Digital type electronic ballast and control method thereof

Abstract

The invention relates to a digital electronic ballast and a control method therefor, comprising a power section and a control section. The control section insists of a microcontroller MCU, a drive curcuit, a half bridge output circuit, a ballast inductance, an igniting circuit, a current sampling circuit, a voltage sampling circuit and an accessory circuit; the MCU selectively realizes digital sweep frequency resonance ignition, digital constant power control, hybrid modulation eliminating acoustic resonance, digital time-sharing stepped light-regulation and fault protection according to a control software. All the functions of the invention basically are finished by a MCU and a control software thereof with the easiest circuit structure. A plurality of functions which looks independent are amalagamated organically in software process of the MCU, but common denominators thereof need change of output frequency to realize functions respectively by hardwares completely, make the circuit be more complex. The invention has high relizbility and low cost.

Description

technical field [0001] The invention relates to a digital electronic ballast and a control method thereof, in particular to a high-pressure sodium lamp electronic ballast using an MCU chip and control software and a control method thereof. Background technique [0002] The traditional high-pressure sodium lamp electronic ballast adopts an analog circuit, and the analog PWM control chip generates a high-frequency drive signal through the drive circuit, drives the half-bridge output circuit to output to the ballast inductor, and the ballast inductor is connected to the high-pressure sodium lamp; the half-bridge output circuit simultaneously It also outputs the current feedback signal and sends it back to the PWM control chip; its power supply circuit includes: AC power input PFC, which generates +400V high voltage and simultaneously inputs the half-bridge output circuit and ignition circuit, and the ignition circuit lights the high-pressure sodium lamp. As shown in Figure 1 is...

AI Technical Summary

Problems solved by technology

[0003] This traditional electronic ballast has the following problems: First, the power control loop is an analog PWM method, and the control accuracy is poor. Especially when new and old lamps are used, the power changes greatly, because the traditional electronic ballast cannot The power difference between the new and old lamps accelerates the aging of the lamps

Secondly, because the output frequency of the high-frequency half-bridge is fixed, the lamp tube is prone to acoustic resonance, which will damage the lamp tube or the circuit.

Third, due to the pulse ignition method, its peak voltage is high, the pulse width is narrow, it is difficult to ignite, and it is easy to cause arcing between the tube electrodes

Fourth, poor auxiliary functions, such as dimming, protection, etc. are difficult to realize

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