CN104076281A - Motor energy efficiency monitoring method based on WSN - Google Patents

Abstract

The invention provides a motor energy efficiency monitoring method based on a WSN. The method includes the steps that first, input information parameters of a motor are determined, and corresponding wireless sensors are installed on the motor according to the parameters; second, the wireless sensor network is formed by the wireless sensors and wirelessly connected with an upper computer; third, the motor is started, and data of the wireless sensors are collected; fourth, the input parameters and output parameters of the motor are calculated online; fifth, the energy efficiency condition of the motor is evaluated. Through the method, non-invasive-mode energy efficiency monitoring can be performed on the motor, monitoring data are uploaded to a data processing unit through the WSN, energy efficiency data can be analyzed and evaluated, and the running energy efficiency condition of the motor is analyzed online.

Description

A kind of motor energy efficiency monitoring method based on WSN

Technical field

The invention belongs to energy efficiency monitoring field, be specifically related to a kind of motor energy efficiency monitoring method based on WSN (Wireless Sensor Networks, wireless sensor network).

Background technology

Now, environment and the energy have become the bottleneck that restriction human society further develops, and implementing energy-saving and emission-reduction strategy is the Important Action that China realizes sustainable development.Motor is the topmost power source of commercial unit, play an important role, but it is also main energy consumption equipment in commercial production in commercial production.According to statistics, motor power consumption accounts for 60% of China's power consumption, and wherein the power consumption of blower fan, pump class, compressor and air conditioner refrigerating device accounts for respectively 10.4%, 20.9%, 9.4% and 6% of national power consumption.The more than 80% electric product efficiency of China is than the low 2%-5% of Foreign Advanced Lerel, and blower fan, pump, compressor product efficiency are than the low 2%-4% of Foreign Advanced Lerel.

China's electric system in use mainly has problems: (1) motor efficiency is low, the outmoded backwardness of the equipment such as motor; (2) system matches is unreasonable, and " low load with strong power " phenomenon is serious, the long-term underrun of equipment; (3) system regulative mode fall behind etc.For addressing these problems, improve China and use electric efficiency, must set up the motor operation efficiency evaluation system of science, widely popularize energy-saving efficient motor and variable-frequency control technique, existing electric system is carried out to reducing energy consumption; Strengthen the monitoring of motor operation information and management, and these all depend on monitoring method and means to motor effective operation simultaneously.

Simultaneously, WSN is an important research branch of wireless Ad-Hoc (self-organization is to equation multi-hop mobile communications network) network, is a kind of new Information acquisi-tion pattern occurring along with MEMS (MEMS (micro electro mechanical system)), sensing technology, wireless telecommunications and developing rapidly of Digital Electronic Technique.It is the network consisting of the mode of self-organization the small node of the sensor of stochastic distribution, data processing unit and communication module, WSN has that cost is low, scale is large, distributed mode, without wiring, cost-saving, towards concrete application, flexible configuration, working frequency range without features such as application and paying, support hardware encryptions, carry out successful application in a lot of fields now, such as Military Application, industry monitoring, data acquisition etc.

Summary of the invention

Technical matters to be solved by this invention is: a kind of motor energy efficiency monitoring method based on WSN is provided, the method can be carried out non-intrusion type energy efficiency monitoring to motor, Monitoring Data is uploaded to data processing unit by WSN, and to efficiency data analysis, assessment, on-line analysis motor operational energy efficiency situation.

The technical solution adopted in the present invention is: a kind of motor energy efficiency monitoring method based on WSN, comprising:

S1) determine motor input message parameter, according to such parameter, corresponding wireless senser is installed on motor;

S2) wireless senser is formed to wireless sensor network, and with host computer wireless connections;

S3) open motor, gather the data of wireless senser;

S4) input to motor, output parameter carry out in line computation;

S5) the efficiency situation of motor is assessed.

Described method, in step S1, the wireless senser of installing on motor comprises voltage, electric current, Hall and frequency sensor.

Described method, in step S2, the data acquisition module of wireless senser is connected with data processing module by serial communication interface, and wireless senser is again by IEEE802.15.4 and Zigbee protocol and aggregation node device and gateway device composition wireless sensor network; Host computer comprises connected successively data processing unit, receive data by wireless unit, and gateway device and receive data by wireless unit carry out wireless connections.

Described method, the parameter that step S4 calculates comprises power input, rotor speed, output torque, output power and efficiency.

Described method, the computing method of power input comprise:

Calculate power input P according to following formula:

$P=\frac{1}{n}[\underset{k=0}{\overset{n-1}{\mathrm{\Σ}}}{u}_{\mathrm{AC}}\left(k\right)\•i\left(k\right)+\underset{k=0}{\overset{n-1}{\mathrm{\Σ}}}{u}_{\mathrm{BC}}\left(k\right)\•i\left(k\right)]$

Wherein, n is number of samples, and u is line voltage, and i is phase current, and subscript A, B, C represent respectively three circuitry phases of motor.

Described method, the computing method of rotor speed comprise:

Calculate rotor speed N according to following formula:

$N=\frac{60}{z_r}(f_{\mathrm{sh}}-f_0)$

Wherein, z _rfor rotor teeth groove number, f _shfor rotor tooth slot harmonic frequency, f ₀for fundamental frequency.

Described method, the computing method of output torque comprise:

Calculate air gap torque T according to following formula (1) ₁:

$T_1=\frac{p}{2\sqrt{3}}\{(i_A-i_{\text{B}})\text{\∫[}{u}_{\mathrm{CA}}-1/2R(i_C-i_A)]\mathrm{dt}-(i_C-i_A)g\∫[u_{\mathrm{AB}}-1/2R(i_A-i_B)]\mathrm{dt}\}---\left(1\right)$

In formula, p is motor number of pole-pairs, i _a, i _b, i _cfor line current, R is line resistance, and t is the time, and g is acceleration of gravity;

Then calculate output torque T according to following formula (2):

$T=T_1-\frac{P_{\mathrm{Fe}}}{2\mathrm{\πN}/60}-\frac{P_s}{2\mathrm{\πN}/60}---\left(2\right)$

In formula, P _fefor the mechanical loss of motor, P _sfor the stray loss of motor.

Described method, the computing method of output power and efficiency comprise:

Press following formula (3) and calculate output power P _m:

$P_M=\frac{2\mathrm{\πN}}{60}T---\left(3\right)$

Press again following formula (4) counting yield η:

$\mathrm{\η}=\frac{P_M}{P}---\left(4\right).$

Described method, the energy efficiency evaluating method of step S5 comprises: draw the curve of efficiency-rotor speed, output torque-rotor speed, power input-rotor speed, output power-rotor speed, output torque-output power, efficiency-output power, determine efficiency optimum point according to these curves.

Advantage of the present invention: the invention provides a kind of motor energy efficiency monitoring method based on WSN, the method adopts non-intrusion type motor stator current signal Signature Analysis Techique, the on-line monitoring of motor operating state and the analysis of efficiency are realized, for user provides a powerful analysis tool, can play great facilitation to the raising of the selection of motor and efficiency.Be suitable for widely used middle and small motor efficiency on-line monitoring and energy management in commercial production.Simultaneously, in the method, adopt wireless sensor network (WSN), ensure that terminal motor efficiency data are uploaded to motor efficiency data processing host computer reliably, easily, overcome that the wiring of traditional cable data acquisition mode is inconvenient, be difficult to the difficulty of image data under rugged surroundings, realized that motor efficiency data monitoring system maintenance cost is low, easy for installation, the plurality of advantages such as conform extensively.

Brief description of the drawings

Accompanying drawing 1 is a kind of motor energy efficiency monitoring block diagram based on WSN.

Accompanying drawing 2 is wireless sensor network Organization Chart.

Embodiment

The invention provides a kind of motor energy efficiency monitoring method based on WSN (wireless sensor network), the method comprises the data acquisition of motor efficiency, Wireless Data Transmission and data processing.Data acquisition comprises parameters such as gathering motor speed, torque, power factor and efficiency; Data transmission is utilized wireless sensor network (WSN) transmission relevant parameter, and network comprises connected aggregation node device and gateway device, and sensor is connected with aggregation node device; Data processing is mainly processed in real time and analyzes the data of WSN transmission, comprises dsp processor and host computer display device.This monitoring method can, in the situation that not affecting the normal operation of electric system, be carried out the online energy efficiency monitoring of non-intrusion type to the electric system that puts into operation, for energy-saving of motor system transformation provides a kind of economic, energy efficiency monitoring method reliably.

A motor energy efficiency monitoring method based on WSN, mainly comprises following steps:

S1) motor operational energy efficiency parameter is classified, mainly can be divided into two classes: a class is motor input message parameter, such parameter can directly obtain by sensor measurement or directly calculate acquisition by measured value; Another kind of is motor output parameter, and such parameter cannot directly obtain, and must indirectly obtain by the estimating algorithm estimation on line to metrical information.

S2 actual measurement parameter is through WSN transmitted data on network processing unit.

S3) motor input message calculation of parameter.

S4) motor output parameter On-line Estimation is calculated.

S5) motor efficiency condition evaluation.

Described method, the two class parameters of described step S1 comprise electric moter voltage, current effective value, motor input electric power, motor output speed, motor output torque, output power of motor, the parameters such as electric efficiency.

Described method, electric current and voltage sensor gather motor input data, and motor input electric power can be calculated and be obtained by gathered voltage, current data, formula is as follows:

$P=\frac{1}{n}[\underset{k=0}{\overset{n-1}{\mathrm{\Σ}}}{u}_{\mathrm{AC}}\left(k\right)\•i\left(k\right)+\underset{k=0}{\overset{n-1}{\mathrm{\Σ}}}{u}_{\mathrm{BC}}\left(k\right)\•i\left(k\right)]$

By can obtain the teeth groove harmonic content of rotor to stator voltage and stator current filtering, by the harmonic frequency detecting, can obtain rotor speed according to the relation of itself and rotating speed.Its computing formula is:

$N=\frac{60}{z_r}(f_{\mathrm{sh}}-f_0)$

In formula, z _r---rotor teeth groove number;

F _sh---rotor tooth slot harmonic frequency;

F ₀---fundamental frequency.

Output torque deducts by air gap torque the torque being produced by mechanical loss and stray loss and obtains, and air gap torque computing formula is:

$T_1=\frac{p}{2\sqrt{3}}\{(i_A-i_{\text{B}})\text{\∫[}{u}_{\mathrm{CA}}-1/2R(i_C-i_A)]\mathrm{dt}-(i_C-i_A)g\∫[u_{\mathrm{AB}}-1/2R(i_A-i_B)]\mathrm{dt}\}$

In formula, p---motor number of pole-pairs;

I _a, i _b, i _c---line current;

U _aC, u _aB---line voltage;

R---line resistance;

Output torque is:

$T=T_1-\frac{P_{\mathrm{Fe}}}{2\mathrm{\πn}/60}-\frac{P_s}{2\mathrm{\πn}/60}$

In formula, P _fe, P _s---be mechanical loss and the stray loss of motor, can quote the given estimated value of IEEE STD-12 standard and calculate.

Output power and efficiency can calculate under the support of above-mentioned data, and formula is as follows:

$P_M=\frac{2\mathrm{\πn}}{60}T$ $\mathrm{\η}=\frac{P_M}{P}$

Described method, the method of step S2, S3, S4 is: corresponding wireless senser is installed on electric system, and form wireless sensor network, and wireless sensor network comprises connected aggregation node device and gateway device, sensor is connected with aggregation node device.The online energy efficiency monitoring system of motor based on WSN is mainly made up of two parts functional unit, on-site data gathering and transmission unit and host computer on-line monitoring and analytic unit.Data acquisition and processing unit are mainly made up of DSP data processor and current/voltage sensor; Host computer on-line monitoring and analysis software adopt LABVIEW software programming, and its major function is that motor operating parameter data are shown in real time.

Described method, the appraisal procedure of step S4 is: the data analysis that WSN is uploaded, on existing knowledge base basis, complete the energy efficiency state of motor operation is evaluated, realize the management of motor day-to-day operation situation or provide technical support to motor energy-saving rebuilding.

Performance analysis of electric machine mainly comprises: efficiency-rotary speed-torque-rotating speed, power input-rotating speed, output power-rotating speed, torque-output power, efficiency-data power etc., and analytic curve and evaluation result report can be provided.

Be described in further detail the present invention below in conjunction with specific embodiment.

The present invention relates to a kind of motor energy efficiency monitoring method based on WSN, be mainly that the parameters such as power input to a machine, output power, power factor, efficiency are carried out in line computation, and the information of motor carried out to the analysis of science.The method, by using infant industry wireless sensor technology, is set up WSN network, uploads Monitoring Data by WSN, and electric system is carried out to real time on-line monitoring.This method adopts air gap torque method to carry out efficiency calculation, has that security of operation, cost are low, monitoring accuracy high, is suitable for widely used middle-size and small-size threephase asynchronous machine in commercial production and uses.And adopting non-intrusion type online test method, maximum reduces impact motor performance being caused due to other equipment being installed.The stator voltage and the stator current data that propose to gather by analysis progressively obtain motor efficiency parameter value, and to various detection techniques and signal analysis theory separating abnormality status information, line voltage, line current, power input, rotating speed, output torque, output power, power factor and efficiency etc. when monitoring motor device operation in time, on-line real time monitoring motor efficiency situation, implements advanced energy management for electric system technical support is provided.

WSN (wireless sensor network) in motor energy efficiency monitoring system mainly forms by being fixed on equipment connected successively sensor node, aggregation node, gateway and monitoring host computer.Parameter of electric machine monitoring sensor institute image data is uploaded to monitoring host computer by wireless sensor network.

A motor energy efficiency monitoring method based on WSN, its key step is as follows:

S1) monitored electric system is installed to wireless senser, mainly comprise voltage, electric current, frequency sensor etc.;

S2) set up WSN wireless sensor network, WSN network comprises main SCI (serial communication interface) serial communication and ZigBee radio communication two parts, carry out data transmission by SCI serial communication and data processing unit, observing the radio communication function of IEEE802.15.4/ZigBee agreement realizes and upper machine communication, realizing system data effectively transmits, can effectively reduce wiring cost, adapt to on-the-spot complex environment simultaneously.Wherein IEEE802.15.4 provides lower floor's communication protocol, and ZigBee provides more services on the former basis.

S3) build motor efficiency data processing host computer, host computer carries out communication by serial ports and WSN data module, and then realizes the control to on-site data gathering and transmission.Host computer on-line monitoring is mainly that motor operating parameter data are shown in real time with analyzing, and it is analyzed, on existing knowledge base basis, complete the energy efficiency state of motor operation is evaluated, realize the management of motor day-to-day operation situation or provide technical support to motor energy-saving rebuilding.

S4) motor efficiency data input message is calculated, and mainly comprises motor input voltage, current value, power input to machine;

S5) motor output parameter estimation on line, mainly comprises motor speed, motor output torque, output power of motor and efficiency parameters.

Concrete implementation step is as follows:

1, the parameter of electric machine is by sensor image data, and general data is the correlation parameters such as electric moter voltage, electric current, frequency.

2, motor efficiency data are uploaded to data acquisition unit by WSN network, and this unit mainly comprises DSP data collecting card and the wireless data transmission unit based on ZigBee.Data acquisition and processing unit are mainly made up of DSP data processor and current/voltage sensor.

3, by host computer, motor terminals sensor institute image data is processed and analyzed, performance analysis of electric machine mainly comprises: efficiency-rotary speed-torque-rotating speed, power input-rotating speed, output power-rotating speed, torque-output power, efficiency-data power etc., and analytic curve and evaluation result report can be provided.

S1) motor input voltage, current monitoring, these data can directly obtain by sensor collection.

S2) motor speed parameter monitoring, known by asynchronous machine design concept, the stator current of motor can be because of the existence of the rotor tooth effect of grooves, and induces the slot ripples component of reflection motor speed information, and rotary speed information also can reflect simultaneously on rotor current.Threephase asynchronous machine works under 50Hz frequency, adopt the current sensor of Hall effect, the effective value of the motor stator current signal collecting and then can be on the basis of motor stator current signal, obtain the characteristic signal of threephase asynchronous machine slot ripples, detection and the rotating speed realized slot ripples frequency are estimated.The last size that finds slot ripples frequency in master routine, brings following formula into and can try to achieve rotating speed.

$N=\frac{60}{z_r}(f_{\mathrm{sh}}-f_0)$

S3) motor torque parameter estimation, air gap, winding and three part composition magnetic circuit systems unshakable in one's determination, under the condition of excitation, air gap both sides produce moment, can make like this rotor motion, output mechanical work.The variation of magnetic field energy is extremely important, and the process that this magnetic field energy, electric energy and mechanical energy are changed is mutually very complicated.Now, power input to a machine is the rate of change sum of stator resistance loss, air gap power and stator magnet field energy, and air gap power is the power that strides across air gap and be delivered to rotor.In the time calculating power input, torque detects can be converted into motor gas-gap torque T and mechanical loss P _fewith stray loss P _sthe detection of P, the computing formula of output torque is:

$T=T_1-\frac{P_{\mathrm{Fe}}}{2\mathrm{\πn}/60}-\frac{P_s}{2\mathrm{\πn}/60}$

S4) electric efficiency estimation, the important foundation of implementing motor energy management is the online detection of electric efficiency, first calculates power input to a machine P, then calculates the output power of motor, and then can obtain the efficiency of motor, formula is as follows:

$P=\frac{1}{n}[\underset{k=0}{\overset{n-1}{\mathrm{\Σ}}}{u}_{\mathrm{AC}}\left(k\right)\•i\left(k\right)+\underset{k=0}{\overset{n-1}{\mathrm{\Σ}}}{u}_{\mathrm{BC}}\left(k\right)\•i\left(k\right)]$

$P_M=\frac{2\mathrm{\πn}}{60}T$

$\mathrm{\η}=\frac{P_M}{P}$

Claims (9)

1. the motor energy efficiency monitoring method based on WSN, is characterized in that comprising:

S1) determine motor input message parameter, according to such parameter, corresponding wireless senser is installed on motor;

S2) wireless senser is formed to wireless sensor network, and with host computer wireless connections;

S3) open motor, gather the data of wireless senser;

S4) input to motor, output parameter carry out in line computation;

S5) the efficiency situation of motor is assessed.

2. method according to claim 1, is characterized in that: in step S1, the wireless senser of installing on motor comprises voltage, electric current, Hall and frequency sensor.

3. method according to claim 1, it is characterized in that: in step S2, the data acquisition module of wireless senser is connected with data processing module by serial communication interface, and wireless senser is again by IEEE802.15.4 and Zigbee protocol and aggregation node device and gateway device composition wireless sensor network; Host computer comprises connected successively data processing unit, receive data by wireless unit, and gateway device and receive data by wireless unit carry out wireless connections.

4. method according to claim 1, is characterized in that: the parameter that step S4 calculates comprises power input, rotor speed, output torque, output power and efficiency.

5. method according to claim 4, is characterized in that, the computing method of power input comprise:

Calculate power input P according to following formula:

$P=\frac{1}{n}[\underset{k=0}{\overset{n-1}{\mathrm{\Σ}}}{u}_{\mathrm{AC}}\left(k\right)\•i\left(k\right)+\underset{k=0}{\overset{n-1}{\mathrm{\Σ}}}{u}_{\mathrm{BC}}\left(k\right)\•i\left(k\right)]$

Wherein, n is number of samples, and u is line voltage, and i is phase current, and subscript A, B, C represent respectively three circuitry phases of motor.

6. method according to claim 5, is characterized in that, the computing method of rotor speed comprise:

Calculate rotor speed N according to following formula:

$N=\frac{60}{z_r}(f_{\mathrm{sh}}-f_0)$

Wherein, z _rfor rotor teeth groove number, f _shfor rotor tooth slot harmonic frequency, f ₀for fundamental frequency.

7. method according to claim 6, is characterized in that, the computing method of output torque comprise:

Calculate air gap torque T according to following formula (1) ₁:

$T_1=\frac{p}{2\sqrt{3}}\{(i_A-i_{\text{B}})\text{\∫[}{u}_{\mathrm{CA}}-1/2R(i_C-i_A)]\mathrm{dt}-(i_C-i_A)g\∫[u_{\mathrm{AB}}-1/2R(i_A-i_B)]\mathrm{dt}\}---\left(1\right)$

In formula, p is motor number of pole-pairs, i _a, i _b, i _cfor line current, R is line resistance, and t is the time, and g is acceleration of gravity;

Then calculate output torque T according to following formula (2):

$T=T_1-\frac{P_{\mathrm{Fe}}}{2\mathrm{\πN}/60}-\frac{P_s}{2\mathrm{\πN}/60}---\left(2\right)$

In formula, P _fefor the mechanical loss of motor, P _sfor the stray loss of motor.

8. method according to claim 7, is characterized in that, the computing method of output power and efficiency comprise:

Press following formula (3) and calculate output power P _m:

$P_M=\frac{2\mathrm{\πN}}{60}T---\left(3\right)$

Press again following formula (4) counting yield η:

$\mathrm{\η}=\frac{P_M}{P}---\left(4\right).$

9. method according to claim 4, it is characterized in that, the energy efficiency evaluating method of step S5 comprises: draw the curve of efficiency-rotor speed, output torque-rotor speed, power input-rotor speed, output power-rotor speed, output torque-output power, efficiency-output power, determine efficiency optimum point according to these curves.