CN2632987Y - Electronic ballast of high-voltage sodium lamp - Google Patents

Abstract

The utility model discloses an electronic ballast for a high-pressure sodium lamp. It includes a rectifier circuit, a high frequency oscillating circuit, a charging and discharging capacitor connected in series at the output end of the high frequency oscillating circuit and the high pressure sodium lamp circuit, and is characterized in that there is a passive power factor correction circuit connected to the high voltage through a DC blocking circuit One end of the sodium lamp is connected; the output end of another pulse trigger circuit sends the high-voltage starting pulse signal to the sodium lamp power supply circuit through a power transformer; a coil connected to the short-circuit protection circuit is added to the transformer secondary of the high-frequency oscillating circuit, The short-circuit protection circuit short-circuits the coil to stop the high-frequency oscillating circuit when the sodium lamp is short-circuited. The device has the advantages of small starting current, high power factor, small size, light weight, low working temperature rise and low cost.

Description

An electronic ballast for high pressure sodium lamp

technical field

The utility model relates to an electronic ballast for a high-pressure sodium lamp.

Background technique

Ordinary magnetic ballasts have the following disadvantages: 1. Large starting current and long starting time; 2. Low power factor; 3. Low luminous efficiency; 4. Large volume, heavy weight and high working temperature.

Contents of the invention

The purpose of the utility model is to provide a high pressure sodium lamp electronic ballast with reliable triggering, stable and perfect working performance, low cost and light weight.

A high-pressure sodium lamp electronic ballast described in the utility model includes: diode rectification circuits D1-D4 connected to 220V AC power supply through filter circuits L1 and C1, and high-frequency oscillation circuit G1 connected to the output end of the diode rectification circuit , G2, and BT1 are connected in series to the output end of the high-frequency oscillating circuit and the charging and discharging capacitor C8 in the high-pressure sodium lamp circuit; it is characterized in that: the positive output end of the diode rectification circuit is connected to the high-frequency oscillating circuit through an isolation diode D5, There is a passive power factor correction circuit D11-D13, C4, C5 whose correction input and output terminals are connected to the high-pressure sodium lamp’s charging and discharging capacitor C8 through a DC blocking capacitor C6; the high-frequency oscillation circuit positive terminal is connected to the high-pressure sodium lamp There is a second charge and discharge capacitor C7 connected between the charge and discharge capacitor C8, and a high frequency feedback capacitor C9 is connected between the positive output end of the DC rectifier circuit and the high pressure sodium lamp connected to the charge and discharge capacitor C8: this electronic ballast also includes A pulse trigger circuit RC1 connected to an AC 220V power supply, the trigger pulse output terminal of the pulse trigger circuit is connected to the primary of a high-frequency current mutual induction coil L2, the secondary of the current mutual induction coil L2 is a high-voltage output coil, and is connected in series between the output end of the high-frequency oscillation circuit and the high-pressure sodium lamp; the secondary side of another high-frequency current mutual induction coil BT2 connected in series between the output end of the high-frequency oscillation circuit and the high-pressure sodium lamp and the shutdown control end of the pulse trigger circuit RC1 3, 4-phase connection; add an induction coil T4 in the secondary of the transformer BT1 of the high-frequency oscillation circuit, the induction coil T4 is connected to the output terminals 3 and 4 of a short-circuit protection circuit RC2, and the input terminal 1 of the short-circuit protection circuit RC2 , 2 are respectively connected to the two ends of the series branch of the high-pressure sodium lamp and the current transformer L2, BT2; a resistor R6 is connected in parallel at the two ends of the charging and discharging capacitor C8; There is conduction between the output terminals 3 and 4.

As mentioned above, an electronic ballast for high pressure sodium lamps, wherein the oscillation circuit is a half-bridge inverter structure.

A high-pressure sodium lamp electronic ballast as described above, wherein the pulse trigger circuit power supply terminals 1 and 2 are connected in parallel with a first series branch composed of a current-limiting resistor R7, a diode D14 and a thyristor SCR1, A second series branch composed of a current-limiting resistor R8, a diode D15, and a charging and discharging capacitor C11 is connected between the trigger terminal of the thyristor SCR1 and the charging and discharging capacitor C11 connected to the diode D15 terminal in the second series branch. The bidirectional diode DB1 constitutes a pulse generating circuit, and the two ends of the thyristor are the trigger pulse output terminals 1 and 2; this circuit also includes the shutdown control terminals 3 and 4 and the diode D16 connected in series and the filter capacitor C12 branch There is a triode G3 whose base and emitter are respectively connected to the two ends of the charge and discharge capacitor C12, and the collector and emitter are respectively connected to the two ends of the charge and discharge capacitor C11 of the above-mentioned pulse generating circuit.

In the electronic ballast for high-pressure sodium lamps described above, a filter capacitor C14 is connected between the base and emitter of a triode G4 in the short-circuit protection circuit, and the filter capacitor C14 is connected to the two input terminals 1 of the circuit. , 2 connected in parallel with resistor R15, the collector and emitter of the triode G4 are respectively connected to the two ends of another charge and discharge capacitor C13; one end of the charge and discharge capacitor C13 is connected to the controllable circuit through a bidirectional diode DB2 The trigger end of the silicon SCR2 is also connected to the positive power supply end of the high-frequency oscillation circuit through the rectifier diode D17 and the resistor R12, and the other end is connected to the cathode end of the thyristor SCR2; the negative and positive poles of the thyristor SCR2 are the output of the circuit Terminal 3, 4.

Compared with the traditional inductance ballast, the utility model has the following advantages and positive effects:

1. The starting current is small, and the starting time is short, only about 2 minutes;

2. High power factor, up to 0.976:

3. When outputting the same power, the device has high luminous efficiency, and the lumen coefficient is above 110%;

4. Small size, light weight, low temperature rise and low cost.

Description of drawings

Fig. 1 is a schematic circuit diagram of an electronic ballast for a high pressure sodium lamp according to the utility model.

Fig. 2 is a schematic diagram of a pulse trigger circuit in a high pressure sodium lamp electronic ballast circuit according to the utility model.

Fig. 3 is a schematic diagram of a short circuit protection circuit in a high pressure sodium lamp electronic ballast circuit according to the utility model.

Detailed ways

The specific working principle of the utility model is shown in the accompanying drawings. In Fig. 1, the AC power supply 220V is rectified by the diodes D1-D4 after the harmful high-frequency components in the power grid are filtered by the capacitor C1 and the inductor L1, and the capacitors C4, C5, D10-D13 After filtering, a DC voltage of about 250V is obtained. At the same time, the pulse trigger circuit RC1 outputs a trigger pulse, and the excitation circuit causes the switching transistors G1 and G2 to oscillate through the resistors R3-R5 and the coil T1-T3, so that the high-pressure sodium lamp starts to work, and the starting current is induced by a high-frequency transformer BT2. A signal is transmitted to The control terminals 3 and 4 of the pulse trigger circuit are turned off, so that the pulse trigger circuit stops working. The operating current and frequency of the high-pressure sodium lamp are adjusted through the choke coil L2 and the capacitors C7 and C8, so as to achieve the best working condition. Capacitor C9 is a high-frequency feedback capacitor. The positive half cycle of high frequency current fills the trough of charging and discharging of the main circuit through diode D5, so as to improve the power factor and reduce the harmonic content. The negative half cycle returns to the power supply. Capacitor C6 is a DC blocking capacitor, and its function is to block the DC relationship between the short-circuit protection circuit RC2 and the main filter circuit, so as to ensure the reliability of the short-circuit protection circuit.

FIG. 2 is a specific circuit schematic diagram of the pulse trigger circuit RC1. A pulse generating circuit is composed of a resistor R7, a diode D14, a capacitor C10, a thyristor SCR1, a bidirectional diode DB1, a resistor R8, a diode D15 and a capacitor C11. Among them, terminals 1 and 2 are AC power terminals, terminals 2 and 6 are pulse output terminals. During the positive half cycle of the power supply, the thyristor is triggered to conduct through the resistor R8, the diode D15, and the bidirectional diode DB1, and at this time, C10 discharges. During the negative half cycle of the power supply, the thyristor is turned off, the capacitor C10 is charged in one direction, and when the capacitor C11 is charged to about 26V, the bidirectional diode DB1 is turned on, thereby generating a pulse signal. The pulse off control circuit is composed of triode G3, diode D16, capacitor C12 and resistors R9-R11. 3. When there is a feedback pulse input at terminal 4, capacitor C12 is charged, and when it reaches 4-5V, G3 is turned on, and both ends of capacitor C11 are short-circuited by transistor G3, causing the pulse generating circuit to fail to work.

FIG. 3 is a specific circuit schematic diagram of the short circuit protection circuit RC2. When working normally, the triode G4 is turned on, the two ends of the capacitor C13 are short-circuited by it, the bidirectional thyristor DB2 is cut off, and the SCR2 can be controlled to cut off, and the induction coil T4 connected to its two ends is open circuit, so the high frequency oscillation circuit works normally. If the sodium lamp is short-circuited, the base of the triode G4 loses its bias voltage and is cut off, the capacitor C13 is charged, the bidirectional diode DB2 is turned on, the thyristor SCR2 is turned on, and the induction coil T4 connected to its two ends is short-circuited, so that the high-frequency oscillation circuit stops Work and play a protective role.

Claims (4)

1. A high-pressure sodium lamp electronic ballast, which includes: a diode rectifier circuit (D1-D4) connected to a 220V AC power supply through a filter circuit (L1), (C1), a high High-frequency oscillation circuits (G1), (G2), and (BT1) are connected in series to the output end of the high-frequency oscillation circuit and the charging and discharging capacitor (C8) in the circuit of the high-pressure sodium lamp; it is characterized in that: the positive output end of the diode rectification circuit is passed An isolation diode (D5) is connected to the high-frequency oscillation circuit, and the correction input and output terminals of a passive power factor correction circuit (D11-D13), (C4), (C5) are connected to each other through a DC blocking capacitor (C6) The high-pressure sodium lamp is connected to the charge-discharge capacitor (C8) terminal; a second charge-discharge capacitor (C7) is connected between the positive terminal of the high-frequency oscillation circuit and the charge-discharge capacitor (C8) terminal of the high-pressure sodium lamp. A high-frequency feedback capacitor (C9) is connected between the output terminal and the high-pressure sodium lamp connected to the charging and discharging capacitor (C8); the electronic ballast also includes a pulse trigger circuit (RC1) connected to the AC 220V power supply, the pulse trigger circuit The trigger pulse output terminal of the trigger pulse is connected to the primary of a high-frequency current mutual induction coil (L2), and the secondary of the current mutual induction coil (L2) is a high-voltage output coil, and is connected in series between the output terminal of the high-frequency oscillation circuit and the high-pressure sodium lamp; The secondary side of another high-frequency current mutual induction coil (BT2) connected in series between the output end of the high-frequency oscillation circuit and the high-pressure sodium lamp is in phase with the shutdown control terminals (3) and (4) of the pulse trigger circuit (RC1). connection; add an induction coil (T4) to the secondary of the transformer (BT1) of the high-frequency oscillating circuit, and the induction coil (T4) is connected to the output terminals (3) and (4) of a short-circuit protection circuit (RC2). The input terminals (1) and (2) of the short-circuit protection circuit (RC2) are respectively connected to the two ends of the series branch of the high pressure sodium lamp and the current transformer (L2), (BT2); A resistor (R6); the short-circuit protection circuit (RC2) conducts between the output terminals (3) and (4) when the input terminals (1) and (2) are short-circuited. 2. An electronic ballast for high-pressure sodium lamps as claimed in claim 1, wherein the oscillating circuit is a half-bridge inverter structure. 3. A high pressure sodium lamp electronic ballast as claimed in claim 1, characterized in that: between the pulse trigger circuit power supply terminals (1) and (2), there is connected a current limiting resistor (R7), The first series branch composed of diode (D14) and thyristor (SCR1), the second series branch composed of current limiting resistor (R8), diode (D15) and charging and discharging capacitor (C11), in this controllable A bidirectional diode (DB1) is connected between the trigger terminal of the silicon (SCR1) and the terminal of the charge-discharge capacitor (C11) connected to the diode (D15) in the second series branch, thus forming a pulse generating circuit, and the two thyristors The terminals are the trigger pulse output terminals (1), (2); this circuit also includes the shutdown control terminals (3), (4) and the diode (D16) and filter capacitor (C12) branches connected in series, and there is a triode The base and emitter of (G3) are respectively connected to the two ends of the charge and discharge capacitor (C12), and the collector and emitter are respectively connected to the two ends of the charge and discharge capacitor (C11) of the pulse generating circuit. 4. A kind of electronic ballast for high-pressure sodium lamps as claimed in claim 1, characterized in that: a filter capacitor (C14) is connected between the base and the emitter of a triode (G4) in the short-circuit protection circuit wherein, The filter capacitor (C14) is connected in parallel with the resistor (R15) connected between the two input terminals (1) and (2) of the circuit, and the collector and emitter of the triode (G4) are respectively connected to another charging and discharging capacitor ( C13) at both ends; one end of the charging and discharging capacitor (C13) is connected to the trigger end of the thyristor (SCR2) in the circuit through a bidirectional diode (DB2), and connected to the rectifier diode (D17) and the resistor (R12) The positive power supply end of the high-frequency oscillation circuit is connected to the cathode end of the thyristor (SCR2); the anode and cathode of the thyristor (SCR2) are the output ends (3) and (4) of the circuit.

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