JPH08221141A - Power supply circuit - Google Patents

Abstract

PURPOSE: To provide a power circuit which is small in power consumption and can use a small-capacity capacitor as for a power circuit which functions to take DC electric power out of an AC power source through a switching element and an accumulator element. CONSTITUTION: A rise-time voltage level detection part 11 detects the rising of an inputted AC voltage waveform and outputs an on signal to a switch part 12. The switch part 12 having received the signal switches on to charge a capacitor 6 connected to output terminals 5c and 5d, and also supply electric power to the outside. Further, a drop-time voltage level detection part 10 detects the falling of the inputted AC voltage waveform and outputs an on signal to the switch part 12. Then the switch part 12 switches on. Then the voltage level detection parts 10 and 11 output the off signals in a period, wherein the voltage is high, represented by the peak time of the AC voltage to turn off the switch part 12. At this time, the capacitor 6 begins to be discharged to supply the electric power to the outside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply circuit.

[0002]

2. Description of the Related Art FIG. 10 is a circuit diagram of a conventional power supply circuit disclosed in Japanese Patent Laid-Open No. 61-195414. This power supply circuit has the purpose of connecting a three-phase AC power supply (not shown) to the input terminals T1 and T2, extracting a DC constant voltage from this AC power supply, and supplying it to the control circuit 9. In FIG. 10, D1 to D3 are diodes, R1 to R5 are resistors, Q1 and Q2 are transistors, SCR is a thyristor, ZD is a Zener diode, C1 and C2 are capacitors, 7 is a constant voltage circuit, and 9 is a control circuit. FIG.
It is the figure which showed the input / output waveform of the conventional power supply circuit. Figure 11
10, (a) is a circuit input voltage supplied through a diode D1 from a three-phase AC power supply connected between T1 and T2 in FIG. 10, (b) is a voltage Vc of a capacitor C2 in FIG. 10, and (c) is a diagram. The output currents i and (d) flowing through the transistor Q2 of 10 indicate the on / off state of the transistor Q2.

Next, the operation will be described. Terminal T1, T
An AC power supply is connected between the two. This power source is rectified as shown in FIG. 11 (a) by the diode D1 which is a rectifier circuit. The voltage rectified by the diode D1 drives the switching transistors Q1 and Q2, charges the capacitor C2, and is supplied to the constant voltage circuit 7 as a power source. The thyristor SCR is connected to the base of the transistor Q1, and the Zener diode ZD of the series circuit of the resistor R4, the Zener diode ZD, and the capacitor C1 connected from the emitter of the transistor Q2.
The gate of the thyristor SCR is connected to a connection point between the capacitor C1 and the capacitor C1. And Zener diode Z
A value for turning off the transistors Q1 and Q2 by driving the thyristor SCR by the Zener voltage of D is set. The operation of this power supply circuit depends on the operation of the transistor Q2.
It can be divided into two periods (a charging period and a discharging period shown in FIG. 11). The operation will be described below for each period.

The operation during the charging period of FIG. 11 is as follows. During the charging period, the voltage rectified by the diode D1 supplies a current to the base of the transistor Q1 through the resistor R1 as the voltage rises at the time of rising of the voltage, and a certain amount of current or more begins to flow. , The transistor Q1 is turned on and started. When the transistor Q1 is turned on, the transistor Q2 is turned on as shown in FIG. 11D, a current flows as shown in FIG. 11C, and the capacitor C2 is charged. Capacitor C2
When the charging voltage of 1 reaches the set level as shown in FIG. 11B, the Zener diode ZD is turned on, and the current flowing through the Zener diode ZD charges the capacitor C1. When the charging voltage of this capacitor C1 reaches a predetermined value,
The thyristor SCR turns on and draws the base current of the transistor Q1, so that the transistor Q1 turns off. When the transistor Q1 is turned off, the transistor Q2 is turned off, cutting the charging current to the capacitor C2. Due to this current cut, the charging period ends and the following discharging period starts. During the charging period, the capacitor C2 is charged by the voltage taken out from the AC power source, and at the same time, the control circuit 9 is supplied with electric power.

In the discharging period, the capacitor C is charged during the charging period.
The control circuit 9 is supplied with power by discharging the electricity charged by the device 2. Therefore, as shown in FIG. 11B, the voltage of the capacitor C2 decreases with discharge. In this power supply circuit, the charging period must be entered again before the voltage of the capacitor C2 becomes equal to or lower than the voltage to be supplied to the constant voltage circuit 7. This is because the voltage of the capacitor C1 decreases due to discharge, and when this voltage becomes lower than a certain voltage, the thyristor SCR turns off. In this state, the circuit input voltage starts to rise again, and the transistors Q1 and Q2 are turned on as described above. It is done by turning on.
As a result, the above charging period starts again.

As described above, the power supply circuit supplies the DC voltage to the control circuit 9 by repeatedly performing the charging period and the discharging period described above.

[0007]

In FIG. 11, since the capacitor C2 is charged only at the rising edge of the input voltage, a capacitor capacity that can hold the voltage until the next rising edge of the input voltage is required, and the load current of the control circuit 9 is required. As the number of charges increases, it is necessary to increase the capacitance of the capacitor C2 accordingly.

However, a capacitor having a large capacity requires a mounting area such as a printed board on which it is mounted, and the cost is high. Therefore, it has been required to form a power supply circuit with a capacitor having a small capacity. .

The present invention has been made to solve the above problems, and an object thereof is to obtain a power supply circuit capable of reducing the capacitance of a capacitor.

[0010]

In the power supply circuit according to the present invention, a switch-on signal is output when the input voltage falls below the switch-on voltage and below, and the input voltage rises above and below the switch-off voltage. When the switch is turned off, the voltage detector outputs a switch-off signal, the switch operates according to the signal from the voltage detector, and the output from this switch charges the battery to discharge it. It is provided with an electricity storage unit that supplies power to the outside.

Further, it has an overvoltage protection circuit for suppressing the voltage applied to the power storage unit when the input voltage exceeds a predetermined voltage.

[0012]

According to the present invention, the switch-on signal is output when the input voltage is equal to or higher than the switch-on voltage and lower, and the switch-off signal is output when the input voltage is equal to or lower than the switch-off voltage. By including a voltage detection unit, a switch unit that operates by a signal from the voltage detection unit, and a storage unit that supplies power to the outside by discharging when the switch unit is switched off,
When the input voltage rises, the power storage unit charges, and then the switch-off signal is output and the switch unit suppresses the current flowing to the power storage unit, so that the power storage unit starts discharging and the switch-on signal changes when the input voltage falls. Is output,
A current flows from the switch unit to the electricity storage device, and after the electricity storage device is charged, discharging is started again.

Further, by having an overvoltage protection circuit that suppresses the voltage applied to the power storage unit when the input voltage exceeds a predetermined voltage, the overvoltage is released by the overvoltage protection circuit.

[0014]

【Example】

Example 1. Embodiment 1 of the present invention will be described below with reference to FIGS. 1 to 3. FIG. 1 is a configuration diagram of an inverter device using a power supply circuit according to the present invention, and FIG.
It is a figure explaining the detail of the electric power supply control circuit 5 shown in FIG. FIG. 3 is a waveform diagram for explaining input / output waveforms of the power supply control circuit 5 and the like. In FIG. 1, 1 is a three-phase AC power supply, 2 is a motor, 3 is an inverter main circuit that converts AC power from the three-phase AC power supply 1 into DC power, and drives the motor 2, and 4 is a three-phase AC power supply 1. Filters A and 5 that remove noise from the voltage of one phase of the three-phase output receive the power supplied from the filter A4 and control the power supplied to a capacitor 6, which will be described later. Is a capacitor which is a charging unit charged by the power supply control circuit 5, and 7 is the power supply control circuit 5 and the capacitor 6.
The constant voltage circuits 7 and 8 for converting the supplied voltage to a constant voltage and outputting the converted voltage are filters B and 9 for removing noise of the voltage supplied from the constant voltage circuit 7, and receiving the power from the filter B8. An inverter control circuit that controls the operation of the inverter main circuit 3, and 200 is a diode that is located between the filter A4 and the power supply control circuit 5 and half-wave rectifies the AC voltage sent from the filter to transmit to the power supply control circuit 5. is there. FIG. 2 illustrates the power supply control circuit 5 of FIG. 2, the same reference numerals as those in FIG. 1 represent the same or corresponding parts, and 5a and 5b are input terminals 5c and 5d of the power supply control circuit 5 connected to the filter A4 of FIG.
Is the output terminal of the power supply control circuit 5 connected to the capacitor 6, and 10 is the voltage level when the voltage supplied from the filter A4 is falling and detects the voltage level. A voltage level detection circuit, 11 detects a voltage level when the voltage supplied from the filter A4 rises, and outputs an output when the voltage becomes a predetermined voltage or less, and a reference numeral 12 designates this rise voltage level. A switch unit that receives output signals from the detection unit 11 and the falling voltage level detection unit, switches on or off, and controls whether to transmit the voltage from the filter A4 to the capacitor 6 and the constant voltage circuit 7 or the like. is there. FIG. 3 shows input / output waveforms of the power supply control circuit 5, and in FIG.
Is the circuit input voltage supplied from the three-phase AC power supply 1 of FIG. 1 to the filter A4, (b) is the voltage Vc of the capacitor 6 in FIG. 1, and (c) is the output current i flowing through the power supply control circuit 5 of FIG. , (D) is an on / off state of the switch unit 12 of FIG. 2, (e) is an output signal of the rising voltage level detection unit 11,
(F) is a diagram showing an output signal of the falling voltage level detection unit 10.

Next, the operation of this power supply circuit will be described. First, the outline of the operation will be described with reference to FIGS. 1 and 3 as follows. The power supply circuit according to the first embodiment converts an AC voltage supplied from the three-phase AC power supply 1 of FIG. 1, for example, a power supply of 200 [V], and supplies a stable DC voltage to the inverter control circuit 9. Circuit. First, the AC voltage is supplied to the power supply control circuit 5 through the filter A4 as shown in FIG.
Supply the circuit input voltage as in (a). The power supply control circuit 5 receiving the circuit input voltage charges the capacitor 6 and supplies power to the constant voltage circuit 7,
The switch is turned on or off under a predetermined condition. This switch on / off is performed in order to control the circuit input voltage so that power is supplied to the capacitor 6 and the like only for a part of the period, and to reduce the power consumed by the entire power supply circuit. When the power supply control circuit 5 is turned on, the capacitor 6 is charged, and the voltage Vc of the capacitor 6 is increased as shown in FIG. The period during which this charging is performed is named the charging period a. Next, the power supply control circuit 5
Is switched off, the discharge period b as shown in FIG.
Then, the power supply from the power supply control circuit 5 to the constant voltage circuit 7 is stopped. Instead, the capacitor 6 charged in the charging period a discharges as shown in FIG. 3B, and the constant voltage circuit 7 is supplied with electric power. Similarly, charging and discharging are repeated in the charging period c and the discharging period d, and the voltage Vc as shown in FIG. 3B is supplied to the constant voltage circuit 7. The constant voltage circuit 7 receives the voltage Vc, adjusts the voltage so that it becomes a constant voltage, and supplies a constant voltage to the inverter control circuit 9. The inverter control circuit 9 is driven by this constant voltage, for example, a constant voltage of 5 [V], and the inverter main circuit 3 is controlled by, for example, a microcomputer stored in the inverter control circuit 9 to rotate the motor 2 or the like. Control. The power supply circuit according to this embodiment realizes the above functions with the capacitor 6 having a smaller capacity than that of the conventional power supply circuit by adding a new condition to the charging / discharging timing of the capacitor 6.

Next, the details of the operation of the power supply circuit according to the first embodiment will be described, centering on the charging / discharging timing of the capacitor 6, which is a feature of the present invention. FIG. 2 is a diagram showing details of the power supply control circuit 5 of FIG. The timing for charging the capacitor 6 will be described with reference to FIG. The circuit input voltage input to the power supply control circuit 5 through the filter A4 has a waveform shown in FIG. 3A, and the circuit input voltage is input between the input terminals 5a and 5b. The voltage level of the circuit input voltage is constantly monitored by the falling voltage level detecting unit 10 and the rising voltage level detecting unit 11, and is set in the falling voltage level detecting unit 10 and the rising voltage level detecting unit 11, respectively. A signal is output so as to turn on the switch unit 12 when the voltage level condition is met, which is hereinafter referred to as an ON signal. A signal is output so as to switch off when the voltage level does not match the set voltage level, which is hereinafter referred to as an off signal. For example, when a thyristor known as a switch element is used as the switch unit 12, the thyristor is turned on by passing a current through the gate. In this case, the current flowing through the gate is an ON signal, and the current flowing through the gate is 0. Can be set as an off signal. Depending on the element used as the switch section 12, there are some that are turned on when the input of the gate equivalent section is 0, and these elements can be used as long as they function as the switch section 12. How to turn on / off the signal is determined according to the characteristics of the switch element. The rising voltage level detection unit according to the first embodiment operates to output an ON signal when the circuit input voltage is rising and is equal to or lower than a predetermined rising switch ON voltage from 0. To do. On the other hand, the falling voltage level detection unit according to the first embodiment outputs the ON signal when the circuit input voltage is at the falling time and is 0 from the predetermined falling switch ON voltage or lower. Works like.

The switch section 12 is a switch for transmitting a current due to the circuit input voltage to the capacitor 6 or the like, and has a function of passing a current when the switch is on and stopping the current when the switch is off. The condition for switching on is when either one of the output of the rising voltage level detection unit 11 and the output of the falling voltage level detection unit 10 is an ON signal. When the switch unit 12 is in the switch-on state, the capacitor 6 is charged by the current passing through the switch unit 12 and the constant voltage circuit 7 is supplied with power. On the other hand, when the switch unit 12 is in the switch-off state, the switch unit 12 cuts off the current, so that the charged capacitor 6 starts discharging and supplies power to the constant voltage circuit 7.

The operation of the power supply control circuit 5 is shown in FIG.
Description will be made while following the change in the circuit input voltage waveform shown in FIG. The input / output waveform of the power supply control circuit 5 described in FIG. 3 can be divided into four periods.
The operation will be described below by dividing it into two periods.

<Charging period a> The charging period a shown in FIG.
Is a period in which the circuit input voltage is equal to or lower than a predetermined rising switch-off voltage in a period in which the circuit input voltage increases, that is, a rising period. The rising switch-off voltage is a voltage set by the rising voltage level detection unit 11, and is indicated by V1 in FIG. In the operation of the power supply control circuit 5 in the charging period a, when the circuit input voltage is 0, the rising voltage level detection unit 11 thereafter outputs the ON signal as shown in FIG.
Upon receipt of this signal, the switch unit 12 is switched on, and as shown in FIG. 3C, the current i is caused to flow by the circuit input voltage, and power is supplied to the capacitor 6 and the like following the power supply control circuit 5. When the current i flows from the power supply control circuit 5, a voltage is generated between the output terminals 5c and 5d, and the capacitor 6 is charged. Subsequently, when the circuit input voltage rises and becomes the rising switch-off signal V1, the rising voltage level detection unit 11 outputs an OFF signal to the switch unit 12 as shown in FIG. The voltage level detection unit 10 does not output the ON signal unless at least the condition that the circuit input voltage decreases, that is, the falling period is satisfied, and thus the OFF signal remains output as in FIG. Therefore, the rising voltage level detection unit 1
1. Since the falling voltage level detection unit 10 also outputs an OFF signal, the switch unit 12 is switched off,
The charging period a ends.

<Discharging Period b> At the same time when the above charging period a is completed, the discharging period b is entered. The discharging period b is a period from the switch-off voltage when the circuit input voltage rises to the switch-on voltage when the circuit input voltage falls, during which the switch unit 12 is in the switch-off state. The switch-on voltage at the time of falling is shown in Fig. 3.
In (a), it is shown as V2. As described above, since the switch unit 12 is switched off,
As shown in (c), the current i flowing from the power supply control circuit 5 to the capacitor 6 and the like becomes zero. (However, there may be some leakage current.) Then, the power supply control circuit 5
The voltage between the output terminals 5c and 5d, which is supplied by, decreases. Then, the voltage of the capacitor 6 charged up to now becomes higher, and the capacitor 6 starts discharging. The voltage due to this discharge is supplied to the constant voltage circuit 7 instead of the voltage generated by the power supply control circuit 5, and works so that the power supply to the constant voltage circuit 7 is not stopped. The voltage due to the discharge gradually decreases as the discharge progresses, as shown in FIG. While the discharge by the capacitor 6 is occurring, the circuit input voltage starts to drop again, and the falling period starts. When the circuit input voltage becomes the switch-on voltage V2 at the time of falling, the voltage level detection unit 10 at the time of falling thereafter outputs an ON signal to the switch unit 12, the switch unit 12 is switched on, and the discharge period b ends.

<Charging period c> At the same time when the above discharging period b ends, the charging period c starts. The charging period c is a period from the switch-on voltage to 0 when the circuit input voltage drops. As described above, since the switch unit 12 is switched on, the current i is caused to flow by the circuit input voltage and the power is supplied to the capacitor 6 and the like following the power supply control circuit 5, as shown in FIG. 3C. Then, the capacitor 6 is charged as in the charging period c. Subsequently, when the circuit input voltage drops and becomes 0, the falling voltage level detection unit 10 thereafter outputs an OFF signal to the switch unit 12, and the rising voltage level detection unit 11 indicates that the circuit input voltage rises. Since the condition is not satisfied and the off signal is still output, the switch unit 12 is switched off and the charging period c ends.

<Discharging Period d> At the same time when the above charging period c ends, the discharging period d starts. The discharge period d occurs when the circuit input voltage is 0. As described above, since the switch unit 12 is switched off or the circuit input voltage becomes 0, the capacitor 6 is discharged as in the discharge period b.
Starts discharging and supplies power to the constant voltage circuit 7. Then, the voltage gradually decreases with discharge as shown in FIG. On the other hand, while the electric power is being supplied by discharging the capacitor 6, the circuit input voltage starts rising and the charging period a starts again. By repeating the cycle shown in the above four periods, the constant voltage circuit 7 is continuously supplied with a voltage equal to or higher than the constant voltage, for example, about 5 [V] to 8 [V].

In the power supply circuit as described above, the first
In addition, it has the advantage of low power loss. The power consumption is
Since it is proportional to the square of the voltage and inversely proportional to the resistance component, a power supply circuit according to the present invention that charges when the circuit input voltage is below a predetermined voltage and applies a voltage below a predetermined value to the constant voltage circuit 7 is As compared with a power supply circuit that transmits all circuit input voltages to the capacitor 6 and the constant voltage circuit 7, the power loss consumed by the power supply circuit can be suppressed to be small. Second
In addition, the capacitor 6 having a small capacitance can be used. During the discharge period in which the capacitor 6 supplies power to the constant voltage circuit 7, the voltage supplied to the constant voltage circuit 7 decreases as the discharge of the capacitor 6 progresses. If the power is not supplied, the capacitor 6 will eventually use up the stored power and the voltage will become zero. If the voltage becomes 0 in this way, the constant voltage circuit 7 can no longer supply a constant voltage to the inverter control circuit 9. Therefore, it is necessary to continue supplying the minimum voltage required for the constant voltage circuit 7 to maintain a constant voltage from the switch unit 12 or the capacitor 6. Therefore,
The voltage between the output terminals 5c and 5d, which decreases due to discharge, must be supplied from the switch unit 12 and the capacitor 6 must be charged before the voltage drops below the minimum required voltage. A large capacity of the capacitor 6 is required in order to keep the discharge period in which the capacitor 6 supplies electric power to the constant voltage circuit 7 for a long time, but the large capacity capacitor 6 is expensive and has a large volume. Still, like the traditional
In the power supply circuit that charges the capacitor 6 only when the circuit input voltage rises and supplies electric power to the constant voltage circuit 7, there is no choice but to employ the large-capacity capacitor 6 corresponding to the long discharge period. On the other hand, in the power supply circuit according to the present invention, not only at the rising of the circuit input voltage, the charging period a, but also at the falling, charging period c, the switch unit 12
Since the electric power is supplied from the electric power source, the one discharge period can be significantly shortened, and the capacity of the capacitor 6 can be reduced accordingly. For example, if the discharge period for one time can be halved, the capacity of the capacitor 6 can theoretically be halved, and a great effect can be obtained.

In addition, as a method of further suppressing power loss, there is a method of setting the switching voltages V1 and V2 as follows. When the time t1 of the discharge period b and the time t2 of the discharge period d are different as shown in FIG. 3, the capacitor 6
The capacity is determined on the basis of t1 having a long period, and
The charging period and the height of the circuit input voltage are also designed in consideration of t1. At this time, in the charging period c, t in the discharging period d
Since 2 is shorter than t1, it is not necessary to charge the capacitor 6 for a long period similar to the charging period a and to charge the capacitor 6 until the circuit input voltage is high. Therefore, the charging period c can be designed corresponding to the short period t2, and the charging period c is set to the charging period a within the range in which the minimum voltage supplied to the constant voltage circuit 7 is maintained during the charging period c. Can be shorter than That is, it is possible to set the voltage lower than the rising switch-off voltage V1. As a result,
Power supply control circuit 5 and constant voltage circuit 7 in the charging period c
It is possible to further suppress the loss voltage generated in the above.

As shown in FIG. 2, the power supply control circuit 5 does not have three components such as the rising voltage level detecting section 11, the falling voltage level detecting section 10 and the switch section 12. However, as long as the switching operation shown in FIG. 3D is performed in accordance with the circuit input voltage applied between the input terminals 5a and 5b, any type may be used.

Example 2. Subsequently, an example of a power supply circuit having a switch unit 12 that operates differently from that of the first embodiment is shown as the second embodiment.
It will be described as. FIG. 4 is a diagram for explaining the power supply control circuit 5 of FIG. 1 in detail. 4, the same reference numerals as those in FIG. 2 indicate the same or corresponding portions, and 100 is the input terminal 5
Always monitor the circuit input voltage level applied between a and 5b,
It is a voltage level detection unit that outputs an ON signal / OFF signal that controls the switch ON / OFF of the switch unit 12 according to this voltage level. However, in the second embodiment, a single-phase AC power supply is used instead of the three-phase AC power supply 1 of FIG. 1 as the AC power supply. FIG. 5 is a diagram illustrating input / output waveforms of the power supply control circuit 5 and the like of the power supply circuit according to the second embodiment. Figure 5
In FIG. 3, waveforms (a) to (d) are shown in FIG.
Corresponds to voltage, current or switch operation up to (d). Further, (e) of FIG. 5 shows the output signal of the voltage level detection unit 100 shown in FIG.

Next, the operation of the power supply circuit according to the second embodiment will be described with reference to FIGS. The voltage level detecting unit 100 shown in FIG. 4 has a function corresponding to the rising voltage level detecting unit 11 and the falling voltage level detecting unit 10 in FIG. 2, but the timing of outputting the ON signal / OFF signal is different. As described in the first embodiment, the operation of the power supply control circuit 5 will be described below divided into four periods. These four periods are similar to the period shown in FIG.

<Charging Period a> The rising switch-off voltage for terminating the charging period a is a voltage set by the voltage level detecting section 100, and in FIG.
Indicated by. First, the charging period a starts from a state in which the switch unit 12 is switched on by the charging period c described later. In the operation of the power supply control circuit 5 in the charging period a, since the switch unit 12 is switched on, the current i is caused to flow by the circuit input voltage as shown in FIG. Power is supplied to the capacitor 6 and the like subsequent to 5. When the current i flows from the power supply control circuit 5, a voltage is generated between the output terminals 5c and 5d,
The capacitor 6 is charged, and the voltage of the capacitor 6 itself increases. Then, when the switch unit 12 is in the switch-on state (although it is always in the switch-on state during this period) and the circuit input voltage rises and becomes the rise-time switch-off signal V11, the voltage level detection unit 100 turns off thereafter. Since the signal is output to the switch unit 12, the switch unit 12
Is switched off and the charging period a ends.

<Discharging Period b> At the same time when the above charging period a ends, the discharging period b starts. The falling switch-on voltage is a voltage set by the voltage level detection unit 100, and the falling switch-on voltage is indicated by V21 in FIG. As described above, the switch unit 12
Is switched off, the current i flowing from the power supply control circuit 5 to the capacitor 6 and the like becomes 0 as shown in FIG. 5C. Then, the capacitor 6 starts discharging. The voltage due to this discharge is supplied to the constant voltage circuit 7 instead of the voltage generated by the power supply control circuit 5, and works so that the power supply to the constant voltage circuit 7 is not stopped. While discharging by the capacitor 6, the circuit input voltage starts to drop again. When the switch unit 12 is in the switch-off state (always in the switch-off state during the discharge period b), the switch-on voltage V21 when the circuit input voltage falls
Then, the voltage level detection unit 100 thereafter outputs an ON signal to the switch unit 12, and the discharge period b ends.

<Charging Period c> At the same time when the above discharging period b ends, the charging period c starts. Since the voltage level detection unit 100 outputs the ON signal as described above, the switch unit 12 is switched on, and the current i is caused to flow by the circuit input voltage as shown in FIG. Power is supplied to the capacitor 6 and the like subsequent to, and the capacitor 6 is charged as in the charging period a. On the other hand, the circuit input voltage gradually decreases as shown in FIG.
When its own voltage exceeds the circuit input voltage, the capacitor 6 starts discharging and the charging period c ends. here,
The difference from the operation of the power supply control circuit 5 of the first embodiment is that the switch unit 12 does not change from switch-on to switch-off with the end of the charging period c. However, the same effect as that of the first embodiment can be realized without switching the switch.

<Discharging Period d> At the same time when the above charging period c ends, the discharging period d starts. As in the discharging period b, the capacitor 6 starts discharging and supplies power to the constant voltage circuit 7. Then, the voltage gradually decreases with discharge as shown in FIG. 5B, and the circuit input voltage starts to increase again while electric power is being supplied by discharging the capacitor 6. The discharging period d ends when charging of the capacitor 6 starts when the circuit input voltage exceeds the voltage of the capacitor 6 itself. Here again, the switch of the switch unit 12 is not switched. By repeating the cycle shown in the above four periods, the constant voltage circuit 7 is continuously supplied with electric power of a certain voltage or more.

As described above, unlike the first embodiment,
Even if the switch section 12 is not switched off during the discharge period d, the same effect can be obtained. Further, since the voltage level detection unit 100 detects the circuit input voltage and outputs the ON signal or the OFF signal when the circuit input voltage reaches a predetermined voltage, even if the frequency of the circuit input voltage changes. The power supply control circuit 5 can appropriately charge the capacitor 6. For example, 50 [Hz]
Even if a circuit input voltage of 60 [Hz] is input to the power supply circuit for the circuit input voltage of, the capacitor 6 is charged at the rising and falling of the circuit input voltage and operates normally as described above. can do.

In the second embodiment, the circuit input voltage,
That is, when the voltage applied between the input terminals 5a and 5b reaches a predetermined voltage, the switch unit 12 switches on / off.
Although it was turned off, the circuit input voltage is detected by the voltage between the output terminals 5c and 5d to which the capacitor 6 is connected,
The switch unit 12 may be switched on when the voltage between the output terminals 5c and 5d becomes equal to or lower than a predetermined voltage.

Example 3. In the above embodiment, the case where the AC input is half-wave rectified has been described, but in this Embodiment 3, the case where the AC input is full-wave rectified will be described. FIG. 6 is a diagram illustrating a power supply circuit according to the third embodiment. 6, the same reference numerals as those in FIG. 1 represent the same or corresponding parts, and 13 is an overvoltage protection circuit for protecting the power supply circuit and the like from the excessive voltage when the excessive voltage is applied to the power supply circuit. 201 is a full-wave rectifier circuit that full-wave rectifies the circuit input voltage input from the AC power supply. FIG. 7 is a diagram illustrating input / output waveforms of the power supply control circuit 5 and the like of the power supply circuit according to the third embodiment. Waveforms (a) to (e) in FIG. 7 correspond to the voltages, currents, or switch operations of (a) to (e) shown in FIG. Further, as the power supply control circuit 5, the power supply control circuit 5 shown in FIG.
The power supply control circuit 5 of FIG. 4 may be used, or the power supply control circuit 5 of FIG. 4 may be used. However, in the third embodiment, the power supply control circuit 5 having the basic configuration described in the second embodiment is used. Then, the power supply control circuit 5 that determines the timing of outputting the ON signal / OFF signal under the following conditions is used. However, the rising switch-off voltage V described in the first and second embodiments
1 · V11 and the falling switch-on voltage V2 · V21 are set to the same value, and the voltages V1 · V11 · V2 ·
The voltage that plays the role of V21 is newly set as the switch reference voltage V3. <Switch condition> Circuit input voltage is switch reference voltage V3
When it is above, the switch is turned off, and when the circuit input voltage is equal to or lower than the switch reference voltage V3, it is turned on.
The switch reference voltage V3 is indicated by V3 in FIG.

Next, the operation of this circuit will be described with reference to FIGS. 6 and 7. In the third embodiment, a single-phase AC power supply is used instead of the three-phase AC power supply 1 shown in FIG. When the voltage from this single-phase AC power supply is rectified by the full-wave rectifier circuit 201, the waveform shown in FIG. How the power supply control circuit 5 operates with respect to the circuit input voltage shown in this waveform will be described by dividing it into a charging period e and a discharging period c. It can also be considered that the basic operation of the power supply circuit according to the third embodiment corresponds to the operation of the second embodiment when the discharge period d becomes very short. Therefore, the characteristic features of this circuit will be described below. Describe.

<Discharging Period b> The discharging period b is a period which occurs after the charging period e described later and discharges the electricity charged in the capacitor 6 during the charging period e. This is as described in the second embodiment. <Charging period e> In the charging period e, the charging period a, the discharging period d, and the charging period c of FIG.
It is a period corresponding to the combined one. First, when the circuit input voltage becomes lower than the switch reference voltage V3 (see FIG. 7A).
In the discharge period b), the switch unit 12 in the power supply control circuit 5 is switched on,
A current flows through the power supply control circuit 5 and the capacitor 6
Also, a voltage is applied to the constant voltage circuit 7. Therefore, the capacitor 6 is charged. During this period, the circuit input voltage is as shown in FIG.
As shown in FIG. 7, the voltage once decreases, then increases, and eventually exceeds the switch reference voltage V3 (shown at the end of the charging period e in FIG. 7A). At this time, the power supply control circuit 5 switches off according to the above switch condition, stops the current passing through the power supply control circuit 5, and ends the charging period. Then, again, the discharge period b in which electric power is supplied by the capacitor 6 is entered. However, during the charging period e,
Although the circuit input voltage may temporarily become lower than the voltage of the capacitor 6 itself, for example, the voltage is 0 [V], and at this time, the constant voltage circuit 7 is powered by the temporary discharge from the capacitor 6. There is a short supply period.

In the power supply circuit according to the third embodiment, compared with the power supply circuit for input / output as shown in FIGS. 3 and 5, for example, the voltage applied to the power supply control circuit 5, the constant voltage circuit 7, etc. during the charging period is It is possible to lower the power consumption, and it is possible to reduce power loss consumed in the power supply control circuit 5, the constant voltage circuit 7, and the like. The reason is that the capacitor 6 needs to be charged during the charging period e until a voltage sufficient to supply power to the constant voltage circuit 7 is obtained during the discharging period b, but this charging requires a predetermined charging time. Will be required. In the power supply circuit for input and output as shown in FIG. 3 and FIG. 5, at the rising or falling part of the half wave of the circuit input voltage,
Since the charging is performed separately, if the above-mentioned required charging time is set, the charging period a and b must be set up to a portion where the circuit input voltage is higher than that in the third embodiment. On the other hand, in the third embodiment, since the charging period e can be a continuous charging period in which the circuit input voltage falls and rises, the voltage is low when the necessary charging time is set. By visiting the part twice in a short period and charging during this period, it is possible to charge during the period when the voltage is low. Comparing FIG. 5 and FIG. 7, comparing the falling switch-on voltage V21 and the rising switch-off voltage V11 of FIG. 5A with the switch reference voltage V3 of FIG. 7A, V3 <V11 , V3 <V21. Looking at the charging period e in detail, there may be a slight discharging period during the charging period e, so it may not be a continuous charging period, but the voltage may drop slightly due to discharging during this slight discharging period. Immediately after that, the circuit input voltage becomes high, and the voltage starts to rise again due to charging.
The necessary extension of the charging time due to the slight discharge is small, and the above-mentioned effects can be obtained.

Further, in the third embodiment, the overvoltage protection circuit 13 is provided as shown in FIG. This overvoltage protection circuit has a role of protecting the power supply control circuit 5, the capacitor 6, the constant voltage circuit 7 and the like from an overvoltage when the circuit input voltage becomes abnormally high. Functionally, when the voltage input to the overvoltage protection circuit 13 exceeds a certain level, a voltage is supplied between two input terminals of the overvoltage protection circuit 13 by passing a current bypassing the filter A4 and the like following this circuit. To keep the proper value. In particular, when the small capacitor 6 is used as the charging unit as described above, the withstand voltage capability of the capacitor 6 also weakens, and therefore such an overvoltage protection circuit 13 is assumed assuming that a high voltage is applied instantaneously. It is good to provide.

Embodiment 4 FIG. FIG. 8 is a configuration diagram of an inverter device in which two power supply circuits are connected to the control circuit 9. 8, the same reference numerals as those in FIG. 1 represent the same or corresponding parts. In the above-described first embodiment, the electric power is extracted from one phase of the three-phase AC power supply 1, but as shown in FIG. 8, two output terminals of the three output terminals of the three-phase AC power supply 1 are two power supply circuits. It is possible to obtain a larger electric power than that in the first embodiment by connecting to each of the above.

Example 5. Next, a fifth embodiment which is another embodiment of the power supply control circuit 5 shown in FIG. 1 will be described with reference to FIG. FIG. 9 is a diagram illustrating the details of the power supply control circuit 5. 9, the same reference numerals as those in FIG. 4 denote the same or corresponding portions, and 101 has a function corresponding to the voltage level detection unit 100 in FIG. 4, but the circuit input voltage is the voltage between the input terminals 5a and 5b. , An input / output terminal voltage level detection unit for detecting using the voltage between the output terminals 5c and 5d. Since the point that the voltage level of the circuit input voltage is detected and the switch unit 12 is driven is the same as in the other embodiments, the characteristic operation of this embodiment will be described below. The input / output terminal voltage level detection unit 10 of the fifth embodiment
1 is not only the voltage applied between the input terminals 5a and 5b,
The switch on / off of the switch unit 12 is controlled in consideration of the voltage of the capacitor 6. First, in the charging period a of FIG. 3, the timing of outputting the switch-on signal is measured by the voltage between the input terminals 5a and 5b, the on-signal is output, and the switch unit 12 is switched on. On the other hand, the voltage between the output terminals 5c and 5d to which the capacitor 6 is connected is detected, and a switch-off signal is output to the switch unit 12 when the voltage between the output terminals 5c and 5d exceeds the switch-off voltage V1 when rising. Then, the switch unit 12 is switched off. In the charging period c of FIG. 4, the input terminal 5a
The off signal is output to turn on the switch unit 12 when the voltage between 5b falls below the switch-on voltage V2 during the fall.
On the other hand, when the voltage between the output terminals 5c and 5d becomes 0, an off signal is output to switch off the switch section.

According to the power supply circuit of the fifth embodiment, the charging period (for example, the charging period ac in FIGS. 3 and 7) is reduced.
In e), when the voltage of the capacitor 6 reaches a predetermined voltage, the switch unit 12 is switched off,
For example, power consumption in the power supply control circuit 5, the capacitor 6, the constant voltage circuit 7, etc. can be further suppressed.

[0042]

As described above, the present invention has the following effects. A voltage detector that outputs a switch-on signal when the input voltage falls below the switch-on voltage and below, and a switch-off signal when the input voltage falls below the switch-off voltage and above, and this voltage By including the switch unit that operates according to the signal from the detection unit and the storage unit that discharges when the switch is off, the power storage unit is charged when the input voltage rises, and after this charging, the switch-off signal is output. The capacitor starts discharging, and when the input voltage falls, the switch-on signal is output, and after the capacitor is charged, it starts discharging again, shortening the time that the charger keeps the voltage above a certain level. The storage capacity required for the container can be reduced.

Further, by having an overvoltage protection circuit that suppresses the voltage applied to the power storage unit when the input voltage becomes equal to or higher than a predetermined voltage, the power storage unit having a low withstand voltage capacity is not applied with an excessive voltage. Can be protected from excessive voltage.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an inverter device using a power supply circuit according to a first embodiment of the present invention.

FIG. 2 is a functional block diagram illustrating a power supply control circuit according to the first embodiment of the present invention.

FIG. 3 is a waveform diagram illustrating input / output waveforms of the power supply control circuit and the like according to the first embodiment of the present invention.

FIG. 4 is a functional block diagram illustrating a power supply control circuit according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating input / output waveforms of a power supply control circuit and the like according to a second embodiment of the present invention.

FIG. 6 is a functional block diagram illustrating a power supply control circuit according to a third embodiment of the present invention.

FIG. 7 is a diagram illustrating input / output waveforms of a power supply control circuit and the like according to a third embodiment of the present invention.

FIG. 8 is a configuration diagram of an inverter device using two power supply circuits according to a fourth embodiment of the present invention.

FIG. 9 is a functional block diagram illustrating a power supply control circuit according to a fifth embodiment of the present invention.

FIG. 10 is a diagram illustrating a conventional power supply circuit.

FIG. 11 is a diagram illustrating input / output waveforms of a conventional power supply circuit.

[Explanation of symbols]

1 three-phase AC power supply, 2 motor, 3 inverter main circuit, 4 filter A, 5 power supply control circuit, 6 capacitor, 7 constant voltage circuit, 8 filter B, 9
Inverter control circuit, 10 falling voltage level detecting unit, 11 rising voltage level detecting unit, 12 switch unit, 100 voltage level detecting unit, 101 input output voltage repell detecting unit 200 diode

Claims (2)

[Claims] 1. A switch-on signal is output when the input voltage falls below a predetermined switch-on voltage and below, and a switch is output when the input voltage falls below a predetermined switch-off voltage or above. A voltage detection unit that outputs an off signal, and a switch on signal from the voltage detection unit that is turned on to output the input voltage to the outside to supply power, and a switch off signal from the voltage detection unit. Switch off to prevent the input voltage from being output to the outside, and the voltage output by this switch is charged, and power is supplied to the outside when the switch is switched off. A power supply circuit including: 2. The power supply circuit according to claim 1, further comprising an overvoltage protection circuit that suppresses a voltage applied to the power storage unit when the input voltage becomes equal to or higher than a predetermined voltage.