WO2008074231A1

WO2008074231A1 - A voltage regulation and control circuit of illumination lamplight

Info

Publication number: WO2008074231A1
Application number: PCT/CN2007/003726
Authority: WO
Inventors: Kawai Eric Cheng; Waifung Choi; Chikeong Cheong; Yan Lu
Original assignee: The Hong Kong Polytechnic University
Priority date: 2006-12-21
Filing date: 2007-12-21
Publication date: 2008-06-26
Also published as: CN101207961A; CN101207961B

Abstract

A voltage regulation and control circuit of illumination lamplight is applied to a single-phase illumination system composed of a main power supply and lighting loads which are in series. The single-phase illumination system includes: a main power supply for outputting sine alternating current, lighting loads; a voltage regulation and control circuit of illumination lamplight which is in series in the loop formed with the main power supply and lighting loads, and includes a voltage regulation circuit and an auxiliary power supply. The voltage regulation circuit produces an auxiliary voltage to regulate and control the amplitude value of sinealternating current voltage on the lighting loads. The power consumption of this voltage regulation and control circuit of illumination lamplight is lower, and the harmonic waves on the lighting loads is also very small, so the alternating voltage on the lighting loads is still a sinusoid and satisfies with the normal voltage demand of lighting system loads. Especially for HID lamps and fluorescent lamps, the input of sinusoid voltage decreases flicker and increases power factor, prolongs the service life of light fixtures. The method can also be applied to other light fixtures with sinusoid voltage input.

Description

Voltage control circuit for lighting

The present invention relates to a voltage regulation technique, and more particularly to a voltage regulation circuit for illuminating a light. Background technique

In recent years, urban night lighting has become the mainstream of night power supply. Bright lighting has made most cities a city that never sleeps, bringing huge economic benefits and convenience to people's life, work, production and entertainment. At the same time, facing The problem is the large amount of power loss in lighting. Therefore, lighting projects need to adopt efficient energy-saving light sources, that is, use light-emitting bulbs or lamps, and adopt measures to install energy-saving control equipment on existing lighting systems. In order to meet the requirements of green, energy saving and environmental protection.

High Intensity Discharged Lamp (HID) is a high-intensity gas discharge lamp. It is a new energy-saving electric light source. It has excellent luminous efficiency due to its high luminous efficiency, good color rendering and long life. It is widely used in urban streets, large supermarkets, stadiums and industrial facilities. Generally, every high-pressure gas discharge lamp, such as a high-pressure sodium lamp, a metal halide lamp (metal halide lamp), a high-pressure mercury lamp, etc., must have a ballast, and most of the ballasts used are magnetic ballasts or electronic towns. Streamer.

When the HTD lamp is started, it is often required to be realized under the power frequency voltage. When it starts to work normally, the gas medium in the lamp tube is also activated until normal light is emitted. At this time, if a certain proportion of input power is reduced, the power is supplied thereto. Not only does it not have much impact on the contrast, but it also effectively extends the life of the lamp. According to a large number of experimental statistics, the illuminance of conventional lamps such as fluorescent lamps is reduced by about 7% for each 10% reduction of the power supply voltage, and the human eye has a logarithmic relationship with the illuminance of the light, that is, when the illuminance of the light is reduced by 10%, in theory, The human visual perception brightness is only reduced by 1%, so a slight change in the illumination caused by the input power of the lamp is not reduced, which will not affect the normal use, but the lamp life can be extended by 70%.

Therefore, when the lighting system needs to be operated under the condition of energy saving or overvoltage protection, the method of adjusting the input voltage is often used to achieve the purpose of illuminating the illuminance of the luminaire. The advantage of this adjustment mode is that a small downward voltage can make The power of the load is greatly reduced, and the energy saving effect is very obvious. This technology is more representative of fixed multi-step buck and thyristor chopper buck technology. Both of these techniques are directed to the direct processing of the voltage of the mains supply of the load.

The crystal oscillating step-down output technology utilizes the thyristor chopping principle. By controlling the conduction angle of the thyristor, the sinusoidal voltage of the grid input (main power) is removed, thereby reducing the average value of the output voltage. To achieve the purpose of regulating voltage and saving energy. But the voltage regulation method exists as Lower defect:

1) The voltage of the thyristor chopping output cannot output a sine wave;

2) A large number of harmonics appear, which form a harmonic pollution to the power grid system, which is extremely harmful. In developed countries abroad, there are already express restrictions on the harmonic content of electrical equipment. In China, large cities such as Beijing, Shanghai, and Guangzhou have already restricted the use of equipment with excessive harmonic content into the grid;

3) In order to eliminate the defects of harmonic pollution, it is very uneconomical to add filter equipment to these high-power thyristor chopper-type power-saving devices.

The advantage of fixed multi-step buck output is to overcome the defects of harmonic generation of thyristor chopping products, realize the sine wave output of voltage, structure and function are very simple, of course, the reliability is also high; The core component of the device is a multi-tap transformer with a variable voltage ratio. The secondary of the transformer has 3 to 5 buck taps (for example: 5V, 10V, 15V, 20V, etc. ), once the terminal is fixed, the reduced voltage value is a fixed value; this discontinuous voltage regulation method has the following defects:

1) When the grid voltage fluctuates, the output voltage of the regulating device will also fluctuate up and down, so that the operating voltage of the illumination is in an unstable fluctuation state, and the light source cannot be precisely regulated;

2) The voltage regulation method uses the AC contactor to switch the gear position. When the AC contactor is mechanically engaged and disconnected during the gear shifting operation, there will be a short power failure of 10~20 milliseconds. , we call it "flash", such a power failure will cause the HID lamp (such as high pressure sodium lamp, metal halide lamp, high pressure mercury lamp, etc.) to go out. The characteristics of this kind of lamp determine that after it is extinguished, it must wait until the lamp is cooled, and the vapor pressure is lowered before it can be lit again. It usually takes about 5 to 10 minutes. Summary of the invention

In view of the deficiencies of the above two voltage regulating technologies, an object of the present invention is to provide a voltage regulating circuit for illuminating lights capable of overcoming the above-mentioned drawbacks, for generating an auxiliary voltage of a main power supply voltage inversion or different phases, so that This auxiliary voltage is loaded onto the load along with the main power source.

Based on the above object, the present invention provides a voltage regulating circuit for lighting, which is suitable for use in a lighting system consisting of a main power source and a lighting load connected in series, wherein the main power source outputs a sinusoidal alternating voltage; The voltage regulating circuit comprises: a voltage regulating circuit connected in series between the main power source and the circuit formed by the lighting load to generate an auxiliary voltage to regulate the voltage value applied to the lighting load; the auxiliary power source is connected to the voltage regulating circuit, To provide regulated power to the voltage regulator circuit.

Preferably, the voltage regulating circuit of the illumination light further comprises: a bypass switch connected to the modulating piezoelectric circuit for switching between the regulated state and the unregulated state. Preferably, the bypass switch is an AC contactor.

Preferably, the voltage regulating circuit comprises: a transformer, the primary is connected to the auxiliary power source; and the switching circuit is composed of a first thyristor (SCR1) and a second thyristor (SCR2) connected in parallel, and The secondary connection of the T/CN2007/003726 press is used to generate an AC auxiliary voltage to be provided on the main power supply and the lighting load connected in series thereto; the bridge rectifier circuit has an input terminal connected to the output of the switch circuit, and an output The terminals are connected in series in a loop formed by the main power source and the lighting load.

Preferably, the voltage regulating circuit further comprises: a low pass filter circuit serially connected between the switch circuit and the bridge rectifier circuit for smoothing the auxiliary voltage waveform output by the switch circuit.

Preferably, the auxiliary power source is an AC power source or a DC voltage source.

Preferably, the AC power source and the main power source are the same power source for supplying power to the primary of the transformer, and further comprising: a rectifier circuit connected to the main power source between the transformer and the main power source; DC-DC conversion And connected to the rectifier circuit; an H-bridge converter connected to the output of the DC-DC converter to generate an AC voltage input to the transformer.

Preferably, the voltage regulating circuits of the illumination lights are respectively connected in series in each phase lighting circuit of the three-phase lighting system to form a voltage regulating circuit of the three-phase lighting.

It can be seen from the above technical solution that the present invention continuously adjusts the input voltage applied to the lighting load without directly processing the voltage of the main power source of the load, thereby achieving the purpose of accurately regulating the illumination load illumination. The voltage regulating circuit of the illumination lamp can reduce the illumination load illuminance slightly, and greatly reduce the power consumption of the illumination load, and the harmonic component contained in the sine wave satisfies the electromagnetic compatibility (Electro Magnetic Compatibility referred to as EMC). The standard of the wave component. That is to say, the voltage regulating circuit of the lighting lamp establishes a new economic operating voltage mode for the lighting principle and electrical characteristics of the gas discharge lamp (mercury lamp, sodium lamp, metal halide lamp, etc.), and the method can make the lighting load ( For example, the HID lamp is operated in a regulated state, so that the voltage applied to the lighting load can be adjusted from the currently used voltage value to the voltage value corresponding to the illumination required by the lighting load, thereby reducing the total power consumption and regulating the illumination. Illumination of the load. The voltage control circuit of the illumination light consumes less power, and the harmonics loaded in the illumination load are also very small, so that the AC voltage loaded on the illumination load is still sinusoidal, meeting the normal voltage demand of the lighting system load, especially for HID lamps or fluorescent lamps, input sinusoidal voltage reduces flicker, improves power factor, and extends the life of lighting fixtures. In addition, this method is also applicable to other lighting fixtures with sinusoidal voltage inputs. DRAWINGS

1 is a basic schematic diagram of a lighting control system based on a voltage control mode according to the present invention; FIG. 2 is a schematic diagram showing a relationship between a load voltage change rate and a light illuminance of a lighting control circuit of the present invention in a dimming mode;

3 is a schematic diagram of a single-phase illumination light control circuit according to an embodiment of the present invention;

4a is a waveform diagram showing current and voltage of a lighting load in an undimmed state (when the current contactor is turned on) according to an embodiment of the present invention; 4b is a waveform diagram of current and voltage of a lighting load in a dimming state (when the current contactor is turned off) according to an embodiment of the present invention;

4c is a waveform diagram of a regulation voltage V _D applied to a bypass switch in a dimming state (when the current contactor is turned off) according to an embodiment of the present invention;

Figure 5a shows a waveform diagram in FIG. 3 loaded on the supply voltage V _c the filter capacitor;

Figure 5b is a waveform diagram showing the voltage V _T outputted by the thyristor in Figure 3;

Figure 5c is a waveform diagram showing the filtered inductor current I _u of Figure 3;

Figure 6a shows the relationship between the switching signals G1 and V _T of the thyristor SCR1 of Figure 3; Figure 6b shows the relationship between the switching signals G2 and V _T of the thyristor SCR2 of Figure 3; Figure 7a shows when the lighting load voltage becomes 200 V Relationship between V _T and V _Q2 ; Figure 7b shows the relationship between V _D and V _G2 when the lighting load voltage becomes 200 V; Figure 8 is a three-phase lighting control of a three-phase lighting control circuit according to an embodiment of the present invention; System diagram

Figure 9 shows a schematic diagram of the auxiliary power supply as a transformer;

Figure 10 shows a schematic diagram of a power electronic converter circuit. detailed description

The light control mode based light control circuit of the present invention will be described in detail below with reference to the accompanying drawings.

Please refer to FIG. 1. FIG. 1 is a schematic diagram of a voltage control system for lighting according to a voltage control mode according to an embodiment of the present invention. As shown, the system includes a main power source 1 and a lighting load 2. In the present embodiment, the voltage V _{M of the} main power source 1 is usually 220 volts AC voltage, and the lighting load 2 can be a high pressure sodium lamp, a low pressure sodium lamp, or a metal. For all gas discharge lamps and lighting fixtures, such as halide lamps and fluorescent lamps, the voltage across the illumination load 2 is VL.

In the circuit formed by the main power source 1 and the lighting load 2, a voltage regulating circuit 5 for illuminating the light is connected in series, and the voltage regulating circuit 5 of the lighting light is used to generate an auxiliary voltage, which is the same as the main power source 1 and is sinusoidal. The AC voltage, which differs only in amplitude and phase (eg, inverting), regulates the voltage value applied to the lighting load 2. The voltage regulating circuit 5 of the illumination lamp comprises a voltage regulating circuit 3 and an auxiliary power source 4; the voltage regulating circuit 3 is connected in series in the main power source 1 and the circuit formed with the lighting load 2; the auxiliary power source 4 is connected to the voltage regulating circuit 3, The voltage circuit 3 supplies power.

In this embodiment, the bypass switch 6 is also connected to the voltage regulating circuit 5 of the illumination light for switching between the regulated state and the unregulated state. That is to say, in the absence of dimming, the bypass switch 6 (for example, an AC contactor) is closed, the voltage regulating circuit 5 of the illumination light is bypassed, and the main power source 1 and the lighting load 2 are connected in series to form a loop, and the lighting load 2 The voltage VL is the voltage V _M . In the dimming state, the bypass switch 6 is turned off, the main power source 1, the lighting load 2, and the illumination lamp The voltage control circuit 5 of N2007/003726 is connected in series to form a loop, and the voltage outputted by the main power source 1 and the voltage regulating circuit 5 of the illumination light is jointly loaded on the illumination load 2, that is, the voltage V _D generated by the voltage regulation circuit 5 of the illumination light is lowered. The effective voltage applied to the lighting load enables the lighting control of the lighting load 2.

The decompression sinusoidal auxiliary power supply used for the regulation of the illumination system lighting based on the voltage control mode is mainly related to the magnitude of the voltage, and has a certain correlation with the phase angle Θ characteristic of the voltage V _D generated by the voltage regulating circuit. Sex. This can be calculated from the following equations.

As can be seen from Figure 1, the voltage v _M loaded on the lighting load is - v _M = v _L + v _D (1)

Suppose V _M is a sine wave and its equation is:

V _M = V _l sin( ωί) (2)

The voltage generated by the voltage regulator circuit is V _D:

V _D = V ₂ sin(^ + (3)

Therefore, the voltage is:

V _L =V _M -V _D = V _x sin(i»t) - V ₂ sin(©t + θ) (4)

Result: V _L =V _n sin^t + ^--) (5)

Where: V _u = grab -V ₂ cos0) ² + (V ₂ sine) ² (6)

Where θ=0, φ=π/2 and VL is reduced to:

V _L = (V _l - V ₂ ) sin( ωί) (8)

It can be seen from the above calculation equation (6) that V ₁₂ only obtains the decompression amplitude of the illumination load, that is, the result of the regulation directly determines the magnitude of the effective voltage on the illumination load 2, and also changes the load on the illumination load. Voltage phase angle.

Please refer to FIG. 2. FIG. 2 is a schematic diagram of a voltage change rate curve in a dimming mode according to an embodiment of the present invention; as can be seen from FIG. 2, the abscissa is the voltage V _D of the voltage regulating circuit, and the ordinate is loaded in the illumination. The voltage VL on load 2. Assume that the main power supply 1 is 220V, and the 0-60V voltage phase angle of the voltage regulator circuit is 0-40 degrees. Then, the five curves included from top to bottom are the phase angles of the voltage regulation circuit are 40, 30, 20, respectively. The change rate curves of voltages VL and V _D at 10 and 0 degrees. As shown in the figure, when the amplitude of the regulation voltage is 60V and the phase angle is 40 degrees, VL is 180V. When the amplitude of the regulation voltage is 60V and the phase angle is 0 degree, VL is 160V; It can be seen that if the voltage amplitude used by the voltage regulator circuit is 60V, the maximum regulation voltage range can be 220V to 160V. In the actual regulation process, it is not necessary to greatly reduce the voltage on the lighting load 2. Therefore, when the voltage of the lighting load 2 such as a fluorescent lamp or a HID lamp is not greatly reduced, as long as the voltage value is reduced 10-20%, there will be very good control effects.

Please refer to FIG. 3. FIG. 3 is a schematic diagram of a specific circuit for single-phase illumination lighting control according to an embodiment of the present invention. Similar to that shown in Fig. 1, the single-phase illumination system includes a main power source 1 and a lighting load 2, and in the loop formed by the main power source 1 and the lighting load 2, a voltage regulating circuit 5 for illuminating the light is connected in series. The voltage regulating circuit 3 in the voltage regulating circuit 5 of the illumination lamp is composed of a transformer 31 for transforming and isolating, a switching circuit 32, a low-pass filter circuit 33, and a bridge rectifier circuit 34. The primary of the transformer 31 is connected to the auxiliary power supply 4, and the secondary of the transformer 31 is connected to the switching circuit 32; the transformer 31 supplies the switching circuit 32 with a low voltage such as V _A = 24V. The switch circuit 32 is composed of a first thyristor SCR1 and a second thyristor SCR2 for generating an auxiliary voltage to be provided on the main power source 1 and the illumination negative carrier 2 connected thereto; the first thyristor SCR1 and the second thyristor SCR2 are respectively The control signal G1 and the control signal G2 control the output; the voltage generated by the first thyristor SCR1 and the second thyristor SCR2 is connected to the Ctl-center- tap point, and the voltage values output by the two transistors are added. The 1⁄2 auxiliary power waveform outputted by the switching circuit 32 is smoothed by the low-pass filter circuit 33, and then input to the bridge rectifier circuit 34 composed of the diode groups D1, D2, D3 and D4; since the 5 output terminals of the bridge rectifier circuit 34 are connected in series In the circuit formed by the main power source 1 and the illumination load 2, therefore, the sinusoidal AC auxiliary voltage output from the bridge rectifier circuit 34 is loaded on the illumination load 2 together with the voltage of the main power source 1, so that the illumination of the illumination system can be realized.

Referring to FIG. 4a, FIG. 4a is a waveform diagram of current and voltage of a lighting load in an undimmed state (when the current contactor is turned on) according to an embodiment of the present invention. The curve below the graph represents the lighting load voltage is 0 210Vrms (200V / div), the curve above the graph represents the lighting load current = 3.5A rms (5A / div). At this time, the table power of the lighting system is 735 VA, the effective power is 434 W, and the power factor is 0.59. This power factor is a typical value of a fluorescent lamp.

Please refer to FIG. 4b. FIG. 4b is a waveform diagram of current and voltage of the lighting load in the dimming state (when the current contactor is disconnected) according to an embodiment of the present invention. When the curve at the bottom of the graph represents the voltage drop to 188

At 15 Vrms (200 V/div), the current represented by the curve above the graph is reduced to 2.12 Arms (5 A/div:).

It can be seen that as an illumination system, the reduction in power does not vary linearly with the decrease in voltage, and is highly nonlinear. That is to say, a small reduction in voltage can significantly reduce the power. The effective power at this time becomes 211W.

Please refer to FIG. 4c, which is a dimming state (when the contactor is disconnected) according to an embodiment of the present invention.

;0 Waveform of the regulated voltage V _D loaded on the bypass switch. Assuming that the amplitude of the regulated voltage is 42 volts, then the curve above the graph represents the illumination load current I (5 A/div) and the curve below the graph represents the illumination regulation voltage V _D (40 V/div). It can be seen from the figure that the harmonic component of the regulation voltage V _D is high, but the ratio of the amplitude of the harmonic voltage to the voltage amplitude of the main power source 1 is small, and therefore, the amplitude of the sinusoidal voltage applied to the load 2 The harmonic component is low.

;5 See Figure 5, the curve at the bottom of Figure 5a shows the voltage applied across the filter capacitor in Figure 3. Waveform of V _c ; Figure 5 b shows a waveform of the voltage V _T generated from the thyristor in Figure 3; this voltage V _T is also the input voltage of the low pass filter circuit. The curve above the graph represents the lighting load current IL. As can be seen from the figure, the switching action of the two thyristors produces some harmonic components. The waveform of the filtered inductor current Iu is shown below Figure 5c, and the upper curve represents the voltage V _T .

Please refer to FIG. 6. FIG. 6 shows the relationship between the switch control signal G1 of the two thyristors and the switch control signals G2 and V _T . Figure 6a shows the relationship between the switching signal and V _T of the transistor SCR1 in Figure 3; the curve above the figure represents the voltage V _T (Ctl_GND SI Ctl - center-tap) (20V/div), and the curve at the bottom of the figure represents Voltage V _G1 (Gl to Ctl__ _GND ) (2V/div). FIG 6 b 3 line graph showing the relationship between ¾ thyristors SCR1 and the switching signal of V _T. FIG located above the curve represents the voltage V _T (Ctl_ _CND to Ctl- center- tap) (20V / div ), located below the curve represents the voltage V of FIG _{_{G2 (G2 to Ctl_ GND) (}} 2V / div). As can be seen from the figure, the waveforms of the control signal G1 and the control signal G2 are complementary to each other.

Please refer to Figure 7. Figure 7 shows another set of experimental data when the lighting load voltage becomes 200 V. Figure 7a shows the relationship between V _T and V _Q2 when the lighting load voltage becomes 200 V; the curve above the graph represents the voltage V _T (Ctl - GND to Ctl - center - tap) (20V / div), located below the figure The curve represents the voltage V _G2 (G2 to Ctl — _GND ) (2V/div). FIG 7 b shows that when the lighting load voltage becomes 200 V V _D and V _∞ off the curve, located above the curve represents the voltage V of FIG. _D (V to Neutral) (40V / div), located below the curve represents the voltage V of FIG. _G2 (G2 to Ctl_ _GND ) (2V/div). As can be seen from the figure, the voltage generated from the voltage regulating circuit has a higher amplitude 3⁄4. The horizontal scale of Figure 4-8 above is 5ms/div.

Please refer to FIG. 8. FIG. 8 is a schematic diagram of a three-phase illumination lighting control system according to an embodiment of the present invention. As shown in the figure, the voltage regulation circuit 5 of the single-phase illumination light is respectively connected in series in each phase illumination circuit of the three-phase illumination system to form a voltage regulation circuit of the three-phase illumination light. The lighting load can be three separate phase lighting loads (load Ll, load L2, load L3), which are powered by a single phase of the three-phase power supply (Ll, L2, L3). In this case, three bypass switches are required to switch between the regulated state and the unregulated state.

It should be noted that the auxiliary power source 4 shown in Fig. 1 can be obtained from an AC power source or a DC voltage source. Specifically, the auxiliary power source 4 can be obtained from energy storage or capacity equipment such as a battery pack and a generator, and can also be obtained from the power supply branch of the main power source 1 of the lighting system using an isolated technique.

Please refer to Figure 9, Figure 9 for an example of the auxiliary power supply 4 using a transformer. As shown, the transformer

The primary connection of 31 (Tr2) is on the lighting system power supply (Mains). Please refer to FIG. 10, which shows a schematic diagram of a power electronic converter. The power supply of the illumination system is used as an input power source, and the voltage directly input to the power supply of the illumination system is processed by a bridge rectifier or other rectifiers to obtain a voltage. The AC voltage input to the transformer 31. Specifically, the main power supply 1 is assumed to be used in the main power supply of the lighting system, wherein the primary of the transformer 31 is connected to the main power supply 1, and Further, between the transformer 31 and the main power source 1, a rectifying circuit, a direct current-direct current (DC/DC) converter, and an H-bridge converter sequentially connected to the main power source 1 are included. The DC current generated by the rectifier circuit is reduced to a low voltage by a DC/DC converter. The H-bridge can be composed, for example, of four metal oxide field effect transistors (T _1A , T _1B , T _1B and T _2B ), H-bridge The converter is connected to the output of the DC/DC converter to generate an AC voltage input to the transformer 31. In addition, the AC voltage uses a sinusoidal pulse width modulation (PWM) technique to generate a sine wave, and directly supplies the secondary output V _A or V _{T of the} transformer 31 with a regulated voltage having an appropriate high frequency waveform.

It is to be understood that the above summary of the invention and the specific embodiments are intended to be illustrative of the application of the invention. Those skilled in the art can make various modifications, equivalent substitutions, or improvements within the spirit and scope of the invention. The scope of the invention is defined by the appended claims.

Claims

Rights request

1. A voltage regulating circuit for lighting, suitable for use in an illumination system consisting of a main power supply (1) and a lighting load (2), wherein the main power supply (1) outputs a sinusoidal alternating voltage, the characteristics thereof The voltage regulating circuit (5) of the illumination light comprises:

a voltage regulating circuit (3) connected in series between the main power source (1) and the lighting load (2) for generating an auxiliary voltage to regulate a voltage value applied to the lighting load (2);

The auxiliary power supply (4) is connected to the voltage regulating circuit (3) for providing a power supply for the voltage regulating circuit (3).

2. The voltage regulating circuit for lighting according to claim 1, wherein the circuit further comprises: a bypass switch (6) connected to the voltage regulating circuit (3) for regulating Switching between state and unregulated states.

3. A voltage regulating circuit for an illumination lamp according to claim 2, characterized in that said bypass switch (6) is an AC contactor.

4. The voltage control circuit for lighting dimming according to claim 1, wherein the voltage regulating circuit (3) comprises:

a transformer (31) whose primary is connected to an auxiliary power source (4);

a switching circuit (32) consisting of a first thyristor (SCR1) and a second thyristor (SCR2) connected in parallel and connected to a secondary of the transformer (31) for generating a string to be provided in the main power source (1) AC auxiliary voltage on the connected lighting load (2);

The bridge rectifier circuit (34) has an input terminal connected to the output end of the switching circuit (32), and an output terminal serially connected in the loop formed by the main power source (1) and the illumination load (2).

The voltage regulating circuit for lighting according to claim 4, wherein the voltage regulating circuit (3) further comprises:

The low pass filter circuit (33) is connected in series between the switch circuit (32) and the bridge rectifier circuit (34) for smoothing the auxiliary voltage waveform output by the switch circuit (32).

6. A voltage regulating circuit for an illumination lamp according to claim 1, characterized in that said auxiliary power source (4) is an alternating current source or a direct voltage source.

The voltage regulating circuit for lighting according to claim 6, wherein the alternating current power source and the main power source (1) are the same power source for supplying power to the primary of the transformer (31), and The transformer and the main power source (1) described further include:

a rectifier circuit connected to the main power source (1);

a DC-DC converter connected to the rectifier circuit;

An H-bridge converter is coupled to the output of said DC-DC converter to produce an AC voltage input to said transformer (31).

8. The voltage regulating circuit for lighting according to any one of claims 1 to 7, characterized in that The voltage control circuit (5) of the illumination light is respectively connected in series to each phase illumination circuit of the three-phase illumination system to form a voltage regulation circuit of the three-phase illumination light.