Driven by the wave of digitization, power electronic devices have deeply integrated into every corner of production and life. However, sudden power outages, voltage fluctuations, and other power supply anomalies are like invisible threats, which may instantly cause equipment hardware damage and core data loss, bringing incalculable losses to enterprises and users. In this context, UPS uninterruptible power supply, as the "guardian" of power safety, has become increasingly important and has become a core equipment for ensuring stable electricity consumption in multiple scenarios such as homes and industries. Today, we will delve into the key requirements and technical details of UPS electromagnetic compatibility testing based on the IEC 62040-2 standard.
1. UPS: The Core Barrier of Power Safety
1.1 Definition and Core Values
UPS is a high-end power protection device with an integrated energy storage device and an inverter as its core. When the mains power is abnormal or even interrupted, it can switch to emergency power supply mode in milliseconds, continuously outputting stable and pure AC power for critical loads, effectively avoiding risks such as equipment shutdown and data loss. It is an indispensable "safety line" in modern power systems.
1.2 Environmental adaptation: Full scene coverage from home to industry
According to the characteristics of the power grid and the differences in electromagnetic environment, the application scenarios of UPS are mainly divided into two categories:
● Class 1 environment：
Including residential areas, commercial areas, and light industrial areas, without the need for intermediate transformers, directly connected to the public low-voltage power supply system.
● Class 2 environment：
Includes all commercial areas, light industrial areas, and industrial areas located outside of Class 1 environment.
Note: Buildings or parts thereof powered by dedicated transformers or generators are examples of Class 1 environments.
1.3 Product classification of UPS in the standard: precise matching of different scenario requirements
According to the electromagnetic compatibility characteristics and applicable scenarios of UPS, IEC 62040-2 standard divides it into four categories to ensure accurate matching of product performance and application environment:
● Class C1: Suitable for Class 1 environments, it can be used without restrictions in residential areas and other scenarios sensitive to electromagnetic interference. It is the mainstream category of household and small commercial UPS.
● Class C2: It focuses on Class 2 environments and can also be extended to Class 1 environments under specific conditions, with stronger environmental adaptability.
● Class C3: designed for medium to high power UPS with output current exceeding 16A, specifically for Class 2 industrial scenarios, and must meet stricter electromagnetic emission limits.
● Class C4: Customized special UPS that cannot be classified as C1, C2, or C3, suitable for scenarios with unique technical requirements, requires customized evaluation and on-site testing verification, and will not be discussed in this article for now.
1.4 UPS system architecture and common port types
2. Electromagnetic compatibility testing: the core threshold for UPS compliance
Electromagnetic compatibility (EMC) is one of the important checks for UPS products entering the market, which is related to the stability of the equipment itself and the electromagnetic impact on the surrounding environment. The following are the detailed requirements for core testing in the IEC 62040-2 standard:
2.1 Emission Requirements
2.1.1 Limit values for power and network ports within the frequency range of 0.15 MHz to 30 MHz
| Product Type | Frequency | Limits | ||||||
| Mains terminal | Network port | |||||||
QP dB (μV) | AVG dB (μV) | QP dB (μV) | AVG dB (μV) | QP dB (μA) | AVG dB (μA) | |||
| Class C1 | 0.15~0.5 MHz | 66~56 | 56~46 | 84~74 | 74~64 | 40~30 | 30~20 | |
0.5~5 MHz | 56 | 46 | 74 | 64 | 30 | 20 | ||
5~30 MHz | 60 | 50 | ||||||
| Class C2 | 0.15~0.5 MHz | 79 | 66 | 97~87 | 84~74 | 53~43 | 40~30 | |
0.5~5 MHz | 73 | 60 | 87 | 74 | 43 | 30 | ||
5~30 MHz | 73 | 60 | ||||||
| Class C3 | 16＜EUT≤100A | 0.15~0.5 MHz | 100 | 90 | 110~100 | 94~84 | 66~56 | 50~40 |
0.5~5 MHz | 86 | 76 | 100 | 84 | 56 | 40 | ||
5~30 MHz | 90~73 | 80~60 | ||||||
| ＞100A | 0.15~0.5 MH | 130 | 120 | 110~100 | 94~84 | 66~56 | 50~40 | |
0.5~5 MHz | 125 | 115 | 100 | 84 | 56 | 40 | ||
5~30 MHz | 115 | 105 | ||||||
2.1.2 Radiated emission limits within the frequency range of 30 MHz to 1000 MHz
| Test Frequency | QP Limits dB(μV/m) | ||
| Class C1 | Class C2 | Class C3 | |
| 30 MHz ~230 MHz | 30 | 40 | 50 |
| 230 MHz ~1000 MHz | 37 | 47 | 60 |
2.2 Requirements for harmonic flicker in power systems
If the rated input current and voltage are within the range specified in IEC 61000-3-2 or IEC 61000-3-12, the limits and test methods specified in IEC 61000-3-2 or IEC 61000-3-12 shall also apply.
2.3 UPS immunity test requirements
| Port type | Test projects and Basic Standard | Class C1 | Class C2/C3 | ||
| Test level | Criterion | Test level | Criterion | ||
Enclosure port | ESD (IEC 61000-4-2) | 4kV Contact 8kV Air | B | 4kV Contact 8kV Air | B |
RS (IEC 61000-4-3) | 80 MHz to 1000 MHz 3 V/m 80 % AM (1 kHz) | A | 80 MHz to 1000 MHz 10 V/m 80 % AM (1 kHz) | A | |
PMF (IEC 61000-4-8) | 3 A/m | A | 30 A/m | A | |
| AC input power ports | EFT (IEC 61000-4-4) | 1kV/5kHz | B | 2kV/5kHz | B |
SURGE (IEC 61000-4-5) | Line to Line:1kV Line to Earth:2kV 1.2/50us(8/20us) | B | Line to Line:1kV Line to Earth:2kV 1.2/50us(8/20us) | B | |
CS (IEC 61000-4-6) | 0,15 MHz to 80 MHz 3 V 80 % AM (1 kHz) | A | 0,15 MHz to 80 MHz 10 V 80 % AM (1 kHz) | A | |
Immunity to low-frequency signals (IEC 61000-2-2) | 10 V 140 Hz to 360 Hz | A | 10 V 140 Hz to 360 Hz | A | |
AC output power ports and DC port | EFT (IEC 61000-4-4) | 1kV/5kHz | B | 2kV/5kHz | B |
SURGE (IEC 61000-4-5) | Line to Line:1kV Line to Earth:2kV 1.2/50us(8/20us) | B | Line to Line:1kV Line to Earth:2kV 1.2/50us(8/20us) | B | |
CS (IEC 61000-4-6) | 0,15 MHz to 80 MHz 3 V 80 % AM (1 kHz) | A | 0,15 MHz to 80 MHz 10 V 80 % AM (1 kHz) | A | |
| DC interface | EFT (IEC 61000-4-4) | 1kV/5kHz Capacitive clamp | B | 2kV/5kHz Capacitive clamp | B |
| Network ports | EFT (IEC 61000-4-4) | 1kV/5kHz Capacitive clamp | B | 2kV/5kHz Capacitive clamp | B |
CS (IEC 61000-4-6) | 0,15 MHz to 80 MHz 3 V 80 % AM (1 kHz) | A | 0,15 MHz to 80 MHz 10 V 80 % AM (1 kHz) | A | |
SURGE (IEC 61000-4-5) | N/A | N/A | 1kV 1.2/50us(8/20us) | B | |
3、Performance evaluation
| Test performance type | Criterion A | Criterion B |
External and internal indications and metering | Change only during test; | Change only during test; |
Control signals to external devices | No change; | Change only temporarily in consistency with the actual UPS mode of operation; |
| Mode of operationa a | No change; | Change only temporarily; |
| a At all times, the UPS shall remain within the performance classification as declared by the UPS manufacturerd (see IEC 62040-3:2011). | ||
Professional Services: Escort UPS Compliance
BTL has years of experience in electromagnetic compatibility testing, equipped with a professional technical team and advanced testing equipment:
● Senior technical team：Composed of dedicated testing engineers and project evaluation engineers, can provide full process technical support from pre testing to certification.
● Top testing capability：The laboratory is equipped with multiple complete EMC testing systems, which can cover full frequency testing from 0.009 MHz to 40 GHz, meeting the testing needs of various UPS products and possessing testing qualifications.
● Efficient service system：With abundant venue resources and standardized processes, we can provide customers with fast and accurate testing services, helping products to be quickly and compliantly launched.
If you want to learn more about the technical details of UPS electromagnetic compatibility testing or need professional testing service support, please feel free to contact us at any time. BTL will be dedicated to serving you!
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