CN87105659A - Fluorescent lamp operation - Google Patents

Abstract

A kind of fluorescent lighting circuit that uses non-preheating cathode, it has initialization circuit, operation circuit and current detection circuit.One power converter circuit is suitable for using with above-mentioned lighting circuit.It has the switching device by the control of drive waveforms circuit, with provide from power supply one-period change sign space ratio signal to output circuit, meet the instantaneous size of the output that space ratio can controlling output circuit, the influence of load variations in the output and power source change is reduced to minimum.Energy ambient light when fluorescent lighting circuit uses with power converter circuit is adjusted the light output of fluorescent tube, prolonging lamp tube service life and reduction power consumption.

Description

The present invention relates to a kind of fluorescent lamp operation, especially, but is not the fluorescent lamp that relates to large area region in the sort of building that is used to throw light on uniquely.

Up to now, usually all be with throw light on large area region in the building of fluorescent lamp.In general, though one or more lamp can be controlled with a single switch, each fluorescent lamp all is wired to a network supply system.Fluorescent lamp is installed in the luminaire, and one or more fluorescent lamps are housed in this luminaire.And each luminaire has one or more starting circuits, other elements that are used to limit the ballast of lamp current and are used to improve power factor.

The problem that this installation had is that the electric power by the power network supply has the nearly variation of plus or minus 10%.Like this, the electric light that design is worked under 240 volts of alternating voltages for example may stand to be about 260 volts of working volts alternating currents, this can make the light output of fluorescent lamp improve again and the design objective when making power dissipation be higher than operate as normal, thereby causes reducing the endurance expectation of lamp.In addition, Qi Dong words in this case, the filament of this class fluorescent lamp (negative electrode) extracts than normal higher electric current, and heating makes temperature also be higher than normal condition, this situation can make (a) to reduce the endurance expectation of filament again, (b) the too high heat that produces in when starting can rise and causes to seal in the end of fluorescent lamp and produce the disadvantageous temperature difference, and this temperature difference will be impelled and seal destruction, and air enters and and then owing to oxidation damages filament and fluorescent tube.And, if lamp is worked being higher than under the normal voltage, and the working temperature of lamp being risen to be higher than ideal situation, this also can reduce the endurance expectation of fluorescent lamp.

Known with independently-powered voltage and driven fluorescent lamp at building intraoral illumination large area region.Common this voltage is about 500 volts or higher, frequency is about 20 kilo hertzs, at 20 kilo hertzs, promptly one is much higher than the effect of working under the mains supply frequency that is about 50 He Zhi normally and is, the phosphorus film is higher than under the repetition rate of decay of afterglow one and is excited, the light quantity of fluorescent tube output is rendered as a constant output like this, or near constant, rather than as the modulation mean value output when working under 50 He Zhi situations.In known systems, in the lamp device of under like this high voltage and high-frequency, working, still fluorescent tube is lighted start by at first providing heating current that the negative electrode of fluorescent tube is heated to a suitable temperature.This heating current applies thermal stress to filament, thereby reduces the endurance expectation of filament, and in addition, the thermal shock on the filament can cause the too early damage of fluorescent tube under for example by the situation of the caused mechanical oscillation of aircondition.

The objective of the invention is to want to improve the endurance expectation of fluorescent lamp, obtain maximum efficient simultaneously.

According to a first aspect of the invention, provide a kind of fluorescent lamp lighting system, it comprises:

(a) power converter is in order to be transformed into the power supply electricity alternating current that is supplied to a fluorescent lamp;

(b) control unit that is connected to described power converter in order to the size of the voltage output of control power converter, thereby is controlled the size of the light output of described fluorescent lamp;

(c) fluorescent lamp control circuit that is connected in described fluorescent lamp and described power converter, described fluorescent lamp control circuit is a non-preheating cathode, fluorescent lamp circuit comprises: a starting circuit, an operating circuit and a current detection circuit, current detection circuit is connected to a fluorescent lamp in the described circuit in when work with starting circuit and operating circuit.Described current detection circuit is such, make when described alternating current is supplied, described starting circuit will be connected to described fluorescent lamp, and when described fluorescent lamp extracts ionization current, described operating circuit will be connected to described fluorescent lamp and then described starting circuit will be become inoperative, described starting circuit can provide enough voltage to the non-preheating cathode of described fluorescent lamp, impels the generation ionic discharge; Described operating circuit has a reactive load, and this reactive load will provide the power factor through overcorrect basically, and limits for the continuation of described fluorescent lamp operation provides electric current.

According to a further aspect in the invention, provide a kind of power converter, especially but be not the sort of uniquely power converter that alternating current is provided to non-preheating cathode fluorescent lamp circuit.Described power converter comprises: be used to be connected to the switching device on the power supply, described switching device is controlled to provide one-period change sign space ratio signal (cyclic varying mark-space ratio signal) from described power supply electricity by a drive waveforms circuit, described change sign space ratio signal is supplied to an output circuit when work, it is transformed into one and exchanges output supply voltage there, the symbol ratio of described mark space scaling signal can be controlled the instantaneous size of a described interchange output supply voltage, described symbol ratio is (this feedback network is connected to described interchange out-put supply and described drive waveforms circuit) that is provided from a waveform that limits with numerical calculation method with constant amplitude that produces a feedback network by described drive waveforms circuit, and can respond so that the influence of load variations on the described interchange out-put supply and the variation in the described power supply is reduced to minimum level.

Consult accompanying drawing now, so that can more clearly understand the present invention; Wherein:

Fig. 1 is the square frame schematic circuit diagram of a best fluorescent lamp lighting system;

Fig. 2 is the circuit diagram of the fluorescent lamp starting circuit of prior art;

Fig. 3 is the oscillogram that is used to illustrate fluorescent lamp operation;

Fig. 4 is the circuit diagram of Filament of fluorescent lamp coil;

Fig. 5 is the circuit diagram according to best fluorescent lamp starting circuit of the present invention,

Fig. 6 is the block diagram of the starting condition of Fig. 5 circuit;

Fig. 7 is the block diagram of the operation conditions of Fig. 5 circuit;

Fig. 8 is the block diagram of control unit shown in Figure 1;

Fig. 9 is the block diagram of power control unit shown in Figure 1;

Figure 10 is the circuit diagram of power converter shown in Figure 9;

Figure 11 is the square frame schematic circuit diagram of address generator shown in Figure 9;

Figure 12 is the square frame schematic circuit diagram of drive waveforms circuit shown in Figure 9;

Figure 13 is the square frame schematic circuit diagram of overload protecting circuit shown in Figure 9;

Figure 14 is the oscillogram of the various waveforms in the optimal circuit.

At first consult Fig. 1, there is shown the square frame schematic overview of a lighting apparatus commonly used in commercial mansion.The bank (bank) of 40 watts wherein common fluorescent lamp 1 group 3 is for being connected in parallel, and each bank 3 all is connected to an electric power controller 5 that is used to control each bank 3 accordingly.Each electric power controller 5 all with the power network AC power of a standard, for example be that the AC power of 50 hertz 45 volts of three-phases is connected.It also can be connected with a dc-battery group or auxiliary power in addition.If this can provide electric power when network supply cuts off the power supply.The function of electric power controller 5 is with required frequency and supplies alternating currents to each bank 3 of fluorescent lamp 1 in a desired manner.Usually bank 3 can comprise 40 * 40 watts of fluorescent lamps.So bank 3 can illuminate some specific zones in the mansion.Each electric power controller 5 is connected to a control unit 7 again.Control unit 7 has a feedback network that comprises photodetector 9, and photodetector 9 is used for being provided with a needed output from electric power controller 5.In this method of attachment, photodetector 9 is to be contained in the light to accept to emit from fluorescent lamp 1 in the mansion, and accepts to enter natural environment light in the mansion by window and so on.Like this, photodetector 9 provides a signal 11 to control unit 7, and control unit 7 is considered to adjust electric power controller 5 by the required light intensity that fluorescent lamp 1 sends.Nature and/or surround lighting greater than a given situation that requires brightness under, electric power controller 5 can be cut off at that time, thereby reduces the endurance expectation that electric power expends and improve fluorescent lamp 1.Be provided with a hand controller 13, so that required intensity level is set.The signal 15 that is provided by hand controller 13 is supplied to control unit 7 and sets required intensity level thus.Control unit 7 has high level tripping operation control 17, its tracking signal 15, thereby and in being higher than signal 15 mansions during the level of surround lighting, this tripping operation control 17 will make electric power controller set disconnection.

Then consult Fig. 2 and Fig. 3 and describe the work of the fluorescent lamp circuit of common prior art.The voltage that voltage waveform 106 representatives are supplied with from power supply 101.This generally can be 240 volts, the alternating current in 50 weeks, perhaps can be some other or the different voltage of frequency.The voltage of voltage waveform 106 supplies of representative when not having fluorescent lamp 1 electric current.During starting state, the voltage of the supply on negative electrode 103 two ends is generally shown in voltage waveform 109.Power supply 101 is connected in the circuit some (Fig. 3) on (the earlier opint) 115 earlier.Here suppose that starter 104 116 makes open circuit at point, and the inductance transient state works to hot cathode ionization voltage 107 as a result, its as a result electricity be that arc value 117 is fallen in fluorescent lamp 1 starting and the voltage drop on fluorescent lamp 1.Fluorescent lamp 1 electric current extinguishes at point 118.During the period 100, the gas in the fluorescent lamp 1 keeps ionization basically, and point 119 places produce igniting again on the negative half period of the voltage waveform of supplying with 106.During the period 113, there is arc current to flow.The above-mentioned then cycle continues.

In an embodiment of the present invention, filament 103 is non-preheatings.Rise even will have the temperature of some regulations during operation, but that filament 103 still keeps is cold, so must provide a higher basically service voltage with the interior gas of " igniting " or ionization fluorescent lamp 1.For illustrative purposes, can see that power supply starts at point 114, produces a voltage with the frequency of supplying with then and rises 111.This voltage arrives level 108 by level 107 under the situation that fluorescent lamp 1 is not lighted, level 108 is cold cathode firing points, fluorescent lamp 1 starting as a result, light tube electric voltage drops to arc value 117(as described above).Because voltage 111 rises, it is by point 112, is that voltage level 108 places light glow discharge in advance at this place generation one low current before lighting.

In the present embodiment, the negative electrode 103 of fluorescent lamp 1 is short circuit as shown in Figure 4.Here line current enters filament 103 through two current paths 121 and 122, so from the surface of filament 103 a single current path 125 is arranged.General loss in the filament 103 in common 40 watts of fluorescent lamps is about 0.25 watt under these conditions.

In prior art circuits device shown in Figure 2, to 40 watts of common fluorescent lamp tubes, heater current flows into filament 103 and is about 2 watts because of the power consumption maximum as a result of electric current 125.Ifs circuit needs open circuit at point 124, and 1 pair of starting that continues of fluorescent tube at that time is useless.In the present embodiment, need at point 124 open circuits as circuit, to as shown in Figure 2 common filament device power consumption at that time with maximum near 2 watts.

Now consult Fig. 5, Fig. 6 and Fig. 7 and narrate the work of the circuit of the embodiment of the invention.The state that following three kinds of different relevant circuit are arranged

(1) initial condition,

(2) starting state and

(3) running status,

The work of circuit under these three kinds of states is described now.

(1) initial condition

In initial condition, when promptly switch 145 does not have closure, there is an effective value to be about 140 to 150 volts, 20 kilo hertzs supply voltage 101.Best circuit is with such supply voltage work, because usually can remove to handle several sort circuits preferably from such control circuit.But should be appreciated that circuit arrangement is not only to only limit to use such power supply, because any common AC power, for example 240 volts 50 kilo hertzs alternating current also can use, and may need circuit component values is done some small corrections.When switch 145 closures, the voltage on the power supply 101 is applied on the circuit.At this state, contact 142 and 143 is in the position shown in Fig. 5, as a result the elementary winding 127 then short circuits of open circuit secondary winding 128 of a transformer.The transformer that generally comprises elementary winding 127 and secondary winding 128 is on a ferrite bar, and around turn ratio rate is 5 to 1, wherein secondary winding 128 has the more number of turn, for input voltage that surpasses the level 108 among Fig. 3 and secondary voltage and be enough.So in general transformer has higher leakage reactance.Therefore, voltage is added to fluorescent lamp 1 from power supply 101 through reactance 129, does not resemble the result of power voltage insufficient with ionization fluorescent lamp 1 and do not have.Simultaneously, chokes Figure 141 is as an autotransformer, and voltage is supplied with relay coil 131 and relevant circuit by rectifier 135 with filtering capacitor 136.Transistor 134,152,153 and 153 is not conducting at first, and electric current makes its conducting by the base stage that resistor 132 flows to transistor 152.Transistor 134 and relay 131 are by diode 150 work, simultaneously to capacitor 148 chargings.Relay 131 work make switch 142 and 143 change states.Switch 142 and 143 becomes among Fig. 6 with the starting state shown in the schematic form circuit then.

(2) starting state

Starting state is as described below: be added in the two ends of elementary winding 127 from the voltage of power supply 101, make at the two ends of secondary winding 128 and produce a secondary voltage.Winding 127 is connected like this with 128, makes that secondary voltage and supply voltage are homophase and addition.Its as a result voltage be added to fluorescent lamp 1 by transformer leakage reactance element 146 other limiting elements 179 and series connection current-limiting impedances 129.In this moment, current detection circuit 144 is not worked, because there is not electric current to flow to fluorescent lamp 1.The voltage as a result that is added in fluorescent lamp 1 two ends is enough to cause igniting, and the effect of electric current by series connection restriction impedance 129 and leakage reactance element 146 be restricted (see figure 5), and by adding that another series element 179 can be added in the loop of switch 143.The ignition process of fluorescent lamp 1 is through above-mentioned aura or the pre-electric arc of low current.The ignition process of fluorescent lamp 1 is seen Fig. 3 at a 112() through above-mentioned aura or the pre-conditions at the arc of low current, enter normal arc or fired state, its process is the time and adds the function of voltage as a result.The lamp current that is subjected to leakage reactance element 146 and restriction impedance 179 and operation restriction impedance 129 restrictions is just arranged after igniting.

(3) running status

During running status, current detection circuit 144 carries out work, and in above-mentioned initial condition, relay 131 is to use one from the drive signal work of transistor 152 by diode 150 through transistor 134.As result, when electric current flows in fluorescent lamp 1, because of this electric current produces a voltage at the two ends of diode 137,140 and resistor 156 as above-mentioned igniting.The positive half wave of described voltage is such, making transistor 152 work by a base bias current is provided via electrical equipment 155.Thereby the base stage that transistor 154 work make current transfer leave transistor 152 also disconnects it.Transistor 153 short circuit to keep producing by resistor 151 and time constant capacitor 138 work by transistor 154.Driving to transistor 134 is removed by the disconnection effect that is put on transistor 152 by transistor 154/153.Transistor 134 will be separated from later at the time constant RC that is set by resistor 147 and capacitor 148. Transistor 152 and 153 forms one at all stable bistable circuit of arbitrary state, comprises that the bistable characteristic of the bistable circuit of transistor 152 and 153 can provide a starting and a running status stably, and does not have the chattering of relay.In order to reset fluorescent tube 1, at first must remove electric power and apply again again to produce start-up function from network 144.The setting of time constant RC is wanted and can be provided time enough for the ionization of fluorescent tube is stable before circuit returns to the running status shown in Fig. 7, and relay is in normal non operating state here.

Normal condition makes relay contact 142 and 143 with elementary winding 127 open circuits, and makes secondary winding 128 short circuits, thereby removes synthetic starting voltage from fluorescent lamp 1.At this moment circuit keeps such state, and lamp current 125 flows through series connection restriction impedance 129 from power supply 101.An electric current in parallel flows through impedance 141 simultaneously.Impedance 141 is used for proofreading and correct the power factor problem because of using series impedance 129 to be produced.In this example, the power factor calibration becomes unification basically. Impedance 141 and 129 is complementary, and promptly they provide opposite reactance so that realize the correction of power factor.

In the present embodiment, the reactance of impedance 129 can be inductive or capacitive under the situation of element 141 for complementation.In other words, capacitor can be replaced with choke, otherwise choke also can be replaced with capacitor.Preferably use the capacitor as impedance 129 of series connection, it has formed a current limiting device with high pass filter characteristic, by such filter, any harmonic wave that exists in power supply 101 or produce trends towards dissipating rather than reflected back power supply 101 in load.In prior art structure shown in Figure 2, the harmonic wave that chokes Figure 102 forms any this class is all wanted the low pass filter that goes in the reflected back power supply.Should be noted that in prior art constructions shown in Figure 2 current limiting device must be an inductor regularly.The existence of power factor correction capacitor 105 does not provide a harmonic wave trap circuit or a dissipator in Fig. 2, there is not loss because talk about it normally, it seems that whole effects that it can play are to make power supply 101 increase any circulation harmonic current that is distributed in the circuit connection, and provide power factor correction with the electric current fundamental frequency.In the present embodiment, under the situation of using capacitive electric current restriction impedance 129, superposition dissipates in fluorescent lamp 1 in the harmonic power that is added on the fundamental frequency, and convert useful light to, thereby show the frequency band of a broad, with the load of power supply 101 couplings, rather than the humorous wave reflection load of a low pass.

Should be appreciated that in the above-described embodiment, because of two current paths 121 and 122 that enter filament 103 are provided, so to any given lamp current, the current density there will lower.And fluorescent tube 1 is to connect like this, makes to compare with common circuit arrangement among Fig. 2, has reducing of essence aspect power dissipation.This will reduce cathode temperature in fact at normal operation period then, and the life-span of corresponding raising negative electrode.This makes the corresponding reduction of temperature of fluorescent lamp sealed end again, thereby will further make fluorescent tube and air completely cut off the endurance expectation of prolonging lamp tube.

Consulting Fig. 8 now, is the block diagram of control unit 7, photodetector 9 and hand controller 13 shown in the figure.The purpose of control unit provides the Low ESR output signal 19 of a representation signal 11 and 15 sums.One low output impedance reference signal 19 is provided, the electric power controller 5 that can connect any requisite number order like this and be suitable for driving, thus be used to control the corresponding bank 3 of fluorescent lamp circuit (hereinafter referred to as fluorescent lamp 1) as shown in Figure 5.Can see that photodetector 9 is connected with a more accurate circuit 23 of low and high restriction.The purpose of low and high restriction calibration circuit 23 provides output signal 11, and signal 11 has the low and high restriction of the setting of pre-determining, and has needed gradient between the height restriction.Usually, detector 9 can comprise any suitable light-sensitive unit, for example photodiode or photo resistance.The design of low and high restriction calibration circuit 23 is considered to known technology, and its details is no longer described in detail here.Output signal 11 offers the summing amplifier 25 with Low ESR output, will provide an output reference signal 19 like this, supply capability controller 5.

Hand controller 13 is connected with the low and high restriction calibration circuit 27 that output signal 15 is provided, and hand controller 13 generally includes such as the such rotary controller of potentiometer.The purpose of low and high restriction calibration circuit 27 is to set a lower restriction and higher restriction for control degree.Design that should the more accurate circuit 27 of low and high restriction also can be used as known technology and no longer describes in detail.Output signal 15 offers amplifier 29, and the effect of amplifier 29 is that a trip signal 21 is provided when signal 11 surpasses the given amount of 15 1 of signals.Signal 15 in amplifier 25 with signal 11 additions, signal 19 changes round about according to signal 11 under the situation that signal 15 remains unchanged like this.Therefore signal 19 has been represented the desired state by the light output of the determined lamp of setting of hand controller 13.

Output 21 is used for cutting off controller during signal 11 surpasses 15 1 specified rates that are set of signal.System is with nonoscillatory like this.The setting of the position of hand controller 13 is to guarantee minimum light quantity in the influence area of detector.

In use, detector 9 is mounted in one can accept the light that emits from fluorescent lamp 1, can accept again to enter the outside in the building or the place of surround lighting by window and so on.Like this, 9 pairs of entire system of detector provide the control of a feedback-type.

Now consult Fig. 9, there is shown the block diagram of electric power controller 5.Electric power controller 5 comprises a power converter 31, power converter 31 produces a symmetrical alternating current output voltage 33 from input AC electricity (for example grid power) and/or from a pair or the input of standby DC power supply, this symmetry output voltage 33 is generally 20 kilo hertzs, in 200 to 260 volts of (effective value) scopes.This output voltage is supplied with the load that comprises fluorescent lamp 1 through isolating transformer 35.Transformer 34 has a secondary winding 37, the circuit that will describe after the little percentage that this winding 37 produces voltage 33 is controlled as feedback voltage.Power converter 31 is by a digital drive waveform circuit 39 controls, and circuit 39 is used for changing the size of symmetrical output voltage 33.Drive waveforms circuit 39 is by an analog to digital address generator 41 controls.Address generator 41 is again by Low ESR signal 19 and 17 controls.Signal 19 and 17 receives from control unit 7, and representative desired intensity level in the construction zone of being thrown light on by lamp 1, and the controller output voltage that is showed with the setting of hand controller 13 and by winding 37 is relevant.

Be provided with a switch 43, thereby eliminate influence from 19 pairs of address generators 41 of signal of control unit 7.And local control 45 can provide a reference signal, and this reference signal can compare with the feedback signal on secondary group 37.Relatively be such: output signal 47 is provided by address generator 41, and address generator 41 makes drive waveforms circuit 39 provide an output signal 49 to power converter 31 again.Output signal 49 is digital signals, it will make from the feedback signal of winding 37 be zero by the two difference of this locality control 45 or 19 reference signals that provide.This will change the size of symmetrical voltage 33 again.

For working condition with the feedback loop that comprises control unit 7, the work of switch 43 is used for isolating local control 45 and external reference signal 19 and from the internal feedback voltage of winding 37, internal feedback voltage from winding 37 is added in add circuit 51 then, and offers address generator 41 as a reference signal.

The feedback circuit that comprises digital-to-analog converter 53 is used as one second summation benchmark, to remove the possibility that produces digital error in the numeral output of address generator 41.

The electric current of fluorescent tube 1 detects by current transformer 55 at isolating transformer 35, and current signal 57 subsequently contrasts limiter 62 and compares in overload protecting circuit 59, to detect overload situations.As measure overload, then be arranged to disconnect signal output 49 from drive waveforms circuit 39 from the output signal 61 of overload protecting circuit 59 as far as possible at once.In general, this will become in little (30n) second 30 and be disconnected, and will disconnect in about 1 microsecond then from the output voltage 33 of power converter 31.Overload protecting circuit 59 includes an overvoltage level detection feature by limitation detector 63.Error condition is by lamp 65 indications.By the overvoltage that any reason causes, be the reason that makes power converter 31 tripping operations, and this carry out by detect the overvoltage level in limitation detector 63 from the feedback signal of secondary winding 37.If detect the excess temperature phenomenon in the power dissipation device in power converter 31, detector 64(sees Figure 10 at that time) provide an output signal 67 to overload bag protective circuit 59, thus and provide overload trip signal 61.

Consult Figure 10 now, there is shown the detailed circuit diagram of power converter 31.Grid alternating current 101 is supplied to a bridge rectifier 67, is converted into direct current there, is suitably supplied with transistor 69 after the filtering.The digital drive signals 71 that forms the part of output signal 49 is supplied to transistor 69 by an isolating transformer 73.Transformer 73 is used for providing DC-isolation between the direct voltage of supplying with transistor 69 and output signal 49 and the element in drive waveforms circuit 39.Waveform 70 at the outlet side of transistor 69 is represented with numeral 70 in the drawings.It has the mark space ratio of the variation that will describe afterwards.Output 70 offers low pass filter 77, and filter 77 comprises inductance 79, electric capacity 81 and clamp diode 83 and not shown be equivalent to one of load that fluorescent lamp 1 caused transformation load.The output of low pass filter 77 is depicted as a waveform signal 85 in the drawings, and the instantaneous D. C. value in waveform signal 85 equals the mean value of the corresponding time model in digital drive signals 71.Its influence is: if digital drive signals 71 has the circulation model of change sign space ratio, then asymmetric waveform signal 85 will repeat with this cycling rate, and its amplitude will be followed this change sign space ratio.

Transistored bridge 87 is used for alternately changing connection with this recycle ratio between low pass filter 77 and transformer 35, and transformer 35 has the alternating voltage 33 that adds there like this.Make this periodic waveform signal 85 repeat a little fix on 0 Fu Chu, the phase place of electric bridge 87 does not so just contain the problem of crossover 0 volt of some place upset like this.Because the crossover characteristic of electric bridge 87 is significantly to the load that is caused by fluorescent lamp 1, this load occurs with the form of conversion, directly in the output of low pass filter 77.

Consult Figure 11 now, at length show the block diagram of address generator 41 among the figure.Two analog input signals 19 and 17(see Fig. 9) after add circuit 51 additions, enter address generator 41 as signal from switch 43.Output from add circuit 51 also is admitted to another add circuit 95, and there with a signal plus from digital-to-analog converter 53, a dead band (deed band) circuit 97 is supplied with in its output then.Dead band circuit 97 is used as a detector, no matter when when limiting a plus or minus value of outside above the base angle (bottomcorner) of dead band circuit 97, the output from add circuit 95 output signal will be arranged, restricting signal 99 as shown in FIG. there.Signal outside one of plus or minus restriction, the output that provides by revolving die door (slowinggate) 151 that will produce a plus or minus.Plus or minus output is counted counter 153 up or down, and its count status is the initial or base address from the digital equivalent value of the output voltage 33 of power converter 31.Like this set of number signal will be arranged, each representative is from the different output signal model of transistor 69.

The clock pulse of change-over gate 151 repeats 155 and has set the address count rate, this also is that power converter 31 is removed error condition, the size of ignoring input 43 changes the frequency of the size of output voltage waveforms 31 up or down, counter 153 is to be provided with like this, make it not counting to surpassing the highest count value upward, or be lower than minimum count value counting in downward direction, and these restrictive conditions are applied by restricting circuits 151.

Now consult Figure 12, there is shown the frame circuit diagram of drive waveforms circuit 39.Here the output signal 47 from address generator 41 is provided for read-only memory (ROM) 159.Signal 47 is a digital address signal and the base address of representing any given amplitude of output voltage 33.When offering ROM159, the most significant part of whole addresses of a series of numeric words at its a series of isolated signs of representative definition interval at interval.These numeric words all become the digital equivalent value of the half-wave amplitude of needed analog output voltage 33.In order to obtain to define the needed numeric word of half-wave model, need scanning or progressively visit (step) memory 159, obtain to have defined word stream as the particular model of being concerned about that can set up on the address in being included in input signal 47 through these number of addresses.This is to be obtained by the low live part of progressively visiting by having defined as the whole address of the physical location of each word in the memory of ROM 159.The number of the word in each needed half-wave model (or frame) is to set in conjunction with each word length by desirable level and smooth envelope resolution (resolution).Described each word length set waveform 33 vertically or the voltage resolution capability frequency of visiting the given number of given word will determine the half the time or the frequency in the cycle of output signal 33.Minimum effective address sweep signal 161 offers ROM159 from digital scan counter 163.The pulse signal 165 that produces in digital scan counter 163 has defined the beginning of scanning each time, and another output signal 167 alternate frame in transistored bridge 87 after scanning is finished each time exchanges.Here, provide an opposite bridge-drive signal 169 of two-phase from door 171.

The numeric word that defines the interval of each mark space in each frame is divided into two parts, and its first 170 sets total part of the symbol in the mark space ratio, and the first 173 of word is used for a little incremental time is added to total part of symbol.This is produced by two delay circuits 172 and 174.

For a umerical example, typical eight bit word to a definition 170+173, four on head in 170 provides 1/16 resolution, in 173 secondly four partly provide 1/16 resolution in described each first four resolution, the total resolution that provides the direct voltage in the power converter 31 like this is 1/256 or 0.4%.This resolution that needs is set by employed digital word length in practice.One fixed intervals are arranged between the numeric word in frame, and like this, after a pleonasm initial pulse was provided by pulse signal 165, independent character pitch can be set as a delay.Pulse signal 165 is provided with memory 175, memory 175 again by two numeric words 170 and 173 provide two that postpone and reset.Independent like this symbol is set by pulse signal 165, and is resetted by pulse signal 176.Next symbol will be set by the pulse signal 165 that then occurs, and be resetted by the pulse signal 176 that then occurs, and almost always after previous delay a different delay be arranged unchangeably.The delay that is caused by partial words 170 is by partial words 170 and another word 177 that obtains from digital scan counter 163 are relatively obtained.Like this, another word 177 makes to postpone by such rate setting that with fixing rate variation promptly described another word 177 is with such rate variation, and ROM 159 is with such speed work.By aforesaid a series of related method thereofs, make the rate request of ROM 159 and other relevant elements reduce at least one factor of 10.

Under the situation of current overload or voltage overrange, a signal 61 from overload protecting circuit 59 is added to memory 175 and door 171, and almost instantaneous cancels their output accordingly separately.Digital drive signals 71 provides as the output from memory 175, and is added to isolating transformer 73, thereby makes transistor 69 produce needed mark space ratio output.

Consult Figure 13 now, there is shown the block diagram of overload protecting circuit 59.Current transformer 55 detects load current signal 57, this makes two ends at resistor 187 produce a change in voltage, this change in voltage is used to trigger the limitation detector 189 and 191 in the limitation detector 63 again, and the restriction of limitation detector is corresponding to the specific level that will appear at resistor 187 two ends.Limitation detector 189 is instantaneous tripping operation devices that are operated in the shortest possibility time, and for such as will by with the same position of current transformer 55 on the longer current overload tripping characteristic that provides of HRC fuse, limitation detector 191 is to trigger by the time delay element that comprises resistor 193 and capacitor 195.

From the output of tripping operation any in the detector 189 or 191, by one or gate device 199 set a storage elements 197, provide a trip signal 61 from the output of memory 197.Trip signal is produced by other elements that will describe at the appropriate time.

Because of any reason, from the voltage overrun on the feedback signal of the transformer secondary output winding 37 of transformer 35, provide effective reason to make power converter 31 tripping operations, and this accomplishes by detecting in limitation detector 63 an overvoltage level, thereby sets memory device element 201 and signal 61 is provided.

Similarly, excess temperature in the power dissipation device in the power converter 31, be detected with detector 64, the there is provided with a restriction in limit setting circuit 203, and when work with result storage in storage elements 205, memory 205 also can produce trip signal 61 when output.Therefore all memory components 197,201 and 205 can be removed by an on/off switch (not shown), and the on/off switch is in power converter 31, and it is purpose and produce a clear signal 207.The visible signs of any error condition is by observing at illuminated lamp 65.Lamp 65 is to be connected the latch devices (not shown) that is used for receiving trip signal 61 by one to be triggered.

Figure 14 shows the time relationship between the various functions in the power converter, especially export by the final AC signal of fluorescent lamp 1 formed load about generation, and from the supply that these waveforms come from the next half-wave waveform 33 of constant amplitude flexible symbol gap digit signal model.

Figure 14 a shows the voltage 169 from the output of the door 171 among Figure 12.Figure 146 shows to have defined and is used for producing each the son interval of a frame model or the pulse train of beginning partly.Figure 14 C shows the digital drive signals 71 from memory 175.Figure 14 d shows the waveform of representing shape, has comprised the amplitude of the mean value of constant amplitude drive waveforms 71.Figure 14 e shows the change sign space ratio output waveform from transistor 69.On behalf of the fixed amplitude flexible symbol from transistor 69 before averaging, waveform 211 export at interval.Figure 14 f representative is from the variable amplitude output signal 85 of filter 77.These amplitudes are caused by the variation that meets in the space ratio in the frame model.All points 213 have been represented the transfer point that the phase change in the transistored bridge 87 has taken place at this place, and this phase change causes the phase transition of signal 85 again, to produce alternating current output signal 33.The mathematical model that is used for as the binary weighting word of the size of waveform 85 has been shown among Figure 14 g.Shown in Figure 14 h the symmetrical alternating current voltage 33 that is added to transformer 35.

It should be noted that, Figure 11 shows a typical dead band circuit 97, but its difference is that output is a digital equivalence value (replacement analog quantity), and its feedback obtains by numeral output is converted to an analog equivalent amount, with the analog input that is suitable for receiving from add circuit 95.Voltage controlled avalanche oscillator after the drive waveforms circuit 39 shown in Figure 12 is similar to oscillator/power supply in fixed frequency.

Filter circuit 77(Figure 10) correctly is the given load resistance work by transformer 35 conversions.Transformer 35 is the outputs that are added in filter 77.Should be noted that the fixed value for inductance 79, its average voltage output will change along with load resistance, and irrelevant with numeral input modulated waveform amplitude (the normal words of amplitude are always fixed).Open-circuit condition result in the load 1 can cause be added on the electric bridge 87 and output transformer 35 on the output voltage of raising surpass the ability that electric feedback loop recovers.In fact, the removal by the feedback control signal on the secondary winding 37 of transformer 35 makes overload protecting circuit 59 tripping operations.This operation institute's time spent is to be about 100 nanoseconds, and its trip-point is set to just in time paranormal operating voltage (crest voltage).

Should be appreciated that, to its frequency of above-mentioned system is so to select, make the work about electric power of fluorescent tube 1 with such frequency, this frequency is lower than the decay time of twilight sunset of the fluorescent material of fluorescent tube basically, and fluorescent tube 1 is to carry out work with the peak light output of the mean value that is equal to or less than the light output when fluorescent tube is worked with longer than the decay time of its fluorescent material twilight sunset basically period frequency, therefore, the fluorescent lamp 1 that is connected in the circuit described here can be with the power consumption work of the per unit light output that reduced basically.Also should understand, fluorescent lamp 1 will strengthen the intensity level level of the surround lighting that receives in building, so just can be to carry out work than light output level lower in the prior art structure, in the prior art structure, the controlled reponse system of lamp neither one is providing a predetermined brightness level in the zone of being thrown light in building, and power consumption will be lower than the consumption of common fluorescent lamp circuit.Lamp 1 also has aforementioned longer endurance expectation like that.Should also be understood that as grid power 101 outages, will will need not to be provided with urgent interruption lighting apparatus like this, also obvious variation can not arranged on intensity level by the direct current power supply direct current.

Claims (16)

1, a kind of fluorescent lamp lighting system is characterized in that it comprises:

(a) power converter that is used for the power supply electricity is transformed into the alternating current that is supplied to fluorescent lamp;

(b) one is connected in described power converter controlling the size of its voltage output, thereby controls the control unit of the light output size of described fluorescent lamp;

(c) fluorescent lamp control circuit that is connected in described fluorescent lamp and described power converter, described fluorescent lamp control circuit is the negative electrode of a non-preheating, fluorescent lamp circuit comprises: a starting circuit, and an operation circuit and is connected to starting circuit and operation circuit current detection circuit on the fluorescent lamp in described circuit in when work; Described current detection circuit is such, make when described alternating current is supplied, described starting circuit will be connected on the described fluorescent lamp, and wherein when described fluorescent lamp extracts ionization current, described operation circuit will be connected on the described fluorescent lamp and described starting circuit will become idle then, described starting circuit can be to the enough voltage of non-preheating cathode supply of described fluorescent lamp, make the generation ionic discharge, described operation circuit has a reactive load, this reactive load will provide corrected basically power factor and to the electric current restriction of the continuous service of described fluorescent lamp.

2, fluorescent lamp lighting system as claimed in claim 1, the frequency that it is characterized in that described alternating current is such frequency, makes fluorescent lamp will be operated in such period frequency, this period frequency equals or is shorter than the decay time of its fluorescent material twilight sunset.

3, fluorescent lamp lighting system as claimed in claim 2, the size that it is characterized in that the voltage of described alternating current can reach required like this degree by described control unit control, such peak light output can be provided, this peak value output equivalent is at the mean value of fluorescent lamp with the light output during in the longer period frequency work of the decay time of twilight sunset than its fluorescent material, thereby make the fluorescent lamp will be to have reduced the power consumption work of the per unit light output when described mean value basically.

4, fluorescent lamp lighting system as claimed in claim 1, it is characterized in that being used to controlling an output of the described control unit of described power converter, be the output of Low ESR, and be connected with a plurality of power converters and receive described output, thereby each converter is controlled.

5, fluorescent lighting system as claimed in claim 4, it is characterized in that having a plurality of described power converters to be connected to described control unit, and each power converter all is connected with corresponding fluorescence control circuit, provides light with selected zone in building.

6, fluorescent lamp lighting system as claimed in claim 1, it is characterized in that described electric power controller comprises one in response to the feedback control network by the light in the zone of described fluorescent lamp lighting system illumination, can export the intensity level that brightness is adjusted to described feedback network automatically and determined to light like this.

7, fluorescent lamp lighting system as claimed in claim 6, it is characterized in that described feedback network comprises the optical detection device of the light that can oil sends from described fluorescent lamp with from other light sources in described zone, its described power converter is such, if make that the environmental light brightness level makes when having the predetermined brightness level in described zone, described fluorescent lamp can be disconnected.

8, fluorescent lamp lighting system as claimed in claim 1, it is characterized in that described electric power comprise grid alternating current and dc-battery power supply the two, so when if grid alternating current sends fault, system can provide unbroken standby light from described dc-battery power supply.

9, fluorescent lamp lighting system as claimed in claim 1, it is characterized in that described power converter comprises: be connected to the switching device on the described power supply, described switching device can be controlled by a drive waveforms circuit, with the mark space scaling signal that provides one-period to change from described power supply, described cycle change sign space ratio signal is provided for an output circuit when work, it is converted into one and exchanges output supply voltage there, the symbol ratio of described mark space scaling signal can be controlled the instantaneous size of described interchange output supply voltage, described symbol ratio is provided by described drive waveforms circuit, it comes from the waveform that limits in the numeral with constant amplitude that is produced by a feedback network that is connected in described interchange out-put supply and described drive waveforms circuit, and response reduces to minimum to the influence of load variations on the described ac output current and the variation in described power supply.

10, a kind ofly be particularly useful for but be not the power converter that is used for uniquely to non-preheating cathode fluorescent lamp circuit supply alternating current, it is characterized in that described power converter comprises: be used to be connected to the switching device on the power supply, described switching device can be controlled by a drive waveforms circuit, with the mark space scaling signal that provides one-period to change from described power supply, described change sign space ratio signal offers an output circuit when work, it is converted into one and exchanges output supply voltage there, the symbol ratio of described mark space scaling signal can be controlled the instantaneous size of described interchange output supply voltage, the symbol ratio that is provided by described drive waveforms circuit is to come from the digital waveform that limits with constant amplitude that produces in the feedback network that is connected in described interchange out-put supply and described drive waveforms circuit, and response reduces to minimum to the influence of load variations on the described interchange out-put supply and the variation in described power supply.

11, power converter as claimed in claim 10, it is characterized in that described output circuit comprises that a flexible symbol space ratio conversion of signals becomes the low pass filter of half-wave shape, and be to be connected with switching device to receive described half-wave and relatively to be inverted half-wave alternately, thereby an AC wave shape is provided, and supply one converts described AC wave shape to the isolating transformer of described interchange out-put supply phone.

12, power converter as claimed in claim 10 is characterized in that it comprises the disconnecting apparatus that is used in its generation overcurrent load or following described interchange output supply voltage disconnection of over-voltage condition.

13, power converter as claimed in claim 10, it is characterized in that it is to be stored in a memory that described numeral limits waveform, and be used in real time from a pair of digit groups sequence time deferred mount generation time change, one of such one group of waveform of the mark space scaling signal string of constant repetition rate.

14, power converter as claimed in claim 10 is characterized in that any required ac output voltage is to obtain by the mathematical model group that is stored in a suitable definition in the memory.

15, power converter as claimed in claim 10, the selection that it is characterized in that ac output voltage are to obtain by the mathematical model that the external feedback control loop is digitally selected to be stored in the memory.

16, power converter as claimed in claim 10 is characterized in that preestablishing the ac output voltage of a numeral definition so that make load circuit consumption or expend constant power.

Images