KR20070088302A - Method for controlling low-voltage using waves ac and system for performing the same - Google Patents

Abstract

A method for controlling low voltage using AC(Alternating Current) power and a system for performing the same are provided to increase efficiency by forming a circuit with resistance and a transistor. A method for controlling low voltage using AC power includes the steps of: rectifying the inputted AC power; switching on a low voltage part with a voltage level lower than control voltage determined by the voltage level on a waveform of the rectified AC power; switching off the high voltage with the voltage level higher than the control voltage; generating four times of output power with the voltage level lower than the control voltage determined from one cycle of the rectified AC power; and converting the low voltage part outputted to output the converted low voltage part.

Description

Low voltage control method using AC power and system for performing the same {METHOD FOR CONTROLLING LOW-VOLTAGE USING WAVES AC AND SYSTEM FOR PERFORMING THE SAME}

The present invention relates to a low voltage control method using an AC power source and a system for performing the same. In particular, it is possible to stably control up to 0% to 100% of the AC power level by supplying a low voltage DC power directly from a commercial AC power source. The present invention relates to a low voltage control method using waveforms of an AC power supply and a system for performing the same, to have an optimal efficiency and to make the system compact.

In general, power control using an AC power source mainly uses a cycle control method and a phase control method. In the period control, when the voltage is zero, that is, as shown in FIG. 1A, when the AC power supplying a sine wave progresses for one period and reaches the point A where the voltage is 0, on / off control is performed. In order to supply 50% of the supplied AC power, in the cycle control method, the power is controlled by repeating on and off by one cycle.

Although this cycle control method is excellent in terms of power noise, it can be used in high-priced equipment because it is economically low because a zero base of AC power, that is, a circuit for finding a point where voltage is zero after one cycle is required, is low. There is a disadvantage in that it is impossible to supply a uniform power in the power control ratio is low compared to the AC power that is controlled.

For example, if the halogen lamp operating at 12V using the 110V / 220V commercial power supply is controlled by the cycle control method, the halogen lamp will be damaged by the power for one cycle, so the transformer or the switching power supply is used. I was using

In addition, as shown in FIG. 1B, the phase control method is used throughout the industry because the method is simple because it controls the power supplied to the load by varying the phase of the supplied AC power, but switching on / off in a high voltage part. There is a disadvantage that the noise is large and not stable in the control of less than 50% of the supplied AC power and also can not supply a uniform power.

That is, the conventional cycle control method and the phase control method perform the control to turn on / off the power on the basis of the phase over time, while the new method proposed in the present invention is to turn on / off the power on the basis of voltage. Control will be performed.

Technical challenge

The present invention has been invented to solve the shortcomings of the above-described periodic control method and phase control method, and by controlling ON / OFF switching operation between the input terminal and the load, the AC power supplied without conversion loss is uniformly and stably controlled. Convert to DC power. Therefore, it is possible to supply high-efficiency DC power from commercial AC power only with semiconductor and resistor, so it has optimal efficiency and economic efficiency, and low voltage control method using AC power to realize power control device with one integrated circuit. The primary purpose is to provide

It is also a second object of the present invention to provide a system for performing the first object.

Technical solution

The present invention for performing the above first object,

A full-wave rectifying step for full-wave rectifying the input AC power;

In the waveform of full-wave rectified AC power, the low voltage part whose voltage level is lower than the control voltage set according to the voltage level is switched on, and the high voltage part whose voltage level is higher than the control voltage is switched off, so A switching step of switching to generate four output powers having a voltage level lower than a control voltage set in one cycle of the power supply;

It is composed of a DC power output step of converting the low voltage portion output in the switching step to a DC output.

According to a preferred embodiment of the present invention, if an overcurrent is applied to the switching step, the overcurrent detection step of blocking the operation of the switching step, and the overvoltage for blocking the operation of the switching step when the output voltage of the switching step is an abnormal voltage A detection step.

In the low voltage control method of the present invention, two outputs having a voltage level lower than the control voltage are generated in the positive (+) positive direction of the input AC power, and the voltage is lower than the control voltage even in the negative (-) negative direction of the input AC power. Switching is performed to generate two outputs with low levels.

In the low voltage control method of the present invention, in converting a commercial AC power source to a DC power source, the DC power source is converted only by switching on / off operation between the input terminal of the AC power source and the load. Therefore, the conversion loss is small and there is little power consumption if the load is not operated. That is, by adopting the method of switching on / off based on the magnitude of the AC waveform input between the AC power and the load, the efficiency is high and the switching is not frequent so there is little noise.

The present invention for performing the second object,

Rectifier for receiving full-wave rectification of the commercial AC power;

A voltage level detecting unit connected to an output terminal of the rectifying unit for detecting a set control voltage required by a load;

A power supply switching unit connected to an output terminal of the voltage level detection unit and operating to switch according to a set control voltage to generate four outputs having a voltage level lower than a set control voltage in one period of the full-wave rectified AC power supply; And

It is composed of a direct current converter for converting the output of the power supply switching unit to direct current.

According to a preferred embodiment of the present invention, the output terminal of the power switching unit further includes an overcurrent detection unit for detecting an overcurrent in the output current of the power switching unit to cut off the supply of the power applied to the power switching unit, the output terminal of the power switching unit over-voltage or more The apparatus further includes an abnormal voltage detection unit that blocks the operation of the power supply switching unit when a voltage is applied.

1A and B are waveform diagrams for explaining a period control method and a phase control method used in general power control.

2 is a waveform diagram illustrating the operation of the low voltage control method according to the present invention.

3 is a block diagram of a system for implementing a low voltage control method according to the present invention.

4 is a first embodiment of a circuit implementing the low voltage control system according to the present invention.

5 is a second embodiment of a circuit implementing the low voltage control system according to the present invention.

6 is a waveform diagram illustrating an output waveform of a power supply passing through the systems of FIGS. 4 and 5.

Best Mode for Carrying Out the Invention

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. 2 is a waveform diagram illustrating the operation of the low voltage control method according to the present invention, and FIG. 3 is a block diagram of a system for implementing the low voltage control method according to the present invention. 4 is a first embodiment of a circuit implementing the low voltage control system according to the present invention, FIG. 5 is a second embodiment of a circuit implementing the low voltage control system according to the present invention, and FIG. 4 and 5 are waveform diagrams for showing output waveforms of a power supply passing through the system of FIG.

In the low voltage control method according to the present invention, as shown in FIG. 2, the low voltage portion lower than the control voltage set according to the magnitude of the power to be passed through the full-wave rectified sinusoidal waveform after the full-wave rectified AC power is switched on. The voltage control is performed so that the high voltage portion higher than the set control voltage is switched off. Therefore, by controlling the AC power to be turned on / off in the low voltage part, the switching noise is reduced compared to the phase control method in which on / off is performed in the high voltage part.

As shown in FIG. 3, the system for performing the low voltage control method according to the present invention includes a rectifying unit 110 configured as a bridge circuit for receiving a commercial AC power and full-wave rectifying it, and at the output terminal of the rectifying unit 110. The voltage level detecting unit 120 for detecting the set control voltage required by the load is connected. In addition, the power supply switching unit 130 is operated at the output terminal of the voltage level detection unit 120 to generate four outputs having a voltage level lower than the control voltage set in one cycle of the AC power rectified by switching according to the set control voltage. ) Is connected, and a DC conversion unit 140 for converting the power output from the power switching unit 130 into direct current is connected to the output side of the power switching unit 130.

In addition, the output terminal of the power switching unit 120 is connected to the over-current detecting unit 150 for detecting the over-current of the output current of the power switching unit 120 to cut off the supply of power applied to the power switching unit 130, When an abnormal voltage such as an overvoltage is applied to the output terminal of the power switching unit 130, an abnormal voltage detection unit 160 that blocks the switching operation of the power switching unit 130 is connected.

The system for performing the low voltage control method according to the present invention detects the voltage level of the sinusoidal waveform of the commercial AC power input and is connected between the input terminal and the load of the commercial AC power supply, and is lower than the set control voltage required by the load. Controls switching on / off the commercial AC power input to pass only the voltage level. In other words, assuming that the power required by the load is 10% of the commercial AC power supply (if the commercial AC power input is 100V, the power required by the load is 10V). It is not a power control in which the smoothness of the power outputted to the load is significantly reduced by controlling the time given by 10 times, and the voltage up to a low voltage level of 20% or less is switched on in the system according to the present invention, and the high voltage is 20% or more. The level is a low-voltage control method in which smoothness is remarkably improved by switching DC and supplying only 10% of the power of a commercial AC power supply by switching off the level and repeating switching on and off.

The system for performing low voltage control according to the present invention can be implemented as a circuit as shown in FIGS. 4 and 5. Embodiment 1 of FIG. 4 is commercialized to AC1 and AC2 terminals to which commercial AC power is applied as the rectifier 110. Bridge circuits D1 to D4 for full-wave rectification of the AC power supply are connected, and voltage level detectors 120 are connected to both output terminals of the bridge circuits D1 to D4. The resistors R1 and R2 are connected in series between both output terminals of the AC power source rectified in the bridge circuits D1 to D4, and a Zener for maintaining a constant voltage between the resistors R1 and R2, respectively. The diode ZD1 and the variable resistor VR1 in which the resistance value changes are connected in series, and the base of the first transistor Q1 for transmitting the switching signal to the variable resistor VR1 according to the set value of the variable resistor VR1. The stage is connected, the emitter terminal of the first transistor Q1 is directly connected to the output terminal of the system, and the collector terminal of the first transistor Q1 is connected to the other output terminal of the system through the resistor R3, so that the voltage level detector 120 ) Is configured.

The power supply switching unit 130 also includes a base of the second transistor Q2 through a resistor R4 connected between the collector terminal of the first transistor Q1 constituting the voltage level detector 120 and the resistor R3. Stage is connected, the emitter stage of the second transistor Q2 is directly connected to the output stage of the system and the collector stage of the second transistor Q2 is connected to the other output stage of the system via series connected resistors R5 and R6. The base terminal of the fifth transistor Q5 of the PNP type is connected between the resistors R5 and R6 connected in series to the collector terminal of the second transistor Q2, and the emitter terminal of the fifth transistor Q5 is directly connected. The collector terminal of the fifth transistor Q5 and connected to the output terminal of the system is configured to be connected to the other output terminal of the system via series connected resistors R7 and R8. In addition, the base terminal of the fourth transistor Q4 is connected between the resistors R7 and R8 connected in series to the collector terminal of the fifth transistor Q5, and the emitter terminal of the fourth transistor Q4 is connected to the resistor R9. Is connected to the output terminal of the system and the collector terminal of the fourth transistor Q4 is directly connected to the other output terminal of the system, and the base of the sixth transistor Q6 is connected between the collector of the fourth transistor Q4 and the resistor R9. The stage is connected, the emitter stage of the sixth transistor Q6 is configured to be connected to the output terminal of the system via a resistor R12 and the collector stage of the sixth transistor Q6 is directly connected to the other output terminal of the system.

In addition, the DC power supply unit 140 is composed of a resistor (R14) and a capacitor (C1) connected in parallel to the output terminal of the power switching unit 130 to smooth the output of the power switching unit 130 to convert to DC.

In addition, the overcurrent detection unit 150 branches between the emitter terminal of the sixth transistor Q6 of the power supply switching unit 130 and the resistor R12 so that the base terminal of the seventh transistor Q7 is connected through the resistor R13. The collector terminal of the seventh transistor Q7 is connected to the base terminal of the second transistor Q2 of the power supply switching unit 130 and the emitter terminal of the seventh transistor Q7 is connected to the output terminal of the system.

The abnormal voltage detector 160 is branched between the resistors R10 and R11 connected in series between the output terminals DC1 and DC2 for outputting the DC power, and the base terminal of the third transistor Q3 of the PNP type is connected. The collector terminal of the third transistor Q3 is connected to the base terminal of the fifth transistor Q5 of the power supply switching unit 130 and the emitter terminal of the third transistor Q3 is connected to the output terminal of the system.

In Embodiment 1 of the system for performing low voltage control according to the present invention configured as described above, when a commercial AC power is applied through the AC1 and AC2 terminals, inputted by the bridge rectifiers D1 to D4 constituting the rectifying unit 110. Full-wave rectification of AC power. The AC power source rectified has a control voltage set by the resistance resistors R1 and R2 of the voltage level detector 120 and the zener diode ZD1 for keeping the voltage constant and the variable resistor VR1 whose resistance value is changed. According to the value, the first transistor Q1 is switched on / off. That is, when the power source rectified by the rectifier 110 is greater than the voltage level set by the resistors R1 and R2 and the variable resistor VR1, the first transistor Q1 is switched on and the first transistor Q1 is turned on. ) Switches on the switching-off state of the second transistor Q2 of the power supply switching unit 130 as the switching-on.When the second transistor Q2 is switched off, the fifth transistor Q5 of the PNP type The fourth transistor Q4 and the sixth transistor Q6 are also inoperative. Therefore, the power switching unit 130 does not output the full-wave rectified power whose voltage level is greater than the control voltage value set by the resistors R1 and R2 and the variable resistor VR1 of the voltage level detector 120.

On the contrary, when the power rectified by the rectifier 110 is smaller than the voltage level value set by the resistors R1 and R2 and the variable resistor VR1, the first transistor Q1 is switched off, and thus, the power switching unit The second transistor Q2 of 130 is switched on, and as the second transistor Q2 is switched on, the fifth transistor Q5 of the PNP type is switched on through the resistor R5. As the fifth transistor Q5 is switched on, the current passing through the fifth transistor Q5 is applied to the fourth transistor Q4 through the resistor R7 to be amplified, and the full transistor is turned on by turning on the sixth transistor Q6. The applied power is applied to the DC converter 140 to smooth the parallel connected resistor R14 and the capacitor C1 to output the DC power. Therefore, only a power source having a voltage level lower than the control voltage value set by the resistors R1 and R2 and the variable resistor VR1 of the voltage level detector 120 is converted into a DC power source and output.

As such, in the process of converting and outputting only the power having a voltage level smaller than the control voltage value set by the resistors R1 and R2 and the variable resistor VR1 of the voltage level detector 120 to the DC power, the DC output terminal. When the output current is excessive at DC2, that is, when the current applied to the resistor R12 is excessive through the emitter terminal of the sixth transistor Q6 of the power source switching unit 130, the seventh of the overcurrent detection unit 150 is excessive. The transistor Q7 is operated to cut off the current applied to the base terminal of the second transistor Q2 of the power switching unit 130 to stop the operation of the power switching unit 130 to protect the circuit even if the output terminal is shorted. do.

When an abnormal voltage is generated in the process of outputting the DC power, the abnormal voltage operates the third transistor Q3 of the PNP type through the resistor R11 of the abnormal voltage detector 160, and the third transistor Q3. ) Cuts off the current applied to the base terminal of the fifth transistor Q5 of the power switching unit 130 to stop the operation of the power switching unit 130, thereby preventing the output of an abnormal voltage such as an overvoltage.

After the low voltage control is performed, four outputs having a voltage level lower than the control voltage value set in one cycle of the full-wave rectified AC power supply are repeated as shown in FIGS. 6A and 6B. The low voltage control method according to the present invention has an advantage that can not be compared with conventional methods when the voltage drop between the input power and the output power is large. For example, suppose that the power supplied to the load is about 10% of the AC power (the output power is 10V when the voltage of the input power is 100V). In the cycle control method of FIG. 1A, only one cycle of the AC power passes and the remaining 9 The period is not passed (switching on and off time ratio is 1:10), which has disadvantages such as enormous switching noise, difficulty in smoothing, and damage to load, whereas in the method of the present invention, the voltage level of switching on and switching off is reduced. This has 15 to 20 (variable according to voltage) and 0, so the level difference between the switching on and off voltage is not so severe that there is an advantage of even output voltage level and smooth power supply to the load.

This advantage of the present invention has strengths when a direct low DC voltage is required in commercial AC power supply voltage, and can be easily utilized as a power supply for DC power devices of low voltage as a commercial power supply.

In addition, in another embodiment of the present invention, as shown in Figure 5, the operation principle is the same as the embodiment of Figure 4, the transformer T1 to the output terminal of the power switching unit 130, the configuration of the DC converter 140 Connect the primary side of and connect the bridge rectifiers D5 to D8 to the secondary side of the transformer T1.Conduct and supply only voltages below a certain voltage level through the detection and switching operation of the voltage level. It changes the voltage and operates to convert to DC through the bridge rectifiers D5 to D8.

In FIG. 5, an insulation transformer T1 is adopted to insulate between a commercial power supply and a load in supplying DC power, and the frequency of the power applied to the transformer T1 is not 60 Hz, but through a switching operation. The frequency above 120Hz or 240Hz decreases the size of the transformer that delivers the same power and increases the efficiency.

As described above, the advantages of the present invention are greatly highlighted in comparison with the conventional power control. As shown in FIG. 1, the periodic control passes through only one cycle in order to output 50% of the AC level of the input AC power, although switching noise is small, which is derived by turning on / off when the voltage level of the input AC voltage is zero. The maximum voltage fluctuation range is obtained because the remaining cycle is not passed.

In addition, phase control has the highest switching noise due to switching on when the voltage level is PEAK, but in order to output 50% of the voltage level of the AC power input, Evenly passing 1/2 of the forward wave and 1/2 of the negative sub-direction wave has the advantage of outputting the voltage level four times more evenly than the period control.

As shown in FIG. 2, in order to output 50% of the voltage level of the AC power input as shown in FIG. 2, 2 times of the positive positive wave and 2 of the negative negative wave are evenly distributed during one cycle. The switching noise can be large by passing it, but the output voltage level is 2 times more uniform than the phase control, and it can be configured with a simple circuit as described above, so it is economical and it is more advantageous when the output voltage level is low. have.

As described above, the lower the output voltage level is, the greater the advantages are. Therefore, when the rectified output is controlled to a low voltage and used as a low voltage DC supply, the most efficient method of converting to DC by lowering the AC voltage until now. It is high (about 80% to 95%), and the possibility of a very small power supply is highlighted, and standby power consumption without load can be 0.1W or less in a BJT circuit, and 0.01W or less in a C-MOS FET. That is, when the low voltage control system of FIGS. 4 and 5 is implemented as an integrated circuit, even up to several tens of watts (W) can be output at a low voltage of about 3V to 12V with a 10mm cube.

As described above, the present invention is a switching method that performs voltage level control on the voltage waveform of AC voltage, which can perform low voltage control with high efficiency and stability, and control of phase below 50% of the voltage level of AC power is unstable. It can solve the shortcomings of periodic control that is not uniform control, and it is possible not only to realize the small size of the power supply which makes low DC voltage directly from the commercial AC voltage. It is a circuit consisting of only a resistor and a transistor, so it can be integrated into a small IC, so that a highly efficient and safe circuit can be designed and integrated to realize an economic power control device.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited thereto and may be improved or modified by those skilled in the art within the scope of the technical idea of the present invention.

Claims (12)

A full-wave rectifying step for full-wave rectifying the input AC power; The low voltage portion of which the voltage level is lower than the control voltage set according to the voltage level in the waveform of the full-wave rectified AC power source is switched on, and the high voltage portion of which the voltage level is higher than the control voltage is switched off to thereby propagate the radio wave. A switching step of switching to generate four output powers having a voltage level lower than a control voltage set in one cycle of the rectified AC power; And a direct current power output step of converting the low voltage portion output in the step into direct current and outputting the direct current. The low voltage control method according to claim 1, further comprising an overcurrent detection step of interrupting the operation of the switching step when the output power becomes an overcurrent after the switching step. The low voltage control method according to claim 1, further comprising an overvoltage detection step of interrupting the operation of the switching step when the output voltage of the switching step is an abnormal voltage. Rectification unit 110 for receiving a commercial AC power supply for full-wave rectification; A voltage level detector 120 connected to an output terminal of the rectifier 110 to detect a set control voltage required by a load; A power supply connected to an output terminal of the voltage level detection unit 120 and operating according to the set control voltage to generate four outputs having a voltage level lower than the set control voltage in one period of the full-wave rectified AC power supply Switching unit 130; And Low voltage control system using the waveform of the AC power supply including a DC converter 140 for converting the output of the power switch 130 to a direct current. 5. The resistors R1 and R2 of claim 4, wherein the voltage level detector 120 is connected in series between two output terminals of the AC power output rectified by the rectifier 110. Zener diode ZD1 for maintaining a constant voltage and a variable resistor VR1 having a variable resistance are connected in series, and the variable resistor VR1 is connected to the variable resistor VR1 in accordance with a setting value of the variable resistor VR1. The base terminal of the first transistor Q1 for transmitting the switching signal is connected, the emitter terminal of the first transistor Q1 is directly connected to the output terminal of the system, and the collector terminal of the first transistor Q1 is connected to the resistor ( Low voltage control system using the waveform of the AC power supply, characterized in that connected to the other output terminal of the system through R3). 5. The second transistor of claim 4, wherein the power supply switching unit 130 is connected to the second transistor through a resistor R4 connected between the collector terminal of the first transistor Q1 of the voltage level detector 120 and the resistor R3. The base terminal of Q2 is connected, the emitter terminal of the second transistor Q2 is directly connected to the output terminal of the system, and the collector terminal of the second transistor Q2 is connected through series connected resistors R5 and R6. A base terminal of the fifth transistor Q5 of the PNP type is connected between the resistors R5 and R6 connected in series with the other output terminal of the system and connected in series with the collector terminal of the second transistor Q2, and the fifth transistor is connected. The emitter terminal of Q5 is directly connected to the output terminal of the system and the collector terminal of the fifth transistor Q5 is configured to be connected to the other output terminal of the system through series connected resistors R7 and R8. Connected in series to the collector terminal of transistor Q5 The base terminal of the fourth transistor Q4 is connected between the terms R7 and R8, and the emitter terminal of the fourth transistor Q4 is connected to the output terminal of the system through the resistor R9 and the fourth transistor Q4 ) Is connected directly to the other output terminal of the system, the base terminal of the sixth transistor (Q6) is connected between the collector of the fourth transistor (Q4) and the resistor (R9), and the sixth transistor (Q6) The emitter stage is connected to the output of the system via a resistor (R12) and the collector stage of the sixth transistor (Q6) is configured to be directly connected to the other output of the system. 5. The low voltage control using the waveform of the AC power supply according to claim 4, wherein the DC power supply unit 140 includes a resistor R14 and a capacitor C1 connected in parallel to the output terminal of the power supply switching unit 130. system. 5. The overcurrent detector of claim 4, wherein the output terminal of the power switching unit 130 detects an overcurrent in the output current of the power switching unit 130 and cuts off the supply of power applied to the power switching unit 130. Low voltage control system using the waveform of the AC power supply further comprising. The method of claim 4 or 8, wherein the overcurrent detector 150 is branched between the emitter terminal of the sixth transistor (Q6) of the power switching unit 130 and the resistor (R12) through the resistor (R13). The base end of the seventh transistor Q7 is connected, and the collector end of the seventh transistor Q7 is connected to the base end of the second transistor Q2 of the power source switching unit 130 and the seventh transistor Q7. The emitter stage of the low voltage control system using the waveform of the AC power supply, characterized in that the configuration is connected to the output terminal. The abnormal voltage detection unit 150 of claim 4, wherein an abnormal voltage is applied to an output terminal of the power switching unit 130 to block the operation of the power switching unit 130 when an abnormal voltage is applied to the output current of the power switching unit 130. Low voltage control system using the waveform of the AC power supply further comprising. 11. The method of claim 4 or 10, wherein the abnormal voltage detector 160 is branched between the resistors (R10, R11) connected in series between the output terminals (DC1, DC2) for outputting a DC power source of the PNP type The base end of the third transistor Q3 is connected, and the collector end of the third transistor Q3 is connected to the base end of the fifth transistor Q5 of the power source switching unit 130 and the third transistor Q3. The emitter stage of the low voltage control system using the waveform of the AC power supply, characterized in that the configuration is connected to the output terminal. 5. The DC rectifier 140 of claim 4, wherein a primary side of the transformer T1 is connected to an output terminal of the power source switching unit 130, and bridge rectifiers D5 to D8 on a secondary side of the transformer T1. Low voltage control system using the waveform of the AC power source, characterized in that the connection is configured.

Images