CN103185645B - High-precision temperature detecting device and detecting method applied to draught fan control system - Google Patents
High-precision temperature detecting device and detecting method applied to draught fan control system Download PDFInfo
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- CN103185645B CN103185645B CN201110451040.4A CN201110451040A CN103185645B CN 103185645 B CN103185645 B CN 103185645B CN 201110451040 A CN201110451040 A CN 201110451040A CN 103185645 B CN103185645 B CN 103185645B
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Abstract
The invention relates to a high-precision temperature detecting device and a detecting method applied to a draught fan control system. The high-precision temperature detecting device comprises a reference voltage source, a voltage division circuit, an n-shaped filter circuit, an over-current protection circuit, a low pass filter, an analog to digital (AD) conversion circuit, an AD self-calibrating circuit, a high-speed optocoupler isolation circuit and a digital signal processor (DSP) chip. The detecting method comprises a first step of achieving reverse solving algorithms including quadratic fit, fast square roots solving, resistance value indexing table finding, piecewise linearization and the like through the DSP chip, a second step of solving a PT resistance value according to the detected voltage values of two ends of the PT, and a third step of reversely solving a high-precision temperature value. The high-precision temperature detecting device and the detecting method applied to the air fan control system have the advantages of solving the problem that double nonlinearity exists in a constant voltage source hardware circuit and a PT thermal resistance indexing table, eliminating the influence of the double nonlinearity on the temperature detecting precision, improving the measuring precision, and being wide in working range, high in measuring precision, self-calibrating and applicable to a wide resistance value range of input resistance.
Description
Technical field
The present invention relates to a kind of temperature detection technology that is applied to aerogenerator, particularly relate to a kind of high-precision temperature-detecting device and method.
Background technology
In recent years, under the vigorously supporting of national policy, wind power equipment manufacturing industry has entered golden period, manufacturing technology and productive capacity fast development, obtain the accumulation of technology and knowhow, especially, in the situation that energy supply and demand contradictory problems is at home more and more serious and electricity needs rises, Wind Power Generation Industry is developed rapidly.
Wind power control system is mainly used to guarantee the safe, reliable, efficient operation of aerogenerator.And temperature information is Important Parameters (the gear case oil temperature in wind power control system, high-speed axle temperature degree, generator-temperature detection, front main bearing temperature, rear min bearing temperature, controller environment temperature), wind power control system requires temperature accurately measure and control, platinum in wind-powered electricity generation industry (PT) thermal resistance is a kind of widely used temperature sensor, it is little that it has volume, accuracy is high, temperature-measuring range is wide, the features such as good stability, but also there is nonlinear shortcoming simultaneously in it, therefore in the time utilizing PT thermal resistance to carry out accurate temperature measurement, except overcoming the noise of metering circuit self, also to correct the non-linear of PT resistance.
Traditional PT resistance temperature measurement mode, has two kinds of modes of two-wire system and three-wire system.These two kinds of modes all provide a constant current source by signal plate, and constant electric current flows through temperature variant resistance, the magnitude of voltage changing.CPU calculates the variation of temperature according to the magnitude of voltage changing.The measuring method of two-wire system is subject to the impact of line resistance larger, and measurement result exists certain error; Three-wire system measuring method can solve the problem of line resistance preferably, but need to increase an analog switch, switches continually between two loops.And this measuring method lacks versatility, if signal plate completes, be just difficult to expand again the way of thermometric.
Above-mentioned two kinds of metering systems, no matter two-wire system or three-wire system all adopt constant current source as reference power supply, and constant current source load capacity is very weak, cannot load PT resistance input more than two-way, otherwise will cause larger power supply error, therefore, all necessary corresponding single constant current sources of each road PT resistance input, not only greatly increase cost, and because constant-current accuracy is lower, also caused temperature measurement accuracy lower.
For existing problem in above-mentioned prior art, research and design a kind of novel PT resistance temperature measurement technology and module, be very necessary thereby overcome existing problem in prior art.
Summary of the invention
For the deficiencies in the prior art, the invention provides high-precision temperature pick-up unit and method for wind power generator control system.
The high-precision temperature pick-up unit that is applied to blower fan control system, is characterized in that comprising:
Reference voltage source, exports bleeder circuit to by being converted into required voltage signal from the voltage signal of external power source;
Bleeder circuit, for resistance and PT resistance are cascaded, and imposes fixing reference voltage, outputs voltage signal to π type filtering circuit;
π type filtering circuit, in parallel with PT resistance, for filtering interfering noise; Input end and output terminal are all voltage signals;
Current foldback circuit, for the protection of A/D convertor circuit, receives the voltage signal from π type filtering circuit, outputs voltage signal to low-pass filter circuit;
Low-pass filter circuit, for exporting filtered voltage signal to A/D convertor circuit;
A/D convertor circuit, for carrying out the voltage signal of input end analog to digital conversion and exporting digital voltage signal to AD self-calibration circuit and optical coupling isolation circuit;
AD self-calibration circuit, for A/D convertor circuit is carried out to self calibration, is connected with A/D convertor circuit;
High speed photo coupling buffer circuit, for dsp chip is protected, input end receives from the digital voltage signal of A/D convertor circuit and the digital controlled signal of dsp chip, and output digital voltage signal is transferred to A/D convertor circuit to dsp chip and by digital controlled signal;
Dsp chip, for the analyzing and processing to voltage signal, and with blower fan control system master station communication.
Described A/D convertor circuit is made up of AD conversion chip and scrambler with built-in PGA register, and AD conversion chip output gating signal is to scrambler; The reference voltage of reference voltage source output exports AD conversion chip to through switch chip.
Described AD self-calibration circuit is made up of 2 switch chips, and reference voltage source output reference voltage is to switch chip.
The high-precision temperature detection method that is applied to blower fan control system, is characterized in that comprising the following steps:
Step 1) A/D convertor circuit initialization;
Step 2) passage of analog input to A/D convertor circuit carries out self calibration;
Step 3) configure PGA parameter, and carry out the analog to digital conversion of voltage data;
Step 4) utilize quadratic fit method to convert the voltage digital amount after analog to digital conversion to resistance value;
Step 5) utilize look-up table and piecewise-linear techniques to draw the accurate temperature value that resistance value is corresponding;
Step 6) by dsp chip, accurate temperature value is uploaded to blower fan control system main website.
Described self calibration comprises the following steps:
Step 1) AD conversion chip is by the respective channel of scrambler gating switch chip;
Step 2) in the time that selected passage is effective, switch chip accesses reference voltage source the corresponding input channel of AD conversion chip;
Step 3) taking the analog voltage reference that is connected with switch chip calibration port as benchmark, demarcate the digital signal of AD conversion chip output.
Described configuration PGA parameter is specially by the parameter of PGA register in the AD conversion chip port modifications chip to A/D convertor circuit.
Described quadratic fit method comprises the following steps:
Step 1) simulate the second order relation curve of resistance and voltage according to the measured data of resistance value and magnitude of voltage;
Step 2) utilize rapid solving square root method, according to the relational expression of second order relation curve
Y=a X
2+ b X+c calculates resistance value
Wherein, Y is magnitude of voltage, and a, b and c are coefficient.
Described rapid solving square root method comprises the following steps:
(1) will be become binary number by the data-switching of evolution, from low level to a high position every 2 be one group separately;
(2) start successively to judge the maximum square root p of high-order first group of number from first group an of high position;
If a high position is 01, p is 1; If a high position is 00, p is 0;
(3) calculate the remainder of first group by high-order first group of number divided by maximum square root p, and this remainder is combined as new remainder with next group array as high-order;
(4) p is brought into (4p+1), judge whether new remainder is greater than (4p+1);
If remainder is greater than (4p+1), the next bit of p is 1; Otherwise be 0;
(5) repeat (2) (3) (4) steps, until all groups all calculated completely, now all bit array of p are combined and are square root.
Described look-up table is specially according to the corresponding integer temperature value of resistance calibration table inquiry resistance value.
Described piecewise-linear techniques is specially and in resistance calibration table, finds out the most close two adjacent resistance values according to resistance value, using integer temperature value corresponding these two resistance values as starting point and terminal, between starting point and terminal, be equally divided into 10 parts, calculate precision and be the temperature value of 0.1 DEG C.
The present invention has following beneficial effect and advantage:
1. the present invention adopts constant pressure source method, utilizes a reference voltage source Wei16 road PT resistance that unified reference power supply is provided, and has solved in existing PT100 resistance Constant Current-Source Design method that constant current source load capacity is weak, precision is low, high in cost of production shortcoming.
2. the AD chip that the present invention uses and the AD circuit of design make this PT resistance measuring module have PGA (Programmable Gain Amplifier) function, in the time of the different PT resistance of input (PT100, PT200, PT1000), only need to revise parameter, without modification circuits plate, just can adjust gain multiple, make whole module can adapt to easily the input resistance without type.
3. the present invention utilizes DSP to realize quadratic fit, oppositely solves, searches resistance calibration table, piece-wise linearization scheduling algorithm, solve the problem that constant pressure source method hardware circuit and PT resistance calibration table exist Double Nonlinear, eliminate the impact of Double Nonlinear on temperature detecting precision, improve measuring accuracy, simultaneously in quadratic fit with designed a kind of rapid solving square root algorithm of novelty in the process oppositely solving, avoid use DSP to carry out floating-point, the directly computing of extracting square root, greatly improved the operation efficiency of DSP and solved speed.
Brief description of the drawings
Fig. 1 is structure drawing of device of the present invention;
Fig. 2 is reference voltage source circuit figure of the present invention;
Fig. 3 is π type filtering circuit of the present invention, current foldback circuit and bleeder circuit figure;
Fig. 4 is low-pass filter circuit figure of the present invention;
Fig. 5 is A/D convertor circuit figure of the present invention;
Fig. 6 is AD self-calibration circuit figure of the present invention;
Fig. 7 is high speed photo coupling buffer circuit figure of the present invention;
Fig. 8 is measuring principle figure of the present invention;
Fig. 9 is temperature detection program flow diagram of the present invention;
Figure 10 is the quadratic fit curve of resistance value of the present invention and magnitude of voltage relation;
Figure 11 is rapid solving square root method flow diagram of the present invention.
Embodiment
Below in conjunction with drawings and Examples, the present invention is described in further detail.
Temperature measuring equipment principle:
First reference voltage source Wei16 road PT resistance as shown in Figure 1 provides standard 5V voltage source, Jing Ge road bleeder circuit dividing potential drop is 2.5V, then disturbed by π type filtering circuit filtering 50Hz power frequency, in order to prevent that input end short circuit from causing circuit to damage, add current foldback circuit, again through low-pass filter circuit filtering high frequency interference, finally be input to each input pin of ADS1256 chip, carry out the AD conversion of voltage, because this module also will be carried out communication and write the reverse solver of PT resistance with control system host CPU, communication program and solver are all integrated in dsp chip, in order to protect dsp chip, so added high speed photo coupling buffer circuit between ADS1256 chip and dsp chip.
Thermometry:
PT resistance is connected into bleeder circuit, in the time that its residing environment temperature changes, the resistance of PT resistance also can be similar to linear variation, because every road bleeder circuit adopts unified divider resistance and magnitude of voltage, therefore in the time that PT resistance changes, its voltage also can change, by in the magnitude of voltage input ADS1256 chip changing, by analyzing the voltage digital amount of this chip output, through quadratic fit, oppositely solve the resistance value that scheduling algorithm can inverse goes out PT resistance, again through searching calibration table, the series of computation such as piece-wise linearization just can calculate now corresponding temperature value.
Hardware system of the present invention forms: Fig. 1 is hardware system structure figure of the present invention, is made up of following components: reference voltage source, π type filtering circuit, current foldback circuit, bleeder circuit, A/D convertor circuit, AD self-calibration circuit, high speed photo coupling buffer circuit.
The reference voltage source circuit of the present invention's design as shown in Figure 2.The input signal of this circuit is 5V voltage, is output as 2.5V reference voltage source.The power supply chip the using REF192 chip that is AD company, this voltage source precision is very high, and maximum error is ± 2mv, accounts for 0.04% of range, and High Output Current is 30mA.Provide 16 road PT resistance inputs because this module is used 2 ADS1256 chips, therefore every chip block provides 8 tunnel inputs.The maximum current that can calculate the PT resistance input of every road according to the bleeder circuit shown in Fig. 3 is 0.5mV, and it is 8mV that total maximum current is inputted on 16 tunnels.Therefore this reference voltage source has enough load capacities and ensures that Wei16 road PT resistance provides accurate, stable voltage source.The PT resistance temperature measurement mode of this constant pressure source utilizes a reference voltage source Wei16 road PT resistance that unified reference power supply is provided, and has solved in existing PT resistance Constant Current-Source Design method that constant current source load capacity is weak, precision is low, high in cost of production shortcoming.
π type filtering circuit, current foldback circuit and the bleeder circuit of the present invention's design are as shown in 1 of Fig. 3,2,3 parts.Wherein bleeder circuit is cascaded the PT resistance of 5K Ω resistance and input, and imposes fixing reference voltage 2.5V, and in the time that the resistance of PT resistance changes with temperature, the variation of approximately linear also can occur the voltage at its two ends.By measuring its both end voltage, just can go out the resistance of PT by inverse, and then obtain the residing environment temperature of PT resistance; The input of π type filtering circuit, output are all the voltage at PT resistance two ends, are mainly used in the power frequency interference noise of filtering 50Hz; Current foldback circuit is made up of 0 Ω resistance, is connected on the voltage input end at PT resistance two ends, and this resistance has the fixing upper current limit of passing through, and in the time that front-end circuit is short-circuited, this resistance disconnects immediately, has played the effect of protection subsequent conditioning circuit.
The low-pass filter circuit of the present invention's design as shown in Figure 4.Low-pass filter circuit is single order low-pass filter circuit, and its input, output are all voltage signal, and this circuit is mainly used to filtering PT resistance input end by the high frequency noise vibrating, electromagnetic interference (EMI) causes.
The A/D convertor circuit of the present invention's design as shown in Figure 5.Adopt the high accurate A/D conversion chip ADS1256 of AD company to carry out analog to digital conversion to the voltage at PT resistance two ends.ADS1256 chip is 24 high-precision adcs of 8 passage, there is low-power consumption (38mw under normal mode, 0.4mw under standby mode), low nonlinearity degree (± 0.001%), 24 without loss of data, 23bit noiseless precision, up to features such as 30ksps sampling rates, built-in programmable gain amplifier (PGA) also simultaneously, when PGA=1, effective resolution up to 25.3 can be provided, when PGA=64, effective resolution up to 22.5 can be provided, this PGA can make temperature measurement module adapt to easily the PT resistance (PT100 of different Standard resistance ranges, PT200, PT1000), in the time of the different PT resistance of access, only need to be by the configuration parameter of PGA register in the DIN port modifications chip of ADS1256 chip in Fig. 5, just can ensure under the prerequisite of conversion accuracy, adapt to easily the detection of different PT resistance.
The AD self-calibration circuit of the present invention's design is by the electric circuit constitute shown in Fig. 5 and Fig. 6.Self-alignment flow process is as follows: in the time that AIN0 passage is calibrated, by the D1-D3 port output gating signal of ADS1256 chip, this signal is by the A0-A2 port of the MC74HC138AD scrambler of motorola inc, gating Y0 passage, the signal of Y0 passage is input to the Y0 input end of the ADG201 of AD company switch chip as shown in Figure 6, in the time that Y0 channel signal is effective, AIN0 signal source is switched to D1 end by ADG201 chip, what D1 end connected is 2.5V reference voltage source, the simulating signal of the now AIN0 passage of ADS1256 input is 2.5V reference voltage source, the output signal that digital quantity of its output is used as benchmark when demarcating this passage of this calibration and normally moving.It is exactly more than the self-calibration process of AIN0 passage.This self-calibration circuit is mainly used in the AIN0-AIN7 passage of ADS1256 chip in the time of initialization, utilize reference voltage source that AD conversion chip is calibrated and demarcated, this self-calibration circuit is improving in accuracy of detection, also greatly simplified the process of calibration, demarcation.The process that can complete simply, easily calibration and demarcate.
The high speed photo coupling buffer circuit of the present invention's design as shown in Figure 7.This circuit adopts the HCPL-092J high speed photo coupling isolating chip of Hewlett-Packard Corporation.Its input, output are digital signal.High speed photo coupling buffer circuit; two ends connect respectively A/D convertor circuit and dsp chip; for dsp chip is protected; for transmitting the control data of dsp chip access A/D convertor circuit; and A/D convertor circuit returns to the data of dsp chip, make a transmission of digital amount signal between A/D convertor circuit and dsp chip and do not transmit analog voltage.
Because the temperature measurement module of the present invention's design need to keep high speed communication with wind power generator control system; so communication program has been write to dsp chip; simultaneously quadratic fit, rapid solving root, search resistance calibration table, piece-wise linearization etc. oppositely the program of derivation algorithm and function also in DSP, realize; therefore the normal operation of DSP is extremely important, must protect.Therefore the present invention has designed high speed photo coupling buffer circuit as shown in Figure 7 and is used for dsp chip and interlock circuit to protect, and avoids the damage causing because of front-end circuit short circuit.Dsp chip adopts the TMS320F2812 chip of TI company.
On the basis of above-mentioned hardware circuit, the schematic diagram of detected temperatures of the present invention as shown in Figure 8.The PT resistance of access is after front end bleeder circuit, π type filtering circuit, current foldback circuit and low-pass filter circuit; the corresponding passage of voltage input ADS1256 at PT resistance two ends; change into the digital quantity value of voltage, then oppositely solve the temperature value of PT resistance environment of living in by the temperature detection program of writing in DSP.
As shown in Figure 9, the whole flow process of the temperature detection program of the present invention's design is:
1. utilize DSP program, by SCLK and the DIN pin of ADS1256, chip is carried out to initialization, the parameter of the registers such as configuration status register, analog multichannel switch register, AD control register, data speed;
2. utilize the self-calibration circuit shown in Fig. 5, Fig. 6, and utilize DSP program to open self calibration by SCLK, the DIN pin of ADS1256, need to carry out self-alignment analog input channel by D1-D3 pin gating, and complete one by one the self-calibration process of all passages;
3. utilize DSP program, by SCLK, DIN pin configuration PGA register (the Programmable Gain Amplifier) parameter of ADS1256, make the current PT resistance scope of module adaptive;
4. start to carry out mould/number conversion, make port number N=1, judge that passage N is current whether to have completed mould/number conversion, if not yet completed, wait for that passage N completes analog-to-digital flag information, if completed conversion, the data register of fetch channel N;
5. voltage digital amount passage N being read converts the PT resistance resistance value that passage N connects to.In order accurately the voltage data of passage N oppositely to be solved, the present invention has designed quadratic fit method, before module is used, input fixing resistance value to each passage, measure the voltage digital value that each passage is corresponding, according to the measured data of resistance value and magnitude of voltage, in Matlab software inediting program, simulate the second order relation curve of resistance and voltage, as shown in figure 10.This curved line relation formula is Y=-0.000001579695X
2+ 8.12817861206X+1222.300144503886.In formula, X is resistance value, and Y is magnitude of voltage.The magnitude of voltage Y reading according to passage N, utilizes above-mentioned formula, just can backwards calculation go out resistance value X;
6. because voltage and resistance are second order funtcional relationship, so reverse resistance value X need to utilize formula:
a=-0.000001579695 in formula, b=8.12817861206, c=1222.300144503886.In above-mentioned formula, relate to extraction of square root computing, but while utilizing DSP to extract square root computing, not only need to carry out floating point arithmetic, and need to call the built-in extraction of square root function of DSP, the number of times of this computing is simultaneously very many (computings of tens extraction of square roots of every ms) also, have therefore greatly reduced efficiency and the arithmetic speed of DSP.
In order to address the above problem, the present invention has designed a kind of rapid solving root algorithm as shown in figure 11 of novelty.The Inspiration Sources of this algorithm is in the principle of hand computation extraction of square root.We look at that 10 system data are hand computation evolutions how first.First suppose that root x is made up of following formula:
x＝10p+q (1)
Formula (1) left and right square obtains afterwards:
x
2＝100p
2+20pq+q
2 (2)
Suppose now that we know x
2and p, wish to obtain q, obtain q and also just obtained x
2square root x.Formula (2) is rewritten as to following form:
q＝(x
2-100p
2)/(20p+q) (3)
There is q this formula left and right, therefore cannot directly calculate q, therefore needs the value of guessing.To calculate 1234567890 square root as example: first by every this number two as one group separately, calculating most significant digit is 3.The namely p in formula (3), remainder is 334, namely (the x in formula (3)
2-100p
2) approximate value, find several q of a 0-9 to make it the most approachingly meet formula (3) below.First p is multiplied by 20 and writes on 334 left sides: we see that q is that the value of 5 o'clock q × (60+q) approaches 334 most, and are no more than 334.Next be exactly to have repeated step above, just repeated no more here.
This manual algorithm is 10 systems, can change above-mentioned algorithm into scale-of-two easily, and formula (3) is rewritten as:
q＝(x
2-4p
2)/(4p+q) (4)
Taking the square root that calculates 100 (binary ones 100100) as example, each step is no longer that p is multiplied by 20, but p is multiplied by 4, namely p is moved to right to two, and because the value of q can only be 0 or 1, so only need to judge remainder (x
2-4p
2) and magnitude relationship (4p+1), be 1 if remainder is more than or equal on (4p+1) so subduplicate position, otherwise be 0.
The calculation procedure of the method is:
(1) will be become binary number by the data-switching of evolution, from low level to a high position every 2 be one group separately;
(2) first group from a high position starts successively to judge p.For example: a high position is that 01 p is 1, a high position is that 00 p is 0;
(3) calculate remainder according to p, and the remainder of this step is combined as new (x with next group array as high-order
2-4p
2);
(4) p is brought into (4p+1), judge whether remainder is greater than (4p+1), if remainder is large, the next bit of p is 1, otherwise is 0;
(5) repeat above-mentioned steps, until all groups all calculated completely, now all bit array of p are combined and are square root.
According to above-mentioned algorithm, the program flow diagram that the present invention writes as shown in figure 11.In figure, Root is the p in above-mentioned steps, Rem is the remainder after every step is calculated, Divisor represents (4p+1), by binary number from low level to a high position every 2 be one group separately, first group from a high position starts successively to judge Root, calculate Rem and Divisor according to Root, judge whether Rem is greater than Divisor, if Rem is large, the next bit of Root is 1, otherwise is 0, repeats above-mentioned steps, until all groups all calculated completely, now all bit array of Root are combined and are square root.Can find out, the computation process of whole extraction of square root is to be all made up of left and right sidesing shifting, plus-minus method, does not use other algorithm.Left and right sidesing shifting and plus-minus method all only need an assembly instruction to complete, and therefore the operand of whole subroutine is very little, has greatly improved arithmetic speed and the efficiency of DSP.
7. just can calculate through above-mentioned steps 5,6 the accurate resistance value that magnitude of voltage is corresponding.Utilize the resistance value of reverse, according to the PT100 resistance calibration table shown in table 1, the present invention has designed look-up table, first set up two arrays according to calibration table, temperature_form[301] and resistance_form[301], the former represents the temperature value of-100 DEG C to 200 DEG C, and each array variable represents an integer temperature value, and the latter represents resistance value corresponding to each temperature in calibration table.After reverse goes out resistance value, by this resistance value and resistance_form[301] variable in array compares successively, after determining lower approximate range, also just determined corresponding integer temperature value.Recycling piece-wise linearization program, is equally divided into 10 parts by each integer temperature value.Just can determine that according to actual measurement resistance value position between adjacent two variablees in resistance array precision is the temperature value of 0.1 DEG C.
Table 1PT100 resistance calibration table
Just the resistance of PT resistance can be detected according to above-mentioned steps 1-7, be finally converted into high-precision temperature value.
Due to temperature-detecting device be wind power generator control system from one of station arrangement, every 5ms, the high-precision temperature value calculating is uploaded to the main website of wind power generator control system by Modbus bus.
Claims (10)
1. the high-precision temperature pick-up unit that is applied to blower fan control system, is characterized in that comprising:
Reference voltage source, exports bleeder circuit to by being converted into reference voltage from the voltage signal of external power source;
Bleeder circuit, for resistance and PT resistance are cascaded, and imposes fixing reference voltage, outputs voltage signal to π type filtering circuit;
π type filtering circuit, in parallel with PT resistance, for filtering interfering noise; Input end and output terminal are all voltage signals;
Current foldback circuit, for the protection of A/D convertor circuit, receives the voltage signal from π type filtering circuit, outputs voltage signal to low-pass filter circuit;
Low-pass filter circuit, for exporting filtered voltage signal to A/D convertor circuit;
A/D convertor circuit, for carrying out the voltage signal of input end analog to digital conversion and exporting digital voltage signal to AD self-calibration circuit and optical coupling isolation circuit;
AD self-calibration circuit, for A/D convertor circuit is carried out to self calibration, connects with A/D convertor circuit;
High speed photo coupling buffer circuit, for dsp chip is protected, input end receives from the digital voltage signal of A/D convertor circuit and the digital controlled signal of dsp chip, and output digital voltage signal is transferred to A/D convertor circuit to dsp chip and by digital controlled signal;
Dsp chip, for the analyzing and processing to voltage signal, and with blower fan control system master station communication.
2. the high-precision temperature pick-up unit that is applied to blower fan control system according to claim 1, it is characterized in that: described A/D convertor circuit is made up of AD conversion chip and scrambler with built-in PGA register, AD conversion chip output gating signal is to scrambler; The reference voltage of reference voltage source output exports AD conversion chip to through the switch chip of AD self-calibration circuit.
3. the high-precision temperature pick-up unit that is applied to blower fan control system according to claim 1, is characterized in that: described AD self-calibration circuit is made up of 2 switch chips, and reference voltage source output reference voltage is to switch chip.
4. the blower fan control system detection method of temperature-detecting device described in employing claim 1, is characterized in that comprising the following steps:
Step 1) A/D convertor circuit initialization;
Step 2) passage of analog input to A/D convertor circuit carries out self calibration;
Step 3) configure PGA parameter in A/D convertor circuit, and carry out the analog to digital conversion of voltage data;
Step 4) utilize quadratic fit method to convert the voltage digital amount after analog to digital conversion to resistance value;
Step 5) utilize look-up table and piecewise-linear techniques to draw the accurate temperature value that resistance value is corresponding;
Step 6) by dsp chip, accurate temperature value is uploaded to blower fan control system main website.
5. blower fan control system detection method according to claim 4, is characterized in that:
Described self calibration comprises the following steps:
Step 1) AD conversion chip is by the respective channel of scrambler gating switch chip;
Step 2) in the time that selected passage is effective, switch chip accesses reference voltage source the corresponding input channel of AD conversion chip;
Step 3) taking the analog voltage reference that is connected with switch chip calibration port as benchmark, demarcate the digital signal of AD conversion chip output.
6. blower fan control system detection method according to claim 4, is characterized in that:
Described configuration PGA parameter is specially by the parameter of PGA register in the AD conversion chip port modifications chip to A/D convertor circuit.
7. blower fan control system detection method according to claim 4, is characterized in that:
Described quadratic fit method comprises the following steps:
Step 1) simulate the second order relation curve of resistance and voltage according to the measured data of resistance value and magnitude of voltage;
Step 2) utilize rapid solving square root method, according to the relational expression of second order relation curve
Y=aX
2+ bX+c calculates resistance value
Wherein, Y is magnitude of voltage, and a, b and c are coefficient.
8. blower fan control system detection method according to claim 7, is characterized in that:
Described rapid solving square root method comprises the following steps:
(1) will be become binary number by the data-switching of evolution, from low level to a high position every 2 be one group separately;
(2) start successively to judge the maximum square root p of high-order first group of number from first group an of high position;
If a high position is 01, p is 1; If a high position is 00, p is 0;
(3) calculate the remainder of first group by high-order first group of number divided by maximum square root p, and this remainder is combined as new remainder with next group array as high-order;
(4) p is brought into (4p+1), judge whether new remainder is greater than (4p+1);
If remainder is greater than (4p+1), the next bit of p is 1; Otherwise be 0;
(5) repeat (2) (3) (4) steps, until all groups all calculated completely, now all bit array of p are combined and are square root.
9. blower fan control system detection method according to claim 4, is characterized in that:
Described look-up table is specially according to the corresponding integer temperature value of resistance calibration table inquiry resistance value.
10. blower fan control system detection method according to claim 4, is characterized in that:
Described piecewise-linear techniques is specially and in resistance calibration table, finds out the most close two adjacent resistance values according to resistance value, using integer temperature value corresponding these two resistance values as starting point and terminal, between starting point and terminal, be equally divided into 10 parts, calculate precision and be the temperature value of 0.1 DEG C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110451040.4A CN103185645B (en) | 2011-12-29 | 2011-12-29 | High-precision temperature detecting device and detecting method applied to draught fan control system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110451040.4A CN103185645B (en) | 2011-12-29 | 2011-12-29 | High-precision temperature detecting device and detecting method applied to draught fan control system |
Publications (2)
| Publication Number | Publication Date |
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| CN103185645A CN103185645A (en) | 2013-07-03 |
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| CN103592508B (en) * | 2013-12-04 | 2016-02-24 | 珠海全志科技股份有限公司 | A kind of current sensing means for coulomb metering |
| CN107014444B (en) * | 2017-05-27 | 2023-08-29 | 山东罗泰风机有限公司 | Fan dynamic performance parameter measurement system |
| CN109405994B (en) * | 2018-12-21 | 2024-04-02 | 歌尔科技有限公司 | Accurate temperature measurement method for sharing one temperature sensor by double systems and split product |
| CN110031122A (en) * | 2019-04-15 | 2019-07-19 | 瑞纳智能设备股份有限公司 | A kind of intelligent self-adaptive temperature measurement circuit |
| CN111256862B (en) * | 2020-03-31 | 2021-12-28 | 西安微电子技术研究所 | High-precision self-calibration intelligent temperature acquisition and control circuit |
| CN111855003B (en) * | 2020-07-31 | 2022-09-20 | 青岛海信电子产业控股股份有限公司 | Temperature determination method and device |
| CN111948520A (en) * | 2020-08-25 | 2020-11-17 | 上海鑫匀源科技有限公司 | Multi-path real-time monitoring power supply system for aging test and test method |
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| US4102199A (en) * | 1976-08-26 | 1978-07-25 | Megasystems, Inc. | RTD measurement system |
| CN201672987U (en) * | 2010-05-04 | 2010-12-15 | 李海亮 | Temperature measuring apparatus |
| CN101957243A (en) * | 2009-07-14 | 2011-01-26 | 中国科学院空间科学与应用研究中心 | High-precision temperature measuring device and method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS59501960A (en) * | 1982-09-24 | 1984-11-22 | ネイル ブラウン インストルメント システムス インコ−ポレ−テツド | automatic temperature measurement circuit |
| JP2000241258A (en) * | 1999-02-25 | 2000-09-08 | T & D:Kk | Instrument and method for temperature measurement |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4102199A (en) * | 1976-08-26 | 1978-07-25 | Megasystems, Inc. | RTD measurement system |
| CN101957243A (en) * | 2009-07-14 | 2011-01-26 | 中国科学院空间科学与应用研究中心 | High-precision temperature measuring device and method |
| CN201672987U (en) * | 2010-05-04 | 2010-12-15 | 李海亮 | Temperature measuring apparatus |
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| JP昭59-501960A 1984.11.22 |
| JP特开2000-241258A 2000.09.08 |
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