KR100724313B1 - Method for converting voltage and converter for performing the same - Google Patents

Abstract

A method for converting a voltage and a converter for performing the same are provided to perform a stable DC power supply to a load by dropping DC/AC power supplied to a power terminal only through switching. A method for converting a voltage includes steps of: charging a DC voltage to an input terminal capacitor by switching inputted DC power; switching a voltage of the voltage-charged input capacitor to charge the switched voltage to an output terminal capacitor connected to a DC output terminal; sensing the DC voltage outputted from the output terminal capacitor; and increasing a switching period of the above charging and switching steps when the DC voltage outputted in the sensing step is below a predetermined value, and decreasing the switching period when the DC voltage outputted in the sensing step is above the predetermined value.

Description

Power conversion method and power converter for performing the same {method for converting voltage and converter for performing the same}

1 is a conceptual diagram of a DC-DC converter as a first embodiment of a power converter according to the present invention.

2 is a conceptual diagram of an AC-DC converter as a first embodiment of a power converter according to the present invention.

3 is a block diagram of a DC-DC converter as a first embodiment of a power converter according to the present invention.

4 is a circuit diagram of a DC-DC converter as a first embodiment of a power converter according to the present invention.

Fig. 5 is a block diagram of an AC-DC converter as a second embodiment of a power converter according to the present invention.

Fig. 6 is a circuit diagram of an AC-DC converter as a second embodiment of a power converter according to the present invention.

<Explanation of symbols for the main parts of the drawings>

102: current limiter 112: switching circuit

112: switching control unit 114: first switching unit

116: second switching unit 120: first capacitor

130: second capacitor

The present invention relates to a power conversion method and a power conversion device for performing the same, and in particular, by supplying the power supplied from the input terminal to the output terminal by the pumping (pumping) method using only a small capacitor to improve the conversion efficiency The present invention relates to a power conversion method for reducing an impact on an input terminal and an output terminal, and a power conversion apparatus for performing the same.

In general, a pulse width modulation (PWM) control method is widely used in a power supply device for stepping down a DC power supplied from a power supply to supply a load. In the PWM control method, the DC voltage inputted according to the pulse width (Duty) output from the PWM control unit is stepped down by a switching method to output a constant voltage. That is, the PWM control method accumulates the DC voltage input when the switching device is "ON" in the PWM control unit, and the DC voltage input when the switching device is "OFF" in the PWM control unit. Is blocked, and the power accumulated by the counter electromotive force is discharged to obtain a desired output voltage. At this time, the output voltage is determined according to the pulse width of the PWM pulse signal output from the PWM control unit.

However, in the voltage step-down power supply circuit using the conventional PWM control method as described above, a large power loss occurs during switching of the switching element, thereby reducing the efficiency of the power supply circuit and generating a lot of heat in the transformer. Therefore, the size of the heat dissipation or cooling system attached to the power circuit for dissipating heat is increased, the overall size of the power circuit has a problem.

The present invention has been invented to solve the above problems, the power supply of the input terminal by using a small capacitor in order to supply a stable DC power to the load by stepping down the DC / AC power supplied from the power supply only by switching. By converting the pump to the bottom to reduce the switching noise applied to the input and output stages, the power conversion method to improve the conversion efficiency of all the power conversion device except the capacitor can be implemented as a single IC and power conversion device for performing the same The purpose is to provide.

The present invention for achieving the above object

A first charging step of charging a DC voltage to an input terminal capacitor by switching an input DC power source;

A second charging step of switching the voltage of the input terminal capacitor charged with the voltage in the first charging step to charge the output terminal capacitor connected to the DC output terminal;

An output voltage sensing step of sensing a DC voltage output from an output capacitor after the second charging step; And

In the output voltage sensing step, the switching period of the first charging step and the second charging step is increased when the output DC voltage is less than or equal to the set value, and the switching period is decreased when the DC voltage output in the output voltage sensing step is greater than or equal to the setting value. And a switching control step of controlling it.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a conceptual diagram of a DC-DC converter, which is a first embodiment of a voltage drop type power converter according to the present invention, and FIG. 2 is an AC of a first embodiment of a voltage drop type power converter, according to the present invention. -Conceptual diagram of the DC converter. 3 is a block diagram of a DC-DC converter as a first embodiment of the voltage drop type power converter according to the present invention, and FIG. 4 is a DC-DC diagram as a first embodiment of the voltage drop type power converter according to the present invention. A circuit diagram of a DC converter. 5 is a block diagram of an AC-DC converter as a second embodiment of the voltage drop type power converter according to the present invention, and FIG. 6 is an AC- as a second embodiment of the voltage drop type power converter according to the present invention. A block diagram of a direct current converter.

1 and 2, the voltage drop type power supply device according to the present invention detects an output voltage between a voltage input from a power supply terminal and an output voltage supplied to a load terminal to switch switching on / off duty. The first capacitor 120 and the second capacitor 130 are configured to sequentially charge electric charges according to the switching operation of the circuit 110 and the switching circuit 110.

According to the present invention, the DC / AC power supplied from the power supply terminal is sequentially charged to the first capacitor 120 and the second capacitor 130 using the switching circuit 110 to step down the power supplied from the power supply terminal. To pump into the load stage. That is, the voltage drop type power supply device according to the present invention can control the power supplied to the load terminal by changing the cycle or the number (duty) of switching the switching on / off in the switching circuit 110. For example, in FIG. 1, the switching circuit 110 alternately turns on / off the contacts a and b, and if the number of switching is reduced (shorter switching on time compared to the switching off time), the voltage supplied to the load The level becomes smaller.

Therefore, if the switching on time is shortened compared with the switching off time, the supply power is substantially the same.

Referring back to FIG. 1, when the switching terminal of the switching circuit 110 is connected to the a terminal, the DC voltage of the input terminal is charged to the first capacitor 120. When the switching terminal of the switching circuit 110 is connected to the b terminal, the voltage charged in the second capacitor 130 is converted by Q (total charge amount) = C (capacitance of capacitor) x V, which is a charge amount conservation law.

For example, if the DC voltage at the input terminal is DC 141V, the capacity of the first capacitor 120 is 10uF, and the capacity of the second capacitor 130 is 90uF, the second capacitor 130 is charged and output when the operation as described above. The direct current voltage becomes 14.1V, and there is little loss in the charging process. In this case, the operation of the switching circuit 110 senses the voltage charged and output to the second capacitor 130 and if the voltage is lower than the desired voltage, the switching terminal is switched to the terminal a and the above operation is repeated. If power is not consumed in the load (not shown) connected to the output terminal of the second capacitor 130, the power is not operated in the switching circuit 110. Therefore, there is almost no power consumption at no load, and the input / output terminals are connected to the capacitors 120 and 130. It gives shock noise as much as it is charged, so it has better ripple and noise characteristics than general switching method.

2 is a principle diagram showing a method of converting from AC power source AC to DC power source DC using the method of the present invention. Substantially the same as FIG. 1, but further comprises a full-wave rectifying unit 121 and a charging capacitor (C) for full-wave rectifying AC power between the AC input terminal and the first capacitor 120 to full-wave rectified AC power to DC power After the conversion, the charging capacitor C is charged and the power is converted and output in the same manner as in FIG. 1.

As shown in FIG. 3, the DC-DC converter, which is the first embodiment of the power converter according to the present invention operating according to the same principle, connects a first capacitor 120 for charging electric charges at a DC input terminal. A second capacitor 130 is connected to the DC output terminal for charging and outputting the charge charged by the first capacitor 120 by a switching operation. One side of the second capacitor 130 is connected to a switching circuit 110 for sensing the voltage output from the second capacitor 130 to change the switching on / off duty.

The switching circuit 110 detects a voltage output from the second capacitor 130 and switches the switching operation according to control signals of the switching controller 112 and the switching controller 112 for converting the switching on / off duty according to the set voltage. It consists of a first switching unit 114 and a second switching unit 116 to. The first switching unit 114 formed between the DC input terminal and the first capacitor 120 switches an operation of charging a voltage to the first capacitor 130 from the DC input terminal, and the first capacitor 120 and the second capacitor ( The second switching unit 116 formed between the 130 switches an operation of charging the voltage from the first capacitor 120 to the second capacitor 130.

Here, a current limiter 102 may be further formed between the DC input terminal and the first switching unit 114 to protect the DC input terminal by preventing a surge current from being applied to the DC input terminal. In addition, the first capacitor 120 uses a capacitor having a large inductance component, and the second capacitor 130 can reduce switching shocks at each stage of the input terminal and the output terminal by using a capacitor having a low inductance component.

When the power conversion device according to the first embodiment of the present invention configured as described above receives a DC input from the DC input terminal and passes the current limiter 102, the switching controller 112 operates the first switching unit 114 to a predetermined amount. DC power is charged in the first capacitor 120. The voltage charged in the first capacitor 120 is moved to the second capacitor 130 by operating the second switching unit 116 under the control of the switching control unit 112. If the capacity of the first capacitor 120 is 10uF, the capacity of the second capacitor 130 is 90uF and the DC input is 100V delivered, then the total charge Q = 10uF × 100V = (10uF + 90uF by Q = C × V X 10V, and the voltage charged in the second capacitor 130 becomes a voltage of 10V.

The second capacitor 130 uses less capacitor than the first capacitor 120 to reduce the spike noise. The switching control unit 112 controls the switching operation by detecting the DC output voltage. When the output voltage is lower than the set voltage, the switching control unit 112 increases the switching count (variable duty) to increase the number of times (fast switching) from the DC input terminal. The first capacitor 120 is charged. When the set voltage is exceeded, the switching controller 112 stops the switching operation so that the set current or more is not output. In recent years, efficient switching operation is possible due to the development of high voltage switching elements, and in the present invention, since it is configured as a simple high voltage switching, it is possible to implement one semiconductor except for the capacitors 120 and 130 for charging. Is a new way to supply DC power with two small capacitors

The DC-DC converter according to the first embodiment of the present invention shown in FIG. 3 may also be implemented with the circuit of FIG. 4. The circuit diagram of FIG. 4 includes a first capacitor 120 connected to a DC input terminal. ) Is connected to the collector terminals of the fifth transistor Q5 and the third transistor Q3 which are NPN transistors through the resistor R9 on one side thereof, and the base terminal of the fifth transistor Q5 is connected to the resistor terminal R8 through the resistor R8. The emitter terminal of the third transistor Q3 is connected, and the emitter terminal of the fifth transistor Q5 is connected to the DC input terminal.

In addition, the second capacitor 130 connected to the DC input terminal is connected to the collector terminals of the sixth transistor Q6 and the fourth transistor Q4, which are PNP-type transistors, through the resistor R11 on one side thereof, and the sixth transistor Q6. Is connected to the emitter terminal of the fourth transistor Q4 through the resistor R10, and the emitter terminal of the sixth transistor Q6 is connected between the first capacitor 120 and the resistor R9. .

The base terminal of the third transistor Q3 is connected to the collector terminal of the first transistor Q1, which is an NPN transistor connected to both ends of the DC input terminal, and the base terminal of the fourth transistor Q4 is connected to both ends of the DC input terminal. It is connected to the collector terminal of the second transistor Q2 which is an NPN transistor.

A resistor R9 connected between the first capacitor 120 and the collector terminal of the fifth transistor Q5 and the third transistor Q3, which are NPN-type transistors, and the sixth capacitor, which is a PNP-type transistor, and the second capacitor 130. The resistor R11 connected between the transistor Q6 and the fourth transistor Q4 is formed so as to limit the current flowing instantaneously to a stable value or less due to the characteristics of the capacitor.

In addition, the fifth transistor Q5 and the third transistor Q3, which are NPN transistors, and the sixth transistor Q6 and the fourth transistor Q4, which are PNP transistors, are configured to operate in opposite operations. When Q5 is conducting, the sixth transistor Q6 is turned off and when the sixth transistor Q6 is turned on, the fifth transistor Q5 is turned on.

The variable resistor R2 for setting the current value output from the second capacitor 130 is connected to one side of the second capacitor 130 and the resistor R1. The output side of the variable resistor R2 is connected to the input side of a voltage-to-frequency controller 113 for converting the voltage signal magnitude into the frequency signal frequency, and the output side of the V / F converter 113. Is connected to the base end of the first transistor Q1. One of the input terminals of the V / F converter 113 is connected to the DC output terminal through a resistor R12. This operation has the same effect as a monostable oscillator or timer that operates when the voltage is low instead of V / F.

The operation of the circuit diagram according to the first embodiment of the power conversion device of the present invention configured as described above is such that the voltage output from the second capacitor 130 is greater than the voltage value set by the variable resistor R2 in the V / F converter 113. When low, the turn-on and turn-off signals are repeatedly output to the first transistor Q1 at a frequency (switching frequency) inversely proportional to the low voltage. When the turn-on signal is applied to the first transistor Q1 according to the frequency output from the V / F converter 113 and the first transistor is turned on, the second transistor Q2 is turned on accordingly. As the first and second transistors Q1 and Q2 are turned on, the third transistor Q3 is turned on, and the fifth transistor Q5 is also turned on so that the first capacitor 120 is charged with the power supplied from the DC input unit. .

In addition, when the turn-off signal is applied to the first transistor Q1 in the V / F converter 113 which repeatedly outputs the turn-on and turn-off signals, the second transistor Q2 is turned off accordingly. Is turned off. As the second transistor Q2 is turned off, the fourth transistor Q4 is turned on and the sixth transistor Q6 is also turned on to supply the voltage charged in the first capacitor 120 to the second capacitor 130. do.

That is, the V / F converter 113 outputs a higher frequency when the voltage output from the second capacitor 130 is low, and the output voltage of the second capacitor 130 is variable through the resistor R1. When the voltage is lowered according to the voltage set by the resistor R2, the number of turn-on and turn-off signals (duty ratio) is further increased in the first transistor Q1 so that the output voltage of the second capacitor 130 has a constant DC voltage. do.

In addition, the V / F converter 113 may detect the output current of the second capacitor 130 through the resistor R11 and stop the operation to output the set current within the set value when the output current is within the set value. The V / F converter 113 may operate in the same manner as a normal timer IC, and circuits for outputting an on / off signal according to a voltage may be used.

In addition, in the preferred embodiment of the present invention, in the circuit of FIG. 4, the charging capacitor and the switching unit under the control of the switching controller 112 of FIG. The advantage of adding a charging capacitor and a switching unit to the input / output terminal of the power source can further reduce (prevent) the shock applied to the input / output terminal when charging, and the switching operation of FIG. By the on / off operation of 112).

In addition, according to another embodiment of the present invention, as shown in FIG. 5, when the power source of the input terminal is AC, a power conversion apparatus for outputting a DC voltage in the same manner as the concept of FIG. In FIG. 5, the configuration of FIG. 3 is added except that a rectifier 104 for full-wave rectifying the AC input and a DC charging capacitor 106 for storing the DC voltage output from the rectifier 102 are added to the AC input terminal. The same code | symbol is attached | subjected to the same structure similarly.

배 전압으로 DC 충전용 커패시터(106)에 충전된다. DC 충전용 커패시터(106)에 충전된 전원은 제 1 스위칭부(114)의 동작에 의하여 제 1 커패시터(120)에 충전되는 데, 제 1 커패시터(120)에 충전되는 전원은 DC 충전용 커패시터(106) 및 제 1 커패시터(120)의 용량에 반비례하는 전압으로 Q=C×V 에 의하여 강압된다. (용량이 동일할 경우는 1/2로 강압됨)마찬가지로, AC 입력단에 전류제한기(도시되지 않음)를 형성하면 입력 전원에 대하여는 전류제한에 의하여 러쉬적인 충격이 흡수된다.Referring again to FIG. 5, when the input AC voltage passes through the rectifier 102, the AC voltage takes the square root of the squared mean of the input voltage.

The DC charging capacitor 106 is charged with the double voltage. The power charged in the DC charging capacitor 106 is charged in the first capacitor 120 by the operation of the first switching unit 114, the power charged in the first capacitor 120 is a DC charging capacitor ( 106 is stepped down by Q = C × V at a voltage inversely proportional to the capacitance of the first capacitor 120. Similarly, if the capacity is the same, the voltage is reduced to 1/2. If a current limiter (not shown) is formed at the AC input terminal, the rush shock is absorbed by the current limit to the input power source.

The voltage charged in the first capacitor 120 is moved back to the second capacitor 130 by the second switching unit 116 under the control of the switching control unit 112. Again, the first capacitor 120 and the first capacitor 120 The voltage is inversely proportional to the capacitance of the two capacitors 130, which is stepped down by Q = C × V. For example, if the capacity of the first capacitor 120 is 10uF, the charged voltage is 100V, and the capacity of the second capacitor 130 is 90uF, Q = C × V according to the law of conservation of charge amount, and 100V. * 10uF = (10uF + 90uF) * 10V so that the voltage of the second capacitor 130 is stepped down to exactly 10V. The amount of current increases by 10 times to be the same as the electric energy. Therefore, a non-inductive winding capacitor having a lower inductance component than a general electrolytic capacitor is used between the lead and the capacitor of the second capacitor 130 to reduce the spike noise at the output.

In the AC-DC power converter of the second embodiment of the present invention, a DC power supply device having low loss and excellent output DC voltage quality without impulsive current flow to the AC input can be implemented, and the rest of the component parts except capacitors. Can be composed of one monolithic IC semiconductor, and in FIG. 5, only one semiconductor and three capacitors are used.

The power converter of FIGS. 3 and 5 has much less loss than a conventional power converter using a transformer, and supplies a good quality DC power with a small capacitor and reduces noise on the input / output side as in the SMPS method. Highly efficient operation is possible.

FIG. 6 is a circuit diagram implementing the block diagram of FIG. 5.

A rectifier 104 for full-wave rectifying the AC input and a DC charging capacitor 106 for storing the DC voltage output from the rectifier 102 are added, and the transistors Q3 to Q6 of the second switching unit are NPN type. Except that the configuration of Figure 3 is the same and the operation is the same, so the description of the configuration and the description of the operation is omitted.

The power converter according to the present invention increases the output frequency (number of times) of the V / F converter 113 or the timer IC used as the switching controller when the DC output voltage falls below an appropriate level, and the DC output voltage is above an appropriate level. In this case, by controlling the output frequency of the V / F converter 113 or the timer IC to decrease, the voltage at the output terminal can be kept constant regardless of the load current.

As described above, the power conversion device according to the present invention by stepping down the DC / AC power supplied from the power supply only by switching to supply a stable direct current power supply to the load by using a small capacitor to load the power supply of the load end It prevents switching noise applied to the input and output stages by pumping the power supply, and the power supply except the capacitor can be implemented as a single monolithic IC, so it has high conversion efficiency, small size, light weight and economical power supply. There is little effect on standby power consumption.

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 (10)

A first charging step of charging a DC voltage to an input terminal capacitor by switching an input DC power source; A second charging step of switching the voltage of the input terminal capacitor charged with the voltage in the first charging step to charge the output terminal capacitor connected to the DC output terminal; An output voltage sensing step of sensing a DC voltage output from an output capacitor after the second charging step; And In the output voltage sensing step, the switching period of the first charging step and the second charging step is increased when the output DC voltage is less than or equal to the set value, and the switching period is decreased when the DC voltage output in the output voltage sensing step is greater than or equal to the setting value. Power conversion method comprising a switching control step of controlling to. The method of claim 1, further comprising a full-wave rectifying step of full-wave rectifying and converting AC power into DC power and a charging step of charging the full-wave rectified DC power in a charging capacitor in a previous step of the first charging step. Power conversion method characterized in that. A first capacitor 120 connected to the DC input terminal for charging power input from the DC input terminal by a switching operation; A second capacitor (130) connected to a DC output terminal for receiving charge charged by the first capacitor (120) by a switching operation and outputting the charge to the DC output terminal; Detects the voltage output from the second capacitor 130 and converts the switching on / off period (duty) of the switching operation of powering the first capacitor 120 and the second capacitor 130 according to the set voltage. Switching control unit 112 to make; A first switching unit (114) for switching power supplied from the DC input terminal to the first capacitor (120) according to the control signal of the switching control unit (112); And a second switching unit (116) for switching the power supplied from the first capacitor (120) to the second capacitor (130) according to the control signal of the switching control unit (112). The method of claim 3, wherein the current limiter 102 is further formed between the DC input terminal and the first switching unit 114 to protect the DC input terminal to prevent the surge current is applied to the DC input terminal. Power converter. [4] The method of claim 3, wherein the front end of the DC input terminal is further provided with a full-wave rectifier 104 for full-wave rectifying and converting AC power into a DC power and a charging capacitor 106 for charging the full-wave rectified DC power. Power converter. The method of claim 3, wherein the first capacitor 120 is formed of a general electrolytic capacitor having a large inductance component, and the second capacitor 130 is formed of a non-inductive sense capacitor having a low inductance component. A power converter characterized by reducing the switching shock of the DC output stage. 4. The power converter of claim 3, wherein the remaining components of the power converter except for the charging capacitor are configured as a single IC. The method of claim 3, wherein the charging operation of the at least one charging capacitor and the charging capacitor is switched between the first capacitor 120 and the second capacitor 130 by the control of the switching controller 112. The switching unit for the power conversion device characterized in that to reduce the impact noise of the input and output. 4. The power converter of claim 3, wherein the switching controller (112) comprises a V / F converter which receives the DC output voltage and outputs a frequency according thereto. 4. The power conversion device of claim 3, wherein the switching control unit (112) comprises a timer IC for receiving the DC output voltage and outputting a signal accordingly.

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