Application of the hottest sy3200 frequency conver

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Application of sy3200 frequency converter in frequency conversion and energy saving transformation of boiler fan

Abstract: This paper introduces the built-in PID and simple PLC of Daye frequency converter, which has obvious energy-saving effect in the transformation of boiler fan

key words: frequency converter boilers in thermal power plants

I. overview:

at present, among all kinds of mechanical and electrical equipment in all walks of life in China, the motors supporting fans and pumps account for about 60% of the installed capacity of motors in the country, and the power consumption accounts for about one third of the total power generation in the country. In particular, it is worth mentioning that most fans and pumps have the phenomenon of big horse pulling small car in the process of use. In addition, due to changes in production and technology, it is necessary to often adjust the flow, pressure, temperature, etc. of gas and liquid; At present, many units still use the backward way to adjust the flow, pressure and temperature of gas or liquid by adjusting the opening of air baffle or valve. In fact, this is to meet the requirements of process and working conditions for gas and liquid flow regulation by artificially increasing resistance and at the cost of wasting electric energy and money. This backward regulation method not only wastes valuable energy, but also has poor regulation accuracy, which is difficult to meet the requirements of modern industrial production and services, and the negative effects are very serious

the emergence of variable frequency governor has brought a revolution to the AC speed regulation mode. With the continuous improvement and development of frequency conversion technology in recent ten years. The performance of variable frequency speed regulation is becoming more and more perfect, and it has been widely used in AC speed regulation in different fields. It has brought considerable economic benefits to enterprises and promoted the automation process of industrial production

variable frequency speed regulation is used for AC asynchronous motor speed regulation, and its performance is far better than any previous AC and DC speed regulation methods. Moreover, with simple structure, wide speed regulation range, high speed regulation accuracy, convenient installation and commissioning, perfect protection function, stable and reliable operation, and remarkable energy-saving effect, it has become the latest trend of AC motor speed regulation

II. Energy saving principle of frequency conversion:

1 Fan operation curve

using frequency converter to control the fan is a power-saving method to reduce aerodynamic force. Compared with the commonly used method of regulating the air volume by damper, it has obvious power-saving effect. The principle of power saving can be explained from the figure:

in the figure, curve (1) is the wind pressure air volume (H-Q) characteristic of the fan at constant speed n1, and curve (2) is the pipe wind resistance characteristic (the damper is fully open). Curve (4) is the frequency conversion operation characteristic (the air valve is fully open)

assuming that the fan works at point a with the highest efficiency, at this time, the air pressure is H2, the air volume is Q1, and the shaft power N1 is proportional to the product of Q1 and H2, which can be represented by the area ah2oq1 in the figure. If the production process requires that the air volume needs to be reduced from Q1 to Q2, then using the method of adjusting the damper is equivalent to increasing the pipe resistance, making the pipe resistance characteristics change to curve (3), and the system changes from the original operating point a to the new operating point B. It can be seen from the figure that the wind pressure increases instead, and the shaft power is proportional to the area bh1oq2. Obviously, the shaft power decreases little. If the frequency converter speed regulation control mode is adopted, the fan speed is reduced from N1 to N2. According to the proportional law of fan parameters, the accuracy of the experimental results is improved, and the air volume (Q-H) characteristics at the speed N2 are drawn, as shown in curve (4). It can be seen that under the condition of meeting the same air volume Q2, the wind pressure H3 decreases significantly, and the power N3 decreases significantly, expressed in area ch3oq2. Saved power △ n= (h1-h3) × Q2, represented by area bh1h3c. Obviously, the economic effect of energy conservation is very obvious

2. Energy saving rate of fan at different frequencies

fan is a mechanical device that transmits gas, and water pump is a mechanical device that transmits liquid. Both of them are machines that convert the shaft power of motor into fluid. How to judge the quality of an electronic tensile testing machine is a kind of machinery, and their working principles are basically the same

according to the principle of fluid mechanics, the fan air volume and water flow of the pump are related to the motor speed power: the air volume (flow) of the fan water pump is directly proportional to the fan water pump (motor) speed, the wind pressure of the fan and the head of the pump are directly proportional to the square of the fan water pump (motor) speed, and the shaft power of the fan water pump is equal to the product of the air volume and the wind pressure, the flow and the head, Therefore, the shaft power of the fan water pump is directly proportional to the quadratic power of the speed of the fan water pump (motor) (that is, the shaft power of the fan water pump is directly proportional to the quadratic power of the power supply frequency):

according to the above principle, changing the speed of the fan water pump can change the power of the fan water pump

for example, if the power supply frequency is reduced from 50Hz to 45Hz, then p45/p50=453/503=0.729, that is, p45=0.729p50

if the power supply frequency is reduced from 50Hz to 40Hz, then p40/p50=403/503=0.512, that is, p40=0.512p50

III. frequency conversion and energy saving transformation of boiler fans:

frequency conversion and energy saving transformation of boilers usually refers to the frequency conversion and energy saving transformation of boiler fans, pumps and other accessories

the boiler fan and water pump are designed according to the maximum working condition. In actual use, the fan needs to be adjusted according to the actual working condition for a lot of time. The traditional method is to adjust by opening and closing the damper and valve. This adjustment method increases the throttling loss of the air and water supply system, and there will be starting impulse current during startup. The adjustment of the system itself is also phased, and the adjustment speed is slow, The ability to reduce losses is very limited, which also makes the whole system work in a fluctuating state; These problems can be solved once and for all by installing variable-frequency governors (devices) on boiler fans and water pumps, which can make the system work smoothly and stably, and recover the investment through variable-frequency energy conservation. An example of the frequency conversion transformation scheme of the boiler is as follows:

overview of the current installation of boiler fans: 2 × 75KW,1 × 55KW。

all fans and water pumps adopt the configuration mode of one-to-one (i.e. one frequency converter with one motor), which retains the original power frequency system and is mutually standby with the frequency conversion system. Generally, the regulation mode is open-loop regulation

IV. investment and energy conservation:

when the variable frequency energy-saving system (device) is used in various speed regulation systems, its energy-saving effect can be achieved for a single device by%, and the average energy-saving effect can also be achieved in the general application of fans and pumps. The average value of these energy-saving effects is obtained from practical application without being affected by other factors, Authoritative data can be found from materials (Books) sold publicly on the market; Through these data summarized in 1 and some simple calculation of investment recovery rate, it can be seen that the investment recovery period of variable frequency energy-saving system (device) is generally months (this is an empirical value and authoritative data)

v. successful application cases

the successful application cases of daily industry frequency converter are as follows:

enterprise name total installed capacity power consumption kwh/daily power saving boiler tonnage investment payback period kW before and after installation kwh% Changchun thermal Tiexi thermal power company 99%2 × 40+2 × 1013 Changchun high tech heating company 41%2 × The 2012 Jinan gold testing machine in Daqing ranghu development zone can be divided into two major steps 97%2 × 20+1 × 1014 Songyuan heating center station 4%1 × 156 Jilin Dongfeng County heating company 57%1 × 30+2 × 2015 Heilongjiang Chengfu food group 4 ×. 47% 7511 Heilongjiang Chengfu food group 4 ×. 01% 759 Heilongjiang first thermal power plant 06%4010

VI. main features of Nikko inverter:

it adopts Hitachi 32-bit motor dedicated CPU, with high-precision frequency output and resolution up to 0.01Hz

it has the functions of automatic torque compensation, automatic slip compensation and dead time compensation

it has the functions of automatic voltage adjustment and restart after power failure

it has overcurrent, overvoltage, undervoltage, overload, overheating and phase loss protection

built in RS485 interface, which can be controlled by computer

built in simple PLC, multi-channel analog and digital input and output, the first choice for automatic control

built in PID function makes closed-loop control easier

the carrier frequency is adjustable, and the carrier frequency is up to 8kHz, silent operation

low speed rated torque output, 5KHz starting can output 100% rated torque, and the operation is stable

VIII. Shenzhen riye Electric Co., Ltd.

Shenzhen riye Electric Co., Ltd. is a high-tech enterprise with venture capital participation, specializing in the development, production and sales of frequency converters. It has first-class technical level and rich experience in development and design. The company's development, production, management and sales personnel have more than 5 years of working experience. The company integrates various professionals. After nearly 10 years of continuous efforts, the company has developed and produced frequency converters, and the product quality has reached the national advanced level. (end)

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