Summary of the invention
In order to solve the above problems, the object of the present invention is to provide a kind of power factor high, to the little LED illumination driver of electrical network high order harmonic component influence, the overall efficiency when it can increase substantially the light source use.
Another object of the present invention is the useful life of effectively improving led light source.
The present invention solves the technical scheme that its problem adopts: a kind of commercial LED illumination driver, and it comprises:
Rectification module, its input inserts utility grid, and input current is carried out rectification and filtering;
Active quasi-resonance power factor correction module, its input links to each other with the rectification module output, can suppress the harmonic wave that led driver produces, and power factor is compensated;
The direct voltage output module, its input links to each other with the output of active quasi-resonance power factor correction module, for LED lamp string provides operating voltage;
As the improvement of technique scheme, said rectification module input is connected with the em filtering module, and its input inserts utility grid, can the harmonic wave that led driver produces be suppressed and absorb, thereby do not influence power grid quality.
Further improvement as technique scheme; Said active quasi-resonance power factor correction module comprises energy storage inductor; Said energy storage inductor input connects the output of rectification module; Said energy storage inductor output connects the input of direct voltage output module; Said energy storage inductor output also is connected with power switch, and said power switch also is connected with the logic control driver element, and said logic control driver element is connected to the output of rectification module through the input voltage sampling unit; Be provided with the current feedback unit between said power switch and the input voltage sampling unit output, link to each other through high-frequency current zero passage detection unit between said energy storage inductor and the logic control driver element.
As the further improvement of technique scheme, link to each other through the voltage limit protected location between said direct voltage output module and the input voltage sampling unit, said voltage limit protected location also links to each other with the logic control driver element.
As the further improvement of technique scheme, said rectification unit is connected with logic control circuit low tension power module, and it is used for to each logic control circuit power supply.
Further improvement as technique scheme; Said driver also is provided with the MCU module; Said MCU module is connected with temperature detecting unit and power drive unit, and said temperature detecting unit can detect the temperature of load LED lamp string, after said MCU module is carried out calculation process to detected load LED lamp string temperature; Output signal to power drive unit, load LED lamp string is carried out power adjustments by power drive unit.
Further improvement as technique scheme; Said power drive unit comprises the energy storage inductor that connects load LED lamp string; Said energy storage inductor is connected with power switch; Said power switch is connected with current sampling unit, and said current sampling unit connects the MCU module through voltage-dropping type constant current tunable optical driving control unit, and said voltage-dropping type constant current tunable optical driving control unit also links to each other with power switch.
Further improvement as technique scheme; Can also connect luminance detection unit or brightness adjusting unit on the said MCU module; It can detect the luminous intensity and the surrounding environment brightness of load LED lamp string; Said MCU module is carried out calculation process to detected ambient brightness signal, outputs signal to power drive unit, by power drive unit load LED lamp string is carried out power adjustments.
The invention has the beneficial effects as follows: commercial LED illumination driver of the present invention is provided with the source power factor correcting circuit after rectification unit, need not isolating transformer, and direct output of DC current is pressed; Reduced the link of power transfer; Capacity usage ratio is high, because circuit of power factor correction is in the quasi-resonance operating state, has reduced the energy loss of high frequency conversion; Improve the energy service efficiency; Reduce the harmonic component of current/voltage simultaneously, thereby improved the power factor of whole driving, and effectively suppressed harmonic wave; Its operating current is in continuous state simultaneously, effectively reduces harmonic component, and makes electric current identical with the phase place of input voltage, and the power factor of entire circuit is brought up to more than 0.99, has reduced the pollution of harmonic wave to electrical network.
In addition; In driver, be provided with temperature detecting unit; With the working temperature of led chip optimal control parameter as driver, fundamentally guarantee led chip in use can be because of temperature too high or thermal breakdown and cause light decay, shorten the useful life of led chip; Fully excavate the long-life advantage of led light source, the through engineering approaches of led chip was brought up to more than 50000 hours from present 5000 hours useful life.
The present invention realizes the optimizing control models of illumination, brightness, operating current, PWM pulse-width modulation in the design of LED illumination driver; Carry out various control signals such as temperature control, brightness of illumination control and be optimized processing; LED lamp string controlled function intelligent, that stylize is provided; Hommization, intelligent controlled function such as realization LED lamp string luminous efficiency height, long service life, control device is flexible, scene effect is variable; And the synthesis energy saving rate of LED illumination driver improved more than 10%, will effectively practice thrift all kinds of social resources, thereby obtain good social benefit.
Embodiment
With reference to Fig. 1, Fig. 2, a kind of commercial LED illumination driver of the present invention, it comprises
The em filtering module is EMC/EMI in the present invention, and its input connects the electrical network input, and it can suppress the harmonic wave that led driver produces and absorb, thereby does not influence power grid quality; It is by harmonic wave inhibition inductance L 1 and be connected across its two ends filter capacitor C1, C2 forms.Because adopt quasi-resonance APFC scheme, driver is very little to the harmonic effects of electrical network.Therefore, adopt simple capacitor filtering and inductance harmonic wave to suppress to reach good EMC/EMI power grid quality control index.
Rectification module, its input links to each other with the output of em filtering module, and input current is carried out rectification and filtering, and it is made up of the rectifier diode D1 that forms bridge rectifier, D2, D3, D4 and filter capacitor C3.
Active quasi-resonance power factor correction module, its input links to each other with the rectification module output, can suppress the harmonic wave that led driver produces, and power factor is compensated.
In the present embodiment; Said active quasi-resonance power factor correction module comprises energy storage inductor; Said energy storage inductor input connects the output of rectification module, and its output connects the input of direct voltage output module, and said energy storage inductor output also is connected with power switch; Said power switch also is connected with the logic control driver element; Said logic control element is connected to the output of rectification module through the input voltage sampling unit, is provided with the current feedback unit between said power switch and the input voltage sampling unit output, links to each other through high-frequency current zero passage detection unit between said energy storage inductor and the logic control driver element.Link to each other through the voltage limit protected location between said direct voltage output module and the input voltage sampling unit, said voltage limit protected location also links to each other with the logic control driver element.Power factor correction module adopts the L6562 chip to design, wherein R9, the sampling of R10 input voltage, and C9 is an input voltage sampling filter electric capacity; R11, R12, C10, T1 are that current over-zero detects; T1 double as energy storage inductor wherein, R14, C11, C12 are compensating circuit, R15, R16 are current feedback; R17, R18 output voltage feedback, Q3 is the power factor correction switch pipe.This power factor correction module adopts the inhibition of band harmonic wave, active, quasi-resonance circuit of power factor correction, when being intended to improve power factor, makes harmonic component as far as possible little.Conducting through exporting modulated high-frequency PWM pulse-width signal power controlling switch at the logic control driver element and ending.When the power switch conducting, the energy storage inductor energy storage of magnetizing; When power switch ends; Because the afterflow effect of inductance produces induced potential and is superimposed upon on the input voltage; Thereby have sufficiently high voltage to give the electric capacity charging of direct voltage output unit, even input voltage magnitude of voltage this moment is very low, input current also is continuous (non-vanishing).Therefore, input current can be modulated in the sinusoidal period of whole input voltage, can obtain very high power factor.
In addition; High-frequency current through to energy storage inductor carries out zero passage detection; Make the logic control driver element begin to export high level constantly and trigger the power switch conducting, make the modulating frequency of entire circuit and the frequency of high-frequency current be in the quasi-resonance operating state in the high-frequency current zero passage.The duty ratio of PWM pulse-width modulation is then followed the tracks of adjusting by the logic control driver element according to the result of input voltage sampled value and the comparison of current feedback average, and when electric current reduced, the power switch ON time prolonged; When current value increases; The power switch ON time shortens; Thereby the instantaneous value (waveform) at the equal may command input current tracking of the sinusoidal period of whole input voltage input voltage makes input current identical with the phase place of input voltage, and power factor is brought up to more than 0.99.
The direct voltage output module, its input links to each other with the output of active quasi-resonance power factor correction module, for LED lamp string provides operating voltage.It is made up of anti-phase blocking diode D9 and filter capacitor C13, C14.
As optimal way, said rectification unit is connected with logic control circuit low tension power module, and it is used for to each logic control circuit power supply.Adopt D5, D6, Q1, Q2, C18, R4, R5, R6, R7 to form an electronic switch at the working power terminal place of L6562 chip in addition; When dim signal will control the power supply disconnection near zero the time; Circuit of power factor correction, led chip drive circuit are not all powered up; The quiescent dissipation of whole commercial LED driver is descended, get into energy-saving mode work.
To Fig. 6,, establish led chip working temperature closed-loop control function with reference to figure 3 for excavating led light source long-life advantage in use.Working temperature through real-time collection LED lamp serial core sheet is controlled the operating current or the PWM pulse-width modulation characteristic of LED lamp string; Automatically control the PN junction temperature of led chip when work; Prevent that led chip from the PN junction of the out of control even thermal breakdown led chip of heating occurring in when work; Influence the life-span of led chip, said driver also is provided with the MCU module, and said MCU module is connected with temperature detecting unit and power drive unit; Said temperature detecting unit can detect the temperature of load LED lamp string; Adopt the temperature of temperature sensor in the negative pole bond pad locations sampling A of led chip, said temperature sensor is preferably thermistor or thermocouple, after the sampling end of said MCU module carries out calculation process with the detected LED lamp of temperature sensor string temperature; Output signal to power drive unit, load LED lamp string is carried out power adjustments by power drive unit.
As preferably, said temperature closed loop control can be adopted following method.The led chip temperature detecting unit adopts the thermistor of small size or near the temperature of the thermocouple sampling A negative pole bond pad locations of middle certain led chip of LED dot matrix.
According to the packaging technology of present led chip, the caloric value of led chip PN junction about 90% is to derive from the negative pole of LED.When adopting obedient sheet to install, led chip contacts very good with aluminium base, if when led chip welds, be coated with the good silica gel of one deck heat conduction again, then can be similar to and think that the temperature of led chip negative pole solder joint is the heat sink temperature of LED.Therefore, when the led chip heat sink temperature is measured, adopt the solder joint of the nearly LED negative pole of temperature-sensitive element card to measure approximate the acquisition.Thermal resistance is the ratio of the power that on the temperature difference on the heat passage and passage, dissipates, and for LED, thermal resistance generally is meant from the thermal resistance of led chip PN junction on heat sink.If the power consumption that junction temperature is TJ, the temperature on heat sink is Tc, LED is PD, then the relation of RJc and TJ, Tc and PD can be expressed as:
RJC=(TJ-TC)/PD
In the following formula: the thermal resistance that RJC is the led chip PN junction on heat sink, TJ is the temperature of led chip PN junction, and TC is the temperature of led chip on heat sink, and PD is a heating power, and the unit of PD is W.
When normal the use; PD is relevant through the duty ratio K1 (K1 is 1 when adopting continuous constant current to work) and the efficient K2 of the opto-electronic conversion of led chip own of electric current with forward voltage drop VF, the forward current IF of LED, the interior led chip of unit interval of LED, and its relational expression can be described as:
PD=K1*K2*VF*IF
In heat radiation is calculated, after having selected great power LED, from data information, can find its RJC value; COEFFICIENT K 2 is a constant, the given signal of brightness when COEFFICIENT K 1 is the LED light modulation (when adopting adjusting LED size of current to come light modulation, COEFFICIENT K 1 is the ratio of current given electric current with respect to rated operational current); Behind the forward current IF that confirms LED, can calculate PD according to the VF of LED; If measured the temperature of TC, then can obtain the PN junction junction temperature TJ of led chip by relational expression.
The Practical Formula of Practical Calculation led chip PN junction temperature is in this programme:
TJ=K1*K2*VF*IF*RJC+TC
Because the major function of led chip is to be used for that electric energy is converted into luminous energy to solve lighting problem, therefore, the PN junction temperature controlling strategy to led chip mainly is to use as upscale protection in the present invention.Promptly when the PN junction temperature of led chip does not reach the higher limit that control sets, be as the criterion with the given signal of brightness the electrical power of led chip is controlled.When the PN junction temperature of led chip reaches or during near higher limit, then through top computing formula the given signal of brightness revised, act on led chip with revised luminance signal and be applied to the electrical power on the led chip with control.
In the present embodiment; Said power drive unit comprises the energy storage inductor that connects load LED lamp string; Said energy storage inductor is connected with power switch; Said power switch is connected with current sampling unit, and said current sampling unit connects the MCU module through voltage-dropping type constant current tunable optical driving control unit, and said voltage-dropping type constant current tunable optical driving control unit also links to each other with power switch.Said energy storage inductor is used to absorb and stores the direct voltage output unit and be added in the overvoltage energy partly on the load LED lamp string when the power switch conducting; When power switch turn-offs, to load LED lamp string afterflow power supply, drive efficient with the integral body that improves the LED power drive unit by energy storage inductor.Said power switch is responsible for the current supply circuit of LED lamp string is carried out switch control.Said current sampling unit is responsible for the operating current of LED lamp string is carried out closed-loop control, with the operating current of control load LED lamp string at steady state value.Said voltage-dropping type constant current tunable optical driving control unit is responsible for receiving the given dim signal to after the optimal control of load led chip; Output PWM pulsewidth brightness adjustment control drive signal; The conducting of power controlling switch with end, to accomplish load LED lamp string is carried out constant current PWM pulsewidth dimming function.This cell driving circuit selects for use the XTL604 chip to design, and makes load LED lamp string be operated in constant-current source PWM pulsewidth brightness adjustment control state.Power drive unit with in one tunnel load LED lamp string wherein is an example, and R20 is used to adjust the PWM modulating frequency, and the LD1 of 7 pin connects the PWM dim signal, and 5 pin are used for the power switch Q4 of driving LED lamp string.The adjusting of luminous power recently realizes through the duty of regulating pwm pulse.Power switch adopts metal-oxide-semiconductor Q4.Current sampling unit is made up of R22, R23, C20, C21.The operating current of load led chip is can be controlled near the higher limit, both fully excavated the operating potential of led chip, can not damage led chip by overcurrent again.Energy storage inductor is when the power switch conducting, and energy storage inductor is used to absorb the unnecessary electric energy of direct voltage output unit, when power switch turn-offs, supplies power to the afterflow of LED lamp string through sustained diode 12, with release stored energy.Wherein the mode of switch control is the control of PWM (pulse width modulation) switch, and the frequency of PWM switch control is by the control of voltage-dropping type constant current tunable optical driving control unit, and the duty ratio of PWM pulse-width regulated is regulated output after by the comprehensive various control informations of MCU automatically.
Further improvement as technique scheme; Also can connect luminance detection unit or brightness on the said MCU module and give cell; It can detect the luminous intensity and the surrounding environment brightness of LED lamp string; Said MCU module is carried out calculation process to detected ambient light illumination signal, outputs signal to power drive unit, carries out power adjustments by power drive unit.Be responsible on the one hand the luminous intensity of led chip is detected, participate in the operating current or the PWM duty ratio of control LED luminescent device, make the LED luminescent device be operated in the high-luminous-efficiency district, improve the photoelectric conversion efficiency of LED luminescent device; On the other hand, be responsible for the illumination of operational environment is detected, make the illumination index of operational environment both meet lighting requirement and reach certain brightness value, do not cause the illumination index too high and waste the energy again.The purpose of luminance detection mainly is to improve the overall efficiency of LED illumination driver, through the actual brightness value of real-time collecting work environment, controls the power consumption and the luminous quantity of led chip automatically.
In the present embodiment, said MCU module is selected the MC9S08QE8 microprocessor for use, to realize the working temperature of led chip, the detection of luminous intensity and the optimal control of LED lamp string light modulation.The PWM conditioning signal of LED chip for driving is that the PWM that links the MCU module regulates port, realizes the isolation fully of forceful electric power light current, promotes the global reliability of drive circuit after isolating through photoelectricity.
Temperature detection and luminous intensity detect forms bridge measuring circuit by R41, R42, R43, after both-end input differential amplifier circuit amplifies, receives the PTB3/PTB2 analog acquisition port of MCU module, realizes the signals collecting of led chip working temperature and luminous intensity.Adopt above-mentioned design, the voltage difference when utilizing energy storage inductor to bear step-down work through inductive energy storage, makes and when driving LED, does not lose electric energy simultaneously, therefore the energy service efficiency is brought up to more than 95%; Adopt the current sample feedback circuit, can make the output constant current come driving LED; Adopt the PWM brightness adjustment control, can be under the operating current controlled condition that keeps LED, keep the luminous colour temperature of LED well and do not receive the influence of light modulation.
In addition, said direct voltage output module output can connect the series-parallel LED lamp of multichannel string, and same, every road series-parallel LED lamp string can carry out the detection and the adjustment of temperature and illumination.
The present invention's initiative is applied to the APFC of quasi-resonance working method in the design of LED illumination driver, realizes the substance of LED illumination driver power factor is improved.The power factor of LED illumination driver is risen to more than 0.99 from 0.5-0.57, make the LED illumination driver get into through engineering approaches and apply the stage.
The present invention includes the mains by harmonics quality index in the concrete design of LED illumination driver in first, and the form factor of LED illumination driver is improved to below 1.2 by about 2.
The present invention initiative is with the working temperature of the led chip optimal control parameter as driver; Fundamentally guarantee led chip in use can be because of temperature too high or thermal breakdown and cause light decay; Shorten the useful life of led chip; Fully excavate the long-life advantage of led light source, the through engineering approaches of led chip was brought up to more than 50000 hours from present 5000 hours useful life.
The present invention initiative realizes the optimizing control models of illumination, brightness, operating current, PWM pulse-width modulation in the design of LED illumination driver, improve the synthesis energy saving rate of LED illumination driver more than 10%.
In addition; The present invention has taken all factors into consideration the through engineering approaches application demand of LED illumination driver; Power factor, form factor are included in the design content of LED illumination driver; Proposed a kind of LED of raising illumination driver power factor and the practical approach that reduces harmonic component, made the LED illumination driver realize qualitative leap aspect the improvement of these two indexs, for the LED illumination real entering through engineering approaches stage of applying provides solid technical foundation.And electricity, optics, the thermal characteristic of led light source have been taken all factors into consideration; The work operating mode of LED is carried out global optimization control; The heating problem that has solved led chip is to the led chip influence in useful life; Make the index in useful life of led light source really obtain qualitative leap, make the LED illumination really possess the value that through engineering approaches is applied.Also the optical characteristics of led light source and electrology characteristic are combined and be optimized control, photoelectric conversion efficiency remains at efficient district when making led chip work, makes the overall efficiency of LED drive system improve more than 10%.
Certainly; The invention is not limited to above-mentioned execution mode; Those of ordinary skill in the art also can make all equivalent variations or replacement under the prerequisite of the utility model spirit, modification that these are equal to or replacement all are included in the application's claim institute restricted portion.