CN202095162U - Thyristor type driver of energy-saving lamp - Google Patents

Abstract

The utility model relates to a thyristor-type energy-saving lamp driver, which is characterized in that the commercial power is composed of a thyristor delay circuit, a power conversion circuit, a half-bridge inverter circuit and a lamp tube circuit in sequence. The utility model adopts half-wave power supply at the moment of start-up, which can greatly reduce the impact of the surge on the filter capacitor at the moment of start-up, and the voltage drop at the moment of lighting the lamp tube, so that the filament of the lamp tube is protected from the impact of high current and plays the role of protecting the main components. ;After the lamp is ignited, it automatically enters the full-wave power supply of the mains to ensure the brightness of the lamp; this driver can be used as a driver for energy-saving lamps, and is also suitable for driving electromagnetic induction EB lamps, which can prolong the overall service life of lamps.

Description

Thyristor type energy-saving lamp driver

Technical field:

The utility model belongs to the field of electronics, in particular to a thyristor type energy-saving lamp driver, which is also suitable for driving electromagnetic induction FB lamps. the

Background technique:

The efficiency coefficient and power consumption of energy-saving lamps are worse than incandescent lamps, but the life of energy-saving lamps is far less than that of incandescent lamps. The new problem of pollution. The reason is mostly due to the design defect of the driver. The impact of large current is generated at the moment of ignition, which causes the lamp filament and the filter capacitor of the main circuit to be impacted. Therefore, the existing energy-saving lamps are suitable for long-term continuous operation, and they are afraid of frequent switching. An electronic ballast previously applied by the applicant, patent publication number CN101754548A, originally proposed the application of the half-bridge inverter technology in the energy-saving lamp driver, and adopted the sliding frequency technology to make the square wave voltage output by the half-bridge inverter The frequency drops continuously from the highest frequency to the high-voltage ignition frequency of the lamp tube until the steady-state operating frequency, which solves the problem of changing the self-excited single-frequency point oscillation into a continuous frequency conversion oscillation mode, and realizes that after the filaments at both ends of the lamp tube in the lamp tube circuit are short-circuited and connected, even if the lamp is disconnected The filament lamp can still be ignited by high pressure smoothly and emit light normally until the lamp fails, thereby prolonging the service life of the lamp. How to overcome the defect of high current impact when starting, promptly becomes the object of the utility model research. the

Invention content:

The purpose of this utility model is to design a thyristor-type energy-saving lamp driver which uses half-wave power supply at the moment of starting and igniting, and then automatically enters the full-wave power supply of the mains, and cooperates with the half-bridge inverter circuit. the

The technical scheme of the utility model is realized as follows: a thyristor-type energy-saving lamp driver, which is characterized in that the commercial power is sequentially composed of a thyristor delay circuit, a power conversion circuit, a half-bridge inverter circuit and a lamp circuit. the

Described thyristor delay circuit: a, main loop circuit: be made up of bidirectional thyristor BCR1, diode VD4, the two are connected in parallel and then connected on the mains input terminal; b, delay circuit: consist of diode VD3, capacitor C5 and resistor R4 form a delay working power supply. The delay circuit is composed of resistors R5, R6, R7 and capacitors C6 and C7, and its output is connected to the trigger terminal of the thyristor BCR1. the

The power conversion circuit includes a bridge rectifier BR and a filter capacitor C1 connected in parallel to the output terminal. the

Half-bridge inverter circuit: including two parts, the start-up circuit and the inverter circuit, wherein the start-up circuit is composed of resistor R1, capacitor C2, and bidirectional diode VD2; the inverter circuit is composed of ring deformer windings T1a, T1b, T1C, resistors R2, R3, Transistor VT1, VT2 composition. the

Lamp circuit: composed of inductor L1, capacitors C3, C4, C5 and filaments FL1, FL2. the

The utility model adopts half-wave power supply at the moment of starting, which can greatly reduce the impact of the surge on the filter capacitor at the moment of turning on, and the voltage drops at the moment of lighting the lamp, so that the filament of the lamp is protected from the impact of large current and plays the role of protecting the main components. ;After the lamp is ignited, it automatically enters the full-wave power supply of the mains to ensure the brightness of the lamp; this driver can be used as a driver for energy-saving lamps, and is also suitable for driving electromagnetic induction EB lamps, which can prolong the overall service life of lamps. the

Description of drawings:

The utility model is further described below in conjunction with specific illustrations:

Figure 1 SCR type energy-saving lamp driver schematic diagram

Figure 2 SCR type energy-saving lamp driver circuit diagram

Figure 3 Equivalent circuit diagram of half-wave starting energy-saving lamp driver

Figure 4 Equivalent circuit diagram of full-wave energy-saving lamp driver

Detailed ways:

Referring to Figure 1 and Figure 2, the schematic block diagram of the thyristor type energy-saving lamp driver, after the mains is connected, it is composed of a thyristor delay circuit, a power conversion circuit, a half-bridge inverter circuit and a lamp circuit in sequence. the

in;

Thyristor delay circuit; a. Main loop circuit: composed of bidirectional thyristor BCR1 and diode VD4; b. Delay circuit: composed of diode VD3, capacitor C5 and resistor R4 to form a delay working power supply, composed of resistors R5 and R6 , R7, capacitors C6 and C7 form a delay circuit, and the designed delay time is 1-2 seconds. the

Power conversion circuit: including bridge rectifier BR and filter capacitor C1 connected in parallel to the output terminal;

Half-bridge inverter circuit: including two parts, the start-up circuit and the inverter circuit, wherein the start-up circuit is composed of resistor R1, capacitor C2, and bidirectional diode VD2; the inverter circuit is composed of ring deformer windings T1a, T1b, T1C, resistors R2, R3, Transistor VT1, VT2 composition. the

Lamp circuit: It is composed of inductance L1, capacitors C3, C4, C5 and filaments FL1 and FL2. The filaments at both ends are connected in parallel, which is also equivalent to the state of broken filaments. the

Electrical principle description:

1. SCR type half-wave power supply delay automatically converts to full-wave power supply:

The mains power passes through the L and N lines, the insurance tube Fu is added to the diode VD3 for half-wave rectification, filtered by the capacitor C5, and the resistor R4 discharges the output to step down to 0.45 mains voltage to supply the DC voltage required by the delay circuit. the

The DC voltage forms a charging circuit through the resistor R5 and the capacitor C6, and delays it. The initial voltage on the capacitor C6 is equal to 0. After 1 second of charging, the voltage of the capacitor C6 is limited by the resistor R6 to trigger the bidirectional thyristor BCR1, the resistor R7, and the capacitor C7. The surge absorbing circuit that forms the bidirectional thyristor trigger pole makes it work stably and reliably. the

After a delay of 1 second, the bidirectional thyristor BCR1 is triggered and turned on, and the mains LN is supplied with full-wave power by the bidirectional thyristor BCR1. the

2. The working principle of the half-bridge inverter circuit is the prior art, so the description is omitted. the

Referring to Figure 3 and Figure 4, the design principle for the above-mentioned thyristor type energy-saving lamp driver is as follows:

Both electromagnetic induction EB lamps and energy-saving lamps need to have the necessary and sufficient conditions for high voltage to appear at "resonance" in order to start and ignite the lamp tube. This article analyzes energy-saving lamps as an example. the

A: Main circuit filter capacitor:

1. Mains (single-phase) half-wave power supply

Figure 3:

E: is the power frequency mains voltage;

C: energy-saving lamp main circuit filter capacitor;

RL: equivalent circuit load resistance;

After power-on, the initial capacitor C has no voltage, and after a short moment (called the transition process) charging, a new equilibrium state is reached. At this time, the voltage on the capacitor C fluctuates up and down UC, and the average voltage is UL. the

The rectifier D is not turned on during the entire positive half cycle, but only when the input AC voltage is higher than the voltage on the capacitor C and exceeds the forward voltage drop of the rectifier D. When the rectifier D is turned on, the rectified current is divided by a small Part of it is supplied to the load resistance RL, and most of it is charged to the capacitor C. The charging resistance is small, the charging current is large, the charging speed is fast, and the charging time is very short. After the rectifier tube D is cut off, the capacitor C discharges to the load RL. The current is the load current at this time. The charging current of the capacitor C is very large, especially during the initial transition process, especially for the rectifier D, it is a surge current. This is a single-phase half-wave rectification and filter circuit. The diode half-wave rectification output is connected in parallel with the filter capacitor, and the ripple can be reduced by using its charging and discharging function. The internal resistance of the initial mains power supply and the diode is very small when the diode is forward-conducting, and the half-wave rectified output current of the diode provides capacitor charging on the one hand and internal load on the other hand. Therefore, almost all the output voltage of the diode is added to the capacitor (in fact, the voltage on the capacitor is equal to the load voltage). The inertia of the capacitor to the voltage, that is, the voltage cannot be changed suddenly, so the original voltage and charge of the capacitor are zero when it is charged for the first time. , so that the charging current is particularly large. We call the current at this time the inrush current of the rectifier tube. In addition to causing instantaneous heating of the rectifier tube or even burning it due to insufficient margin of the flow tube, what is more serious is that it is manifested in a numerical value. A large current passes through the capacitor, and at the same time, the inside of the capacitor is impacted by the surge current and severely heats up. the

After entering normal operation, each charging current only needs to replenish the charge lost due to capacitor discharge to the first charging state, so the current is much smaller than the first charging current. the

The half-wave rectification charging the capacitor can be regarded as intermittent. Compared with the continuous charging state of the full-wave rectification capacitor, the average voltage of the former is only 1/2 of the latter, and the capacitor is impacted by a large current and the capacitor is heated. The former is greatly reduced, so half-wave rectification is used for charging in the first 1 to 2 seconds, which can effectively protect the capacitor and prolong its service life. the

Before the energy-saving lamp is ignited, the output of the rectifier can be regarded as no-load output, and the voltage is close to √2E. After the lamp is ignited, the capacitor C discharges rapidly, and the output voltage drops sharply, making the filter output close to 0.45E . the

2. Bridge rectification of energy-saving lamps:

Figure 4

E: power frequency mains voltage

C: energy-saving lamp main circuit filter capacitor

ZL: energy-saving lamp bridge rectifier

RL: Equivalent circuit load resistance

3. Comparison of the initial voltage of the filter capacitor C:

From the energy-saving lamps shown in Figure 3 and Figure 4, there is such a large difference in the voltage value of the filter capacitor C at the moment of half-wave and full-wave power supply. It can be seen that the use of half-wave instantaneous power supply can completely avoid "surge current" The great threat to the filter capacitor C can be seen in figures with an average value of 0.9E>0.45E. the

B: lamp filament:

1. Instantaneous high pressure at startup:

It can be seen from Figure 3 that the filter capacitor C is in the transitional charging process during the half-wave power supply of the mains, and the output voltage of the rectifier is close to √2E. When the internal driving frequency of the energy-saving lamp rises to the LC natural frequency of the lamp circuit, resonance occurs, and the voltage here is There is no difference between the "no-load" voltage and the filter output of normal mains full-wave power supply. Therefore, the high voltage in the "resonance" state is enough to start the lamp. The output voltage increases immediately due to the load of the energy-saving lamp tube, the filter capacitor C accelerates the discharge, and the output voltage drops sharply, making the filter output voltage close to 0.45E. It is precisely because the voltage drops instantly at this time that the lamp filament is protected from high current impact . the

2. Automatically enter full-wave power supply:

The circuit of this design can delay from the "half wave" to the "full wave" automatically from the mains power supply state, ensuring the normal operation of the energy-saving lamp. the

3. In the half-wave power supply stage, the energy-saving lamps operate in the small current stage, which slows down the magnetic saturation process of the (toroidal transformer) winding in the base circuit of the switch tube, so that the frequency of the square wave voltage output by the alternate conduction of the two switch tubes is changed by The low gradually changes to high, and it is precisely because of this continuous frequency change, that is, frequency sweep, that the lamp can be ignited smoothly. the

Claims (5)

1. A thyristor type energy-saving lamp driver is characterized in that the commercial power is formed through a thyristor delay circuit, a power conversion circuit, a half-bridge inverter circuit and a lamp circuit successively. 2. The thyristor type energy-saving lamp driver according to claim 1, characterized in that the thyristor delay circuit is as follows: a, main circuit circuit: composed of bidirectional thyristor BCR1 and diode VD4, and the two are connected in parallel Connected to the mains input terminal; b. Delay circuit: a delay working power supply composed of diode VD3, capacitor C5, and resistor R4, and a delay circuit composed of resistors R5, R6, R7, and capacitors C6, C7, and its output is connected to Triac BCR1 trigger extreme. 3. The thyristor-type energy-saving lamp driver according to claim 1, wherein the power conversion circuit includes a bridge rectifier BR and a filter capacitor C1 connected in parallel to the output terminal. 4. The thyristor-type energy-saving lamp driver according to claim 1, characterized in that the half-bridge inverter circuit includes two parts: a start-up circuit and an inverter circuit, wherein the start-up circuit is composed of a resistor R1, a capacitor C2, and a bidirectional diode VD2 ; The inverter circuit is composed of ring deformer windings T1a, T1b, T1C, resistors R2, R3, transistors VT1, VT2. 5. The thyristor type energy-saving lamp driver according to claim 1, characterized in that the lamp circuit is composed of inductor L1, capacitors C3, C4, C5 and filaments FL1 and FL2. the

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