EMC Harmonic testing equipment is a key tool in electromagnetic compatibility (EMC) testing, specifically used to evaluate the Harmonic Current Emissions of electrical and electronic equipment in the power grid. Ensure that it complies with international/national standards (such as IEC 61000-3-2, GB 17625.1, etc.).

1. Core function

Harmonic current emission test

Pollution of the power grid by detection equipment

Measure the harmonic current (such as 2nd to 40th harmonics) injected into the power grid by the measuring equipment during operation to prevent grid voltage distortion, transformer overheating or other equipment failures caused by excessive harmonics.

Compliance certification

Verify whether the product complies with mandatory standards (such as the harmonic limit requirements in the EU CE certification and China CCC certification).

(2) Voltage fluctuation and flicker test

Evaluate the impact of equipment on the stability of the power grid

Detect voltage fluctuations (ΔV) and flickers (Flicker) caused by the start and stop of the detection equipment or changes in load to prevent interference with sensitive equipment such as medical instruments and lighting systems.

2. Composition of the testing equipment

Harmonic analyzer

High-precision current probe +FFT analysis module, decomposing the current waveform into various harmonic components (such as 50Hz fundamental wave, 100Hz second harmonic, etc.).

Analog grid power supply

Provide pure AC power supply (220V/50Hz or 110V/60Hz) and isolate from external power grid interference.

Load simulator

Control the load status of the equipment under test (EUT) in different working modes (such as standby and full load).

Software platform

Automatically calculate the harmonic content, generate A report and compare it with the standard limit curve (such as Class A/B/C/D classification limits).

3. Testing process

Device connection

The EUT is connected to the test system through a current probe, and the power supply end is connected to the simulated power grid.

Data collection

During a typical working cycle (such as 15 minutes), the current waveform is recorded in real time and a Fourier transform (FFT) is performed.

Harmonic analysis

Calculate the effective value (RMS) of each harmonic and the total harmonic distortion rate (THD).

Result determination

Compare with the limit table of IEC 61000-3-2 (for example, Class D is applicable to devices such as PCS and televisions).

4. Typical application scenarios

Household appliances

Harmonic testing of high-power equipment such as air conditioners and washing machines (must meet the Class A or Class B limit values).

LED lighting

The high-frequency harmonics of the drive power supply are prone to exceed the standard and require strict testing (Class C).

Industrial equipment

Design verification of harmonic suppression for nonlinear loads such as frequency converters and servo motors.

Information technology equipment

Harmonic current (Class D) of switching power supplies for computers, servers, etc.