Dynamic voltage restorer based on super capacitor

Abstract

The utility model discloses a dynamic voltage restorer based on a super capacitor, which is used for compensating the voltage of a subway escalator and comprises a super capacitor energy storage device, an inverter circuit, a detection and control circuit, a series transformer and a bypass unit, the super-capacitor energy storage device is connected to the inverter circuit and is used for storing energy when the voltage of the subway alternating-current power grid is normal and releasing energy when the voltage of the subway alternating-current power grid is sag; the inverter circuit is connected to the bypass unit through the series transformer; the detection and control circuit is used for detecting power supply voltage and load voltage of the escalator and generating modulation waves, and the detection and control circuit is connected to the inverter circuit; the bypass unit is arranged between a subway escalator power supply and a subway escalator load, the bypass unit is a switch, when voltage sag is detected, the switch is switched off, and the inverter circuit supplies power. The voltage restorer based on the super capacitor has the advantages of being high in response speed, high in cost effectiveness and compact in size.

Description

Technical Field

[0001] The utility model relates to the technical field of urban rail transit, in particular to a dynamic voltage restorer based on a supercapacitor. Background Art

[0002] With the acceleration of urbanization, subways, as an important part of urban public transportation, have a direct impact on the public's travel experience and the city's operating efficiency due to their safety and reliability. In the subway system, escalators are key facilities for transporting passengers, and they have extremely high requirements for voltage stability. However, during the operation of the power grid, voltage sags may occur due to various factors (such as power grid failures, load mutations, etc.). Such voltage sags often cause sensitive equipment such as subway escalators to operate unstably and stop suddenly, causing inconvenience to passengers and, in serious cases, may cause safety accidents.

[0003] Existing solutions to voltage sags include using uninterruptible power supplies (UPS) or static voltage restorers (SVR), which usually have problems such as slow response, bulky size, and high cost. The applicability of these solutions is limited, especially in environments such as subway stations where space is limited and there are strict requirements on equipment performance and size.

[0004] Therefore, it is urgent to invent a dynamic voltage restorer to solve the problems of slow response speed, bulky size and low cost-effectiveness of the existing voltage recovery devices for subway escalators. Summary of the invention

[0005] In view of this, an embodiment of the present invention provides a dynamic voltage restorer based on a supercapacitor, which at least partially solves the problems existing in the prior art.

[0006] Other features and advantages of the present invention will become apparent from the following detailed description or may be learned in part from the practice of the present invention.

[0007] In order to achieve the above purpose, the embodiment of the utility model provides the following technical solutions:

[0008] According to a first aspect of an embodiment of the utility model, a supercapacitor-based dynamic voltage restorer is provided for compensating the voltage of a subway escalator, the restorer comprising: a supercapacitor energy storage device, an inverter circuit, a detection and control circuit, a series transformer and a bypass unit;

[0009] The supercapacitor energy storage device is connected to the inverter circuit and is used to store energy when the voltage of the subway AC grid is normal and release energy when the voltage of the subway AC grid temporarily drops;

[0010] The inverter circuit is connected to the bypass unit via the series transformer, and the series transformer is used for electrical isolation, compensation voltage matching and power transmission;

[0011] The detection and control circuit is used to detect the escalator power supply voltage and the escalator load voltage and generate a modulation wave, and the detection and control circuit is connected to the inverter circuit;

[0012] The bypass unit is arranged between the subway escalator power supply and the subway escalator load. The bypass unit is a switch. When a voltage drop is detected, the switch is disconnected and the inverter circuit supplies power.

[0013] Furthermore, the supercapacitor energy storage device is formed by at least two standard supercapacitor modules connected in series.

[0014] Further, the detection and control circuit includes a voltage detection circuit and a control circuit;

[0015] The voltage detection circuit is used to detect the power supply voltage and the load voltage of the subway escalator, and send the generated compensation voltage reference value to the control circuit;

[0016] The control circuit is used to receive the compensation voltage reference value and generate a PWM modulation wave by combining power supply voltage feedforward with double closed-loop control of load voltage and capacitor current;

[0017] The supercapacitor-based dynamic voltage restorer adopts PWM modulation technology.

[0018] Furthermore, the inverter circuit includes at least one single-phase full-bridge circuit; and each of the single-phase full-bridge circuits is connected in parallel.

[0019] Furthermore, the single-phase full-bridge circuit includes a DC side capacitor C, a first bridge arm and a second bridge arm;

[0020] The DC side capacitor C, the first bridge arm and the second bridge arm are sequentially connected in parallel with the output end of the supercapacitor energy storage device;

[0021] The midpoint of the first bridge arm and the midpoint of the second bridge arm serve as output ports of the single-phase full-bridge circuit.

[0022] Furthermore, the first bridge arm includes a first switch tube Q1 and a second switch tube Q2;

[0023] The emitter of the first switch tube Q1 is connected to the collector of the second switch tube Q2 to form a first bridge arm;

[0024] The second bridge arm includes a third switch tube Q3 and a fourth switch tube Q4;

[0025] The emitter of the third switch tube Q3 is connected to the collector of the fourth switch tube Q4 to form a second bridge arm.

[0026] Furthermore, the switch tube adopts an insulated gate bipolar transistor IGBT.

[0027] Furthermore, the inverter circuit further includes an inverter low-pass filter, which is formed by a filter inductor La and a filter capacitor Ca connected in series, and the filter capacitor Ca is connected in parallel with the bypass unit.

[0028] Furthermore, the inverter circuit includes three single-phase full-bridge circuits, which are connected in parallel, and each single-phase full-bridge circuit is respectively connected to each phase of the three-phase main circuit of the subway escalator.

[0029] According to a second aspect of an embodiment of the utility model, a subway escalator voltage recovery system is provided, the system comprising a subway escalator power supply and a subway escalator load, and also comprising a supercapacitor-based dynamic voltage restorer as described in any of the above items.

[0030] The utility model has the following advantages:

[0031] The utility model discloses a supercapacitor-based dynamic voltage restorer for subway escalators, which can realize dynamic compensation of subway escalator voltage, while reducing maintenance difficulty and cost, and effectively improving the economy of the voltage restorer. The utility model provides a supercapacitor-based dynamic voltage restorer, which can quickly compensate for the voltage of subway escalators, effectively prevent the subway escalators from generating safety hazards due to temporary voltage drops, and has the advantages of fast response speed, high cost performance and compact size. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the implementation of the utility model or the technical solution in the prior art, the following is a brief introduction to the drawings required for the implementation or the prior art description. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0033] Figure 1 A schematic diagram of the structure of a dynamic voltage restorer based on a supercapacitor provided in an embodiment of the utility model;

[0034] Figure 2 One of the wiring diagrams of a supercapacitor-based dynamic voltage restorer provided in an embodiment of the utility model;

[0035] Figure 3 The second wiring diagram of the supercapacitor-based dynamic voltage restorer provided in the embodiment of the utility model;

[0036] Figure 4 A schematic structural diagram of a subway escalator voltage recovery system provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. 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.

[0039] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0040] In the description of the present utility model, it should be noted that the nouns indicating orientation or positional relationships appearing in the content of this specification are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationships in which the utility model product is usually placed when in use. They are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as a limitation on the present utility model.

[0041] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] refer to Figure 1The embodiment of the utility model provides a supercapacitor-based dynamic voltage restorer for compensating the voltage of a subway escalator. The supercapacitor-based dynamic voltage restorer includes: a super energy storage device, an inverter circuit, a detection and control circuit, and a bypass unit.

[0043] The supercapacitor energy storage device is connected to the inverter circuit to store energy when the subway AC grid voltage is normal and release energy when the subway AC grid voltage drops temporarily, outputting a DC voltage U dc .

[0044] Specifically, the supercapacitor energy storage device is formed by connecting at least two standard supercapacitor modules in series, the capacitance value of the supercapacitor module is selected according to the stored energy, and the number of standard supercapacitor modules is determined by the DC voltage.

[0045] The supercapacitor module model in the embodiment of the utility model is MCP0165C0-0048R0, the output voltage is 48V, and the capacity is 165F; 10 supercapacitor modules are connected in series, that is, the output DC voltage U dc It is 480V.

[0046] The inverter circuit is connected to the bypass unit through a series transformer, which is used for electrical isolation, compensation voltage matching and power transfer.

[0047] Specifically, refer to Figure 2 The above-mentioned inverter circuit includes at least one single-phase full-bridge circuit, and each single-phase full-bridge circuit is connected in parallel.

[0048] Furthermore, the above-mentioned single-phase full-bridge circuit includes a DC side capacitor C, a first bridge arm and a second bridge arm; the DC side capacitor C, the first bridge arm and the second bridge arm are connected in parallel with the output end of the supercapacitor energy storage device in sequence, and the midpoint of the first bridge arm and the midpoint of the second bridge arm serve as the output port of the single-phase full-bridge circuit.

[0049] Furthermore, the first bridge arm includes a first switch tube Q1 and a second switch tube Q2, the emitter of the first switch tube Q1 is connected to the collector of the second switch tube Q2, forming the first bridge arm; the second bridge arm includes a third switch tube Q3 and a fourth switch tube Q4, the emitter of the third switch tube Q3 is connected to the collector of the fourth switch tube Q4, forming the second bridge arm; wherein the switch tube adopts an insulated gate bipolar transistor IGBT. The supercapacitor energy storage device inputs direct current into the DC side capacitor C, one end of the DC side capacitor C is connected to the collector of the first switch tube Q1 and the collector of the third switch tube Q3, and the other end of the DC side capacitor C is connected to the emitter of the second switch tube Q2 and the emitter of the fourth switch tube Q4.

[0050] In addition, since the output of the single-phase full-bridge circuit is a series of rectangular waves, it includes not only the 50Hz power frequency voltage component, but also the high-frequency harmonics of the same switching frequency and its multiples. In order to obtain the 50Hz power frequency voltage, the inverter circuit also includes an inverter low-pass filter. The inverter low-pass filter adopts an LC second-order filter, which is composed of a filter inductor La and a filter capacitor Ca connected in series. The filter capacitor Ca is connected in parallel with the bypass unit. The output port of the single-phase full-bridge circuit is connected to the inverter low-pass filter, that is, the midpoint of the first bridge arm and the second bridge arm is connected to the inverter low-pass filter. The output of the inverter low-pass filter is connected to the main circuit of the subway escalator, that is, the filter capacitor Ca is connected in series to the main circuit of the subway escalator. In this embodiment, La takes 1mH and Ca takes 100uF.

[0051] The cutoff frequency of the above-mentioned inverter low-pass filter must be much higher than the power frequency, and the voltage drop on the filter inductor La must be less than the rated voltage of the load. Therefore, the cutoff frequency in this embodiment is 10 times the power frequency, that is, the cutoff frequency is 500Hz, and the voltage drop of the inductor is 20% of the rated voltage of the escalator load.

[0052] The independent single-phase full-bridge supercapacitor-based dynamic voltage restorer has a clear structure and adopts PWM modulation, which is easy to implement in engineering.

[0053] The detection and control circuit is used for detecting the escalator power supply voltage and the escalator load voltage and generating a modulation wave, and the detection and control circuit is connected to the inverter circuit.

[0054] Specifically, the detection and control circuit includes a voltage detection circuit and a control circuit; the voltage detection circuit is respectively connected to the subway escalator power supply and the subway escalator load through a data acquisition module, detects the subway escalator power supply voltage and the subway escalator load voltage, and sends the generated compensation voltage reference value to the control circuit; the control circuit is used to receive the compensation voltage reference value, and uses a combination of power supply voltage feedforward and double closed-loop control of load voltage and capacitor current to generate a PWM modulation wave and input it into the inverter circuit.

[0055] The bypass unit is arranged between the subway escalator power supply and the subway escalator load of the subway escalator main circuit, and the bypass unit is a switch SCR (thyristor); when the subway escalator power supply is normal, the subway escalator power supply current flows to the escalator load through the bypass unit, and the bypass unit bypasses the other parts of the dynamic voltage restorer based on the supercapacitor; when the voltage detection circuit detects a voltage drop in the escalator power supply network, the bypass unit is disconnected and the inverter circuit starts to supply power to ensure the stability of the subway escalator voltage.

[0056] Preferably, reference Figure 3, corresponding to the above-disclosed dynamic voltage restorer based on supercapacitor, the embodiment of the utility model further discloses a dynamic voltage restorer based on supercapacitor, wherein the inverter circuit includes three single-phase full-bridge circuits, the three single-phase full-bridge circuits have the same structure, namely, A-phase full-bridge circuit, B-phase full-bridge circuit and C-phase full-bridge circuit, the three-phase voltage is independently compensated, there is no common connection point between the three phases except the input parallel connection, and the output of each phase compensation voltage is +Udc and -Udc. Each single-phase full-bridge circuit is connected to the bypass unit on each phase of the three-phase main circuit of the subway escalator through an inverter low-pass filter, and each phase main circuit of the above-mentioned three-phase main circuit of the subway escalator includes a subway escalator power supply and a subway escalator load.

[0057] Corresponding to the above-disclosed dynamic voltage restorer based on supercapacitor, the utility model embodiment discloses a subway escalator voltage recovery system, referring to Figure 4 The above system includes a subway escalator power supply and a subway escalator load, and also includes a supercapacitor-based dynamic voltage restorer as described in any of the above items.

[0058] The embodiment of the utility model provides a dynamic voltage restorer based on supercapacitor, which is used to compensate the voltage of subway escalator. The restorer includes: supercapacitor energy storage, inverter circuit, detection and control circuit, series transformer and bypass unit; the supercapacitor energy storage is connected to the inverter circuit, which is used to store energy when the voltage of subway AC grid is normal, and release energy when the voltage of subway AC grid drops temporarily; the inverter circuit is connected to the bypass unit through the series transformer; the detection and control circuit is used to detect the escalator power supply voltage and the escalator load voltage and generate a modulated wave, and the detection and control circuit is connected to the inverter circuit; the bypass unit is arranged between the subway escalator power supply and the subway escalator load, and the bypass unit is a switch. When the voltage drops temporarily, the switch is disconnected and the inverter circuit supplies power. The voltage restorer based on supercapacitor disclosed by the utility model has the advantages of fast response speed, high cost-effectiveness and compact size.

[0059] The above-listed embodiments show and describe the basic principles and main features of the utility model, but the utility model is not limited to the above-mentioned embodiments. Any modifications, equivalent changes and modifications made to the utility model by those skilled in the art without making any creative work should fall within the scope of protection of the technical solution of the utility model.

Claims

1. A dynamic voltage restorer based on supercapacitor, characterized in that: Used to compensate for the voltage of subway escalators, the restorer includes: a supercapacitor energy storage device, an inverter circuit, a detection and control circuit, a series transformer and a bypass unit; The supercapacitor energy storage device is connected to the inverter circuit and is used to store energy when the voltage of the subway AC grid is normal and release energy when the voltage of the subway AC grid temporarily drops; The inverter circuit is connected to the bypass unit via the series transformer, and the series transformer is used for electrical isolation, compensation voltage matching and power transmission; The detection and control circuit is used to detect the escalator power supply voltage and the escalator load voltage and generate a modulation wave, and the detection and control circuit is connected to the inverter circuit; The bypass unit is arranged between the subway escalator power supply and the subway escalator load. The bypass unit is a switch. When a voltage drop is detected, the switch is disconnected and the inverter circuit supplies power.

2. The supercapacitor-based dynamic voltage restorer according to claim 1, characterized in that: The supercapacitor energy storage device is formed by at least two standard supercapacitor modules connected in series.

3. The supercapacitor-based dynamic voltage restorer according to claim 1, characterized in that: The detection and control circuit includes a voltage detection circuit and a control circuit; The voltage detection circuit is used to detect the power supply voltage and the load voltage of the subway escalator, and send the generated compensation voltage reference value to the control circuit; The control circuit is used to receive the compensation voltage reference value and generate a PWM modulation wave by combining power supply voltage feedforward with double closed-loop control of load voltage and capacitor current; The supercapacitor-based dynamic voltage restorer adopts PWM modulation technology.

4. The supercapacitor-based dynamic voltage restorer according to claim 1, characterized in that: The inverter circuit includes at least one single-phase full-bridge circuit; each of the single-phase full-bridge circuits is connected in parallel.

5. The supercapacitor-based dynamic voltage restorer according to claim 4, characterized in that: The single-phase full-bridge circuit comprises a DC side capacitor C, a first bridge arm and a second bridge arm; The DC side capacitor C, the first bridge arm and the second bridge arm are sequentially connected in parallel with the output end of the supercapacitor energy storage device; The midpoint of the first bridge arm and the midpoint of the second bridge arm serve as output ports of the single-phase full-bridge circuit.

6. The supercapacitor-based dynamic voltage restorer according to claim 5, characterized in that: The first bridge arm includes a first switch tube Q1 and a second switch tube Q2; The emitter of the first switch tube Q1 is connected to the collector of the second switch tube Q2 to form a first bridge arm; The second bridge arm includes a third switch tube Q3 and a fourth switch tube Q4; The emitter of the third switch tube Q3 is connected to the collector of the fourth switch tube Q4 to form a second bridge arm.

7. The supercapacitor-based dynamic voltage restorer according to claim 6, characterized in that: The switch tube adopts an insulated gate bipolar transistor IGBT.

8. The supercapacitor-based dynamic voltage restorer according to claim 1, characterized in that: The inverter circuit further includes an inverter low-pass filter, which is formed by a filter inductor La and a filter capacitor Ca connected in series, and the filter capacitor Ca is connected in parallel with the bypass unit.

9. The supercapacitor-based dynamic voltage restorer according to any one of claims 4 to 6, characterized in that: The inverter circuit includes three single-phase full-bridge circuits, which are connected in parallel, and each single-phase full-bridge circuit is respectively connected to each phase of the three-phase main circuit of the subway escalator.

10. A subway escalator voltage recovery system, characterized in that: The system includes a subway escalator power supply and a subway escalator load, and also includes a supercapacitor-based dynamic voltage restorer as described in any one of claims 1-9.

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