(1. Wuxi Lighting Engineering Co., Ltd.; 2 Yancheng Teachers College. The working conditions are shown in Table 1. Table 1 Time-sharing main circuit work table (single sodium lamp 250W) output voltage circuit current sodium lamp voltage sodium lamp resistance ffl anti-angular 0 shift Phase angle a has a similar idea of ​​a variable power ballast that uses a gas discharge lamp to operate normally when the operating current is properly reduced. By increasing the ballast reactance in the middle of the night, the light source current is reduced and the street light is reduced. The power consumption of the main proportion of the system power consumption is the purpose of the overall energy saving of the street lamp system. The electronic switch is generally used to control the power reduction of the street lamp. The working process is as follows: under normal circumstances, the logic control unit controls the electronic switch to close ( Short circuit), the external voltage is directly applied to the street lamp circuit through the electronic switch, so that the street lamp works at the rated power state.
In the case of power reduction control, the logic control unit controls the electronic switch to open (open circuit), and the external voltage can only be applied to the street lamp circuit through the power reduction inductor. At this time, the inductive load of the street lamp circuit increases, and the working current of the street lamp decreases, thereby reducing the power of the street lamp, reducing the energy consumption, and achieving the effect of energy saving.
When the grid voltage is low or the light source is in poor condition, the power-down operation may flash. Even during the power-down operation period, the control circuit will automatically control the electronic switch to be closed to prevent the street lamp from going out.
3 electronic ballast energy-saving electronic ballast power saving effect is obvious, the report is generally 30% 40%, and the power factor is very high, generally reaching 0.97 or more. At present, the technical bottleneck of the HID electronic ballast is performance stability, that is, the service life problem. The electronic ballast is a converter that converts power frequency (50HZ/60HZ) alternating current into high frequency alternating current and enables one or several HID lamps to start and stabilize normally.
3.1 Basic principle: The high-frequency conversion circuit is composed of electronic components. First, the lighting AC power supply is rectified into DC power, and then the "inverter" becomes high-frequency AC power. The high-frequency voltage of 2050KHZ is generated by the oscillation circuit to start and light up the HID lamp. The 19th edition of the Taiwan Strait lighting technology and marketing The high-f-bridge design of the seminar can be correctly matched with the lamp to meet the starting voltage, lamp voltage and lamp current of different power lamps to achieve normal operation.
It is a classic high voltage sodium lamp electronic ballast circuit diagram.
Among them, the EMI module and the APFC module are fully mature, and have been successfully applied in the 600W high-power high-pressure sodium lamp. At present, the reliability and service life of electronic ballasts affecting high-pressure sodium lamps are drive circuits because they are directly exposed to high voltage (35kV) and high temperature (about 75C) environments. Therefore, in the design of the electronic ballast of the high-pressure sodium lamp, the driving circuit, the lighting starting circuit and the protection circuit are the core of the whole device, which directly affects the reliability and service life of the device. The modular design concept helps to reduce duplication of effort and ensure the performance of the device. The following describes a simple high-voltage sodium lamp electronic ballast circuit for low power, as shown in Figure 3, based on the IR2155 common drive circuit topology.
The ignition circuit, the start-up circuit, is the second key to the high-pressure sodium lamp electronic ballast. The ignition voltage of the high-pressure sodium lamp is 3kV~5kV, and the high voltage is generated in two ways: (1) LC resonance, and (2) step-up transformer. Figure 4 is a half-bridge inverter type high-pressure sodium lamp driving circuit that combines the ignition circuit and the drive control.
Off-bridge Inverter Type Sodium Iridium Lamp Ignition and Drive Circuit 3.2 Electronic Ballast Features Compared with traditional inductive high-pressure sodium lamp ballasts, HID electronic ballasts have the following advantages: saving electricity and saving energy than the same size inductor ballast The power saving is 2530% for the following reasons: high frequency operation, improving the luminous efficiency of the lamp. Experiments show that the light efficiency increases with the increase of the operating frequency (50HZ50KHZ), and the input power of the electronic ballast decreases with the illumination; the power consumption is low, about 5% of the lamp power (15% lower than the inductance ballast); The power-saving effect of the tube drive and high-power electronic ballast is more significant; the line power factor is improved (from the 0.5 of the magnetic ballast to 0.9 or more), the power utilization rate is correspondingly improved, and the indirect energy saving is realized; The amount of heat generated by small heat is reduced accordingly; the power factor is high, the input current is reduced, the power wiring installation requirements and cost are reduced; the starter is not required, and the replacement time and cost are omitted; (2) no stroboscopic, soft lighting, It is beneficial to protect eyesight; (3) quick start, no repeated blooming and flickering; preheating start function, greatly extending lamp life; (4) quiet operation, no noise, improve lighting environment quality; (5) available city Power and DC power supply, can start under low voltage (150V), allow voltage fluctuation range (±10~15%); (6) adopt frequency modulation, pulse width modulation (PWM), light receiving and other technologies, easy to achieve Fluorescent lamp dimming and light control intelligent switch; (7) with abnormal state (light open circuit, short circuit, overload, etc.) protection function to extend the life of the ballast; (8) small size, light weight, easy to install and use; 4 problems and Countermeasure High-pressure sodium lamp electronic ballast is prone to failure in actual production and use, which brings great losses to users and also imposes a great burden on after-sales service. From the surface phenomenon, when the fault occurs, the main performance is the damage of the power switch tube, the damage of the drive integrated circuit, the failure of the high voltage trigger circuit, and the overall temperature rise of the ballast. Through experimental analysis, it is found that there are many reasons for the failure, which can be divided into design factors and process factors for implementing the design. The design of the 19th Lighting Technology and Marketing Seminar on the two sides of the ballast is to determine the selected components of the circuit according to the parameters. The structure must also be designed to match the circuit, and the overall thermal design must also be made. The corresponding considerations. From the concept of design reliability, to make the system reliable, there must be considerable redundancy in the design of each component. In general, redundancy is high and reliability is high.
Table 2 electronic ballast and inductance ballast performance comparison, 40W; trivial magnetic ballast 屯 f ballast illumination i for 50HZ. Bamboo Yan 茧钕 lightning sense coil m flow, Lu Dalu harm visual production rate >20KBZ. Shaftless lightning 1 = device ballast. No towel protection, wish to lift i: as a conditional ring network power m low insov can not always start as low as isov can still start normally. Rfr. But let ft lower the maximum ft up to +i2r. When a fire occurs, the heat is controlled by the heat control, and the power consumption of the line current is increased. Can not be started, the starter turns off the cathode of the lamp. Shortening the life of the lamp will be a short-term maintenance. B裉 Bad lamps have a hot function of dumplings. The second start, you can do not need to worry about the long lamp. Qihui appliance different state protection function. M long ballast right coffee, but the redundancy and economy are contradictory, the redundancy will inevitably lead to an increase in input and cost. Therefore, a moderately redundant 3 high-pressure sodium lamp needs a trigger voltage of 3kV~5kV when starting, and the load characteristic changes from the original open state to the low-resistance state after the lamp is started, triggering the high voltage stop. However, in fact, the triggering of the high voltage after the lamp is started may not be immediately stopped, and the power supply end of the output pole switch tube and the power supply end of the front stage push the integrated circuit have an influence, so that the power supply end of the two devices is short-circuited to the ground, and the damage is promoted. Integrated circuits and switching power transistors cause ballast function failure. This phenomenon often occurs when it is turned on.
In addition, the output pole switch tube will also generate voltage surges. At this time, the voltage of the switch tube is at least twice that of the power supply voltage, which will damage the output stage switch tube and cause a breakdown between the source and drain stages. The preamplifier pushes the power supply of the integrated circuit to be supplied by the output stage power supply terminal, and the voltage surge causes the output stage to change, so that the power supply terminal K of the integrated circuit instantaneously increases sharply, causing the integrated circuit to break through. Although the voltage regulator is provided at the power input of the driver stage integrated circuit, the voltage regulation is relatively simple and cannot keep up with the surge voltage. Therefore, when the instantaneous high-speed surge voltage comes, the voltage is still stabilized in the future, and the circuit has been broken down.
There are two ways to solve the above problems: First, using new devices, such as MOS tubes with high withstand voltage and low cost, IGBTGCT or MCT with market voltage up to 6kV can also solve the breakdown problem, but the expensive price makes them Not applicable to electronic ballasts. Second, innovative design ideas. The normal operation of the high-pressure sodium lamp is that the lamp terminal voltage is only 50V70V. If the ignition circuit, that is, the trigger voltage generating circuit of 3kV~5kV can be isolated from the normal driving circuit, it is expected to solve the stability of the 19th session of the Taiwan Strait. Seminar questions. Just as the APFC technology brought a vast world of fluorescent lamp electronic ballasts, the solution to high-pressure sodium lamp electronic ballasts must use new design ideas or new devices.
Finally, for high-pressure sodium lamp electronic ballasts, the circuit must be designed in accordance with its nominal parameters. Reliability is difficult to guarantee if designed with a rigid combination of multiple components. Some companies' piracy behaviors, such as finding some better-made products, I use the capacitors you use. I also follow the transistor you used. The result is that the reliability of the product is very poor, and the life expectancy is only one. Until two months. It should be pointed out here that although the selected components and the components on the copied products are of the same model or even produced by the same factory, there are some specific indicators that are quite different. Such as: magnetic material temperature characteristics, frequency characteristics, initial permeability, effective permeability and other parameters, although the same model, the same material, the dispersion of the same batch and the difference between different batches is far away, can not be used. In order to do electronic ballasts, we must work hard on the design of component parameters. Only by designing important parameter standards that meet our own products can we produce high-quality electronic ballasts with stable performance.
5 Conclusion With the economic development is the deterioration of environmental pollution, the fact that Wuxi Taihu Lake cyanobacteria problem is reflected: small chemical industry, small refinery is not the only source of environmental pollution, and controlling energy consumption per unit of GDP is one of the effective ways to solve pollution. .
The compromise reached by the United States at the G8 summit with Japan and Europe on emissions has also challenged China's energy problems. The State Council, the National Development and Reform Commission and other departments have adopted energy conservation measures as one of the important assessment indicators for tax rebates. Street lamps, as a major energy consumer in the power sector, have received attention from the power sector at all levels. Researching and improving the stability of electronic ballasts and improving their energy-saving indicators is a subject of both technical and economic value.
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