Detailed explanation of the working principle of energy-saving lighting power supply

        1 Product Name

　　ILUEST intelligent lighting control device

　　2 Characteristics of lighting power supply

　　Lighting has become an indispensable and important measure in all social activities such as human life, work, production, and entertainment. With the rapid development of society and technology, people's requirements for lighting are not limited to seeing objects clearly, but have risen to the height of bright, soft, environmentally friendly and visually beautiful. With the expansion of industrial production scale, the corresponding lighting capacity will inevitably increase. In recent years, urban night scene lighting has become the mainstream of night power supply. Bright lights have made most cities a city that never sleeps, which has brought huge economic benefits and various conveniences and enjoyment to people's life, work, production, and entertainment.

　　However, many units still have many problems to be solved in lighting: a large amount of power loss causes high electricity bills; frequent replacement of lamps forces units to pay more for lamps and their accessories; the increase in human resources caused by lamp repair and maintenance; light pollution caused by strong lights; heat radiation caused by large-area lighting lamps, etc. In order to solve these negative effects, the National Energy Office has imposed the requirement that lighting projects must meet the requirements of green, energy-saving and environmental protection.

　　In response to the above problems, electricity users have taken some measures to improve and alleviate these contradictions.

　　3 Working principle of energy-saving lighting power supply

　　3.1 Main ways to save energy in lighting

　　The two ways to save energy in lighting are: first, to use efficient energy-saving light sources, that is, to use bulbs or tubes with high luminous efficiency; second, to install energy-saving control equipment on the existing lighting system.

　　From the perspective of practical application, the first solution is suitable for newly designed lighting circuits. For existing lighting systems, since all lamps need to be replaced, the initial investment in funds and manpower is relatively large. In lighting places where lamps cannot be updated in batches, the one-time investment is too large, which makes many units reluctant to do so. High-efficiency energy-saving light sources (lamp tubes, bulbs) are 5 to 10 times the price of traditional light sources. If the purchased energy-saving lamps themselves have quality problems or the power supply quality of the power grid is not good, the service life of the energy-saving lamps is very short, which may cause the user unit to experience the abnormal phenomenon of "saving energy but not saving money".

　　For energy-saving transformation of existing lighting systems, it is more economical and practical to install energy-saving equipment. At present, there are many lighting energy-saving equipment sold in China, among which lighting control and regulation devices account for the largest proportion. They can be roughly divided into three categories based on the working principle:

　　(1) Thyristor chopper type lighting energy-saving device

　　The thyristor chopping principle is adopted to control the conduction angle of the thyristor (silicon controlled rectifier) ​​to chop off a part of the sine wave voltage input from the power grid, thereby reducing the output voltage value and achieving the purpose of voltage control and power saving. This type of energy-saving control equipment has a fast and high-precision voltage regulation speed for the lighting system, can be adjusted in real time in different time periods, and has a voltage stabilizing effect. Because it is mainly electronic components, it is relatively small in size, light in weight, and low in cost.

　　However, this voltage regulation method has a fatal flaw: due to chopping, the voltage cannot achieve a sinusoidal output, and a large number of harmonics will appear, forming harmonic pollution to the power grid system, which is extremely harmful. It cannot be used in circuits with capacitor compensation (modern lighting design requirements stipulate that the power factor of the lighting system must reach above 0.9, while the power factor of gas discharge lamps is generally below 0.5, so capacitors are used to compensate the power factor). In foreign countries, there are clear regulations to limit the harmonic content of electrical equipment. In China, major cities such as Beijing, Shanghai, and Guangzhou have restricted the access to the power grid for equipment with excessive harmonic content.

　　High-power thyristor chopper-type energy-saving devices have the defect of harmonic pollution. If filtering equipment is installed, the cost is too high, so this type of equipment is not suitable for use in lighting circuits.

　　(2) Auto-coupling step-down control device

　　The most popular lighting energy-saving products on the market are of this type. The principle is to use an autotransformer to connect different fixed taps of the transformer according to the input voltage, and reduce the input voltage by 5, 10, 15, 20V, etc., so as to achieve the purpose of voltage reduction and power saving.

　　The biggest advantage of this type of product is that it overcomes the defect of thyristor chopper products in generating harmonics and achieves sinusoidal voltage output. The structure and function are simple, and of course the reliability is relatively high. However, there are obvious technical defects:

　　①Fixed multi-stage step-down device

　　Since its core component is a multi-tap transformer, the transformation ratio is fixed. Generally, there are 3 to 5 step-down taps on the secondary side, which reduce 5V, 10V, 15V, and 20V respectively. Once the terminal is fixed, the reduced voltage is a fixed value. When the grid voltage fluctuates, the output voltage of the control device will also fluctuate up and down, so that the working voltage of the lighting fixture is in an unstable fluctuation state and cannot play a protective role for the electric light source. When the grid voltage is high, the power saving rate is not optimal; when the grid voltage is low, undervoltage may occur, causing the lamp to fail to light up normally, but reducing the life of the lamp. This is the biggest defect of this type of control device. When the power consumption is at peak, the grid voltage is too low and the lighting equipment cannot operate normally.

　　②Contactor type voltage reducer

　　In order to achieve normal start-up at rated voltage and jump to bypass (safety protection of equipment) in case of overvoltage and undervoltage, this type of control device generally uses AC contactor for switching, which is the simplest and most commonly used method. However, if the contactor is used as the voltage adjustment device of the power-saving product, its safety, reliability and trouble-free working life cannot be guaranteed, and there are safety hazards, because the AC contactor is mechanically attracted and disconnected during the switching action, and there will be a short 10-20ms power outage, which is generally called "flash break". Such a power outage will cause the HID lamp (High Intensity Discharged Lamp-high pressure gas discharge lamp, such as high pressure sodium lamp, metal halide lamp, high pressure mercury lamp, etc.) to go out. The characteristics of this lamp determine that after it goes out, it must wait until the lamp tube cools down and the vapor pressure drops before it can be lit again, which generally takes 5-10 minutes. In use, this will be a serious fault.

　　For the above reasons, AC contactors cannot be used to control lighting control devices for frequent switching. Therefore, manufacturers who produce and sell such energy-saving products generally cannot achieve functions such as real-time voltage stabilization and multi-period control, which is also a serious disadvantage of such energy-saving products.

　　(3) Using the intelligent lighting control device produced by Seliklu can solve the problems existing in traditional lighting solutions (described later)

　　To sum up, these energy-saving solutions cannot meet the requirements of energy saving and environmental protection. For this reason, the ILUEST intelligent lighting control device developed and produced by the Spanish company Cericru has scientifically solved this series of contradictions and problems.

　　ILUEST intelligent lighting control system has the following functions:

　　①Soft start/soft transition function

　　One of the most important factors that reduce the life of lamps is the overvoltage from the power grid, especially the overvoltage when the lighting system is in the process of starting. ILUEST's high-quality soft start function can greatly alleviate the impact of the cold start high current on the light source during the lamp startup process, thereby extending the service life of the light source and reducing the replacement cost and labor maintenance cost of the lamp and its accessories. As shown in Figure 3-1, 80% of the lamps powered by ILUEST will be able to work for 24,000 hours. For lamps powered directly by the mains, 80% of the lamps can only work for 8,000 to 12,000 hours. It can be said that almost everyone has seen the phenomenon of sparks and unstable repeated starting when the lamp is started. This phenomenon is a fatal blow to the lamp. In severe cases, the lamp may be damaged at once. Usually, starting once is equivalent to igniting the lamp for 2 to 3 hours. If the above phenomenon occurs, the damage to the life of the lamp is immeasurable, and the soft start function can well avoid the above phenomenon.

　　② Voltage stabilization function

　　The working status of the equipment is divided into voltage stabilization soft start, voltage stabilization preheating status (stable at 90% rated voltage), voltage stabilization operation status (stable at rated voltage), voltage stabilization soft transition 1 (smooth voltage reduction in ramp mode), energy-saving voltage stabilization working status, and voltage stabilization soft transition 2 (smooth voltage increase in ramp mode). Regardless of the working stage of the equipment and how the grid voltage fluctuates, the output voltage accuracy is ±2%.

　　Voltage fluctuations during the operation of lamps are also one of the main factors that shorten the life of lamps. When lamps operate at a voltage higher than the rated voltage, not only will the life of the lamps be reduced, but also energy waste will be caused by the increase in voltage. The relationship between voltage and power (i.e. power consumption) can be obtained through calculation:

　　P=I2R=U2/R

　　Example: Voltage rises 10% → U2 = U1 × 1.1

　　P2=U22/R=(U1×1.1)2/R=(U12×1.21)/R=P1×1.21

　　Conclusion: Overvoltage 10%, power loss increases 21%! ③ Energy saving function

　　Energy saving can be achieved by lowering the voltage, with the energy saving effect reaching 30% to 70%.

　　Example: Voltage drops 16% → U2 = U1 × 0.84

　　P2=U22/R=(U1×0.84)2/R=(U12×0.7)/R=0.7P1

　　Conclusion: Reduce pressure by 16% and save power by 30%!

　　④Intelligent control function

　　ILUEST has a programmable astronomical controller that can automatically and accurately predict the daily sunrise and sunset times based on the longitude and latitude of the location where the equipment is used, thereby controlling the opening and closing times of the line and the energy-saving time.

　　⑤Green environmental protection equipment

　　ILUEST has zero harmonic distortion and will not pollute the power supply system. It can also avoid the harm to humans caused by light pollution such as flickering and glare of lamps, making it a green power supply device.

　　3.2 Technical features of ILUEST intelligent lighting control system

　　(1) Power range

　　3.5～150kVA, can meet users' various power level requirements.

　　(2) Wide input voltage range

　　In terms of the output rated voltage, the input range can reach +25% to -5%; in terms of the mercury lamp energy-saving output voltage, the input range can reach +11% to -19%; in terms of the sodium lamp energy-saving output voltage, the input range can reach +10% to -25%.

　　(3) Using multi-tap transformer compensation technology

　　It can step up and down the voltage, and the output voltage quality is high (accuracy is less than ±2%).

　　High efficiency (greater than 97%).

　　(4) Since fast thyristors are used as electronic switches, the voltage regulation speed is fast

　　Ensure that the load works at the rated voltage, the instantaneous overvoltage will not be transmitted to the load, and the instantaneous voltage drop will not cause the lamp to extinguish.

　　(5) Highly intelligent control system

　　The time of sunrise and sunset can be predicted based on the longitude and latitude of various parts of the world, thereby controlling the opening and closing times of the lines.

　　(6) Power saving function

　　According to the needs of the site, power saving control can be implemented at the appropriate time, and the power saving can reach more than 30%. After the gas lamp is fully started, the voltage is reduced to the energy-saving voltage to achieve the purpose of energy saving. According to the characteristics of gas lamps, the energy-saving voltage of sodium lamps is set to 180V, and the energy-saving voltage of mercury lamps is set to 190V, and the illumination will not change significantly.

　　(7)Soft start function

　　According to the characteristics of gas discharge lamps, there is a certain preheating time when starting, which can extend the service life of gas discharge lamps, reduce maintenance costs and save human resources.

　　(8) Three-phase independent regulation function

　　For three-phase load equipment, it has three-phase independent adjustment function, strong operability, and can withstand 100% three-phase unbalanced load. (9) Computer remote control and remote control function

　　When the intelligent lighting control device needs to be adjusted, remote control can be implemented through the RS232 interface.

　　(10) Automatic static bypass

　　Solid-state bypass has no noise and zero switching, and each phase of the three-phase load is equipped with a static bypass to ensure uninterrupted output voltage and better meet the needs of the site.

　　3.3 Working principle of ILUEST

　　The main structures of ILUEST intelligent controller are as follows (see Figure 3-2):

　　Compensation transformer

　　Multi-tap transformer

　　Automatic static bypass

　　Electronics with microprocessor (on each phase) 　　Time programmer

　　After the equipment is powered on, the normal daily cycle work process can begin. The system soft start starts from 200V and maintains at this level for 2.5 minutes. After that, it enters the "slow ramp" lighting mode for 5 minutes until the voltage slowly rises to the rated voltage of 220V, as shown in Figure 3-3.

　　During the startup process, the output voltage stabilizes at the corresponding value. Once the startup process is completed, the device will provide a stable rated voltage to the connected device until the device receives an instruction to reduce the supply voltage.

　　This command is issued by an external device (such as an intelligent controller, remote control device, etc.), which can be connected to the wiring terminals of the ILUEST device as a remote control device. After that, the voltage is in the "slow ramp" voltage reduction mode and lasts for 10 minutes until the voltage drops to the power saving level. This process is set to be repeated many times, even in the event of a power failure.

　　By adjusting the output voltage of the system, the purpose of soft start, soft transition, voltage stabilization and energy saving can be achieved. The microprocessor is used to control the position of the thyristor static switch connected to each tap of the multi-tap transformer, and then adjust the compensation voltage △U of the compensation transformer, so as to achieve the purpose of adjusting the output voltage. Therefore,

　　Uout=Uin+△U (△U can be positive or negative)

　　4ILUEST's energy-saving effect

　　Take fluorescent lamps, which are widely used in factories, as an example:

　　The total lighting time per year (average 12 hours per day) is 4380 hours.

　　The total working time at rated voltage is 1095h.

　　The total working time under energy-saving voltage is 3285h.

　　The cost per kWh is 0.9 yuan.

　　The design life of lighting fixtures is 3000h.

　　The cost of a 40W fluorescent lamp is 10 yuan.

　　The energy saving percentage (rated 220V, energy saving 190V) is 26%.

　　4.1 Direct energy saving benefits (40W/lamp, 1500 lamps)

　　The total lighting power is 60kW. Calculated based on 12 hours of electricity consumption per day, the daily electricity consumption is: 60kW×12h=720kWh.

　　The electricity fee is calculated at 0.9 yuan per kilowatt-hour.

　　Daily electricity cost: 720×0.9=648 yuan.

　　After adopting this system, the energy saving is calculated as 26%:

　　Daily electricity savings: 60kW×9h×0.9×0.26=126.36 yuan.

　　Annual electricity savings: 126.36×365=46121.4 yuan. 4.2 Indirect benefits

　　After adopting this system, the life of lamps is extended by 2 to 3 times. Calculated as 2 times, the actual service life of general lamps is 4000h, which can reach 8000h after adopting this system, and the total number of lamps is 1500.

　　Before adopting this system, lamps were replaced approximately 1.09 times per year.

　　After adopting this system, lamps are replaced about 0.54 times per year.

　　Each fluorescent lamp (40W) is calculated at 10 yuan (taking 1,500 lamps as an example):

　　Annual saving of lighting cost: 10×1500×(1.09-0.54)=

　　8250 yuan

　　This will save a total of 54,371.4 yuan in direct and indirect costs each year and will also reduce the workload of maintenance personnel.

　　If the grid voltage often fluctuates around 230V, the energy-saving benefits will be more obvious, as shown in Table 3-1.

　　If the energy saving percentage is 48%, the annual cost savings can reach 93,397.3 yuan!

　　It can be seen that the cost can be recovered within two years, and the service life of this equipment is up to 15 years.　　5. Installation method of ILUEST

　　The installation of ILUEST or its addition to the original line is very simple, as shown in Figure 3-4.

　　ILUEST can be directly connected to the ON/OFF switch of the input main power supply at the starting point of the lighting circuit without any additional wiring. ILUEST is divided into two types: indoor and outdoor, with flexible configuration. The indoor type can be installed on the indoor control distribution board to form a lighting control distribution panel; the outdoor type is made of high-grade polyester material, with a protection level of IP54 chassis structure, and the installation location can be selected according to user needs.

　　Users can purchase ILEUST lighting regulators and intelligent controllers separately and configure low-voltage lighting power supply devices by themselves, or they can order ILUEST complete sets of devices.

　　6ILUEST main technical parameters (see Table 2)