JP2011228235A - Energy saving light-emitting diode (led) light - Google Patents

Abstract

PROBLEM TO BE SOLVED: In recent years, LED lighting has been increasingly popularized rapidly from the viewpoint of energy saving and longevity, such as the start of sales by major lighting fixture manufacturers. The present invention relates to an energy-saving control method for LED lighting that adjusts its own brightness according to ambient brightness. In this case, it is necessary to accurately detect the ambient brightness without being affected by the adjacent LED lighting and to control the driving current of the LED lighting.
SOLUTION: The present invention leads a direct current output obtained from an alternating current power source through a PFC circuit composed of a step-up chopper circuit combining a rectifier circuit, a switch and an inductor to an LED circuit by connecting the switch circuit in series, While the AC power supply voltage waveform is near zero voltage, the brightness of the surroundings is detected while the series switch to the LED is turned off, and the DC current is increased by the switch of the PFC circuit so that the LED has the required brightness. Energy-saving LED lighting characterized by controlling the height.
[Selection] Figure 2

Description

  The present invention takes advantage of the fact that the LED can be instantaneously turned on and off, and the ability to continuously control the current, and by controlling to the required brightness according to the environment in which the lighting fixture is attached, The purpose is to realize an energy-saving drive.

  In recent years, LED lighting fixtures are expected to spread rapidly, and many LED lighting fixtures have been released. However, LED lighting fixtures are currently not controlled in brightness according to the environment in which the lighting fixtures are installed, although the brightness can be freely controlled.

  Among conventional lighting fixtures, some lighting with fluorescent lamps that are controlled to be turned on and off according to the surrounding environment are on the market, but continuous control is difficult.

  The present invention takes advantage of the fact that the LED can be instantaneously turned on and off, and the brightness can be freely controlled by continuously controlling the current, and is necessary according to the environment in which the lighting fixture is installed. The purpose is to realize an energy-saving drive by controlling the brightness.

  In order to achieve this purpose, it is necessary to detect the brightness in each environment where the luminaire is installed.

  For this reason, it is conceivable that a brightness sensor is attached to the luminaire itself and the LED current is controlled in accordance with the detection amount.

  And when a single lighting fixture is attached, the objective which can perform illumination control according to the surrounding brightness can be achieved in the environment where the lighting fixture is attached.

  However, when there is an influence of brightness from a large number of adjacent lighting fixtures, it is not possible to detect appropriate brightness in the installation environment.

  When a single luminaire that can adjust the brightness according to the surrounding environment detects the ambient brightness, it is necessary to leave all neighboring luminaires in a non-working state.

  For this reason, when a single lighting fixture that can adjust the brightness according to the surrounding environment detects ambient brightness, a special control device for signal transmission and reception for special synchronization to turn off the neighboring lighting fixture It is considered that installation of is not acceptable as a lighting fixture in terms of price.

  In the present invention, it is a problem required for simplification of lighting fixtures to simultaneously turn off the lighting fixtures in synchronism without performing a special synchronization signal for turning off adjacent lighting fixtures.

  According to the present invention, the power source of the LED lighting apparatus is obtained from the AC power source, and therefore, when the AC power supply voltage is near zero, the synchronization is performed simultaneously without performing any special synchronization signal between the lighting apparatuses. The lighting fixtures can be turned off, and each lighting fixture can detect the ambient brightness at the time of turning off, and it is installed without being affected by the light from the neighboring lighting fixtures. It is possible to control the brightness appropriately according to the location of the lighting fixture being used.

  As a result, it is possible to achieve an appropriate illuminance that suppresses unnecessary brightness in an installation environment that changes with time in individual lighting fixtures, without providing an adjacent lighting fixture and a special synchronization signal processing circuit. It is possible to maintain the environment, and it seems extremely useful as an energy-saving drive method for lighting fixtures.

  In addition, instead of attaching an optical sensor for detecting brightness, simplification of the lighting fixture can be expected by detecting brightness using an illumination LED.

Explanatory drawing of the presence or absence of the influence of ambient lighting and the detectable state of the present invention Main circuit configuration and control system diagram in an embodiment realizing the control principle of the LED lighting apparatus of the present invention Power supply synchronous lighting on / off control operation waveform in an implementation circuit example of the lighting circuit of the present invention Power supply voltage and current waveform in the embodiment when the PFC circuit is incorporated in the embodiment of the lighting circuit of the present invention The experimental operation waveform (current waveform when the surroundings are dark) of the circuit of the embodiment of the present invention. The experimental operation waveform (current waveform when the surrounding is bright) of the circuit of the embodiment of the present invention.

  As shown in FIG. 1 (a), when a photodiode is attached to an LED lighting fixture, the ambient brightness is detected if one LED lighting fixture is in an OFF state and another LED lighting fixture is in an ON state. It is feared that it is not possible to be affected by the adjacent LED lighting apparatus.

  Therefore, in order to accurately detect the brightness around the LED lighting apparatus using the photosensor, it is necessary to turn off all the LED lighting apparatuses as shown in FIG.

  In order to detect brightness while all LED lighting fixtures are turned off, it is necessary to turn off all LED lighting fixtures synchronously. Information exchange by means of is not practical because the system becomes complicated.

  The present invention can be turned off at the same time without requiring special wiring or the like by turning off the lights in synchronism near the zero point of the commercial power supply, and LED lighting fixtures attached with a photo diode in the meantime. It features a method for detecting ambient brightness.

  FIG. 2 shows a main circuit configuration and a control system of the proposed LED lighting apparatus. A number of LEDs for illumination are connected in series, and the circuit is configured to operate at a power supply voltage higher than the maximum value.

The boost switch S _1, the inflow current waveform controlled rectified sine wave, and charges its output to the capacitor Cd. The current control reference current waveform uses a sine wave absolute value waveform by the full-wave rectified voltage waveform, and PFC control is applied so that the actual current waveform matches this.

Here, the magnitude of the current reference is controlled in inverse proportion to the signal from the optical sensor. The signal from the light sensor in synchronization with the power supply cycle, the only switch S ₂ supply voltage near zero, while off the LED, performs detection, power synchronization lighting control another section to be lit It depends on the method.

表１は、ＬＥＤ照明の回路パラメータであり、ＬＥＤは直列に接続されており、その等価回路定数は順電圧降下１５０Ｖ、内部抵抗１５０Ωとし、直流基準電圧２００Ｖで働かせた。

Table 1 shows circuit parameters of LED lighting. The LEDs are connected in series, and the equivalent circuit constants are a forward voltage drop of 150 V, an internal resistance of 150 Ω, and a DC reference voltage of 200 V.

FIG. 3 shows a synchronous lighting control operation waveform. For detecting the brightness in the vicinity of the LED lighting is installed, the power supply voltage indicates the OFF control operation waveform by the switch S ₂ in the vicinity of zero.

  Although the direct current is accompanied by a pulsation of 120 Hz, the brightness is determined by this average current.

  FIG. 4 shows a power supply current waveform with respect to the power supply voltage waveform. A sine wave current waveform in phase with the power supply voltage is obtained, and PFC control can be confirmed to improve power factor.

  Although it was the same as the circuit parameter shown in Table 1, it experimented using the LED lamp of the fluorescent lamp type which connected NS6W083B made from Nichia Corporation in series as illumination LED. The DC reference voltage was 200V.

  As a result of the experiment, almost the same operation as the operation waveform obtained by the simulation analysis can be confirmed.

  FIG. 5 shows a current operation waveform when the light to the photodiode is changed. (A) When the surrounding brightness is dark, a large current is passed to brighten the LED illumination. ) When the surrounding brightness is bright, it can be confirmed that the control for suppressing the current flowing to the LED is small.

  It was also confirmed that the power supply current waveform was a waveform close to a sine wave in phase with the power supply voltage.

  Next, two LED illuminators described above were manufactured and tested, and it was confirmed that they could be detected without being affected by each other's LED light source even when they were close to each other.

Fig. 1 A ... Lighting fixture adjacent to Fig. 1 B ... Lighting fixture detecting brightness Fig. 2 Fig. 4 ea ... AC power supply voltage diagram 2 Fig. 4 ia ... AC power supply current diagram 2 DB ... Diode bridge rectifier circuit diagram 2 L ... Reactor Fig. 2 Cd ... Capacitor Fig. 2 S1 ... Semiconductor switch for AC power supply current waveform control and LED current control Fig. 2 S2 ... Semiconductor switch for turning off LED current Fig. 2 LED illumination ... Series connection circuit diagram of LED, Fig. 3, Fig. 2 Fig. 4 i _LED ... Current waveform of LED

Claims (1)

  A DC output obtained from an AC power supply through a PFC circuit composed of a step-up chopper circuit combining a rectifier circuit, a switch, and an inductor is led to an LED circuit by connecting the switch circuit in series, and the AC power supply voltage waveform is near zero voltage The feature is that while the series switch to the LED is turned off, the ambient brightness is detected and the magnitude of the direct current is controlled by the switch of the PFC circuit so that the LED has the required brightness. Energy saving LED lighting.

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