1 Introduction With the rapid development of China's economy and the increasing living standards of the people, the problem of power shortage is particularly prominent, and it has gradually become a bottleneck restricting economic development. Street lighting accounts for a large amount of electricity used in the city. In order to save electricity in the city, a street lamp power saving controller is generally used. It utilizes voltage fluctuations in different time periods. Under the premise of ensuring illumination standard and illumination quality, the step-down method is adopted to reduce the energy loss in the illumination system and utilize the electric energy most effectively. Generally, most of the systems use the internal timing mode of the MCU for software timing, but the counter is required. This not only occupies hardware resources, but also does not have a real-time clock. It can only be controlled simply, and the power saving effect cannot be maximized. The X1227S8I can solve the real-time clock of the system, and can also save the power of the system parameters. By using X1227S8I as the core device and combining with the single-chip technology, it is possible to automatically turn on the street light according to sunrise and sunset time, so as to minimize the switching time of the street lamp and obtain the maximum power saving effect. This article refers to the address: http:// 2 Introduction to X1227S8I 3 system design 3.1 System design basis Because the power consumed by the gas discharge lamp depends on the input voltage, according to the operating characteristics of the high-pressure sodium lamp with the change of the power supply voltage, when the working voltage rises to 106% of the rated voltage, the power consumption of the sodium lamp will rise to the rated power. 115%; when the operating voltage rises to 110% of the rated voltage, the power consumption of the sodium lamp will rise to 130% of the rated power. For example, for a sodium lamp with a rated power of 400 W, when the power supply voltage rises to 108% of the rated voltage, the power consumption of the lamp will increase to 480 W, which will cause a large increase in power consumption. Since the normal brightness needs have been taken into consideration when designing the road brightness, the power consumption should not be reduced by reducing the brightness, but considering that the vehicle flow is greatly reduced in the latter half of the night, the power supply voltage is increased due to the reduction of the power load. It is also feasible to reduce the luminous flux of the light source by lowering the supply voltage. Assuming that the supply voltage is increased by 10% in the latter half of the night, and then the supply voltage is reduced to 90% of the rated voltage to operate, the luminous flux is reduced to 70% of the rated value, and the power consumption can be reduced by 55%. 3.2 System Block Diagram Figure 1 is a block diagram of the system design. The system hardware is mainly composed of processor (CPU) clock circuit, display keyboard circuit, current voltage signal processing circuit, communication interface circuit, power supply automatic switching voltage stable output control circuit and other five parts. The clock circuit is responsible for providing the clock and saving the system configuration parameters; the display keyboard circuit is responsible for completing the setting and display of the parameters; the current voltage signal processing circuit is used for completing the measurement signal conversion of the three-phase current and voltage; the communication interface circuit is responsible for completing the system upgrade. And use GPRS communication mode for remote control, real-time monitoring of three-phase voltage and current, and setting remote lighting and turning off control parameters, etc., to reduce the labor intensity of street lamp administrators, realize the modernization of urban lighting management; The output control circuit is used to complete the segmentation adjustment control of the voltage in the power saving scheme. 3.3 Clock, Parameter Memory Circuit Figure 2 shows the X1227S8I application circuit. Since the P89V51RD2 reset pin RESET is different from the X1227S8I output reset RESET level, the 74HC02 conversion level is used. The V12 of the X1227S8I is connected to a 3 V lithium battery. When the VCC power fails, the device can be powered to ensure the real-time clock is accurate. The SCL serial clock input in the X1227S8I is used to clock the data of all input and output devices. The serial data terminal (SDA) is a bidirectional pin that is used to input or output data to the device. The open-drain output requires the use of a pull-up resistor output. The single-chip microcomputer adopts a P89V51RD2 type 80C51 microcontroller manufactured by Philips. Its main features are 64 KB of non-volatile Flash program memory and 1,024 bytes of data RAM memory. The former supports parallel and serial in-system programming (ISP), which is a low EMI mode (ALE disable); has four 8-bit I/O ports, and three high-current P1 ports (current for each I/O port is 16) mA) compatible with TTL and CMOS logic levels. The cost-effectiveness of the microcontroller simplifies the entire system circuit and reduces system cost. The serial interface communication method can not only complete the system upgrade, but also realize the remote control system. 4 system software design 4.1 memory address allocation 4.2 Program Design Flowchart Figure 3 shows the main program flow chart of the system. It is programmed in C language. Figure 4 shows the flow chart of the power saving gear control. In the figure, t is the current time, t1 is the light-on time, t2 is the night light time, t3 is the half-light time, t4 is the light-off time, and tf is the work status flag to prevent repeated adjustment of the same gear. Figure 5 shows the flow chart of the communication interface, and the communication uses the interrupt mode. 5 Conclusion Because the street lamp power-saving controller system adopts the X1227S8I clock device, the software timing consumes a lot of CPU hardware resources; using the I2C bus, the interface resources are also greatly reduced, the system cost is low, the timing is accurate, and the system is not affected by the power failure. Reliable; the system can automatically turn on the street light according to the real-time clock using sunrise and sunset time, thus minimizing the switching time of the street lamp, making the system more intelligent and the power saving effect is more ideal. Ethernet Switch,Internet Switches,Ethernet Splitter,Gigabit Managed Ethernet Switch Chinasky Electronics Co., Ltd. , https://www.chinaskyswitches.com
The X1227S8I is a real-time clock (RTC) with a clock, calendar, CPU monitoring circuitry and two polling alarms. It uses a low-cost 32.768 kHz crystal as input, accurate to seconds, minutes, hours, days, weeks, months. To show the time and automatically adjust the leap year to 2096. The X1227S8I also provides an alternate power supply input pin (VBACK) that allows the device to use a non-rechargeable battery as a backup power source. The X1227S8I features a 4 Kbit EEPROM array that preserves system configuration parameters and is secure and confidential. This memory is unaffected when both the primary and backup power supplies fail. In addition, the X1227S8I also has a single 2.7 ~ 5.5 V power supply; its operating temperature range is -40 ° C ~ +85 ° C; using a small 8-pin SOIC package.
The basic principle of street lighting energy saving should be based on the principle of ensuring that the visual requirements of the site are not reduced. Under the premise of ensuring the brightness standard and the lighting quality, according to the nonlinear relationship between the street lamp voltage and the power, the energy loss in the lighting system is reduced, which is most effective. Use electricity. The system adopts step-down power-saving and power-saving, that is, using time-controlled automatic switching and pressure-adjusting power adjustment technology to automatically track the grid voltage and automatically adjust the lighting power to realize automatic and accurate switching of lamps and voltage and illuminance output. The fuzzy adjustment solves the interference of the light-controlled automatic switching mode. Intelligently adjust the actual power supply of the street lamp to make the output voltage relatively stable, and ensure that the input power of the lamp is optimally matched with the actual illumination requirement, thereby achieving efficient power saving, and the power saving rate is 15% to 38%, and Extends the life of the luminaire. 
The memory address 0x35~0x30 in the X1227S8I device is used to define the year, month, day, hour, minute, and second. Address 0x3f is the status register (SR) that controls the write enable latch (WEL) and the register write enable latch (RWEL) write enable latch. The addresses 0x80~0x93 are three custom working modes. The mode 1 is working overnight. It automatically calculates the sun sunrise and sunset time according to the latitude and longitude, and controls the switch completely by sunrise and sunset time. Mode 2 is working in the middle of the night at sunset. Time is on, the user is timed off; mode 3 is self-set work, the user can set the on and off time, power saving plan (normal, night light, midnight light), turn-on time, night light time, midnight light time, off Lamp time, longitude, latitude, deviation and voltage fluctuation deviation. Among them, the power saving scheme has three different sizes of step-down files. Longitude and latitude are used to calculate sunrise and sunset times. Due to the scattering effect of the atmosphere, the sky is not completely black at sunset, and it will continue for a while, so it is necessary to correct the sunset time to minimize the power loss of the street lamp. The deviation is used to adjust the morning and evening of the switch light. When the deviation is ±5 is positive, the larger the number, the later the light is turned on, the earlier the light is turned off; when the deviation is negative, the larger the number, the earlier the light is turned on, the later the light is turned off; when the deviation is zero, then It is the standard sunrise and sunset moment (commonly known as dusk). The deviation between each sunrise and sunset time is about 5 minutes. The voltage fluctuation deviation is used to automatically adjust the deviation of the voltage from the set value. 
