CN116470542A - 一种提高电力电子变压器电网适应性的控制策略 - Google Patents

一种提高电力电子变压器电网适应性的控制策略 Download PDF

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CN116470542A
CN116470542A CN202310383862.6A CN202310383862A CN116470542A CN 116470542 A CN116470542 A CN 116470542A CN 202310383862 A CN202310383862 A CN 202310383862A CN 116470542 A CN116470542 A CN 116470542A
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voltage
power
electronic transformer
power grid
energy storage
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张家齐
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Shenyang Power Supply Co of State Grid Liaoning Electric Power Co Ltd
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Shenyang Power Supply Co of State Grid Liaoning Electric Power Co Ltd
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02JCIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00Circuit arrangements for ac mains or ac distribution networks
    • H02J3/28Arrangements for balancing of the load in a network by storage of energy
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00Details of apparatus for conversion
    • H02M1/08Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/088Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00Conversion of dc power input into dc power output
    • H02M3/22Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • H02M3/33576Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements having at least one active switching element at the secondary side of an isolation transformer
    • H02M3/33584Bidirectional converters
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02MAPPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/02Conversion of ac power input into dc power output without possibility of reversal
    • H02M7/04Conversion of ac power input into dc power output without possibility of reversal by static converters
    • H02M7/12Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/217Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M7/219Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only in a bridge configuration

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Supply And Distribution Of Alternating Current (AREA)

Abstract

本发明涉及电力电子变换技术领域,公开了一种提高电力电子变压器电网适应性的控制策略,通过电力电子变压器与储能相互配合,保证在电网异常情况下维持直流母线电压稳定供给负载。实时检测到电网电压故障时,快速切换至储能支撑直流母线电压,而电力电子变压器DC/DC不停止工作,当故障恢复时可快速由储能切换为电力电子变压器进行工作,保证在电网异常情况下维持直流母线电压稳定供给负载,提高了电力电子变压器的电网适应性。

Description

一种提高电力电子变压器电网适应性的控制策略
技术领域
本发明涉及电力电子变换技术领域,尤其涉及一种提高电力电子变压器电网适应性的控制策略。
背景技术
电力电子变压器(Power Electronic Transformer,PET)是基于电力电子变换技术从而把某一特定电力属性能量转化为另一种电力属性能量的新型电力装置。传统电力变压器的主要功能有电力的经济输送、分配和安全升高或降低电压等,电力电子变压器除了能够完成传统变压器的功能外还可以实现其他附加功能,例如:无功优化、提高电能质量等。但是当电网中出现输电故障时,电力电子变压器会出现电压中断的问题。
目前电力电子变压器主要为并网使用,依托于能量路由器将10kV电网转换为750V直流电供负荷使用。当10kV电网存在短时故障时,如10kV电网单相接地、相间短路故障,虽然短时故障电网可自动重合闸,但在电网故障时刻电力电子变压器易出现过压、过流等故障导致停机。一般情况电力电子变压器可设置故障自重启,但大容量电力电子设备均需软启动,电压建立的时间过长,导致直流母线停电时间过长而影响直流负荷供电。
发明内容
本发明针对现有技术存在的不足和缺陷,提供了一种提高电力电子变压器电网适应性的控制策略,通过电力电子变压器与储能相互配合,保证在电网异常情况下维持直流母线电压稳定供给负载,提高了电力电子变压器的电网适应性。
本发明的目的可以通过以下技术方案来实现:
一种提高电力电子变压器电网适应性的控制策略,包括以下步骤:
S1:当10kV电网正常供电时,电力电子变压器正常工作,整流级将10kV交流电转换为多个900V直流端口,DC/DC变换级进一步变换电压等级,工作在纯正向模式,维持直流母线电压稳定在750V,给直流侧负载进行供电,同时系统判断储能电量未满时对储能进行充电,电量充满后即可断开储能开关;
S2: 控制器实时检测10kV交流电网电压,当检测到电网电压过欠压,电压差绝对值超过10kV额定电压Xu时,Xu取20%,或者出现电网频率畸变,偏离正常电网频率50Hz误差超过fe时,fe取2Hz,此时若电力电子变压器持续运行,会导致系统过欠压或者过流故障而导致停机,此时整体系统进入储能支撑模式;
S3: 系统由电力电子变压器稳压转为储能稳压,储能开关闭合;
S4: 储能快速启动,启动至750V进行预充电,完成预充电操作闭合预充电开关;
S5: 电力电子变压器所有模组整流级拓扑关闭驱动,断开电网与电力电子变压器电气连接,其中的DC/DC变换级转为同步工作模式,由直流母线750V反向支撑900V端口电压,此时所有直流侧负载均由储能提供;
S6: 控制器检测到电网电压恢复正常时,电力电子变压器所有模组中的整流级恢复驱动,且其中的DC/DC级转为纯正向驱动模式,同时断开储能侧开关,储能关闭,整体系统进入正常工作模式。
进一步地,所述S2中Xu、fe的取值根据现场环境调整。
进一步地,所述S5中的模组DC/DC级同步工作模式时,高压桥臂和低压桥臂同步工作,具备双向功率传输能力。
进一步地,所述S6中的模组DC/DC级纯正向工作模式时,仅有高压桥臂工作,仅可正向功率传输。
本发明的有益技术效果:实时检测到电网电压故障时,快速切换至储能支撑直流母线电压,而电力电子变压器DC/DC不停止工作,当故障恢复时可快速由储能切换为电力电子变压器进行工作,保证在电网异常情况下维持直流母线电压稳定供给负载,提高了电力电子变压器的电网适应性。
附图说明
图1为本发明系统架构图;
图2为本发明控制流程框图;
图3为本发明单个模组拓扑框图;
图4为本发明所述DC/DC级同步工作模式驱动示意图;
图5为本发明所述DC/DC级纯正向工作模式驱动示意图。
实施方式
为了使本发明的目的、技术方案及优点更加清楚明白,以下结合附图及实施例,对本发明进行进一步详细说明。应当理解,此处所描述的具体实施例仅用以解释本发明,并不限定本发明。
实施例
在实际应用场景中,根据应用场景的不同10kV电网稳定性存在不同,往往出现短时故障。当10kV线路出现单相接地故障或者相间短路故障时,根据电网故障的严重程度,电力电子变压器不进行特殊处理情况下能够维持几十至几百ms运行,但电网故障始终未恢复时,电力电子变压器往往产生网侧电流过流或报出故障而停机。使用本发明所提出的控制策略,在上述情况发生时,可快速切换至储能支撑直流母线电压,保证直流母线电压的稳定。而在电网正常的情况下,可以进一步给储能进行充电,保证长期稳定运行。
如图1所示,本发明所述控制策略主要针对图中所示架构,电力电子变压器为三相电网连接,每一相电路具有N个模组,其中每个模组可分为整流级拓扑与DC/DC变换级拓扑,整理级将10kV转为多个低压直流端口,DC/DC变换级进一步变换电压等级。同时,低压直流母线一般优选750V,此直流母线挂接储能,其中储能容量及功率根据负载范围选定。
如图2所示,一种提高电力电子变压器电网适应性的控制策略,包括以下步骤:
S1:当10kV电网正常供电时,电力电子变压器正常工作,整流级将10kV交流电转换为多个900V直流端口,此时电力电子变压器DC/DC级工作在纯正向工作模式,如图5所示,仅有高压侧开关管进行驱动,在保证功率传输的同时降低开关损耗,维持直流母线电压稳定在750V,给直流侧负载进行供电,同时系统判断储能电量未满时对储能进行充电,电量充满后即可断开储能开关;
S2: 控制器实时检测10kV交流电网电压,当检测到电网电压过欠压,电压差绝对值超过10kV额定电压Xu时,Xu取20%,或者出现电网频率畸变,偏离正常电网频率50Hz误差超过fe时,fe取2Hz,此时若电力电子变压器持续运行,会导致系统过欠压或者过流故障而导致停机,此时整体系统进入储能支撑模式;
Xu取20%,fe取2Hz,Xu、fe的取值可以根据现场环境调整。
S3: 系统由电力电子变压器稳压转为储能稳压,储能开关闭合;
S4: 储能快速启动,启动至750V进行预充电,完成预充电操作闭合预充电开关;
S5: 电力电子变压器所有模组整流级拓扑关闭驱动,断开电网与电力电子变压器电气连接,其中的DC/DC变换级转为同步工作模式,如图4所示,由直流母线750V反向支撑900V端口电压,以便电网恢复之后电力电子变压器可以快速启动,从而减少电力电子变压器预充电及预充电环节,此时所有直流侧负载均由储能提供;
模组DC/DC级同步工作模式时,高压桥臂和低压桥臂同步工作,具备双向功率传输能力。
S6: 控制器检测到电网电压恢复正常时,电力电子变压器所有模组中的整流级恢复驱动,且其中的DC/DC级转为纯正向驱动模式,同时断开储能侧开关,储能关闭,整体系统进入正常工作模式。
模组DC/DC级纯正向工作模式时,仅有高压桥臂工作,仅可正向功率传输。
上述实施例是对本发明的具体实施方式的说明,而非对本发明的限制,有关技术领域的技术人员在不脱离本发明的精神和范围的情况下,还可做出各种变换和变化以得到相对应的等同的技术方案,因此所有等同的技术方案均应归入本发明的专利保护范围。

Claims (4)

1.一种提高电力电子变压器电网适应性的控制策略,其特征在于,包括以下步骤:
S1:当10kV电网正常供电时,电力电子变压器正常工作,整流级将10kV交流电转换为多个900V直流端口,DC/DC变换级进一步变换电压等级,工作在纯正向模式,维持直流母线电压稳定在750V,给直流侧负载进行供电,同时系统判断储能电量未满时对储能进行充电,电量充满后即可断开储能开关;
S2: 控制器实时检测10kV交流电网电压,当检测到电网电压过欠压,电压差绝对值超过10kV额定电压Xu时,Xu取20%,或者出现电网频率畸变,偏离正常电网频率50Hz误差超过fe时,fe取2Hz,此时若电力电子变压器持续运行,会导致系统过欠压或者过流故障而导致停机,此时整体系统进入储能支撑模式;
S3: 系统由电力电子变压器稳压转为储能稳压,储能开关闭合;
S4: 储能快速启动,启动至750V进行预充电,完成预充电操作闭合预充电开关;
S5: 电力电子变压器所有模组整流级拓扑关闭驱动,断开电网与电力电子变压器电气连接,其中的DC/DC变换级转为同步工作模式,由直流母线750V反向支撑900V端口电压,此时所有直流侧负载均由储能提供;
S6: 控制器检测到电网电压恢复正常时,电力电子变压器所有模组中的整流级恢复驱动,且其中的DC/DC级转为纯正向驱动模式,同时断开储能侧开关,储能关闭,整体系统进入正常工作模式。
2.根据权利要求1所述的一种提高电力电子变压器电网适应性的控制策略,其特征在于,所述S2中Xu、fe的取值根据现场环境调整。
3.根据权利要求1所述的一种提高电力电子变压器电网适应性的控制策略,其特征在于,所述S5中的模组DC/DC级同步工作模式时,高压桥臂和低压桥臂同步工作,具备双向功率传输能力。
4.根据权利要求1所述的一种提高电力电子变压器电网适应性的控制策略,其特征在于,所述S6中的模组DC/DC级纯正向工作模式时,仅有高压桥臂工作,仅可正向功率传输。
CN202310383862.6A 2023-04-12 2023-04-12 一种提高电力电子变压器电网适应性的控制策略 Pending CN116470542A (zh)

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