电力电子市场－全球产业规模、份额、趋势、机会及预测（按元件类型、材料、电压、应用、地区和竞争格局划分，2021-2031年）

全球电力电子市场预计将从 2025 年的 528.5 亿美元成长到 2031 年的 761.6 亿美元，复合年增长率为 6.28%。

电力电子技术利用固体技术，实现各种能源系统中电能的高效率控制与转换。推动该市场发展的关键因素包括：可再生能源的加速转型、工业自动化的发展以及交通运输领域的广泛电气化。为了支援这些不断扩展的应用，该产业正在大幅提升其生产基础设施，以满足对关键组件的需求。根据SEMI的报告，预计2025年，全球半导体产能将达到每月3,360万片晶圆。

然而，宽能带隙材料（例如碳化硅）的高製造成本和复杂的供应链给这一市场带来了巨大挑战。儘管这些材料具有卓越的能源效率，但与传统硅相比，其复杂的製造要求和较低的产量比率会阻碍规模化生产。这项技术壁垒使得低成本、大规模应用难以实现，并延缓了下一代电力模组的广泛商业化进程。

市场驱动因素

电动和混合动力汽车的快速普及是电力电子产业的主要驱动力。随着汽车製造商逐步淘汰内燃机，对牵引逆变器、车载充电器和电池管理系统等关键零件的需求激增。这些子系统高度依赖先进的功率模组来确保高压管理和高效的能量传输，这迫使整个产业转向使用更高功率密度的材料。根据国际能源总署（IEA）于2024年4月发布的《2024年全球电动车展望》，2023年全球电动车销量将接近1400万辆，这表明向电动化出行的稳步转型直接导致了对半导体需求的增长。

同时，可再生能源发电和併网的扩张正推动市场强劲成长。太阳能光伏系统和风力发电机需要先进的逆变器和转换器，将波动的直流电 (DC) 转换为稳定且与电网相容的交流电 (AC)。这种转变需要高效率的功率元件，能够以最小的能量损耗处理高功率负载。根据国际能源总署 (IEA) 于 2024 年 1 月发布的《2023 年再生能源报告》，到 2023 年，全球可再生能源年装置容量将成长约 50%，达到近 510 吉瓦。为了适应这个快速成长的产业需求，主要企业正积极扩大其生产能力。例如，英飞凌科技股份公司决定在 2024 年追加投资 50 亿欧元，用于扩建位于马来西亚的碳化硅功率装置製造厂。

市场挑战

宽能带隙材料（尤其是碳化硅）高昂的製造成本和复杂的供应链要求是限制全球电力电子市场规模化发展的主要障碍。虽然这些材料能够提高能源效率，但其复杂的製造週期导致其产量比率低于成熟的硅基装置。这种差异推高了单位成本，阻碍了其在汽车製造和消费电子等价格敏感型产业的广泛应用。因此，难以与传统技术实现成本竞争力已成为瓶颈，延缓了下一代功率模组的全面商业化进程。

这些挑战显着增加了进入和扩张市场所需的资本密集度，迫使企业将大量资源投入专门的基础建设，而非即时推出产品。有效解决这些製造障碍所需的巨额资本实际上限制了能够扩大生产规模的企业数量。根据SEMI预测，截至2025年10月，包括化合物半导体在内的功率元件领域，未来三年预计将产生270亿美元的资本支出。如此高的製造设施资本需求直接阻碍了製造商扩大生产规模的速度，从而抑制了市场整体扩张的步伐。

市场趋势

电动车向 800V 电气架构的过渡是一项重大变革，旨在缩短充电时间并提高系统效率。将工作电压从标准的 400V 提高一倍，使汽车工程师能够显着降低电流，从而减少电阻发热，并可以使用更细更轻的电缆。这一转变直接影响电力电子市场，需要能够承受更高热应力和电应力的先进驱动逆变器和车载充电器，从而推动了对专用碳化硅元件的需求。为了支持这个高压生态系统，主要元件供应商正在大力投资建立本地製造能力。例如，安森美半导体在 2024 年 6 月的新闻稿中宣布，计划投资高达 20 亿美元在捷克共和国建立一座垂直整合的碳化硅製造工厂。

同时，人工智慧的普及正迫使资料中心从传统的 12V 供电架构过渡到 48V 供电架构。现代高效能电脑架需要高功率密度，而 12V 系统因铜损增加和线缆笨重，效率低。 48V 中间汇流排架构透过更有效率地向伺服器主机板供电来缓解这些挑战，负载点转换器会根据特定处理器的需求降低电压。这种结构性变革对于应对运算带来的全球能源负荷快速成长至关重要。根据国际能源总署 (IEA) 于 2024 年 1 月发布的《2024 年电力报告》，到 2026 年，资料中心、人工智慧和加密货币产业的电力消耗量可能会翻一番，达到约 1,000兆瓦时。

目录

第一章概述

第二章调查方法

第三章执行摘要

第四章：客户评价

第五章 全球电力电子市场展望

• 市场规模及预测
  • 按金额
• 市占率及预测
  • 按元件类型（功率分离式元件、功率模组、功率积体电路）
  • 依材料分类（硅、碳化硅、氮化镓、其他）
  • 按电压（低压、中压、高压）
  • 按应用领域（资讯通讯技术、家用电子电器、工业、汽车、航太与国防、其他）
  • 按地区
  • 按公司（2025 年）
• 市场地图

第六章：北美电力电子市场展望

• 市场规模及预测
• 市占率及预测
• 北美洲：国家分析
  • 我们
  • 加拿大
  • 墨西哥

第七章：欧洲电力电子市场展望

• 市场规模及预测
• 市占率及预测
• 欧洲：国家分析
  • 德国
  • 法国
  • 英国
  • 义大利
  • 西班牙

第八章 亚太电力电子市场展望

• 市场规模及预测
• 市占率及预测
• 亚太地区：国家分析
  • 中国
  • 印度
  • 日本
  • 韩国
  • 澳洲

第九章：中东与非洲电力电子市场展望

• 市场规模及预测
• 市占率及预测
• 中东和非洲：国家分析
  • 沙乌地阿拉伯
  • 阿拉伯聯合大公国
  • 南非

第十章：南美洲电力电子市场展望

• 市场规模及预测
• 市占率及预测
• 南美洲：国家分析
  • 巴西
  • 哥伦比亚
  • 阿根廷

第十一章 市场动态

• 司机
• 任务

第十二章 市场趋势与发展

• 併购
• 产品发布
• 最新进展

第十三章 全球电力电子市场：SWOT分析

第十四章：波特五力分析

• 产业竞争
• 新进入者的可能性
• 供应商电力
• 顾客权力
• 替代品的威胁

第十五章 竞争格局

• Mitsubishi Electric Corporation
• Fuji Electric Co. Ltd.
• Toshiba Corporation
• Infineon Technologies AG
• ON Semiconductor Corporation
• STMicroelectronics International NV
• Texas Instruments Incorporated
• Renesas Electronics Corporation
• Vishay Intertechnology Inc.
• NXP Semiconductors NV

第十六章 策略建议

第十七章：关于研究公司及免责声明

The Global Power Electronics Market is projected to expand from USD 52.85 Billion in 2025 to USD 76.16 Billion by 2031, registering a CAGR of 6.28%. Power electronics utilize solid-state technologies to effectively control and convert electric power across various energy systems. This market is primarily driven by the accelerating shift toward renewable energy, the growth of industrial automation, and the widespread electrification of the transportation sector. To support these expanding applications, the industry is significantly boosting its production infrastructure to satisfy the demand for critical components. As reported by SEMI, global semiconductor capacity was anticipated to reach 33.6 million wafers per month in 2025.

Nevertheless, the market faces a notable challenge regarding the high fabrication costs and supply chain complexities of wide-bandgap materials such as silicon carbide. While these materials offer superior energy efficiency, their intricate manufacturing requirements and lower yields relative to traditional silicon can hinder scalable production. This technical barrier complicates the achievement of cost-effective mass adoption, thereby delaying the broader commercialization of next-generation power modules.

Market Driver

The rapid adoption of electric and hybrid vehicles acts as a major catalyst for the power electronics sector. As automotive manufacturers move away from internal combustion engines, the demand for essential components like traction inverters, on-board chargers, and battery management systems has surged. These subsystems depend heavily on advanced power modules to manage high voltages and ensure efficient energy transfer, pushing the industry toward materials with higher power density. According to the International Energy Agency's 'Global EV Outlook 2024' from April 2024, global sales of electric cars neared 14 million in 2023, indicating a robust shift toward electrified mobility that directly necessitates increased semiconductor volume.

Concurrently, the expansion of renewable energy generation and integration drives significant market momentum. Solar photovoltaic systems and wind turbines require sophisticated inverters and converters to transform variable direct current into stable alternating current for grid compatibility. This transition demands high-efficiency power devices capable of handling substantial power loads with minimal energy loss. According to the International Energy Agency's 'Renewables 2023' report from January 2024, global annual renewable capacity additions increased by almost 50% to nearly 510 gigawatts in 2023. To accommodate such rapid industry growth, major players are aggressively expanding manufacturing capabilities; for instance, Infineon Technologies AG committed an additional five billion euros in 2024 to expand its silicon carbide power fabrication facility in Malaysia.

Market Challenge

The substantial fabrication costs and intricate supply chain requirements associated with wide-bandgap materials, specifically silicon carbide, constitute a primary obstacle to the scalable growth of the global power electronics market. Although these materials provide enhanced energy efficiency, their complex manufacturing cycle leads to lower production yields relative to established silicon-based components. This discrepancy results in elevated unit prices, which discourages widespread adoption in price-sensitive industries such as automotive manufacturing and consumer appliances. Consequently, the inability to achieve cost parity with traditional technologies creates a bottleneck that delays the comprehensive commercialization of next-generation power modules.

This challenge significantly increases the capital intensity required for market entry and expansion, forcing companies to allocate vast resources toward specialized infrastructure rather than immediate product proliferation. The magnitude of the financial commitment needed to address these manufacturing hurdles effectively limits the number of players capable of scaling production. According to SEMI, in October 2025, the power-related segment, including compound semiconductors, was projected to invest $27 billion in equipment spending over the subsequent three years. Such high capital requirements for fabrication facilities directly hamper the speed at which manufacturers can ramp up production, thereby moderating the overall pace of market expansion.

Market Trends

The transition toward 800V electrical architectures in electric vehicles represents a critical evolution aimed at reducing charging times and enhancing system efficiency. By doubling the operating voltage from the standard 400V, automotive engineers can significantly lower current levels, which reduces resistive heating and allows for the use of thinner, lighter cabling. This shift directly impacts the power electronics market by necessitating advanced traction inverters and onboard chargers capable of withstanding higher thermal and electrical stresses, driving the demand for specialized silicon carbide components. To support this high-voltage ecosystem, major component suppliers are heavily investing in localized manufacturing. For example, Onsemi announced in a June 2024 press release plans to invest up to 2 billion dollars to establish a vertically integrated silicon carbide manufacturing facility in the Czech Republic.

Simultaneously, the proliferation of artificial intelligence is compelling data centers to shift from legacy 12V to 48V power distribution architectures. Modern high-performance computing racks require power densities that render 12V systems inefficient due to excessive copper losses and bulky cabling requirements. A 48V intermediate bus architecture mitigates these issues by delivering power more efficiently to the server motherboard, where point-of-load converters then step it down for specific processors. This structural change is essential to manage the surging global energy load created by computational processing. According to the International Energy Agency's 'Electricity 2024' report from January 2024, electricity consumption from data centers, artificial intelligence, and the cryptocurrency sector could double to roughly 1,000 terawatt-hours by 2026.

Key Market Players

• Mitsubishi Electric Corporation
• Fuji Electric Co. Ltd.
• Toshiba Corporation
• Infineon Technologies AG
• ON Semiconductor Corporation
• STMicroelectronics International N.V.
• Texas Instruments Incorporated
• Renesas Electronics Corporation
• Vishay Intertechnology Inc.
• NXP Semiconductors N.V.

Report Scope

In this report, the Global Power Electronics Market has been segmented into the following categories, in addition to the industry trends which have also been detailed below:

Power Electronics Market, By Device Type

• Power Discrete
• Power Module
• Power IC

Power Electronics Market, By Material

• Silicon
• Silicon Carbide
• Gallium Nitride
• Others

Power Electronics Market, By Voltage

• Low Voltage
• Medium Voltage
• High Voltage

Power Electronics Market, By Application

• ICT
• Consumer Electronics
• Industrial
• Automotive
• Aerospace and Defence
• Others

Power Electronics Market, By Region

• North America
  • United States
  • Canada
  • Mexico
• Europe
  • France
  • United Kingdom
  • Italy
  • Germany
  • Spain
• Asia Pacific
  • China
  • India
  • Japan
  • Australia
  • South Korea
• South America
  • Brazil
  • Argentina
  • Colombia
• Middle East & Africa
  • South Africa
  • Saudi Arabia
  • UAE

Competitive Landscape

Company Profiles: Detailed analysis of the major companies present in the Global Power Electronics Market.

Available Customizations:

Global Power Electronics Market report with the given market data, TechSci Research offers customizations according to a company's specific needs. The following customization options are available for the report:

Company Information

• Detailed analysis and profiling of additional market players (up to five).

Table of Contents

1. Product Overview

• 1.1. Market Definition
• 1.2. Scope of the Market
  • 1.2.1. Markets Covered
  • 1.2.2. Years Considered for Study
  • 1.2.3. Key Market Segmentations

2. Research Methodology

• 2.1. Objective of the Study
• 2.2. Baseline Methodology
• 2.3. Key Industry Partners
• 2.4. Major Association and Secondary Sources
• 2.5. Forecasting Methodology
• 2.6. Data Triangulation & Validation
• 2.7. Assumptions and Limitations

3. Executive Summary

• 3.1. Overview of the Market
• 3.2. Overview of Key Market Segmentations
• 3.3. Overview of Key Market Players
• 3.4. Overview of Key Regions/Countries
• 3.5. Overview of Market Drivers, Challenges, Trends

4. Voice of Customer

5. Global Power Electronics Market Outlook

• 5.1. Market Size & Forecast
  • 5.1.1. By Value
• 5.2. Market Share & Forecast
  • 5.2.1. By Device Type (Power Discrete, Power Module, Power IC)
  • 5.2.2. By Material (Silicon, Silicon Carbide, Gallium Nitride, Others)
  • 5.2.3. By Voltage (Low Voltage, Medium Voltage, High Voltage)
  • 5.2.4. By Application (ICT, Consumer Electronics, Industrial, Automotive, Aerospace and Defence, Others)
  • 5.2.5. By Region
  • 5.2.6. By Company (2025)
• 5.3. Market Map

6. North America Power Electronics Market Outlook

• 6.1. Market Size & Forecast
  • 6.1.1. By Value
• 6.2. Market Share & Forecast
  • 6.2.1. By Device Type
  • 6.2.2. By Material
  • 6.2.3. By Voltage
  • 6.2.4. By Application
  • 6.2.5. By Country
• 6.3. North America: Country Analysis
  • 6.3.1. United States Power Electronics Market Outlook
    • 6.3.1.1. Market Size & Forecast
      • 6.3.1.1.1. By Value
    • 6.3.1.2. Market Share & Forecast
      • 6.3.1.2.1. By Device Type
      • 6.3.1.2.2. By Material
      • 6.3.1.2.3. By Voltage
      • 6.3.1.2.4. By Application
  • 6.3.2. Canada Power Electronics Market Outlook
    • 6.3.2.1. Market Size & Forecast
      • 6.3.2.1.1. By Value
    • 6.3.2.2. Market Share & Forecast
      • 6.3.2.2.1. By Device Type
      • 6.3.2.2.2. By Material
      • 6.3.2.2.3. By Voltage
      • 6.3.2.2.4. By Application
  • 6.3.3. Mexico Power Electronics Market Outlook
    • 6.3.3.1. Market Size & Forecast
      • 6.3.3.1.1. By Value
    • 6.3.3.2. Market Share & Forecast
      • 6.3.3.2.1. By Device Type
      • 6.3.3.2.2. By Material
      • 6.3.3.2.3. By Voltage
      • 6.3.3.2.4. By Application

7. Europe Power Electronics Market Outlook

• 7.1. Market Size & Forecast
  • 7.1.1. By Value
• 7.2. Market Share & Forecast
  • 7.2.1. By Device Type
  • 7.2.2. By Material
  • 7.2.3. By Voltage
  • 7.2.4. By Application
  • 7.2.5. By Country
• 7.3. Europe: Country Analysis
  • 7.3.1. Germany Power Electronics Market Outlook
    • 7.3.1.1. Market Size & Forecast
      • 7.3.1.1.1. By Value
    • 7.3.1.2. Market Share & Forecast
      • 7.3.1.2.1. By Device Type
      • 7.3.1.2.2. By Material
      • 7.3.1.2.3. By Voltage
      • 7.3.1.2.4. By Application
  • 7.3.2. France Power Electronics Market Outlook
    • 7.3.2.1. Market Size & Forecast
      • 7.3.2.1.1. By Value
    • 7.3.2.2. Market Share & Forecast
      • 7.3.2.2.1. By Device Type
      • 7.3.2.2.2. By Material
      • 7.3.2.2.3. By Voltage
      • 7.3.2.2.4. By Application
  • 7.3.3. United Kingdom Power Electronics Market Outlook
    • 7.3.3.1. Market Size & Forecast
      • 7.3.3.1.1. By Value
    • 7.3.3.2. Market Share & Forecast
      • 7.3.3.2.1. By Device Type
      • 7.3.3.2.2. By Material
      • 7.3.3.2.3. By Voltage
      • 7.3.3.2.4. By Application
  • 7.3.4. Italy Power Electronics Market Outlook
    • 7.3.4.1. Market Size & Forecast
      • 7.3.4.1.1. By Value
    • 7.3.4.2. Market Share & Forecast
      • 7.3.4.2.1. By Device Type
      • 7.3.4.2.2. By Material
      • 7.3.4.2.3. By Voltage
      • 7.3.4.2.4. By Application
  • 7.3.5. Spain Power Electronics Market Outlook
    • 7.3.5.1. Market Size & Forecast
      • 7.3.5.1.1. By Value
    • 7.3.5.2. Market Share & Forecast
      • 7.3.5.2.1. By Device Type
      • 7.3.5.2.2. By Material
      • 7.3.5.2.3. By Voltage
      • 7.3.5.2.4. By Application

8. Asia Pacific Power Electronics Market Outlook

• 8.1. Market Size & Forecast
  • 8.1.1. By Value
• 8.2. Market Share & Forecast
  • 8.2.1. By Device Type
  • 8.2.2. By Material
  • 8.2.3. By Voltage
  • 8.2.4. By Application
  • 8.2.5. By Country
• 8.3. Asia Pacific: Country Analysis
  • 8.3.1. China Power Electronics Market Outlook
    • 8.3.1.1. Market Size & Forecast
      • 8.3.1.1.1. By Value
    • 8.3.1.2. Market Share & Forecast
      • 8.3.1.2.1. By Device Type
      • 8.3.1.2.2. By Material
      • 8.3.1.2.3. By Voltage
      • 8.3.1.2.4. By Application
  • 8.3.2. India Power Electronics Market Outlook
    • 8.3.2.1. Market Size & Forecast
      • 8.3.2.1.1. By Value
    • 8.3.2.2. Market Share & Forecast
      • 8.3.2.2.1. By Device Type
      • 8.3.2.2.2. By Material
      • 8.3.2.2.3. By Voltage
      • 8.3.2.2.4. By Application
  • 8.3.3. Japan Power Electronics Market Outlook
    • 8.3.3.1. Market Size & Forecast
      • 8.3.3.1.1. By Value
    • 8.3.3.2. Market Share & Forecast
      • 8.3.3.2.1. By Device Type
      • 8.3.3.2.2. By Material
      • 8.3.3.2.3. By Voltage
      • 8.3.3.2.4. By Application
  • 8.3.4. South Korea Power Electronics Market Outlook
    • 8.3.4.1. Market Size & Forecast
      • 8.3.4.1.1. By Value
    • 8.3.4.2. Market Share & Forecast
      • 8.3.4.2.1. By Device Type
      • 8.3.4.2.2. By Material
      • 8.3.4.2.3. By Voltage
      • 8.3.4.2.4. By Application
  • 8.3.5. Australia Power Electronics Market Outlook
    • 8.3.5.1. Market Size & Forecast
      • 8.3.5.1.1. By Value
    • 8.3.5.2. Market Share & Forecast
      • 8.3.5.2.1. By Device Type
      • 8.3.5.2.2. By Material
      • 8.3.5.2.3. By Voltage
      • 8.3.5.2.4. By Application

9. Middle East & Africa Power Electronics Market Outlook

• 9.1. Market Size & Forecast
  • 9.1.1. By Value
• 9.2. Market Share & Forecast
  • 9.2.1. By Device Type
  • 9.2.2. By Material
  • 9.2.3. By Voltage
  • 9.2.4. By Application
  • 9.2.5. By Country
• 9.3. Middle East & Africa: Country Analysis
  • 9.3.1. Saudi Arabia Power Electronics Market Outlook
    • 9.3.1.1. Market Size & Forecast
      • 9.3.1.1.1. By Value
    • 9.3.1.2. Market Share & Forecast
      • 9.3.1.2.1. By Device Type
      • 9.3.1.2.2. By Material
      • 9.3.1.2.3. By Voltage
      • 9.3.1.2.4. By Application
  • 9.3.2. UAE Power Electronics Market Outlook
    • 9.3.2.1. Market Size & Forecast
      • 9.3.2.1.1. By Value
    • 9.3.2.2. Market Share & Forecast
      • 9.3.2.2.1. By Device Type
      • 9.3.2.2.2. By Material
      • 9.3.2.2.3. By Voltage
      • 9.3.2.2.4. By Application
  • 9.3.3. South Africa Power Electronics Market Outlook
    • 9.3.3.1. Market Size & Forecast
      • 9.3.3.1.1. By Value
    • 9.3.3.2. Market Share & Forecast
      • 9.3.3.2.1. By Device Type
      • 9.3.3.2.2. By Material
      • 9.3.3.2.3. By Voltage
      • 9.3.3.2.4. By Application

10. South America Power Electronics Market Outlook

• 10.1. Market Size & Forecast
  • 10.1.1. By Value
• 10.2. Market Share & Forecast
  • 10.2.1. By Device Type
  • 10.2.2. By Material
  • 10.2.3. By Voltage
  • 10.2.4. By Application
  • 10.2.5. By Country
• 10.3. South America: Country Analysis
  • 10.3.1. Brazil Power Electronics Market Outlook
    • 10.3.1.1. Market Size & Forecast
      • 10.3.1.1.1. By Value
    • 10.3.1.2. Market Share & Forecast
      • 10.3.1.2.1. By Device Type
      • 10.3.1.2.2. By Material
      • 10.3.1.2.3. By Voltage
      • 10.3.1.2.4. By Application
  • 10.3.2. Colombia Power Electronics Market Outlook
    • 10.3.2.1. Market Size & Forecast
      • 10.3.2.1.1. By Value
    • 10.3.2.2. Market Share & Forecast
      • 10.3.2.2.1. By Device Type
      • 10.3.2.2.2. By Material
      • 10.3.2.2.3. By Voltage
      • 10.3.2.2.4. By Application
  • 10.3.3. Argentina Power Electronics Market Outlook
    • 10.3.3.1. Market Size & Forecast
      • 10.3.3.1.1. By Value
    • 10.3.3.2. Market Share & Forecast
      • 10.3.3.2.1. By Device Type
      • 10.3.3.2.2. By Material
      • 10.3.3.2.3. By Voltage
      • 10.3.3.2.4. By Application

11. Market Dynamics

• 11.1. Drivers
• 11.2. Challenges

12. Market Trends & Developments

• 12.1. Merger & Acquisition (If Any)
• 12.2. Product Launches (If Any)
• 12.3. Recent Developments

13. Global Power Electronics Market: SWOT Analysis

14. Porter's Five Forces Analysis

• 14.1. Competition in the Industry
• 14.2. Potential of New Entrants
• 14.3. Power of Suppliers
• 14.4. Power of Customers
• 14.5. Threat of Substitute Products

15. Competitive Landscape

• 15.1. Mitsubishi Electric Corporation
  • 15.1.1. Business Overview
  • 15.1.2. Products & Services
  • 15.1.3. Recent Developments
  • 15.1.4. Key Personnel
  • 15.1.5. SWOT Analysis
• 15.2. Fuji Electric Co. Ltd.
• 15.3. Toshiba Corporation
• 15.4. Infineon Technologies AG
• 15.5. ON Semiconductor Corporation
• 15.6. STMicroelectronics International N.V.
• 15.7. Texas Instruments Incorporated
• 15.8. Renesas Electronics Corporation
• 15.9. Vishay Intertechnology Inc.
• 15.10. NXP Semiconductors N.V.

16. Strategic Recommendations

17. About Us & Disclaimer