CN111817125A - Laser power self-recovery control system - Google Patents
Laser power self-recovery control system Download PDFInfo
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- CN111817125A CN111817125A CN202010712819.6A CN202010712819A CN111817125A CN 111817125 A CN111817125 A CN 111817125A CN 202010712819 A CN202010712819 A CN 202010712819A CN 111817125 A CN111817125 A CN 111817125A
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- 238000001514 detection method Methods 0.000 claims abstract description 13
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- VVUFLQVAKXEWGR-IJXDZZBXSA-N 2-[2-[2-[[(3s,8s,9s,10r,13r,14s,17r)-10,13-dimethyl-17-[(2r)-6-methylheptan-2-yl]-2,3,4,7,8,9,11,12,14,15,16,17-dodecahydro-1h-cyclopenta[a]phenanthren-3-yl]oxy]ethoxy]ethoxy]ethanol Chemical compound C1C=C2C[C@@H](OCCOCCOCCO)CC[C@]2(C)[C@@H]2[C@@H]1[C@@H]1CC[C@H]([C@H](C)CCCC(C)C)[C@@]1(C)CC2 VVUFLQVAKXEWGR-IJXDZZBXSA-N 0.000 description 1
- 230000005679 Peltier effect Effects 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/106—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity
- H01S3/108—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating by controlling devices placed within the cavity using non-linear optical devices, e.g. exhibiting Brillouin or Raman scattering
- H01S3/109—Frequency multiplication, e.g. harmonic generation
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/0014—Monitoring arrangements not otherwise provided for
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/02—Constructional details
- H01S3/025—Constructional details of solid state lasers, e.g. housings or mountings
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/02—Constructional details
- H01S3/04—Arrangements for thermal management
- H01S3/042—Arrangements for thermal management for solid state lasers
Abstract
The invention discloses a laser power self-recovery control system. The laser power detection module is arranged in the laser body and used for detecting the laser power emitted when the laser body is started and outputting the laser power to the control module; and the control module is used for comparing the received laser power with a set value, and controlling an execution component for installing the frequency doubling crystal in the laser body to move if the laser power is less than or equal to the set value, so that the position of the frequency doubling crystal is adjusted, and the laser is enabled to avoid a damaged point on the frequency doubling crystal. The laser power detection module is arranged in the laser, whether the laser power is attenuated or not is detected when the laser is started every time, and if the laser power attenuation is detected to exceed a fixed value, the position of the frequency doubling crystal is translated through the rotation of the driving motor, so that the laser avoids the damaged surface of the frequency doubling crystal.
Description
Technical Field
The invention belongs to the technical field of laser control, in particular to a laser power self-recovery control system, relates to a controller used in an industrial solid laser, and is mainly suitable for laser coding, cutting, scribing machines and the like.
Background
At present, the solid laser has the characteristics of small volume, convenient use and high output power, and is mainly used for packaging food and medicines, marking production date and identification codes on the surfaces of automobile parts and the like. Generally, nonferrous and non-nonferrous metals have good absorption of laser light of far infrared wavelength; the noble metal has good absorption of laser light with near infrared wavelength, and has small thermal influence on the surface of the material. The output wavelength of the mainstream laser used for marking on food and medicine packages is 355nm, and the mainstream laser is generated by first frequency multiplication and second frequency multiplication of a 1064nm light source generated by amplification in a laser cavity. Because the laser oscillates and is modulated in the cavity, and the laser with high energy density is incident to the surface of the frequency doubling crystal, the heat of the incident surface per unit area is greatly improved, so that the frequency doubling crystal is easy to damage in the frequency doubling process, and a crystal dead pixel is formed, thereby reducing the frequency doubling efficiency and the laser output power, and shortening the whole service life of the laser. The frequency doubling crystals provided in the current market cannot overcome the high thermal damage, so how to improve the frequency doubling crystals and optimize the laser design become the main means for improving the laser.
Disclosure of Invention
The present invention is directed to solve the above-mentioned drawbacks of the prior art, and provides a laser power self-recovery control system to improve the service life of a laser.
The technical scheme adopted by the invention is as follows: a laser power self-recovery control system comprises a laser body, wherein the laser body is internally provided with a laser power self-recovery control system
The laser power detection module is used for detecting the power of the emitted laser when the laser body is started and outputting the power to the control module;
and the control module is used for comparing the received laser power with a set value, and controlling an execution component for installing the frequency doubling crystal in the laser body to move if the laser power is less than or equal to the set value, so that the position of the frequency doubling crystal is adjusted, and the laser is enabled to avoid a damaged point on the frequency doubling crystal.
Further, the laser power detection module comprises a Seebeck sensor and a temperature adjustment module,
after the surface A of the ceramic plate of the Seebeck sensor is irradiated by laser, electromotive force is generated at two ends of a semiconductor in the Seebeck sensor;
the temperature adjusting module and the control module are matched to adopt temperature closed-loop control to make the temperature of the surface B of the ceramic wafer of the Seebeck sensor constant;
and the control module acquires the electromotive force after determining that the temperature of the B surface is constant, and determines the laser power according to the calibrated laser power-electromotive force comparison table.
Further, the temperature adjusting module comprises a temperature sensor and a TEC refrigerating plate,
the temperature sensor is used for detecting the temperature of the surface B of the ceramic plate of the Seebeck sensor and outputting the temperature to the control module;
the control module is used for determining a driving current according to the received temperature and a set value and outputting the driving current to the TEC refrigeration piece;
and the TEC refrigerating plate is used for heating or refrigerating the surface B of the Seebeck sensor according to the driving current.
Further, the temperature sensor is a Pt100 platinum resistor, the control module comprises a linear processing circuit, the linear processing circuit carries out linear processing on the resistance value of the Pt100 platinum resistor, and the temperature is determined through a calibrated temperature-resistance value comparison table according to the processed signal.
Further, the linear processing circuit comprises a first connector, a resistor Rlin1, a resistor Rlin2, a resistor Rcm, a resistor Rz, a switching tube Q1 and an amplifier U1, wherein an input end of the first connector is connected to two ends of a Pt100 platinum resistor, a first output end of the first connector is connected to one end of a resistor Rlin1 and an IR _2 pin of an amplifier U1, a second output end of the first connector is connected to one end of the resistor Rz and a base electrode of the switching tube, a third output end of the first connector is connected to an emitter of the switching tube and one end of the resistor Rcm, the other end of the resistor Rlin1 is connected to one end of a resistor Rlin2 and a VLIN pin of the amplifier U1, the other end of the resistor Rlin2 is connected to an IR _1 pin of the amplifier U1 and the other end of the resistor Rz, and the other end of the resistor Rcm is connected to an IRET pin of the amplifier U1.
Further, the control module comprises
The error calculation module is used for calculating a temperature error according to the received temperature and a set value and outputting the temperature error to the PID module;
the PID module is used for carrying out PID operation according to the temperature error to determine the PI output quantity and outputting the PI output quantity to the PWM module;
the PWM module is used for generating a PWM signal according to the received PI output quantity and outputting the PWM signal to the driving module;
and the driving module is used for generating driving current for driving the TEC refrigerating sheet to heat or refrigerate according to the PWM signal.
Furthermore, the driving module comprises a first driving circuit, a second driving circuit and a second connector, the input ends of the first driving circuit and the second driving circuit are respectively connected with the two output ends of the PWM module, the output ends of the first driving circuit and the second driving circuit are respectively connected with the two terminals of the second connector, and the other two terminals of the second connector are respectively connected with the two ends of the TEC refrigeration piece.
Further, the first driving circuit comprises a first driving chip, a MOS transistor K1 and a MOS transistor K2, an input end of the first driving chip is connected with an output end of the PWM module, a high-end control pin and a low-end control pin of the first driving chip are respectively connected with gates of the MOS transistor K1 and the MOS transistor K2, a VS pin of the first driving chip is connected with a source electrode of the MOS transistor K1 and a drain electrode of the MOS transistor K2, the VS pin of the first driving chip is connected with a terminal of the second connector through an inductor L1, the drain electrode of the MOS transistor K1 is connected with a power supply, and a source electrode of the MOS transistor K1 is grounded.
Furthermore, the second driving circuit includes a second driving chip, a MOS transistor K3 and a MOS transistor K4, an input end of the second driving chip is connected to an output end of the PWM module, a high-side control pin and a low-side control pin of the second driving chip are respectively connected to gates of the MOS transistor K3 and the MOS transistor K4, a VS pin of the second driving chip is connected to a source of the MOS transistor K3 and a drain of the MOS transistor K4, the VS pin of the second driving chip is connected to a terminal of the second connector through an inductor L2, the drain of the MOS transistor K3 is connected to a power supply, and the source of the MOS transistor K1 is grounded.
The laser power detection module is arranged in the laser, whether the laser power is attenuated or not is detected when the laser is started every time, and if the laser power attenuation is detected to exceed a fixed value, the position of the frequency doubling crystal is translated or rotated through the rotation of the driving motor, so that the laser avoids the damaged surface of the frequency doubling crystal, the laser power returns to a normal range, the service life of the laser is prolonged through the mode, and the method is simple, low in cost and easy to implement.
Drawings
FIG. 1 is a schematic diagram of a laser power detection module according to the present invention.
FIG. 2 is a schematic diagram of an actuator for driving a frequency doubling crystal in a laser according to the present invention.
Fig. 3 is a schematic diagram of a linear processing circuit of the present invention.
FIG. 4 is a schematic diagram of a PWM waveform outputted by the PWM module according to the present invention.
Fig. 5 is a schematic diagram of input levels of the driving module according to the present invention.
Fig. 6 is a schematic current flow diagram of the driving module according to the present invention.
Fig. 7 is a schematic current flow diagram of another driving module according to the present invention.
In the figure: 1-seebeck sensor; 2-a temperature sensor; 3-TEC refrigeration piece; 4-frequency doubling crystals; 5-driving a motor; 6-laser.
Detailed Description
The following further describes embodiments of the present invention with reference to the drawings. It should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
As shown in fig. 1-7, the present invention provides a laser power self-recovery control system, which comprises a laser body, wherein the laser body is provided with a laser power self-recovery control device
The laser power detection module is used for detecting the power of the emitted laser by moving the driving component to the laser light path when the laser body is started and outputting the power to the control module; the drive member may be a motor or other actuator.
And the control module is used for comparing the received laser power with a set value, and if the laser power is less than or equal to the set value, controlling an execution component (namely, a driving motor 5) arranged in the laser body and provided with the frequency doubling crystal to act, so that the position of the frequency doubling crystal 4 is adjusted, and the laser 6 is enabled to avoid a damaged point on the frequency doubling crystal. The frequency doubling crystal is arranged on the electric moving platform through the base, and the electric moving platform is driven by the driving motor, so that the frequency doubling crystal is driven to move.
In the scheme, the laser power detection module comprises a Seebeck sensor 1 and a temperature adjustment module, wherein electromotive force is generated at two ends of a semiconductor in the Seebeck sensor 1 after the surface A of a ceramic wafer of the Seebeck sensor is irradiated by laser; the temperature adjusting module and the control module are matched to adopt temperature closed-loop control to make the temperature of the surface B of the ceramic wafer of the Seebeck sensor constant; and the control module acquires the electromotive force after determining that the temperature of the B surface is constant, and determines the laser power according to the calibrated laser power-electromotive force comparison table. The laser power detection module of the present invention is not limited to the seebeck sensor 1 and the temperature adjustment module, and may be other forms of laser power detection devices.
The invention uses a Seebeck sensor with the size of 4mm x 4mm x 1.5mm as a detection laser power element. From the seebeck effect, it can be seen from equation 1 that the voltage increases as the temperature difference between both ends of the semiconductor material is larger when the semiconductor material is fixed. When laser irradiates on the surface A of the ceramic plate of the sensor and is converted into heat, the temperature difference is generated between the heat of the surface A of the ceramic plate and the temperature of the surface B of the ceramic plate, so that the internal semiconductor generates current, the two ends of the semiconductor are respectively led out by using conducting wires, and the voltage is measured at the two ends of the conducting wires by using a voltmeter.
V ═ (Sa-Sb) (T2-T1); equation 1
V is electromotive force at two ends of the semiconductor;
sa is the material coefficient of the semiconducting A surface;
sb is the material coefficient of a semiconductor B surface;
t1, the temperature of the surface A of the ceramic plate;
t2, the temperature of the surface B of the ceramic plate;
when the semiconductor material is fixed, the difference value (Sa-Sb) is also a fixed value, and the TEC refrigeration plate is used to maintain the temperature of the surface a of the ceramic wafer at a constant temperature, and it can be known from equation 1 that when T1 is greater than T2, the electromotive force is a negative value, so when the temperature set for the surface a of the ceramic wafer is the temperature at which the surface B of the ceramic wafer is not irradiated by laser, that is, the ambient temperature at the surface B of the ceramic wafer, the magnitude of the electromotive force only increases with the temperature increase at T1, that is, the surface a of the ceramic wafer.
Table 1 shows the magnitude of electromotive force generated by the conductor when the laser was irradiated on the surface a of the ceramic sheet.
| Laser power (W) | Electromotive force (mV) |
| 0.1 | 4 |
| 0.2 | 8 |
| 0.3 | 12 |
| … | … |
| 3.0 | 126 |
| 4.0 | 164 |
| 5.0 | 203 |
TABLE 1
The voltage signal on the Seebeck sensor is collected through a 12-bit analog-to-digital conversion function on the closed-loop regulation controller, then the quantized digital signal is converted into a corresponding laser power numerical value, see table 2, and the numerical value obtained by converting the quantized signal is very close to the actual laser power numerical value.
| Laser power (W) | Electromotive force (mV) | Converted value |
| 0.1 | 4 | 98 |
| 0.2 | 8 | 196 |
| 0.3 | 12 | 294 |
| … | … | … |
| 3.0 | 126 | 3096 |
| 4.0 | 164 | 4030 |
| 5.0 | 203 | 4988 |
TABLE 2
In the scheme, the temperature adjusting module comprises a temperature sensor 2 and a TEC refrigerating plate 3, wherein the temperature sensor 2 is used for detecting the temperature of the surface B of the ceramic plate of the Seebeck sensor 1 and outputting the temperature to the control module; the control module is used for determining a driving current according to the received temperature and a set value and outputting the driving current to the TEC refrigerating plate 3; and the TEC refrigerating plate 3 is used for heating or refrigerating the surface B of the Seebeck sensor according to the driving current.
The temperature sensor is a Pt100 platinum resistor, the control module comprises a linear processing circuit, the linear processing circuit carries out linearization processing on the resistance value of the Pt100 platinum resistor, and the temperature is determined through a calibrated temperature-resistance value comparison table according to the processed signal.
The linear processing circuit comprises a first connector P1, a resistor Rlin1, a resistor Rlin2, a resistor Rcm, a resistor Rz, a switch tube Q1 and an amplifier U1, wherein the input end of the first connector P1 is connected with two ends of a Pt100 platinum resistor, the first output end of the first connector P1 is connected with one end of the resistor Rlin1 and an IR _2 pin of an amplifier U1, the second output end of the first connector is connected with one end of the resistor Rz and a base electrode of the switch tube, the third output end of the first connector is connected with an emitter of the switch tube and one end of the resistor Rcm, the other end of the resistor Rlin1 is connected with one end of the resistor Rlin2 and a VLIN 73pin of the amplifier U25, the other end of the resistor Rlin2 is connected with an IR _1 pin of the amplifier U1 and the other end of the resistor Rz, and the other end of the resistor Rcm is connected with an IRET pin of the amplifier.
The control module comprises
The error calculation module is used for calculating a temperature error according to the received temperature and a set value and outputting the temperature error to the PID module;
the PID module is used for carrying out PID operation according to the temperature error to determine the PI output quantity and outputting the PI output quantity to the PWM module;
the PWM module is used for generating a PWM signal according to the received PI output quantity and outputting the PWM signal to the driving module;
and the driving module is used for generating driving current for driving the TEC refrigerating sheet to heat or refrigerate according to the PWM signal.
In the above scheme, the driving module includes a first driving circuit, a second driving circuit and a second connector, the input ends of the first driving circuit and the second driving circuit are respectively connected to the two output ends of the PWM module, the output ends of the first driving circuit and the second driving circuit are respectively connected to the two terminals of the second connector, and the other two terminals of the second connector are respectively connected to the two ends of the TEC refrigeration piece.
The first driving circuit comprises a first driving chip, an MOS tube K1 and an MOS tube K2, wherein the input end of the first driving chip U2 is connected with the output end of the PWM module, a high-end control pin and a low-end control pin of the first driving chip are respectively connected with the grids of the MOS tube K1 and the MOS tube K2, a VS pin of the first driving chip U2 is connected with the source electrode of the MOS tube K1 and the drain electrode of the MOS tube K2, the VS pin of the first driving chip is connected with the wiring end of the second connector through an inductor L1, the drain electrode of the MOS tube K1 is connected with a power supply, and the source electrode of the MOS tube K1 is grounded.
The second driving circuit comprises a second driving chip U3, a MOS tube K3 and a MOS tube K4, wherein the input end of the second driving chip is connected with the output end of the PWM module, a high-end control pin and a low-end control pin of the second driving chip are respectively connected with the grids of the MOS tube K3 and the MOS tube K4, a VS pin of the second driving chip is connected with the source electrode of the MOS tube K3 and the drain electrode of the MOS tube K4, the VS pin of the second driving chip is connected with the terminal of the second connector through an inductor L2, the drain electrode of the MOS tube K3 is connected with a power supply, and the source electrode of the MOS tube K1 is grounded.
The principle that the temperature of the B surface of the ceramic wafer of the Seebeck sensor is constant by adopting temperature closed-loop control through the cooperation of the temperature adjusting module and the control module is as follows:
the Pt100 platinum resistor is adopted as a temperature sensing device, and the ambient temperature is between 0 and 40 ℃ in general, so the corresponding platinum resistance value is before 100.0 to 115.54 omega. The Pt100 has a large nonlinearity in this interval, so the collected resistance value must be linearized, fig. 3 is a linear processing circuit of the Pt100, the Pt100 platinum resistor is connected from P1, the signal is linearized through a resistor Rlin1, a resistor Rlin2 and a switching tube Q1, and then amplified 1000 times through an amplifier XTR105, and finally output to an ARM single chip microcomputer in a control module in the form of current.
The DataSheet provided by TI may derive the conditioned signal output equation:
RTD(Tmin)＝0℃＝100Ω；RTD(Tmid)＝50℃＝119.4Ω；
RTD(Tmax)＝100℃＝138.51Ω
Rz＝Rmin＝100Ω
Rg＝2(Rmax–Rz)(Rmid–Rz)/(Rmax–Rz)
＝2x(38.51x 19.4)/19.11
＝78.18
Rlin＝1000Ω
Rlin1＝Rlin(Rmax-Rmid)/2(2Rmid-Rmax-Rz)
＝(1000x 38.51)/(2x(238.8-38.51))
＝47.7
Rlin2＝(Rlin+Rg)(Rmax-Rmid)/2(2Rmid-Rmax-Rz)
＝1078.18x 19.11/400.58
＝982.93
Rcm_min＝1.25v/2x 800uA＝781.3R；
the resistance with the accuracy of ± 0.1% of the calculated value is shown in table 3.
TABLE 3
Electromotive forces obtained by substituting resistance values corresponding to 0 ℃ to 100 ℃ into equation 2 are shown in table 4:
| temperature (. degree.C.) | Rrtd(Ω) | Io(mA) | Vo(mV) |
| 0 | 100.00 | 4.00 | 1000 |
| 10 | 103.90 | 5.72 | 1430 |
| 20 | 107.79 | 7.33 | 1832 |
| 30 | 111.67 | 8.9 | 2225 |
| 40 | 115.54 | 10.55 | 2637 |
| 50 | 119.40 | 12.1 | 3025 |
| 60 | 123.24 | 13.73 | 3432 |
| 70 | 127.08 | 15.31 | 3827 |
| 80 | 130.90 | 16.94 | 4235 |
| 90 | 135.71 | 18.66 | 4665 |
| 100 | 138.51 | 20.2 | 5025 |
TABLE 4
The signal obtained by the linear processing circuit is a current signal, and the analog-digital conversion input integrated by the ARM single chip microcomputer is a voltage signal, so a sampling resistor Re must be added in front of the ARM single chip microcomputer, the resistance value is set to be 250 omega, 1/4W and 0805 packaged resistors, and a voltage signal corresponding to the temperature can be obtained.
The ARM single chip microcomputer compares the collected temperature with the set temperature to generate an error result, and then PID operation is carried out, wherein the mathematical model of the PID algorithm is
The PID mathematical model is discretized, so that the ARM single chip microcomputer can conveniently execute. Ti and Ti are the integral time constant and the derivative time constant, respectively, with a timer setting these two values to 1 ms.
u(k)＝Kp[e(k)-e(k-1)]+Kie(k)+Kd[e(k)-2e(k-1)+e(k-2)]
u (k) the output value of the controller;
e, (k) the error value between the input value of the controller and the set value;
e (k-1) the error value between the last controller and the set value;
e (k-2) the error value between the last controller and the set value;
kp is a proportionality coefficient;
ke is an integral coefficient;
kd is the differential coefficient.
The main loop of the ARM single chip microcomputer continuously collects temperature values of analog-to-digital conversion through a getADC () function, the collected values are compared with a set value, a pidCalc (& PID _ Ch1) function is used for generating a current error value, and the generated error value dError is substituted into a discretization PID formula to obtain an output quantity pp- > LastOut.
The ARM single chip microcomputer is internally integrated with a PWM (pulse-width modulation) module, and PWM waveforms can be output from a specified IO (input/output) port by setting a related register set.
Two key registers of the PWM modulation block are TCNTn, OCnx. From fig. 4, one control output frequency and one control duty cycle can be known.
The output frequency of the PWM module can be calculated by the following formula:
fclk _ I/O is the input clock frequency of the singlechip;
n is a clock division coefficient, which is generally 1, 8, 64, 256 or 1024;
TOP frequency output compare register.
The output duty cycle of the PWM module can be calculated by the following formula:
Duty＝ICFn/OCRn；
and assigning the output result pp- > LastOut obtained by the calculation of the PID operation function to ICFny to change the PWM waveform output by the specified I/O port, wherein when the error is larger than the set value, the output PWM duty ratio is larger, and vice versa.
The output PWM signal is transmitted to the first driving chip and the second driving chip, the driving chip outputs a driving MOSFET, and finally the driving MOSFET is connected with the external TEC refrigerating piece through the second connector JP 3. Taking the first driver chip as an example, when the IN input is high, HO is high, LO is low, and corresponding K1 is turned on and K2 is turned off; when the IN input is low, HO is low, LO is high, and corresponding K1 is off and K2 is on.
The principle of the TEC is based on the peltier effect, i.e., the Thermoelectric effect, a phenomenon that a metal contact absorbs heat while releases heat occurs, and the material and the Thermoelectric effect are different, so that the TEC is generally used and made of a semiconductor material. Under the action of an external electric field, the electron current can bring internal energy from one side to the other side, namely, the cold and hot surfaces of the TEC can be switched due to different current directions.
The TEC refrigerating plate is driven to work through the driving module, the conductor time of the MOS tube K1 and the conductor time of the MOS tube K2 are changed to control the current passing through the TEC refrigerating plate, and the refrigerating degree of the TEC is changed. As shown in fig. 6 and 7:
if the MOS tube K1 is set to be conducted, the MOS tube K2 is cut off, the MOS tube K3 is cut off, when the MOS tube K4 is conducted, current flows through the MOS tube K4 from the MOS tube K1 to the inductor L1 through the second connector JP3, at the moment, the second connector JP3 is connected with the TEC, the surface A of the ceramic wafer of the TEC generates a cooling effect, and the surface B of the ceramic wafer of the TEC generates a heating effect; if the MOS tube K1 is set to be cut off, the MOS tube K2 is conducted, the MOS tube K3 is conducted, when the MOS tube K4 is cut off, current flows from the MOS tube K3 to the inductor L2, the second connector JP3 flows through the MOS tube K2, the surface A of the ceramic chip of the TEC generates a heating effect, and the surface B of the ceramic chip of the TEC generates a cooling effect.
Therefore, when the temperature of the Pt100 platinum resistor deviates from a set value, the duty ratio of the PWM sent to the first driver chip and the second driver chip changes, and the magnitude of the change changes due to the variation of the deviation, and at this time, the operating states of four MOSFET transistors, namely, the MOS transistor K1, the MOS transistor K2, the MOS transistor K3, and the MOS transistor K4, are also changed, and the injection current of the externally connected TEC refrigeration fin is controlled, so that the cooling or heating amount is finally generated on the TEC refrigeration fin.
By making T2 in equation 1 a constant through the closed-loop control described above, the output V value is only changed with the change of T1. Obtaining a sampling value, comparing the sampling value with a set power value, and if the error is within +/-10%, not adjusting the controller and entering a normal use mode; if the error is outside of 10%, the controller enters the regulation mode.
The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Those not described in detail in this specification are within the skill of the art.
Claims (9)
1. A laser power self-recovery control system comprises a laser body, and is characterized in that: the laser body is internally provided with
The laser power detection module is used for detecting the power of the emitted laser when the laser body is started and outputting the power to the control module;
and the control module is used for comparing the received laser power with a set value, and controlling an execution component for installing the frequency doubling crystal in the laser body to move if the laser power is less than or equal to the set value, so that the position of the frequency doubling crystal is adjusted, and the laser is enabled to avoid a damaged point on the frequency doubling crystal.
2. The laser power self-recovery control system of claim 1, wherein: the laser power detection module comprises a Seebeck sensor and a temperature adjusting module,
after the surface A of the ceramic plate of the Seebeck sensor is irradiated by laser, electromotive force is generated at two ends of a semiconductor in the Seebeck sensor;
the temperature adjusting module and the control module are matched to adopt temperature closed-loop control to make the temperature of the surface B of the ceramic wafer of the Seebeck sensor constant;
and the control module acquires the electromotive force after determining that the temperature of the B surface is constant, and determines the laser power according to the calibrated laser power-electromotive force comparison table.
3. The laser power self-recovery control system of claim 2, wherein: the temperature adjusting module comprises a temperature sensor and a TEC refrigerating plate,
the temperature sensor is used for detecting the temperature of the surface B of the ceramic plate of the Seebeck sensor and outputting the temperature to the control module;
the control module is used for determining a driving current according to the received temperature and a set value and outputting the driving current to the TEC refrigeration piece;
and the TEC refrigerating plate is used for heating or refrigerating the surface B of the Seebeck sensor according to the driving current.
4. The laser power self-recovery control system of claim 3, wherein: the temperature sensor is a Pt100 platinum resistor, the control module comprises a linear processing circuit, the linear processing circuit carries out linear processing on the resistance value of the Pt100 platinum resistor, and the temperature is determined through a calibrated temperature-resistance value comparison table according to the processed signal.
5. The laser power self-recovery control system of claim 4, wherein: the linear processing circuit comprises a first connector, a resistor Rlin1, a resistor Rlin2, a resistor Rcm, a resistor Rz, a switch tube Q1 and an amplifier U1, wherein the input end of the first connector is connected with two ends of a Pt100 platinum resistor, the first output end of the first connector is connected with one end of the resistor Rlin1 and an IR _2 pin of an amplifier U1, the second output end of the first connector is connected with one end of the resistor Rz and a base electrode of the switch tube, the third output end of the first connector is connected with an emitter of the switch tube and one end of the resistor Rcm, the other end of the resistor Rlin1 is connected with one end of a resistor Rlin2 and a VLIN pin of an amplifier U1, the other end of the resistor Rlin2 is connected with an IR _1 pin of an amplifier U1 and the other end of the resistor Rz, and the other end of the resistor Rcm is connected with an IRET pin of an amplifier U.
6. The laser power self-recovery control system of claim 3, wherein: the control module comprises
The error calculation module is used for calculating a temperature error according to the received temperature and a set value and outputting the temperature error to the PID module;
the PID module is used for carrying out PID operation according to the temperature error to determine the PI output quantity and outputting the PI output quantity to the PWM module;
the PWM module is used for generating a PWM signal according to the received PI output quantity and outputting the PWM signal to the driving module;
and the driving module is used for generating driving current for driving the TEC refrigerating sheet to heat or refrigerate according to the PWM signal.
7. The laser power self-recovery control system of claim 6, wherein: the driving module comprises a first driving circuit, a second driving circuit and a second connector, the input ends of the first driving circuit and the second driving circuit are respectively connected with the two output ends of the PWM module, the output ends of the first driving circuit and the second driving circuit are respectively connected with the two wiring ends of the second connector, and the other two wiring ends of the second connector are respectively connected with the two ends of the TEC refrigeration piece.
8. The laser power self-recovery control system of claim 7, wherein: the first driving circuit comprises a first driving chip, an MOS tube K1 and an MOS tube K2, wherein the input end of the first driving chip is connected with the output end of the PWM module, a high-end control pin and a low-end control pin of the first driving chip are respectively connected with the grids of the MOS tube K1 and the MOS tube K2, the VS pin of the first driving chip is connected with the source electrode of the MOS tube K1 and the drain electrode of the MOS tube K2, the VS pin of the first driving chip is connected with the wiring end of the second connector through an inductor L1, the drain electrode of the MOS tube K1 is connected with a power supply, and the source electrode of the MOS tube K1 is grounded.
9. The laser power self-recovery control system of claim 7, wherein: the second drive circuit comprises a second drive chip, an MOS tube K3 and an MOS tube K4, wherein the input end of the second drive chip is connected with the output end of the PWM module, a high-end control pin and a low-end control pin of the second drive chip are respectively connected with the grids of the MOS tube K3 and the MOS tube K4, the VS pin of the second drive chip is connected with the source electrode of the MOS tube K3 and the drain electrode of the MOS tube K4, the VS pin of the second drive chip is connected with the terminal of the second connector through an inductor L2, the drain electrode of the MOS tube K3 is connected with a power supply, and the source electrode of the MOS tube K1 is grounded.
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| CN202487964U (en) * | 2012-03-30 | 2012-10-10 | 福州高意通讯有限公司 | Frequency doubler/multiplier for high-power laser |
| US20140240698A1 (en) * | 2013-02-22 | 2014-08-28 | Chris Wagner | Method for correcting for dark current variation in tec cooled photodiodes |
| CN107453193A (en) * | 2017-09-21 | 2017-12-08 | 中国科学院长春光学精密机械与物理研究所 | The high efficiency temperature controlled circuit of laser based on thermoelectric cooling |
| CN108683073A (en) * | 2018-08-29 | 2018-10-19 | 深圳市杰普特光电股份有限公司 | Long-life non-maintaining ultraviolet laser |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202487964U (en) * | 2012-03-30 | 2012-10-10 | 福州高意通讯有限公司 | Frequency doubler/multiplier for high-power laser |
| US20140240698A1 (en) * | 2013-02-22 | 2014-08-28 | Chris Wagner | Method for correcting for dark current variation in tec cooled photodiodes |
| CN107453193A (en) * | 2017-09-21 | 2017-12-08 | 中国科学院长春光学精密机械与物理研究所 | The high efficiency temperature controlled circuit of laser based on thermoelectric cooling |
| CN108683073A (en) * | 2018-08-29 | 2018-10-19 | 深圳市杰普特光电股份有限公司 | Long-life non-maintaining ultraviolet laser |
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Application publication date: 20201023 |