Dynamic voltage restorer system with detection and predictive control mechanisms

Abstract

A dynamic voltage restorer system with a detection and predictive control mechanism includes: an input switch with one end connected to the mains power; a static bypass switch with one input end connected to the other end of the input switch; an output switch with one end connected to the output end of the static bypass switch, and the other end of the output switch connected to the load; a multi-stage inverter module with one input end connected to the other end of the input switch and the input end of the static bypass switch, and an output end of the multi-stage inverter module connected to the output end of the output switch and the output end of the static bypass switch. This dynamic voltage restorer system can pre-inject compensation voltage before switching and quickly switch to full inverter power supply when the voltage drops or rises significantly, ensuring continuous and stable load operation, thus achieving the objective of this invention.

Claims

1. A dynamic voltage restorer system, comprising: an input switch, one end of which is connected to a mains input terminal; a static bypass switch, one input terminal of which is connected to the other end of the input switch; an output switch, one end of which is connected to an output terminal of the static bypass switch, and the other end of which is connected to a load terminal; a multi-stage inverter module, one input terminal of which is connected to the other end of the input switch and the input terminal of the static bypass switch, and one output terminal of which is connected to the output terminal of the output switch and the output terminal of the static bypass switch; and an energy storage module, one charging / discharging terminal of which is connected to the multi-stage inverter module; wherein the multi-stage inverter module comprises: an AC-DC rectifier, one input terminal of which is the input terminal of the multi-stage inverter module; A DC-DC converter, one input terminal of which is connected to an output terminal of an AC-DC rectifier; and a DC-AC inverter, one input terminal of which is connected to an output terminal of the DC-DC converter, the output terminal of which is the output terminal of the multi-stage inverter module; wherein the mains input terminal, the input terminal and the output terminal of the AC-DC rectifier, the output terminal and the input / output terminal of the DC-DC converter, the input terminal and the output terminal of the DC-AC inverter, the input terminal and the output terminal of the static bypass switch, the charging / discharging terminal of the energy storage module, or the load terminal are all key nodes of the dynamic voltage restorer system, and each of these key nodes is equipped with its own sensor to measure the voltage and / or current on the key nodes respectively, and the information measured by the sensor is transmitted to a central control module of the dynamic voltage restorer system.

2. The dynamic voltage restorer system as described in claim 1 further includes: a maintenance bypass switch, one end of which is connected to the mains input terminal, and the other end of which is connected to the load terminal.

3. The dynamic voltage restorer system as described in claim 1, wherein the charge / discharge terminal of the energy storage module is connected to an input / output terminal of a DC-DC converter in the multi-stage inverter module, and the DC-DC converter charges and discharges the energy storage module via the charge / discharge terminal of the energy storage module.

4. The dynamic voltage restorer system as described in claim 1, wherein the static bypass switch is a silicon controlled rectifier.

5. The dynamic voltage restorer system as described in claim 1, wherein the energy storage module is a supercapacitor.

6. The dynamic voltage restorer system as described in claim 1, wherein the dynamic voltage restorer system can enter a normal mode, a mains inverter mode, or an energy storage compensation inverter mode during operation, depending on the voltage at the mains input terminal and the load at the load terminal.

7. As described in claim 1, when the dynamic voltage restorer system needs maintenance, the input switch is turned off, and the system determines whether to enter a maintenance bypass mode based on the voltage of the mains input terminal. If the maintenance bypass mode is entered, the mains input terminal is connected to the load terminal via a maintenance bypass switch.

8. The dynamic voltage restorer system as described in claim 1, wherein when the multi-stage inverter module is removed, the input switch, the static bypass switch, and the output switch are all set to be on, so that the mains power at the mains input terminal can still be conducted to the load terminal through the input switch, the static bypass switch, and the output switch.

9. The dynamic voltage restorer system as described in claim 1, wherein when the central control module confirms, based on information measured by the sensors, that the voltage or current of any of the key nodes has exceeded a preset threshold, the dynamic voltage restorer system is immediately triggered to enter a mains inverter mode or an energy storage compensation inverter mode.

10. The dynamic voltage restorer system as described in claim 1, wherein within one cycle, the central control module reads the measured values ​​of voltage and / or current of the key nodes and predicts the voltage fluctuation of the key nodes in the next cycle. If the predicted voltage fluctuation is greater than a switching threshold, an inverter PWM modulation interface is called to perform compensation in advance. If the predicted voltage fluctuation is greater than or equal to the switching threshold, the static bypass switch is turned off, and an energy storage compensation inverter mode powered by both the energy storage module and the mains input terminal or a mains inverter mode powered only by the mains input terminal is started.

11. As described in Request 1, in the dynamic voltage restorer system, when the measured values ​​of voltage and / or current at these critical nodes return to normal, the power supply of the DC-AC inverter is first synchronized with the mains power at the mains input terminal, and then the static bypass switch is turned on to supply power.

12. The dynamic voltage restorer system as described in claim 1, wherein within one cycle, the central control module reads the measured values ​​of voltage and / or current of the key nodes and predicts the voltage fluctuation of the key nodes in the next cycle. If the predicted voltage fluctuation is greater than a switching threshold, the PWM duty cycle in the DC-AC inverter or the firing angle of a silicon controlled rectifier in the static bypass switch is dynamically adjusted according to the predicted voltage fluctuation.

13. The dynamic voltage restorer system as described in claim 1, when the measured values ​​of voltage and / or current at these critical nodes continuously exceed the switching threshold, can switch the DC-AC inverter to supply power to the load terminal, or switch a maintenance bypass switch to allow the mains input terminal to directly supply power to the load terminal.

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