control system

The subject of the invention is an electronic ballast for sodium vapor, mercury vapor, halogen and other arc lighting sources for balanced power driving, modified structure arc lighting source, and power control system, making possible longer working life by regulating the functioning of arc lighting sources, as well as more economical operation adaptable to the magnitude of the local line voltage.

The ballast can be economically applied in case of any arc lighting sources, it is especially suitable for functioning high-pressure street lamp network in an optimum way, more economical, than before.

Generally there are two electrodes in arc lighting sources in a space, filled with high- pressure gas. During operation gas is ionized, a conductor plasma is created, in which light is generated. Meanwhile metallic particles come away from the electrodes to the gas space, generally depositing on the wall of lower temperature of the gas space. As these particles absorb a part of the light created in the gas space, the intensity of the light, the lamp power decreases during the working life of the lighting source, the body of the lamp is growing hot more and more, less and less proportion of the consumed power is utilized as light, the lamp body breaks down.

During operation the lamp power of the generally used arc (gas discharge) lighting sources depends on the driving power. Currently driving takes place with alternating current, A.C. of sinusoidal character, the peak current is 1.41 times more, than the effective current intensity.

The working life of the electrodes of the lamp is shortened by the load pressure resulting from the periodic peak currents. When using traditional inductive adapters for driving, according to findings the operating power is abt. 30% higher, than the indicated apparent power, when switching on, it is considerably higher, starting output can even be seven times higher, resulting in the considerable loading of the network as well as the lighting source. After starting, a warming up time of even 30 seconds is needed, when lamp power is low, or fluctuating.

According to the state of the art the CN 1388562 patent description makes known multiple-electrode low-mercury vapor pressure discharge fluorescent lamp. The fluorescent lamp includes inductive ballast, lamp tube with two basic electrodes, preheating starter, capacitor, one (or more increased electrode between the ends of the lamp tube and two opposite diodes with N end connected to the increased electrode and P end connected to one of the basic electrodes. The fluorescent lamp with three or more electrodes, after being connected to the circuit, has lower working voltage, increased working current, raised power factor, reduced negative particle bombardment to the basic electrodes, and thus excellent working performance and long service life. The KR 100654896 patent description makes known an electronic ballast for high intensity discharge lamp. The electronic ballast for a high pressure discharge lamp is provided to minimize the size thereof by reducing the number of parts and simplifying a control circuit. In an electronic ballast for a high pressure discharge lamp, an EMI filter removes various kinds of noises from AC power to be inputted. A boosting converter compensates a power factor of the AC power filtered through the EMI filter, and rectifies the AC power into predetermined DC voltage. A voltage detecting unit is located inside the boosting converter, and detects the size of DC voltage to be outputted and changes the voltage detecting reference according to a control signal to be inputted. A PFC control circuit maintains output voltage of the boosting converter as a predetermined value based on the size of voltage detected in the voltage detecting unit. An ignition circuit initially starts a lamp turned on by a voltage signal output from the boosting converter. A step-down buck converter converts the DC voltage output from the boosting converter to an AC signal of a predetermined frequency. A main controlling unit outputs a control signal for driving the step-down buck converter by detecting the value of voltage and conducting current value on the lamp, and upwardly adjusts the voltage detecting reference of the voltage detecting unit.

The WO 02077739 patent description makes known electronic dimmable ballast for high intensity discharge lamp. The dimmable electronic ballast for an HID lamp includes a rectifier stage for rectifying an AC input and providing a rectified DC output, a power factor correction stage for modifying a power factor of the AC input and for providing an increased voltage DC output from the rectified DC output, an electronic ballast control circuit for providing a driving signal comprising a pulse train for controlling a switching operation of an output switch stage driving the HID lamp; the output switch stage having at least one electronic switching element coupled to the increased voltage DC output for providing a pulsed power signal to the HID lamp to power the lamp, the electronic ballast control circuit having a feedback input comprising a signal related to the power dissipated by the HID lamp for maintaining the power at a desired level, the desired level being set by a dimming control input to the electronic ballast control circuit. The circuit provides high frequency power, typically above 50 kHz, to the HID lamp.

The WO 2004084585 patent description makes known high intensity discharge lamp ballast circuit. The integrated circuit controls a power converter that includes single stage buck-boost converter and a switching full bridge that may be used to drive an HID lamp. The single stage buck-boost converter reduces the complexity and parts count of the power converter, or electronic ballast, while permitting PFC and DC bus voltage regulation under control of the integrated circuit. The integrated circuit also provides all the drive signals to operate the switching full bridge circuit to maintain constant power on the HID lamp. A wait timer provides an interval of time between restart attempts for the HID lamp to permit the lamp to cool so that high hot restart voltages are avoided. The integrated circuit simplifies the design of power converters and electronic ballasts in particular, while contributing to reducing part count, complexity and cost in conjunction with the single stage buck-boost converter. The WO 2006096638 patent description makes known automotive high intensity discharge lamp ballast circuit. The electronic ballast for driving a high intensity discharge (HID) lamp is provided. The electronic ballast includes a voltage boost stage for receiving a DC input voltage and outputting a boosted DC output voltage with a controlled current. It further includes a switching stage for converting the boosted DC output voltage to a switched AC voltage capable of driving the HID lamp. An integrated circuit (IC) is coupled to the voltage boost stage and the switching stage for controlling both. The IC includes a lamp power control circuit comprising a sensing circuit for sensing an output current from the switching stage and the boosted DC output voltage, a current control loop which controls the lamp power if the lamp current is at a maximum level and a power control loop which controls the lamp power if the lamp current is below a maximum level. The IC also includes a controller unit interface and provides an ignition mode and a regular operation mode.

The shortcoming of the solutions, known and used in practice is, that they do not ensure the permanent regulation of the lamp power in real time, in the complete power range, independently from place and time.

When working out the solution according to the invention we aimed at

-making operating power and lamp power of arc lighting sources steadier and more regulated, that is the lamp power can be regulated in the complete power range in real time, indepently from place and time, resulting in the increase of efficiency of energy consumption, because resulting from the power regulation only as much energy is used as stipulated, respectively exactly as much, as needed,

-starting of arc lighting sources can be carried out with a starting power not exceeding nominal power, or even much smaller than that,

- the new drive could be possibly used with any traditional arc lighting source,

-the new drive could be used possibly within a wide range of active voltage independent from the country of application,

- the working life of the lighting source should increase,

- the lamp source and the working life should possibly increase without modifying the arc lighting source, respectively with slight modification only with identical power.

The solution according to the invention is based on that finding, that modification of the sinusoidal character of the voltage, current intensity and consumed power of alternating current makes possible to achieve steadily higher lamp power with the same energy feed.

The inventional finding is based on the fact, that with inserting an electronic ballast containing micro controller, line rectifier unit, phase correction block, direct current voltage storage, DC/DC converter unit operated by switching, DC/AC inverter unit and choke transformer, the sinusoidal character of the voltage, current intensity and consumed power of alternating current is set to constant periods, with a nought transition with close to zero deadtime, in given case with a linear power boosting of ten seconds at starting. The invention is on the one part an electronic ballast for arc lighting sources for more balanced power driving, which is characterized by that, it has a line rectifier unit for supplying line alternating current, phase correction block, direct current voltage storage, DC/DC converter unit operated by switching, DC/AC inverter unit and choke transformer, connectable to the electrodes of the arc lighting source where a microcontroller with independent supply unit is connected to the DC/DC converter unit operated by switching, making possible the power regulation.

The invention is further a modified structure arc lighting source, which is characterized by that, that there is a third collecting electrode of higher potential level beside the two electrodes situated on the wall of the high pressure gas space, and said collecting electrode is connected to a voltage generator of high voltage with independent supply unit.

The invention is furthermore a power regulating system, primarily with the application of the ballast according to the invenion, as well as the lighting source according to the invention, which is characterized by that, the controlling microcontroller has powerline interface suitable for long distance control.

In a preferred application of the system according to the invention, the controlling microcontroller has ambient light sensing device.

In another preferred application of the system according to the invention, this driving produces more lamp power by using less energy during its operation.

In a further preferred application of the system according to the invention, the working life of the arc lighting sources is extended during the operation, resulting from the low starting power.

In a further preferred application of the system according to the invention, during the operation the drive ensures lamp power free of vibration.

In a further preferred application of the system according to the invention, during the operation there is no deadtime at the inverter driving.

In a further preferred application of the system according to the invention, during the operation there is constant power control.

In a further preferred application of the system according to the invention, during the operation the frequency of the drive of the lamp can be synchronous with the line frequency, but max. 200 Hz is recommended.

In a further preferred application of the system according to the invention, during the operation the peak current in every period is controlled. In a further preferred application of the system according to the invention, during the operation constant (permanent) current is ensured during full time or partial time of the half period.

The solution according to the invention is set forth furthermore on basis of the enclosed drawings:

Fig 1 shows the comparison of the characteristics of the traditional main current and the characteristics achieved with the new ballast.

Fig 2 shows the block-diagram of a preferable realization of the electronic ballast.

Fig 3 shows a possible realization of the new electronic ballast in circuit.

Fig 4 shows the circuit diagram of the new ballast with an arc lighting source of two electrodes.

Fig 5 shows the scheme of the modified lighting source completed with collecting electrode.

Fig 1 shows the comparison of the characteristics of the traditional network current and the ones achieved with the new ballast.

As it can be seen in the drawing, the characteristics according to the invention aim at establishing a constant value, which in frequency and phase is the same as the original, but in squaring, that is a constant value within a half, resp. quarter period (current intensity, voltage and power), with the closest deadtime to 0 (zero) at the change between the positive and negative range of alternating current (full-bridge drive). According to the findings, such shortening of the transition decreases considerably the vibration or fluctuation of light, even at low frequency.

Fig 2 shows the block-diagram of a preferable realization of the electronic ballast.

Lighting source 1, line rectifier unit 2, phase correction block 3, direct current voltage storage 4, DC/DC converter unit operated by switching 5, DC/ AC inverter unit 6 and the choke transformer 7 can be seen. Furthermore the controlling microcontroller 8, the current sensing element 9, the power line interface 10, and the supply unit 11 of control connecting to the collecting electrode 19 of the voltage generator 12 can be seen. The supply unit 13 of the voltage generator and the ambient light sensing device 14 can be seen as well. Furthermore the lighting source 1, the gas space wall 17, the electrodes 18 of the lighting source and the collecting electrode 19 of lighting source can be seen.

Fig 3 shows a possible realization of the new electronic ballast in circuit.

The drawing shows the definite connection built with the integrated circuits, with the Tl , T2, T3 coils respectively with the transformers, as well as the logic gates, operation amplifiers, furthermore with resistors R, condensers C, diodes D.

Fig 4 shows the circuit diagram of the new ballast with an arc lighting source of two electrodes.

The drawing shows the two electrodes 18 of the lighting source 1 , driving of which takes place with a circuit controlled by two integrated circuits. Fig 5 shows the scheme of the modified lighting source 1 completed with collecting electrode.

There is a third collecting electrode 19 of higher potential level beside the two electrodes 18 situated in the high pressure gas space, formed in the gas space wall 17 of the arc lighting source 1 of modified structure, and said collecting electrode 19 is connected to a voltage generator 12 of high voltage with independent supply unit 3.

Beneficial forms, applications:

The electronic ballast can be used for balanced power driving of arc lighting sources 1 and it has line rectifier unit 2, phase correction block 3, direct current voltage storage 4, DC/DC converter unit operated by switching 5, DC/ AC inverter unit 6 that can be connected to main alternating current, and a choke transformer 7 that can be connected to the electrodes 18 of the lighting source 1. A controlling microcontroller 8 with independent supply unit 1 1 joins the DC/DC converter unit operated by switching 5, that makes possible the power regulation.

In case of a beneficial, preferable realization of the solution according to the invention, the power regulation takes place in real time, in the complete power range, independent from place and time. To achieve this, the regulating system according to the invention has such an unit, that makes power regulation possible. A controlling microcontroller 8 with independent supply unit 1 1 joins the DC/DC converter unit operated by switching 5, that makes possible the power regulation. Explanation: power regulation takes place with the outgoing current regulation of the DC/DC converter unit, the level of which can be freely changed. Its value determines the output power. The inverter (DC/AC inverter unit) produces from this constant direct current a tetragonal current of constant amplitude - for the lighting source.

The ballast producing the new charateristics (driving circuit, electronic ballast) consists of circuit blocks of well separable functions:

- block improving power factor: rectification of the incoming alternating current takes place here, as well as a voltage modification ensuring its applicability independently from the magnitude of the incoming line voltage. In the experiments the ingoing alternating current is 86-264 V ac, the outgoing direct voltage is 380-400 Vdc.

- a block connected with it, ensuring constant current intensity,

- it changes back the direct current of 380-400 Vdc coming from the block improving the power factor into an alternating voltage of tetragonal characteristics with frequency conforming with the line voltage and phase. In order to achieve a steady power level an analogous multiplier in a regulating loop supplies the lighting source with voltage and current intensity in the required ratio. A built-in microcontroller ensures the linear power running up.

In a preferable case the control unit is combined with an ambient light sensing device 14, making the operation of the system cost-effective.

According to the realization of the invention ensuring balanced power driving and longer working life for arc lighting sources 1 a third collecting electrode 19 of higher potential level is placed beside the two electrodes 18 traditionally situated in the high pressure gas space of the arc lighting sources 1. The collecting electrode 19 attracts the metallic particles released into the gas space from the two electrodes 18, so they can not deposit on the gas space wall 17, so the lamp power does not decrease, and overheating can stop. The collecting electrode 19 is preferably continously connected with a potential of high voltage, created by a separated unit. As control is done with low frequency, efficiency is great, so practically there is loss of direct current only.

The solution according to the invention can be realized with more up-to-date solutions as the state of the art changes, with safety technology applications.

The advantages of the solution according to the invention:

The invention is a new, electronic drive for sodium discharge and other type of arc lighting sources, which can be applied independently from the magnitude of the local line voltage, it is of higher efficiency than the ones used so far, it makes possible the regulation of the lamp power (in the optimal, power range bigger than 90%) without vibration, it increases the working life of the lamp making possible considerable savings.

The advantage of the new driving, compared with the traditional driving of arc lighting sources, that can be justified with calculations are as follows:

• greater lamp power with smaller input power,

• working life of lighting source of new structure is increased resulting from the small starting power,

• considerable energy saving compared with inductive ballasts,

• quazi - zero deadtime driving,

• quazi-constant power driving,

• resulting from the heating flow used as collecting electrode 19 no ignition impulse is necessary for the ionization of the plasma cloud,

• setting of lamp power is possible both through distant control and/or through setting of lamp power by programming adjusted to the time of day,

• a RKV unit can be integrated into the ballast unit, ensuring the possibility of regulating the individual lighting sources independently from place, time and user's requirements,

• it ensures vibrationless light from the point of view of the eyes,

• energy consumption is smaller during warming up, than in operation mode,

• light emmission is bigger in case of the same lighting source and the same energy takeup,

• it can be supplied with optional input alternating voltage,

• all in all the technology offers the possibility of regeneration (restarting) of lamps, respectively lighting sources (without mechanical damages).

The new drive can work through partial-circuits and can be compiled from spare parts known in themselves and available from serial production, it can be applied independently from the magnitude of the ingoing voltage, any of the widely used arc lighting sources can be operated with the modified current emitted - this way it can be inserted into the existing systems easily and in a cost-effective way, achieving better lighting quality and considerable savings - with small investment and without compromises.

With the application of the modified lighting source additional significant increase of efficiency and extension of working life can be achieved. In case of the traditional inductive ballasts the peak power at the start can be even seven times that of the operating power of the lighting sources. The solution according to the invention ensures considerable decrease of the starting power, even to the lowest level of the power range of the lighting source.

Further advantage of use and application resulting from the above are as follows:

- starting of the lamps can take place in any power range (even with a starting power of 3 W) in a stabile and vibrationfree way,

- in the nominal power range regulation is continous in real time,

-optional operating power makes possible the needed light emission, production is easy and economical, as for the fixing only the old circuit - adapter— must be changed to the new ballast, no new wire, or the exchange of the lamp body is needed,

- the electronic ballast is„lamp-friendly", is able to restart unserviceable lamps (free of mechanical damages),

- the working life of the lamps is extended considerably,

- setting of the power values, respectively the lamp power can automatically take place separately for each lamp controlled by a central server.

Changing of the ballast, involving low costs, can mean the revival of arc lamps. The feasibility and actuality of our invention is beyond argument.

In order to justify our findings, lighting technical tests (TTJV 28209062001 ) were carried out in an accredited laboratory. It is important to highlight the minimum starting power and -with comparative measuring -in our case the higher lamp power.

The principle of the solution according to the invention according to our findings can be applied to xenon, respectively inductive lamps as well.

List of references:

1 - lighting source

2 - line rectifier unit

3 - phase correction block

4 - direct current voltage storage

5 - DC/DC converter unit operated by switching

6 - DC/AC inverter unit

7 - choke transformer

8 - controlling microcontroller

9 - current sensing element

10 - power line interface

1 1 - supply unit (control)

12 - voltage generator connecting to collecting electrode (19)

13 - (voltage generator) supply unit

14 - ambient light sensing device

17 - gas space wall

18 - electrode (lighting source)

19 - collecting electrode (lighting source)