in case of fault, fully utilize the distribution network asset stock by using online power flow transfer, realize load balancing between heavy load lines and light load lines, and improve the reliability, safety and economy of the transformer area distribution network power supply.

[0045] In one embodiment, please refer to Figure 5 , the embodiment more specifically includes the AC 511, the AC 521, the transformer T3, the transformer T4, the capacitor C2, the bypass switch Q 14 , the parallel side rectifier 531, the series side inverter 541, the switch tube Q 15 , the switch tube Q 16 , the switch tube Q 17 , the switch tube Q 103 , the switch tube Q 104 . The first end of the switch tube Q 15 is connected to the AC 511, and the second end is connected to the primary side of the transformer T4; the first end of the switch tube Q 16and the second end is connected with the secondary side of the transformer T3; the first end of the switch tube Q 17 is connected with the AC power 511 and the second end is connected with the AC power 521; the input end of the parallel side rectifier 531 is connected with the secondary side of the transformer T4 and the output end is connected with both ends of the capacitor C2; the capacitor C2 is connected in parallel with the output end of the series side inverter 541; the input end of the series side inverter 541 is connected with both ends of the capacitor C2 and the output end is connected with the bypass switch Q 14 ; the other end of the bypass switch Q 14 is connected with the secondary side of the transformer T3; the first end of the switch tube Q 103 is connected with the second end of the capacitor C2 and the second end is connected with the positive end of the DC bus 55; the first end of the switch tube Q 104 is connected with the first end of the capacitor C2 and the second end is connected with the negative end of the DC bus 55.

[0046] As an example, the parallel side rectifier 531 includes the switch tube Q 21 , the switch tube Q 31 , the switch tube Q 41 and the switch tube Q 51 . Wherein, the first end of the switch tube Q 21 is connected with the secondary side of the transformer T4 and the second end is connected with the second end of the capacitor C2; the first end of the switch tube Q 31 is connected with the first end of the capacitor C2 and the second end is connected with the first end of the switch tube Q 21 ; the first end of the switch tube Q 41 is connected with the secondary side of the transformer T4 and the second end is connected with the second end of the capacitor C2; the first end of the switch tube Q 51 is connected with the first end of the capacitor C2 and the second end is connected with the first end of the switch tube Q 41 .

[0047] As an example, the series side inverter 541 includes the switch tube Q 61 , the switch tube Q 71 , the switch tube Q 81 and the switch tube Q 91 . Wherein, the first end of the switch tube Q 61 is connected with the secondary side of the transformer T3 and the second end is connected with the second end of the capacitor C2; the first end of the switch tube Q 71 is connected with the first end of the capacitor C2 and the second end is connected with the first end of the switch tube Q 61 ; the first end of the switch tube Q 81 is connected with the secondary side of the transformer T3 and the second end is connected with the second end of the switch tube Q 61 ; the first end of the switch tube Q 91 is connected with the first end of the switch tube Q 71 and the second end is connected with the first end of the switch tube Q81 The first end.

[0048] As an example, transformer T3 can be a series-coupled transformer, and transformer T4 can be an isolation transformer.

[0049] As an example, the AC ports (such as AC 51, AC 511, etc.) perform preliminary processing and voltage transformation on the input AC power through corresponding switching transistors and transformers. The DC ports (such as DC bus 55) receive power input from other ports and simultaneously perform filtering and voltage regulation through switching transistors and capacitors, preparing for subsequent conversion and transmission. The power is further converted in intermediate stages through parallel-side rectifiers 53 and 531, and series-side inverters 54 and 541. During the conversion process, the power is stored in capacitors C1 and C2, achieving balanced power supply to adjacent transformer areas and mutual power transfer during faults, thus improving the economy, safety, and reliability of the power supply.

[0050] As an example, throughout the entire operation, the unified power controller performs reactive power optimization, coordination optimization, and load balancing based on real-time monitored parameters such as voltage and current. It also implements mode switching, local coordination control, and protection functions. When the unified power controller malfunctions, the fault bypass system activates. The electronic bypass quickly conducts within <1ms, short-circuiting the faulty equipment, followed by the mechanical bypass switching within <30ms, ensuring uninterrupted power supply. During maintenance, the switching transistor Q can be manually operated. 13 and switching transistor Q 17 The unified power controller is isolated for maintenance, and then switched back to normal operation after maintenance is completed.

[0051] The aforementioned unified power controller achieves comprehensive management of power quality issues through parallel-side rectifiers and series-side inverters, improving the power quality of the distribution area. The flexible use of switching transistors enables fault bypass and uninterrupted maintenance, ensuring the reliability of power supply, reducing power outage time caused by equipment failure and maintenance, and improving user satisfaction.

[0052] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0053] The above-described embodiments are merely illustrative for the present application and are described in more detail and specifically, but should not be understood as a limitation to the patent scope. It should be noted that for those skilled in the art, some modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

[0054] Although the present application has been disclosed with the above embodiments, it is not intended to limit the present application, and anyone skilled in the art can make some changes and modifications without departing from the spirit and scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A unified power controller, comprising: Comprise: A first transformer, the input end is connected with the first alternating current, and the output end is connected with a load; A first parallel side rectifier, the input end is connected with the first alternating current; A first series side inverter, the input end is connected with the output end of the first parallel side rectifier, and the output end is connected with the secondary side of the first transformer; A first capacitor, the first capacitor is connected in parallel with the input end of the first series side inverter; A first bypass switch, the first end of the first bypass switch is connected with the secondary side of the first transformer, and the second end is connected with the output end of the first series side inverter; A second transformer, the input end of the second transformer is connected with the first alternating current, and the output end is connected with the input end of the first parallel side rectifier; A direct current bus, the direct current bus is connected in parallel with the first capacitor; Energy storage, the energy storage is connected with the direct current bus; Photovoltaic, the output end of the photovoltaic is connected to the direct current bus.

2. A unified power controller according to claim 1, wherein, The first parallel side rectifier comprises: A first switch tube, the first end is connected with the first alternating current, and the second end is connected with the second end of the first capacitor; A second switch tube, the first end is connected with the first end of the first capacitor, and the second end is connected with the first end of the first switch tube; A third switch tube, the first end is connected with the first alternating current, and the second end is connected with the second end of the first capacitor; A fourth switch tube, the first end is connected with the first end of the second switch tube, and the second end is connected with the first end of the third switch tube.

3. The unified power controller of claim 1, wherein, The first series side inverter comprises: A fifth switch tube, the first end is connected with the secondary side of the first transformer, and the second end is connected with the second end of the first capacitor; A sixth switch tube, the first end is connected with the first end of the first capacitor, and the second end is connected with the first end of the fifth switch tube; A seventh switch tube, the first end is connected with the secondary side of the first transformer, and the second end is connected with the second end of the fifth switch tube; An eighth switch tube, the first end is connected with the first end of the sixth switch tube, and the second end is connected with the first end of the seventh switch tube.

4. The unified power controller of claim 1, wherein, The load comprises a second alternating current.

5. The unified power controller of claim 1, wherein, Further comprise: A ninth switch tube, the first end is connected with the first alternating current, and the second end is connected with the primary side of the second transformer; A tenth switch tube, the tenth switch tube is connected in series with the output end of the first transformer; An eleventh switch tube, the first end is connected with the first end of the ninth switch tube, and the second end is connected with the second end of the tenth switch tube.

6. A unified power controller according to claim 5, wherein, Further comprise: A twelfth switch tube, the first end is connected with the second end of the first capacitor, and the second end is connected with the positive end of the direct current bus; A thirteenth switch tube, the first end is connected with the first end of the first capacitor, and the second end is connected with the negative end of the direct current bus.

7. A unified power controller according to claim 6, wherein, Further comprise: A third transformer, the input end of the third transformer is connected with a third alternating current, and the output end is connected with a fourth alternating current; A second parallel side rectifier, the input end is connected with the third alternating current; A second series side inverter, the input end is connected with the output end of the second parallel side rectifier, and the output end is connected with the secondary side of the third transformer; A second bypass switch, the first end of the second bypass switch is connected with the secondary side of the third transformer, and the second end is connected with the output end of the second series side inverter; A fourth transformer, the input end of the fourth transformer is connected with the third alternating current, and the output end is connected with the input end of the second parallel side rectifier; A fourteenth switch tube, a first end of which is connected to the third alternating current, and a second end of which is connected to a primary side of the fourth transformer; A fifteenth switch tube, which is connected in series between the third transformer and the third alternating current, a first end of the fifteenth switch tube being connected to an output end of the third transformer, and a second end of the fifteenth switch tube being connected to the third alternating current; A sixteenth switch tube, a first end of which is connected to the first end of the fourteenth switch tube, and a second end of which is connected to the second end of the fifteenth switch tube; A second capacitor, which is connected in parallel to an output end of the second series side inverter; A seventeenth switch tube, a first end of which is connected to a second end of the second capacitor, and a second end of which is connected to a positive end of the direct current bus; An eighteenth switch tube, a first end of which is connected to a first end of the second capacitor, and a second end of which is connected to a negative end of the direct current bus.

8. A unified power controller according to claim 7, wherein, A direct current load is connected to the direct current bus.

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