Performance comparison of sine wave electronic dimmer and thyristor dimmer

1 Thyristor dimmer

Principle: Adjust the output voltage by controlling the SCR phase-shifting conduction angle and AC chopping.

Features: mature technology, stable and reliable, small size and large noise.

Thyristor dimming is to cut a 50 Hz/60 Hz sine wave AC power supply, control the output energy per unit time, and absorb the power of the power grid is a distorted non-sinusoidal current, the power factor is low, the moment the thyristor is turned on, The current pulse passing through the lamp rises rapidly, causing the circuit to generate a large amount of electromagnetic harmonics, thereby generating electromagnetic interference to the outside. The harmonic spectrum range is extremely large, from a few hundred hertz to a few thousand hertz, and can even reach a few megahertz.

The output voltage of the thyristor dimming process contains a lot of harmonics, which will mainly generate 3, 5, 7, 9, 11, and 13 harmonic currents. The larger the load power, the higher the power of the higher-order components, which pollutes the power grid. It also interferes with audio and video equipment on the same network. Although a huge dedicated choke coil is connected in series through the circuit to extend the rise time and reduce the generated interference, it is impossible to completely eliminate the interference of each harmonic. Various measures such as isolation and shielding are always taken during the construction of the performance project, which not only increases the construction and maintenance costs, but also cannot completely suppress harmonic interference.

2 Sine wave electronic dimmer

Principle: Combining pulse width modulation technology (PWM) and IGBT 180° time-sharing control technology to achieve AC-AC sine wave output voltage adjustment control, so that the absorption of grid current and output are pure sinusoidal currents.

Features: high power factor, good waveform quality, no interference, high efficiency, low noise, high degree of intelligence, no need for special power grid management.

Sine wave electronic dimming is the amplitude modulation of pure sine wave, which can adjust the standard AC sine wave output of 0～220V to drive the load. The sine wave electronic dimmer absorbs the power of the power grid as a sinusoidal current, which can greatly reduce the content of the power grid and output harmonics. The dimmer can reduce the size of the passive filter components due to the high-frequency switching state, further reduce the cost of the product and improve Product performance.

At present, the sine wave electronic dimming equipment is the fifth generation of dimming equipment. It has its unique advantages in improving the output voltage, current waveform and reducing the harmonics of the power system. Therefore, it has also significantly improved the suppression of external electromagnetic interference and fully complies with national standards. It has a more perfect control system, more intelligent and humanized. The sine wave electronic dimming circuit has also added over-current and short-circuit protection parts, and the work safety and reliability have been greatly improved. Since the sine wave electronic dimmer only changes the amplitude of the sine wave to achieve dimming, the loss of the entire distribution system is significantly reduced, and because it has no load characteristic restrictions, it can not only realize the dimming of resistive load spotlights and imaging lamps It can also control the speed of the motor and electric fan, dimming the gas discharge lamp, fluorescent lamp, energy-saving lamp, etc. The output power can be paralleled in multiple circuits to match the application of greater output power.

The sine wave electronic dimmer has no pollution to the power grid, reducing the loss of the power supply system and lines. There is no need to set up independent power supply transformers, and there is no need to adopt measures such as isolation and shielding, which saves costs.