The power consumption rate of circulating fluidized bed (CFB) boiler generator sets is as high as about 12%, significantly offsetting the advantages of CFB boilers such as high combustion efficiency, low emissions, and strong coal adaptability. With the rapid development of large-scale CFB boilers in my country, the problem of high power consumption rate is becoming increasingly prominent; if this issue is not addressed quickly, it will become a bottleneck restricting the development of large-scale CFB boilers. Actively adopting variable frequency speed control technology (high-voltage and low-voltage variable frequency devices) and chopper internal feedback speed control motor technology in the design phase, along with owner-led research into the problems and solutions encountered in the application of variable frequency and other speed control technologies in power plants, and focusing on these energy-saving measures during the design phase, can reduce the power consumption rate of CFB boiler generator sets to a level close to that of similar pulverized coal boiler generator sets. Based on a 135MW unit, this can save nearly 30 million kWh of electricity annually, worth nearly 10 million yuan. [b]1 Energy Saving Analysis of Variable Frequency Speed ​​Control Technology in Application[/b] 1.1 Development Status of Variable Frequency Speed ​​Control Technology In power production, pumps and fans are widely used rotating equipment. Their energy consumption, throttling losses of related equipment such as valves and baffles, and maintenance and repair costs account for 7% to 25% of production costs. With the continuous deepening of power system reform and the continuous promotion of competitive bidding for grid connection, energy conservation and consumption reduction have become one of the important means to reduce production costs, improve product quality, and enhance the competitiveness of power plants. Variable frequency speed control technology meets the requirements of industrial production automation development and has ushered in a new era of energy conservation and consumption reduction. The basic principle of variable frequency speed control technology is based on the proportional relationship between motor speed and the input frequency of the working power supply. By changing the frequency of the working power supply of the motor, the motor speed can be changed. The frequency converter is a comprehensive electrical product based on the above principle, using AC-DC-AC power conversion technology, power electronics, microcomputer control, and other technologies. The application of variable frequency speed control technology has changed the outdated mode where ordinary electric motors could only operate at a fixed speed. It allows the motor and its driven load to adjust their speed output according to production process requirements without any modifications, thereby reducing motor power consumption and achieving efficient system operation. Currently, variable frequency speed control technology has become a major development direction in modern electric drive technology. When selecting a variable frequency system, automatic control of the equipment system can be achieved through an intelligent interface with a DCS. 1.2 Energy Saving Analysis of Variable Frequency Speed ​​Control Technology In power production, the most common control method is adjusting the opening of valves, dampers, and baffles to regulate the rotation of pumps and fans. This means that regardless of production demand, the fan must operate at its rated speed, and changes in operating conditions result in energy being consumed through throttling losses at valves, dampers, and baffles. During production, not only is control precision limited, but it also causes significant energy waste and equipment wear. This leads to increased production costs, shortened equipment lifespan, and persistently high equipment maintenance and repair costs. Most fans and pumps operate using direct drive from asynchronous motors, which suffers from drawbacks such as high starting current, mechanical shock, and poor electrical protection characteristics. This not only affects equipment lifespan but also fails to provide instantaneous protection when mechanical failures occur, often resulting in pump damage and motor burnout. In recent years, driven by the urgent need for energy conservation and continuously improving product quality, coupled with the ease of operation, maintenance-free operation, high control precision, and high functionality of variable frequency drives (VFDs), VFD-driven solutions have gradually replaced control schemes using dampers, baffles, valves, and hydraulic couplers. According to the basic laws of fluid mechanics, fans and pumps are square torque loads, and their rotational speed n is related to flow rate Q, pressure H, and shaft power P by the following relationships: Q∝n, H∝n², P∝n³; that is, flow rate is directly proportional to rotational speed, pressure is directly proportional to the square of rotational speed, and shaft power is directly proportional to the cube of rotational speed. Using variable frequency speed control technology to change the motor speed is more energy-efficient and economical than using valves and baffles for regulation, and the operating conditions of the equipment will also be significantly improved. 1.3 Compared with slip speed control, slip speed control is a typical and reliable control method, but it has disadvantages such as poor speed control accuracy, narrow range, poor linearity, and high energy consumption. The characteristics of variable frequency speed control system overcome the shortcomings of traditional slip speed control system. It has the characteristics of high efficiency, no slip loss, wide speed range, hard characteristics, high accuracy, convenient and flexible starting and braking, and low energy consumption. It has the advantages of AC induction motor and DC motor speed control performance, and has a very significant reliable energy-saving effect. Compared with traditional slip motor, variable frequency speed control system has advantages such as less maintenance, lower starting current, more complete system functions, and convenience for operators.   [b]2 Wide application of high and low voltage variable frequency technology[/b] Equipment such as domestic water pumps, fire pumps, and demineralized water pumps that use 380V motors can use low voltage variable frequency technology for variable frequency speed control. Pumps and fans using 6KV motors can benefit significantly from high-voltage frequency conversion technology. Taking a large 440t/h CFB boiler generator set as an example: multiple high-voltage frequency converters can be designed and installed (e.g., primary air fan 6KV, 1400KW; induced draft fan 6KV, 1250KW; secondary air fan 6KV, 710KW; coal feeding booster fan 6KV, 250KW; condensate pump 6KV, 280KW; feedwater pump 6KV, 3400KW; circulating water pump 6KV, 800KW). Multiple low-voltage frequency converters can also be designed and installed (4-6 sets of metering belt feeders, 5 sets of Roots blowers, 1 set of limestone feeder, 2 sets of slag coolers, 2 sets of ignition booster fans, domestic water pumps, fire pumps, demineralized water pumps, etc., and 2 sets of ignition booster fans). After the generator unit is officially put into operation with the above measures, the plant power consumption rate can be reduced to below 9%, which is comparable to that of similar pulverized coal boilers. This effectively overcomes the high plant power consumption rate of CPB boilers. Practice has proven that frequency converters have achieved significant energy-saving effects in the drive control of fans and pumps, making them an ideal speed control method. This improves equipment efficiency, meets production process requirements, and significantly reduces equipment maintenance and repair costs, as well as downtime. The direct and indirect economic benefits are substantial. 3. Actively Applying Chopper Internal Feedback Speed ​​Control Motor Technology In recent years, feedback AC speed control motor technology and control systems have developed rapidly, with products available in large and medium capacity 6KV and 10KV voltage levels. The chopper internal feedback speed control system utilizes modern electronic technology to control the induced current of the motor rotor (wound rotor), thereby controlling the rotor output torque to achieve speed regulation. Compared to frequency converter speed control, the internal feedback speed control system is connected to the motor rotor circuit, operates at a lower voltage, is more stable and reliable, and maintains a higher power factor and efficiency even at low speeds. Compared to traditional speed control methods, the internal feedback speed control system achieves smooth speed regulation without changing the motor wiring, eliminating the need for additional switches and improving switch operating conditions, which is significant for high-voltage motors. The internal feedback speed control system uses an inverter circuit to feed the rotor's residual energy back to the power supply system, consuming no electrical energy and achieving extremely high efficiency. The chopper internal feedback speed control motor system changes the traditional starting and flow regulation modes of fans and pumps. It reduces flow rate according to load conditions while reducing motor output power to achieve energy saving, and also enables soft starting of the motor. This system can achieve stepless speed regulation, replacing flow control by dampers, baffles, and valves. By sending relevant physical quantities to a microcomputer monitoring system through sensors, automatic speed regulation can also be achieved, and fault memory and detection functions can be added, which can greatly improve the level of production automation management. Through investigation of power plants using this technology, it was found that the chopper internal feedback speed control motor has a good energy-saving effect. Using the chopper internal feedback speed control motor can save more than 40% of electricity under speed control conditions. Practical use has proven that it can significantly reduce the power consumption of many fans and pumps, resulting in significant annual power savings. Early equipment components had some issues with quality, and system shutdowns were sometimes caused by burnt-out components, but the speed control system shutdown did not affect the normal operation of the motor. Recently, such accidents have significantly decreased, and the after-sales service for this product is good; generally, on-site repairs are available within one day of an accident. Overall, the internal feedback AC speed control motor technology and control system have certain advanced features, significant adoption value, and significant economic benefits. [b]4 Reducing Plant Power Consumption in System Design[/b] Careful consideration should be given to reducing plant power consumption in the initial design phase. The plant power consumption level of CFB boiler generator sets can then approach that of pulverized coal boiler generator sets. In the initial design phase of a power plant, the design unit should engage in extensive communication with boiler manufacturers, auxiliary equipment manufacturers, and other design institutes to discuss issues such as auxiliary equipment capacity selection, system configuration, and resistance calculation, laying a solid technical foundation for reducing plant power consumption. Optimization should be implemented in fan selection. First, the boiler manufacturer should provide a relatively accurate resistance calculation value (without any margin). Finally, after calculating the resistance of the entire flue gas and air system, the margin should be uniformly considered according to the "Large-Scale Fire Protection Design Code." This avoids situations where fans, couplings, and motors operate outside their high-efficiency range due to repeated calculations of margins, effectively reducing power consumption. It should also be noted that the flow rate and pressure head margins specified for fans in the circulating fluidized bed section of the "Large-Scale Fire Protection Design Code" are much larger than those specified for conventional pulverized coal boiler forced draft and induced draft fans. Extensive investigation and reasonable selection are necessary to ensure that the fans operate within their high-efficiency range. New and reliable slag removal methods should be adopted. Replacing the conventional combined air-water fluidized bed slag cooler used in boiler plants with a drum-type or steel belt-type slag cooler can reduce the slag system's power consumption from 330-400kW to 100-200kW, resulting in a significant reduction in plant power consumption (energy saving effect). The need for coarse crushing should be determined based on the fineness of the incoming coal; ideally, a primary screening system should be designed to ensure the boiler's particle size requirements are met, effectively prevent over-crushing, and reduce plant power consumption to some extent. Measures should be taken in the overall power plant layout to reduce energy consumption: (1) A slag silo should be located near the furnace side, and a limestone powder silo should be located between the two furnaces to shorten the conveying distance and reduce power consumption; (2) Primary and secondary fans should be located close to the air preheater to reduce duct resistance and thus power consumption; (3) Ash silos should be located within the plant area and close to the electrostatic precipitator to significantly reduce the power consumption of the pneumatic ash removal system. The boiler design by the boiler manufacturer has a significant impact on plant power consumption. During equipment bidding, differences in parameters such as air volume and velocity should be compared, and their impact on plant power consumption should be considered. **5 Conclusions** The high power consumption rate of circulating fluidized bed (CFB) boiler generator sets, reaching 10-12%, significantly negates many of the advantages of CFB boilers. This high power consumption rate has become a bottleneck restricting the rapid development of large-scale CFB boilers. However, by widely adopting high and low voltage speed regulation and energy-saving technologies such as variable frequency and chopper internal feedback speed-regulating motors in the design, and by taking effective measures in boiler body design, system configuration, and auxiliary equipment selection, the power consumption rate of CFB boiler generator sets can be reduced to a level close to that of similar pulverized coal boiler generator sets, comparable to the power consumption level of similar pulverized coal boiler generator sets using wet flue gas desulfurization devices. References: 1. Jiang Jiao. Analysis and Reduction Measures of Power Consumption in CFB Power Plants. Thermal Power Technology. 2004-4. 2. Compilation of Technical Exchange Materials of the National Power Industry CFB Unit Technical Exchange and Service Cooperation Network (Volumes 1, 2, and 3), Beijing: Science and Technology Service Center of China Electricity Council, 2003. 3. AC Speed ​​Control System. Shanghai Jiaotong University Press. 4. Xu Zhenmao. Variable Frequency Speed ​​Control Device and its Commissioning, Operation and Maintenance. Ordnance Industry Press.