WO2007076641A1

WO2007076641A1 - Electronic ballast startup output current-limited circuit for high voltage sodium lamp

Info

Publication number: WO2007076641A1
Application number: PCT/CN2006/000158
Authority: WO
Inventors: Xiuqing Chen
Original assignee: Shi, Junsheng
Priority date: 2006-01-05
Filing date: 2006-01-26
Publication date: 2007-07-12
Also published as: CN2870376Y

Abstract

A electronic ballast startup output current-limited circuit for high voltage sodium lamp (4), which includes a triggering circuit (1) and a startup circuit (2), the startup circuit (2) has two transformer T3, T4, the triggering circuit (1) supplies starting signal to startup circuit (2); which characterized by connecting two relays J1, J2 between two transformers T3, T4 of startup circuit (2), secondary coils in said two transformers being connected in series, two relays acting due to the signal supplied by control circuit (3) after the startup circuit (2) generating strike voltage, the primary coil in two transformers which has the current limited function being converted from series connection to parallel connection. In this way, on the one hand, the bulb is able to trigger startup reliably, and the output power of electronic ballast can also meet the challenge; on the other hand, the resistance drops to one quarter which is in series connection after parallel connection, controls the heating-up of T3, T4, electronic ballast's whole temperature rise drops above 30%, improves stability and reliability of electronic ballast.

Description

High-pressure sodium lamp electronic ballast start output current limiting circuit

Technical field

The utility model relates to the field of electric lighting, in particular to a circuit device for ignition and control of a discharge lamp. Background technique

High-intensity discharge lamps (HID lamps) are a new type of energy-saving electric light source with a wide range of applications, and have gradually become the preferred source of light for public places and home lighting. The starting output circuit of the current electronic ballast is usually a method in which a transformer is connected in series, such as Chinese patent ZL00246388. 1 discloses a "low-cost electronic ballast for high-power high-intensity discharge lamps", the electronic town The resonant output circuit of the flow device is composed of an inverter circuit, an oscillation starting circuit and a ballast lighting circuit. The ballast lighting circuit is composed of a transformer T2 and a capacitor C14. The transformer T2 is composed of two main coils connected in series and two sub coils connected in series. The transformer T2 generates a resonant high frequency and high voltage to provide a starting voltage and a ballast voltage for the metal halide lamp. After the metal halide lamp is triggered, the primary winding of the transformer acts as a current limiting coil to control the current change of the lamp to stabilize the lamp. However, the current ignition voltage generated by electronic ballasts can only reach 2000 to 3000V, while the high voltage sodium lamps such as power 400W require a higher starting voltage, generally 5KV or more, so general electronic ballasts cannot be applied to High-pressure sodium lamp with output power above 400W. Since the current limiting coils acting as ballasts have a large impedance after being connected in series, the heat generation of the transformer is large, and the stability and reliability of the electronic ballast are poor. Summary of the invention

The purpose of the utility model is to provide a high-voltage sodium lamp electronic ballast starting output current limiting circuit with large output power, low heat generation and stable performance. In order to achieve the object of the present invention, the technical scheme adopted by the utility model is: A high-pressure sodium lamp electronic ballast starting output current limiting circuit, comprising a trigger circuit and a starting circuit, the starting circuit has two transformers T3, Τ4, a trigger circuit A start signal is provided for the start circuit; two relays J1 and 12 are connected between the two transformers 、3 and Τ of the start circuit, and the secondary coils of the two transformers are connected in series, and the two relays are controlled by a control circuit after the start circuit generates the ignition voltage. The signal is supplied to operate, and the primary coils that function as current limiting in the two transformers are converted from a series connection to a parallel connection. The control circuit has a triode Q7 and an RS flip-flop U6; the signal output end of the RS flip-flop U6 is The base of the transistor Q7 is connected, the emitter of the transistor Q7 is grounded, and the collector of the transistor Q7 is connected to the relay J1. When the transistor Q7 is turned on, the relay J1 is energized. The primary windings of the transformers T3 and T4 of the starting circuit are connected in series through the normally closed contacts of the relay J2; the normally open contacts of the relay J2 are connected to the load, and the primary coil of the transformer T4 is turned on when closed; the relay J1 Two normally closed contacts are suspended, one normally open contact of relay J1 is connected to the low voltage power supply, and when closed, the coil of relay J2 is energized; the other normally open contact of relay J1 is connected with the primary coil of transformer T3, closed The primary winding of the transformer T3 is turned on; one end of the coil of the relay J1 is connected to the low voltage power supply, and the other end of the coil of the relay J1 is connected to the collector of the transistor Q7 of the above control circuit. The diodes D11 and D12 functioning as a step-down function are also disposed between the relay J1 and the low-voltage power source. The model of the RS trigger U6 is CD4013. Compared with the prior art, the above technical solution has the following advantages: The utility model controls the connection method of the primary windings of the transformers T3 and Τ4 by using a control circuit, and the primary windings of the Τ3 and Τ4 are connected in series before the trigger point of the bulb, and The inductance is relatively large, ensuring that the bulb can be reliably triggered to illuminate. About 4 to 6 seconds after the lamp is triggered to light up, the control circuit converts the control terminals J1 and J2 to change the primary windings of T3 and Τ4 from the original series connection to the parallel connection. In this way, on the one hand, the bulb can be reliably triggered to start, and the output power of the electronic ballast can also meet the requirements; on the other hand, after parallel connection, the impedance is reduced to about a quarter of the series connection, and the temperature of Τ3, Τ4 The rise is controlled, and the current-limiting method in which the temperature rise is connected in series with the common inductor is reduced by at least 50%, so that the overall temperature rise of the electronic ballast is reduced by at least 30%, thereby greatly improving the stability and reliability of the electronic ballast. Sex. DRAWINGS

In order to make the content of the present invention more easily understood, the present invention will be further described in detail below based on the specific embodiments and the accompanying drawings, wherein

Figure 1 is a block diagram of the circuit of the present invention;

Figure 2 is a circuit schematic diagram of the present invention; 3 is a block diagram of a circuit structure of an application example of the present invention;

4 is a circuit schematic diagram of an application example of the present invention. detailed description

Example

Referring to FIG. 1 and FIG. 2, the high-voltage sodium lamp electronic ballast starting current limiting output circuit of the embodiment has a trigger circuit 1 and a starting circuit 2, the starting circuit 1 has two transformers T3 and Τ4, and the trigger circuit 1 provides a starting circuit for the starting circuit 2. Signal; two relays J1, J2 are connected between the two transformers Τ3 and Τ4 of the starting circuit 2, and the secondary coils of the two transformers are connected in series, and the two relays provide signals by a control circuit 3 after the starting circuit generates the ignition voltage. An action occurs in which the primary coils acting as current limiting in the two transformers are converted from a series connection to a parallel connection. Referring to FIG. 2, the flip-flop circuit 1 is composed of resistors R34 to R36, R40 to R45, a capacitor C22, a bidirectional trigger diode DB3, and a thyristor Q6. The resistors R40 to R44 are connected to form a voltage dividing circuit. One end of the bidirectional trigger diode DB3 is connected to the control electrode of the thyristor Q6, and the other end is connected to the voltage dividing circuit. The capacitor C22, the thyristor Q6 and the secondary windings of the transformers T3, Τ4 are connected into a discharge loop, wherein the cathode of the thyristor Q6 is grounded. The control circuit 3 is composed of an RS flip-flop U6 of the type CD4013 and its peripheral components, a transistor Q7, diodes D11 and D12, and relays J1 and J2. The signal output terminal 1 of the RS flip-flop U6 is connected to the base of the transistor Q7, the emitter of the transistor Q7 is grounded, and the collector of the transistor Q7 is connected to the relay J1. After diodes D11 and D12 are connected in series, the anode of D11 is connected to a low voltage power supply of 15V, and the cathode of D12 is connected to relay J1 and RS flip-flop U6, respectively. The RS flip-flop U6 can issue a control signal at a set time, control the relay J1 to operate, and then control the relay J2 to operate, so that the primary windings of the transformers T3 and Τ4 are connected in series by parallel connection. The start-up circuit 2 is composed of transformers Τ3 and Τ4. The secondary windings of the transformers 、3 and Τ4 are connected in series, and the primary windings of the transformers Τ3 and Τ4 are connected in series through the normally closed contacts of the relay J2; the normally open contacts of the relay J2 are connected to the load, and the primary coils of the transformer Τ4 are closed when closed. The two normally closed contacts of relay J1 are suspended, one normally open contact of relay J1 is connected with the low voltage power supply, and the coil of relay J2 is energized when closed; the other normally open contact of relay J1 is connected with the transformer Τ3 Primary coil connection, change when closed The primary winding of the voltage converter T3 is turned on; one end of the coil of the relay J1 is connected to the low voltage power supply, and the other end of the coil of the relay J1 is connected to the collector of the transistor Q7 of the above control circuit. After the power is turned on, a DC voltage signal of about 350V is generated on the sampling end of the start signal, and the voltage signal charges the capacitor C22 through the resistors R34, R35, and R36, and the voltage on the capacitor C22 is added through the secondary windings of T3 and Τ4. On the anode of the thyristor Q6, a voltage dividing circuit composed of resistors R40 to R44 divides the voltage on the capacitor C22. When the voltage on the bidirectional trigger diode DB3 reaches the turning voltage, the DB3 triggers the conduction, and the gate of the thyristor Q6 is obtained. A control signal, thyristor Q6 is turned on, at which point capacitor C22 is discharged to ground through the secondary windings of T3, Τ4 and thyristor Q6. Since the equivalent resistance of the capacitor C22 discharge circuit is relatively small and the discharge current is relatively large, a large induced electromotive force is generated on the secondary winding of Τ3, Τ, which is coupled to the primary windings of Τ3, Τ4, because匝3, Τ4 The primary and secondary windings have a turns ratio of about 20: 1, so a high-voltage pulse of about 5KV will be generated on the primary windings of Τ3 and Τ4, and the high-pressure sodium lamp will be triggered to illuminate. This process takes about 1 second from the time the power is turned on until the lamp is lit. After the lamp is lit, the voltage signal on the “釆” of the start signal is formed through the resistors R34, R35, the primary winding of the bulb, T3, and Τ4 to the ground, because the impedance of the resistor R36 is much larger than the primary of the bulb, Τ3, Τ4. The total impedance of the winding, the voltage across the capacitor C22 divided by the resistors R40~R44 is not enough to make the DB3 trigger conduction, the thyristor Q6 is turned off, and the secondary windings of T3 and Τ4 have substantially no current flowing, Τ3. The primary winding of Τ4 will no longer generate high voltage pulses. The C terminal is connected to the output of the high frequency conversion circuit. At the same time as the power is turned on, the 15V DC voltage is applied to the positive pole of the diode D11, and the voltage is reduced by the diodes D1 l and D12 to obtain a DC voltage of about 13. 5V to supply power to the U6, the relay Jl, J2; In the second, the output of pin 1 of U6 is low level, the transistor Q7 is cut off, and the relays Jl and J2 remain in the original state, and the primary windings of T3 and Τ4 are connected in series; the power is turned on for about 6 seconds, U6 The output of pin 1 is high, and the transistor Q7 is turned on. At this time, relay J1 is energized to start, J1's normally closed contact is open, normally open contact is closed, and the primary winding of Τ4 is instantaneously short-circuited; The normally open contact of J1 is closed, the coil of J2 is turned on, J2 is energized, the normally closed contact of J2 is open, the normally open contact is closed, and the primary winding of Τ4 is turned on. At this point, the primary windings of Τ3 and Τ4 are changed from the original series connection to the parallel connection. When the parallel connection is made, the impedance of the output current limiting circuit drops to a quarter of the series connection, and the current drop through the primary windings of Τ3 and Τ4 is Use one-half of the connection in series. In this way, not only the output power of the electronic ballast can be 1000W or even 1000W, but also the temperature rise of Τ3 and Τ4 is reduced by at least 50%, so that the overall temperature of the electronic ballast The drop of more than 30% has fundamentally solved the problem of high performance electronic ballasts affecting performance, stability and reliability due to excessive temperature rise. Application example

Referring to FIG. 3, the electronic ballast for the sodium lamp of the application example includes a filter circuit 1, a first rectifier circuit 2, a power factor correction circuit 3, a high frequency conversion circuit 4, a startup output current limiting circuit 5, and a filter. A second rectifying circuit 9 is further connected between the circuit 1 and the low-voltage DC circuit 6. The protection circuit 7 is respectively connected to the power factor correction circuit 3 and the PWM pulse control circuit 8, and the low-voltage DC circuit 6 and the power factor correction circuit 3 are respectively activated. The current limiting circuit 5, the protection circuit 7, and the P-pulse control circuit 8 are connected. Referring to Fig. 4, the filter circuit 1 includes capacitors Cl, C2, C3, C4 and a high frequency inductor L1. Wherein, the connections of the capacitors C3 and C4 are grounded. On the one hand, the filter circuit suppresses electromagnetic interference from the power grid, on the other hand, it suppresses interference from itself and other electrical appliances to the town of township to ensure that the power grid is free from pollution. The first rectifier circuit 2 is composed of a bridge rectifier circuit KBU1 and a capacitor C5. The second rectifier circuit 9 is constructed by connecting a bridge rectifier circuit KBU2 and a capacitor E3. The power factor correction circuit 3 is an active power factor correction circuit composed of a model MC33262 power factor corrector U1 and its peripheral components, a transformer T1, a field effect transistor Q1, and a connection. The high frequency conversion circuit 4 is composed of FETs Q4 and Q5, a transformer T2, capacitors C9 and C23, diodes D8, D9, D10, Z3, Z4, and Z5, resistors R28, R29, R30, and R31, and transistors Q2 and Q3. During operation, the FETs Q4 and Q5 are turned on in turn to provide high-frequency current for the load (high-pressure sodium lamp).

,

The low-voltage DC circuit 6 is composed of a photocoupler U3, a switching power supply single-chip U2 of the type T0P211Y, its peripheral components, and a transformer T5. The second rectifying circuit 9 and the low-voltage DC circuit 6 have independent groundings from other circuits to prevent mutual interference with other circuits and ensure the stability of the output voltage of the low-voltage DC circuit. The protection circuit 7 is composed of a four-op amp integrated circuit U4 of the type LM324 and its peripheral components.

The P-pulse control circuit 8 is composed of a voltage type PWM integrated controller U5 of the type SG3525A and its peripheral components. After the power is turned on, the filter circuit 1 filters the voltage signal input by the power grid, and the filtered voltage signal is output to the first rectifier circuit 2 and the second rectifier circuit 9, respectively; the first rectifier circuit 2 rectifies the input AC power, and rectifies The subsequent signal is output to the power factor correction circuit 3; the second rectifier circuit 9 rectifies the input alternating current, the rectified signal is output to the low voltage direct current circuit 6, the second rectifier circuit 9 has an independent ground, and the low voltage direct current circuit 6 inputs The signal is converted to output a stable low voltage direct current to power the power factor correction circuit 3, the P pulse control circuit 8 and the active devices in the protection circuit 7. The low voltage DC circuit 6 also provides a voltage signal for the startup output current limiting circuit 5. The power factor correction circuit 3 converts the input signal, outputs a stable DC voltage, and supplies power to the high pressure sodium lamp through the high frequency conversion circuit 4. The P-pulse control circuit 8 outputs a pulse signal and controls the high-frequency conversion circuit 4 to be turned on. A start output current limiting circuit 5 is connected between the high frequency converting circuit 4 and the high pressure sodium lamp. The two output terminals of the protection circuit 7 are respectively connected to the input terminals of the power factor correction circuit 3 and the pulse control circuit 8, and provide automatic protection for unexpected failure of the circuit to open or short. Wherein, the primary windings of the transformers T3 and Τ4 that start the output current limiting circuit 5 start to be connected in series, and about 4 to 6 seconds after the bulb is triggered to light, the primary windings of the Τ3 and Τ4 are changed from the original series connection to the parallel connection. . In this way, on the one hand, the series has a large inductance, so that the bulb can be reliably triggered to start, and the output power of the electronic ballast can also meet the requirements. On the other hand, the bulbs become parallel after lighting, and the impedance drops to a quarter of the series connection in parallel, so that the temperature rise of Τ3 and Τ4 is controlled, and the temperature rise is at least 50% lower than the current limiting method connected in series. The overall temperature rise of the electronic ballast is reduced by at least 30%, which greatly improves the performance stability and reliability of the electronic ballast.

Claims

Rights request:

1. A high-pressure sodium lamp electronic ballast starts output current limiting circuit, comprising a trigger circuit and a starting circuit, the starting circuit has two transformers T3 and Τ4, and the trigger circuit provides a starting signal for the starting circuit; the characteristic is: Two relays J1 and J2 are connected between the transformers 、3 and Τ4, and the secondary coils of the two transformers are connected in series. The two relays are operated by a control circuit after the startup circuit generates the ignition voltage, and the two transformers are activated. The current limiting primary coil is converted from a series connection to a parallel connection.

2. The high-voltage sodium lamp electronic ballast start output current limiting circuit according to claim 1, wherein: the control circuit has a triode Q7 and an RS flip-flop U6 _; a signal output end of the RS flip-flop U6 and a triode Q7 The base connection, the emitter of the transistor Q7 is grounded, the collector of the transistor Q7 is connected to the relay J1, and when the transistor Q7 is turned on, the relay J1 is energized.

3. The high-pressure sodium lamp electronic ballast start output current limiting circuit according to claim 2, wherein: the primary windings of the transformers T3 and T4 of the starting circuit are connected in series by a normally closed contact of the relay J2; The normally open contact of relay J2 is connected to the load. When closed, the primary coil of transformer T4 is turned on. The two normally closed contacts of relay ji are suspended. Relay: A normally open contact of Γ1 is connected to the low voltage power supply, and when closed, The coil of relay J2 is energized; the other normally open contact of relay J1 is connected to the primary coil of transformer T3, and the primary coil of transformer T3 is turned on when closed; the end of the coil of relay J1 is connected to the low voltage power supply, relay J1 The other end of the coil is connected to the collector of the transistor Q7 of the above control circuit.

4. The high-voltage sodium lamp electronic ballast start output current limiting circuit according to claim 3, wherein: the relay J1 and the low voltage power supply are further provided with diodes D11 and D12 for reducing voltage.

5. The high voltage sodium lamp electronic ballast start output current limiting circuit according to claim 2, wherein: the RS flip-flop U6 is of the type CD4013o.