CN201238414Y - High strength gas discharge lamp electronic ballast - Google Patents

Abstract

The utility model relates to an electronic ballast for a high-intensity gas discharge lamp. The utility model includes a rectifier circuit, a PFC circuit, a half-bridge inverter circuit, a starting circuit and an HID lamp. The input voltage is sent to the subsequent PFC circuit through the rectifier circuit. , the PFC circuit generates a stable bus voltage, which is sent to the next half-bridge inverter circuit, and the square wave generated by the inverter circuit is added to the HID lamp, and the voltage on the HID lamp and the voltage in the inverter circuit are sent to the Start the circuit. The starting circuit is connected with the discharge circuit of the HID lamp, with few components and reliable operation. The starting voltage can be adjusted according to the turn ratio, which is simple and easy. Once the lamp is ignited, the starting circuit will stop working by itself with little loss. Automatically repeat restart after start failure, the repeat start time is set according to the temperature of the lamp and the value of circuit resistance and capacitance.

Description

Electronic Ballasts for High Intensity Discharge Lamps

technical field

The utility model relates to an electronic ballast for a high-intensity gas discharge lamp (HID), which is suitable for the electronic ballast of a high-pressure sodium lamp and a metal halide lamp.

Background technique

High-intensity discharge lamps play an important role in today's lighting systems. High-intensity gas discharge lamps have many advantages such as good light efficiency, long life and wide power range. They have become the third generation of electric light sources after incandescent lamps and fluorescent lamps, and are widely used in indoor and outdoor lighting environments such as squares, docks, workshops and roads. middle. During ignition of a high-intensity discharge lamp, a beam of electrons passes through a gaseous medium to produce light. Due to the negative resistance characteristics of high-intensity gas discharge lamps, that is, as the lamp current increases, the lamp voltage decreases and the system is in an unstable state, so it cannot be directly applied to the voltage source, otherwise the slight voltage fluctuation will cause the lamp to overload and fail. If the lamp tube is burned or the arc is extinguished, a ballast device (that is, a ballast) needs to be added to make the HID lamp work stably. With the development of power electronics technology, high-frequency electronic ballasts have increasingly replaced traditional inductive ballasts. It has high efficiency, small size, flexible control and can save a lot of non-ferrous metals such as iron and copper. . The high-frequency electronic ballast generally consists of a rectification and power factor correction circuit, a half-bridge inverter circuit, a high-voltage pulse ignition circuit and a high-intensity gas discharge lamp. The half-bridge inverter circuit makes the lamp work at high frequency. Two power tubes Alternate action to generate high-frequency square wave output. Most of the high-frequency ignition circuit circuits use LC parallel resonance or LCC series-parallel resonance. This method has simple circuits and no additional circuits. When it is near the switching frequency, if the lighting fails or the lamp is open, it will cause the inductance to saturate and generate a large current impact, which will affect the reliability. In order to completely avoid the disadvantages of starting circuits in LC parallel resonance and LCC series parallel resonance modes, the utility model proposes a new type of pulse starting circuit. In the existing technology, the ballast ignition circuit and the high-power high-intensity gas discharge circuit are two independent circuits, which makes the electronic ballast circuit more complicated, with more components and parts, and the cost is increased.

Utility model content

1. Technical problems to be solved:

The utility model provides a design for the above problems. The voltage of the ignition circuit is taken from the working voltage of the HID lamp, so that the ignition circuit is relatively simple and reliable, and once it is ignited, the ignition circuit will automatically exit to reduce loss. After a failed start, it can be started again, and the electronic ballast for high-intensity discharge lamps with unlimited restart time.

2. Technical solution:

The utility model includes a rectification circuit, a PFC circuit, a half-bridge inverter circuit, a starting circuit and an HID lamp. The input voltage is sent to the subsequent PFC circuit through the rectification circuit, and the PFC circuit generates a stable bus voltage, which is then sent to the next stage. A half-bridge inverter circuit, the square wave generated by the inverter circuit is added to the HID lamp, and the voltage on the HID lamp and the voltage in the inverter circuit are sent to the starting circuit.

3. Beneficial effects:

The start-up circuit is connected with the discharge circuit of the HID lamp, with few components and reliable operation. The starting voltage can be adjusted according to the turn ratio, which is simple and easy. Once the lamp is ignited, the starting circuit will stop working by itself with little loss. Automatically restart after startup failure, and the restart time is set according to the temperature of the lamp and the value of the circuit resistance and capacitance.

Description of drawings

Figure 1 is a block diagram of the basic structure of a general high-frequency electronic ballast.

Fig. 2 is a block diagram of the circuit structure of the utility model.

Fig. 3 is a structural schematic diagram of the utility model.

Detailed ways

HID lamps are high-pressure discharge lamps. Normally, the ignition voltage is above 2kV. There is a transition stage from lamp ignition to normal ignition. This transition stage is divided into take-over stage and voltage increase (run-up) stage, in less than 1ms after the lamp is ignited, the lamp tube breaks down, and the lamp voltage is only about 25% of its rated value (about 20 volts), forming a lamp conduction channel, and then the lamp voltage gradually increases to its normal operating value, making the lamp enter the ignition phase. When the HID lamp is not ignited, the resistance is very large, which is equivalent to an open circuit. After the lamp is ignited, regardless of the take-over stage, the voltage increase (run-up) stage and the final ignition stage, the lamp resistance is small, and the low-power lamp The working voltage on the board is less than 100V. The utility model is realized according to this characteristic of the HID lamp.

Figure 2, the electronic ballast for high-intensity gas discharge lamps includes input rectification circuit, PFC circuit, half-bridge inverter circuit, starting circuit and HID lamp. The input AC 220V is sent to the subsequent PFC circuit through the rectification circuit. The PFC circuit generates a stable bus voltage, which is then sent to the next half-bridge inverter circuit. The square wave generated by the inverter circuit is added to the HID lamp. The voltage on the lamp and the voltage in the inverter circuit are sent to the starting circuit.

Figure 3, (1) The rectifier circuit consists of diodes V10, V11, V12 and V13.

(2) The PFC circuit is composed of inductor L2, IGBT tube V9, diode V8 and capacitor C4.

(3) The half-bridge inverter circuit is composed of MOS tubes V1, V2, capacitor C1 and inductor L1.

Compared with the full-bridge inverter, the half-bridge inverter has a simpler circuit and lower cost. For small and medium-power HID lamps, after the lamp is lit, the effective value of the lamp voltage is less than 100V. For the bus voltage of 400V (Vin), The output voltage of the half bridge is sufficient. In the half-bridge inverter, the MOS transistors V1 and V2 are turned on alternately, and the capacitor C1 acts as a DC blocker. The output terminal of the capacitor obtains a square wave with an amplitude of Vin/2 (positive and negative amplitudes of Vin/2), and the frequency of the square wave is MOS Control the switching frequency of V1 and V2, this square wave voltage is added to the inductor L1.

(4) The starting circuit is composed of resistors R1, R2, R3, R4, capacitors C2, C3, diodes V5, V6, V7, bidirectional trigger diode V4, IGBT tube V3 and inductor L1.

The positive terminal of diode V5 is connected with one end of the HID lamp and the 4 pin of inductor L1, the negative terminal of diode V5 is connected with the positive terminal of diode V6, the negative terminal of diode V6 is connected with the positive terminal of diode V7, and the negative terminal of diode V7 is connected with the positive terminal of diode V6. One end of resistor R1 is connected to one end of resistor R1, the other end of resistor R1 is connected to one end of capacitor C2, one end of resistor R2 is connected to pin 1 of inductor L1, the other end of capacitor C2 is grounded, the other end of resistor R2 is connected to one end of capacitor C3 1. One end of the resistor R3 is connected to one end of the bidirectional trigger diode V4, the other end of the capacitor C3 and the resistor R3 is grounded, the other end of the bidirectional trigger diode V4 is connected to the base of the IGBT tube V3 and one end of the resistor R4, and the resistor R4 The other end is grounded to the emitter of the IGBT tube, and the source of the IGBT tube is connected to pin 2 of the inductor L1.

The specific working method of the starting circuit is as follows: when the HID lamp is not lit, L1 is in the transformer working mode, and the voltage of the primary side 1-2 and secondary side 3-4 is related to the turn ratio n2 and n1. When the HID lamp is not lit, the resistance of the HID lamp is very large, which is equivalent to an open circuit. The square wave voltage of the half bridge is applied to both ends of the HID lamp. The voltage charges C2 through diodes V5, V6, V7 and R1, and at the same time C2 The voltage on C3 charges C3 through R2. When the voltage on C3 reaches the breakdown value of the bidirectional trigger diode V4 of 34V, the IGBT tube V3 works, and the voltage on C2 (the peak value of the square wave voltage, about 200V) is added to the winding of L1. On the primary side 1-2, since the number of turns of the secondary side of L1 is 10 times that of the primary side (n2:n1=10 in this example), a high voltage of about 2000V will be generated on the secondary side of L1, which is applied to the HID lamp On, ignite the HID lamp. Once the lamp is ignited, the effective value of the voltage on the HID lamp is less than 100V. This voltage charges C2 through diodes V5, V6, V7 and R1. The charging voltage on C2 must not reach 100V. The voltage on C2 passes through R2 To charge C3, since the resistance of resistor R2 is 4 times the resistance of resistor R3, the voltage of C3 cannot reach the breakdown value of 34V of bidirectional trigger diode V4, the IGBT tube V3 will not work, and the ignition circuit will not work. After the lamp is lit, the starting circuit does not work, L1 is equivalent to the working mode of the inductance, and the square wave generated by the half-bridge inverter is loaded on the HID lamp through the inductance, so that the HID lamp can stably emit light and work. In this example, since the voltage on the HID lamp is 2000V at start-up, three diodes connecting the voltage from the HID lamp to the capacitor C2 of the start-up circuit are connected in series, so that a switching diode with a withstand voltage of 1000V can be selected (such as FR157), the resistor R1 is added after the diode in series to limit the charging current of the capacitor C2 and play a protective role. If the starting voltage requirement of the HID lamp is high, it can be conveniently changed by adjusting the turn ratio n2 and n1 of L1. If one ignition is unsuccessful, because the resistance of the HID lamp is still very large, the half-bridge square wave voltage charges C2, and the voltage on C2 is very high, which can trigger the bidirectional trigger diode V4 again to make the starting circuit work again, and the time for restarting is not limited. .

(5) HID lamps, consisting of a high-intensity gas discharge lamp.

Although the utility model has been disclosed as above with preferred embodiments, they are not used to limit the utility model, and any skilled person can make various changes or changes without departing from the spirit and scope of the utility model. modification, so the protection scope of the present utility model shall be defined by the protection scope of the claims of the present application.

Claims (2)

1, a kind of electronic ballast of high intensity gas discharge lamp, comprise rectification circuit, pfc circuit, half-bridge inversion circuit and HID lamp, input voltage is through rectification circuit, deliver to back level pfc circuit, pfc circuit produces stable busbar voltage, this busbar voltage is delivered to the next stage half-bridge inversion circuit again, the square wave that inverter circuit produces is added on the HID lamp, it is characterized in that: electronic ballast of high intensity gas discharge lamp also comprises start-up circuit, and voltage on the HID lamp and the voltage in the inverter circuit are delivered to start-up circuit.

2, electronic ballast of high intensity gas discharge lamp according to claim 1 is characterized in that: start-up circuit comprises resistance R 1, R2, R3, R4, capacitor C 2, C3 and diode V5, V6, V7, bidirectional trigger diode V4, IGBT pipe V3 and inductance L 1; The anode of diode V5 is connected with an end of HID lamp and 4 pin of inductance L 1, the negative terminal of diode V5 is connected with the positive pole of diode V6, the negative terminal of diode V6 is connected with the anode of diode V7, the negative terminal of diode V7 is connected with an end of resistance R 1, one end of the other end of resistance R 1 and capacitor C 2, one end of resistance R 2 is connected with 1 pin of inductance L 1, the other end ground connection of capacitor C 2, one end of the other end of resistance R 2 and capacitor C 3, one end of resistance R 3 is connected with the end of bidirectional trigger diode V4, the other end ground connection of capacitor C 3 and resistance R 3, the other end of bidirectional trigger diode V4 is connected with the base stage of IGBT pipe V3 and an end of resistance R 4, the emitter grounding of the other end of resistance R 4 and IGBT pipe, the source electrode of IGBT pipe is connected with 2 pin of inductance L 1.

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