A high-low voltage ride-through transient control system
Patent Information
- Application Number
- CN202522563200.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-03
- Publication Date
- 2026-10-30
- Estimated Expiration
- 2035-12-03
AI Technical Summary
然而，当电网发生故障时，将引发电压骤升或骤降，即电压暂态现象
[0012]有益效果：本实用新型为一种高低电压穿越暂态控制系统，通过电压检测模块实时采集电网电压与直流母线电压，主控制器根据采集信号判断电压暂态并控制功率变换模块进行高低电压穿越控制；同时，设置硬件保护电路应对瞬时过压/过流，在电压异常时直接封锁驱动信号有效防止器件损坏，利用泄放电路在直流母线电压过高时消耗多余能量，同时解决了低电压穿越时的过流问题和高电压穿越时的过压问题，提高了静态无功发生器的可靠性与电网适应性。
Smart Images
Figure CN224923404U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of reactive power compensation technology in power systems, specifically a high and low voltage ride-through transient control system. Background Technology
[0002] Static var generators (SVG), as core devices in flexible AC transmission systems, are widely used in power grid systems to achieve dynamic reactive power compensation and grid voltage stabilization. However, when a grid fault occurs, it will cause a sudden rise or fall in voltage, i.e., voltage transient phenomena.
[0003] Traditional SVG control systems operate well under normal grid voltage conditions, but exhibit significant problems during periods of severe grid voltage fluctuations: During grid voltage dips, to maintain DC-side voltage stability and output the specified reactive current, the SVG AC side generates a large overcurrent, which can easily damage power switching devices; when grid voltage surges, energy may be fed back from the grid side to the SVG DC side, causing a sharp increase in DC bus voltage. If this exceeds the withstand voltage limit of the capacitors, it can lead to DC-side overvoltage risks. Drastic voltage changes can cause the phase-locked loop (PLL)-based synchronization mechanism to fail, resulting in the current inner-loop control losing its precise reference coordinate system and causing instability in the static var generator (SGG) control system. Utility Model Content
[0004] To address the aforementioned problems, this invention provides a high and low voltage ride-through transient control system applied to a static var generator. The static var generator is electrically connected to the power grid. The system includes a voltage detection module, a main controller, a drive circuit, and a power conversion module. The power conversion module has a DC bus capacitor electrically connected to its DC side and a reactor electrically connected to its AC side. The voltage detection module is electrically connected to the main controller, the main controller is electrically connected to the drive circuit, the output of the drive circuit is electrically connected to the power conversion module, and the output of the power conversion module is connected to the power grid.
[0005] The voltage detection module is electrically connected to both the power transmission grid and the DC bus inside the static var generator.
[0006] The high and low voltage ride-through transient control system also includes a hardware protection circuit. The input terminal of the hardware protection circuit is electrically connected to the voltage detection module, and its output terminal is electrically connected to the drive circuit.
[0007] The hardware protection circuit includes a voltage comparator U1, a logic gate circuit U2, and resistors R1-R2. Resistors R1-R2 form a series circuit connected to the inverting input terminal of the voltage comparator U1. The reference voltage is connected to the inverting input terminal of the voltage comparator U1. The output terminal of the voltage comparator U1 is electrically connected to the logic gate circuit.
[0008] The logic gate circuit uses NAND gates.
[0009] In a specific implementation, the main controller uses a TMS320F2837x processor.
[0010] The high and low voltage ride-through transient control system also includes a discharge circuit, which is connected in parallel across the two ends of the DC bus capacitor and electrically connected to the main controller.
[0011] The discharge route consists of a controllable switch and a power-consuming resistor connected in series.
[0012] Beneficial effects: This utility model is a high and low voltage ride-through transient control system. It collects grid voltage and DC bus voltage in real time through a voltage detection module. The main controller judges the voltage transient based on the collected signals and controls the power conversion module to perform high and low voltage ride-through control. At the same time, a hardware protection circuit is set to deal with instantaneous overvoltage / overcurrent. When the voltage is abnormal, the drive signal is directly blocked to effectively prevent device damage. The discharge circuit consumes excess energy when the DC bus voltage is too high. It solves the overcurrent problem during low voltage ride-through and the overvoltage problem during high voltage ride-through, thereby improving the reliability and grid adaptability of the static var generator. Attached Figure Description
[0013] The advantages and solutions of this application will become clear to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this invention.
[0014] In the attached diagram: Figure 1 This is a circuit diagram of a high- and low-voltage ride-through transient control system. Figure 2 This is a hardware protection circuit diagram. Detailed Implementation
[0015] Exemplary embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings.
[0016] Example 1 See Figure 1 This embodiment provides a high and low voltage ride-through transient control system applied to a static var generator (SVG). The SVG is electrically connected to the power grid. The system includes a voltage detection module, a main controller, a drive circuit, and a power conversion module. The DC side of the power conversion module is electrically connected to a DC bus capacitor, and its AC side is electrically connected to a reactor.
[0017] The voltage detection module is electrically connected to the main controller. It is also electrically connected to both the power grid and the DC bus inside the static var generator (SGG). This module collects the three-phase AC voltage signal and the DC bus voltage signal from the power grid in real time and transmits the collected signals to the main controller. The main controller receives the collected signals from the voltage detection module and determines whether the power grid voltage has entered a transient range. The main controller uses a TMS320F2837x processor. When the detected power grid voltage is normal, the main controller executes vector control based on a dual-closed-loop mechanism, controlling the SVG to output or absorb reactive power. When the power grid voltage is determined to have entered a transient range, the main controller is electrically connected to the drive circuit. The output of the drive circuit is electrically connected to the power conversion module. The main controller sends a PWM control signal to the drive circuit, which then drives the power conversion module to operate according to the PWM control signal, thereby achieving high and low voltage ride-through control.
[0018] When the voltage of the power grid drops, the main controller controls the SVG to output a support voltage to the power grid. The power conversion module converts the stored energy into a support current through the DC bus capacitor on the DC side and transmits it to the power grid. The reactor on the AC side of the power conversion module is used to suppress overcurrent of the support voltage output by the SVG and prevent instantaneous surge current faults.
[0019] When the voltage of the power grid rises suddenly, the main controller controls the SVG to suppress the voltage rise. The power conversion module stores energy through the DC bus capacitor on the DC side and filters harmonics through the AC side reactor to prevent the distorted voltage from affecting the output current of the SVG.
[0020] In addition, the high and low voltage ride-through transient control system also includes a hardware protection circuit. The input terminal of the hardware protection circuit is electrically connected to the voltage detection module, and its output terminal is electrically connected to the enable terminal of the drive circuit. The hardware protection circuit can acquire the voltage detection signal from the voltage detection module and, when an abnormal voltage is detected, directly send a trigger signal to the drive circuit to control the drive circuit to stop sending drive signals to the power conversion module, thereby protecting the electronic components of the entire system.
[0021] Specifically, such as Figure 2As shown, the hardware protection circuit includes a voltage comparator U1, a logic gate circuit U2, and resistors R1-R2. The voltage detection signal acquired at the input of the hardware protection circuit is connected to the inverting input of the voltage comparator U1 via a series circuit composed of resistors R1-R2. The reference voltage is connected to the inverting input of the voltage comparator U1. The output of the voltage comparator U1 is electrically connected to the logic gate circuit, which is a NAND gate U2. The hardware protection circuit compares the detected voltage signal with a reference voltage set by a regulated power supply. The reference voltage is set to be close to the safe withstand voltage limit of the IGBT in the power conversion module. When the detected voltage signal is greater than the reference voltage, the output of the voltage comparator U1 flips, outputting a low-level active blocking signal through the NAND gate U2, which is transmitted to the enable terminal of the drive circuit.
[0022] Meanwhile, to prevent excessive energy storage in the DC bus capacitor on the DC side of the power conversion module, the system also includes a discharge circuit, which is connected in parallel across the DC bus capacitor. The discharge circuit consists of a controllable switch and a power dissipation resistor connected in series. The discharge circuit is connected to the main controller. When the main controller detects that the DC bus voltage exceeds a preset threshold, it controls the controllable switch to turn on, and the power dissipation resistor actively consumes the excess energy stored in the DC bus capacitor.
Claims
1. A high- and low-voltage ride-through transient control system, applied to a static var generator, wherein the static var generator is electrically connected to the power transmission grid, characterized in that, The system includes a voltage detection module, a main controller, a drive circuit, and a power conversion module. The DC side of the power conversion module is electrically connected to a DC bus capacitor, and its AC side is electrically connected to a reactor. The voltage detection module is electrically connected to the main controller, the main controller is electrically connected to the drive circuit, the output terminal of the drive circuit is electrically connected to the power conversion module, and the output terminal of the power conversion module is connected to the power transmission grid.
2. The high and low voltage ride-through transient control system according to claim 1, characterized in that, The voltage detection module is electrically connected to both the power transmission grid and the DC bus inside the static var generator.
3. The high and low voltage ride-through transient control system according to claim 1, characterized in that, It also includes a hardware protection circuit, the input of which is electrically connected to the voltage detection module, and its output is electrically connected to the drive circuit.
4. The high and low voltage ride-through transient control system according to claim 3, characterized in that, The hardware protection circuit includes a voltage comparator U1, a logic gate circuit U2, and resistors R1-R2. Resistors R1-R2 form a series circuit connected to the inverting input terminal of the voltage comparator U1. The reference voltage is connected to the inverting input terminal of the voltage comparator U1. The output terminal of the voltage comparator U1 is electrically connected to the logic gate circuit.
5. The high and low voltage ride-through transient control system according to claim 4, characterized in that, The logic gate circuit uses NAND gates.
6. The high and low voltage ride-through transient control system according to claim 1, characterized in that, The main controller uses a TMS320F2837x processor.
7. The high and low voltage ride-through transient control system according to claim 1, characterized in that, The system also includes a discharge circuit, which is connected in parallel across the DC bus capacitor and electrically connected to the main controller.
8. The high and low voltage ride-through transient control system according to claim 7, characterized in that, The discharge route consists of a controllable switch and a power-consuming resistor connected in series.