JP6076215B2 - Power supply system - Google Patents

Description

  The present invention relates to a power supply system.

  In a power supply system that converts AC power supplied from a commercial power source into DC power and supplies it to a load, a lithium-ion battery is used as a backup power source in case of disconnection from the commercial power source, such as during a power failure There are those using a secondary battery such as. As such a power supply system, for example, a charging power source for charging a lithium ion battery as a secondary battery in addition to a direct current output device that supplies power to a load device in a normal time (non-power failure) There is a device that supplies power to a load device from a lithium ion battery when the output voltage of the DC output supply device decreases due to a power failure or the like (for example, Patent Document 1).

JP 2006-223050 A

  In the above prior art, the switching of the power supply line in which power is supplied from the lithium ion battery to the load device when the output voltage of the DC output supply device decreases due to a power failure or the like is passively realized by a diode. Yes. In order to realize the switching by the diode, the output voltage of the DC output supply device is set higher than the output voltage of the lithium ion battery. As a result, power is supplied from the DC output supply device to the load device during a normal time (when no power failure occurs), and power is supplied from the lithium ion battery to the load device via the diode during a power failure. For this reason, in the above-described conventional technology, the voltage applied to the load device is different between the normal time and the power failure time. Therefore, for example, the load device is applied to a load device having a limited operating voltage range such as a low upper limit voltage. Since it is necessary to install a new power supply circuit such as a linear regulator or switching regulator so that the voltage does not exceed the upper limit voltage of the load device, there is a problem that it has a large effect on the increase in circuit size and cost. It was.

  The present invention has been made in view of the above, and without newly providing a power supply circuit such as a linear regulator or a switching regulator, the voltage applied to each load is set to the upper limit of each load regardless of the normal time / power failure. An object of the present invention is to provide a power supply system that can be lower than the voltage and can suppress the influence on the enlargement of the circuit and the cost increase while suppressing the influence on the enlargement of the circuit and the cost increase. .

  In order to solve the above-described problems and achieve the object, a power supply system according to the present invention converts AC power supplied from a commercial power source into DC power, and has an upper limit than the first load and the first load. A power supply system for supplying a second load having a large voltage, the rectifier circuit for rectifying the output voltage of the commercial power supply, and the output of the rectifier circuit being larger than the upper limit voltage of the first load. A first power converter for converting the first predetermined voltage smaller than the upper limit voltage of the load to supply DC power to the DC common unit, and an output of the rectifier circuit from the upper limit voltage of the first load A second power conversion unit that converts the second predetermined voltage into a small second predetermined voltage and supplies DC power to the DC common unit, and is charged by the second predetermined voltage, and the current from the first power conversion unit Through a unidirectional element to prevent A power storage unit that supplies DC power to the DC common unit, and a DC power supply path to the first load configured to be able to supply DC power from the DC common unit to the first load and the second load. And when the power supply to the first load is not performed at the time of non-power failure of the commercial power supply, and the output of the first power converter is on-controlled A control circuit for turning off the switch circuit and controlling the output of the first power converter when turning off the switch circuit and supplying power to the first load. It is characterized by providing.

  According to the present invention, without newly providing a power supply circuit such as a linear regulator or a switching regulator, the voltage applied to each load can be set to be equal to or lower than the upper limit voltage of each load regardless of the normal time / power failure. It is possible to suppress the influence on the increase in size and cost.

FIG. 1 is a diagram of a configuration example of the power supply system according to the first embodiment. FIG. 2 is a diagram illustrating a current path when the power supply to the first load is not necessary in the power supply system according to the first embodiment when the commercial power supply is not powered (normal time). FIG. 3 is a current path when power supply to the first load is necessary in the power supply system according to the first embodiment at the time of a power failure of the commercial power source and at the time of a non-power failure of the commercial power source (normal time). FIG. FIG. 4 is a diagram illustrating the relationship between the control state of the first power conversion unit and the voltage of the DC common unit when the power supply system according to the first embodiment is not in a power outage (normal time). FIG. 5 is a time chart of the power supply system according to the first embodiment. FIG. 6 is a diagram illustrating a current path when the power supply to the first load is not necessary in the power supply system according to the second embodiment when the commercial power supply is not powered (normal time).

  Hereinafter, a power supply system according to an embodiment of the present invention will be described with reference to the accompanying drawings. In addition, this invention is not limited by embodiment shown below.

Embodiment 1 FIG.
FIG. 1 is a diagram of a configuration example of the power supply system according to the first embodiment. In the example illustrated in FIG. 1, an example in which AC power supplied from the commercial power supply 1 is converted into DC power and supplied to the load group 20 connected to the power supply system 100 is illustrated. The power supply system 100 according to the first exemplary embodiment is disconnected from the commercial power supply 1 due to a normal power supply (normal power failure) when the commercial power supply 1 is normally supplied with power and a power failure of the commercial power supply 1 (hereinafter referred to as the power supply system 100) , "When power failure occurs").

  In the example illustrated in FIG. 1, the load group 20 includes a first load 21 having an upper limit voltage V1 and a second load 22 having an upper limit voltage V2.

  As shown in FIG. 1, the power supply system 100 according to the first exemplary embodiment includes a voltage detection circuit 7 that detects the voltage of the commercial power source 1, a rectifier circuit 2 that rectifies the output voltage of the commercial power source 1, and a rectifier circuit 2. The first power conversion unit 3 that converts the output of the output into the first predetermined voltage Va and supplies the DC power to the DC common unit 8, and the output of the rectifier circuit 2 is the second lower than the first predetermined voltage Va. The second power conversion unit 4 that converts to the predetermined voltage Vb and the commercial power source 1 are charged with the second predetermined voltage Vb when the commercial power source 1 is not powered (normally), and at the time of the power failure of the commercial power source 1 Connected to the power supply system 100 from the DC common unit 8 and the power storage unit 5 that supplies DC power to the DC common unit 8 via a unidirectional element (diode) 6 that blocks current from the power conversion unit 3 Configured to supply DC power to the load group 20 Based on the voltage detection value of the power branch unit 11 in which the switch circuit 10 is provided in the power supply path to the first load 21 and the voltage detection circuit 7, the power failure of the commercial power source 1 is detected. When power is not supplied to the first load 21 at the time of non-power failure (normal time), the output of the first power conversion unit 3 is controlled to be on, the switch circuit 10 is controlled to be off, and the first When power is supplied to the load 21, the first power conversion unit 3 is controlled to be turned off, and the control circuit 9 is turned on to control the switch circuit 10. In the configuration described above, the voltage detection circuit 7 is provided as one of the power failure detection means for detecting the power failure of the commercial power source 1, and the power failure of the commercial power source 1 is detected based on the voltage detection value of the voltage detection circuit 7. However, the power failure detection means of the commercial power source 1 is not limited to this, and a known power failure detection means for detecting whether or not there is a power failure may be provided to detect the power failure of the commercial power source 1. The present invention is not limited by the power failure detection means of the commercial power source 1.

  The voltage Vo1 applied to the first load 21 becomes the voltage of the DC common unit 8 when the switch circuit 10 is ON-controlled by the control circuit 9, and the voltage Vo2 applied to the second load 22 is The voltage of the DC common unit 8 is always set. Here, it is assumed that the first load 21 is a load that requires power supply only for a short time, such as a latch-type contactor.

  The power storage unit 5 is a secondary battery such as a lithium ion battery, for example, and the upper limit value of the charging current of the power storage unit 5 is defined by Imax. Therefore, second power conversion unit 4 is configured such that output current Ib is equal to or lower than charging current upper limit value Imax of power storage unit 5 (Ib ≦ Imax). Note that the output current Ia of the first power conversion unit 3 and the power storage unit current Ibtt when DC power is supplied from the power storage unit 5 vary according to the power consumption of the load group 20.

  In the present embodiment, the magnitude relationship between the first predetermined voltage Va and the second predetermined voltage Vb is Vb <Va. As a result, when the commercial power source 1 is not powered (normally), it is not necessary to supply power to the first load 21 and the outputs of the first power converter 3 and the second power converter 4 are on-controlled. When the switch circuit 10 is controlled to be turned off, DC power is supplied from the first power converter 3 to the load group 20 via the DC common unit 8, but the output of the first power converter 3 No power is supplied to the first load 21 whose upper limit voltage V1 is smaller than the first predetermined voltage Va that is a voltage. Further, at the time of a power failure of the commercial power source 1 and at the time of a non-power failure of the commercial power source 1 (normal time), power supply to the first load 21 is necessary, and the first power conversion unit 3 and the second power are required. When the output of the conversion unit 4 is off-controlled and the switch circuit 10 is on-controlled, the first load 21 and the second load constituting the load group 20 from the power storage unit 5 through the diode 6 and the DC common unit 8. DC power is supplied to both of the loads 22.

  Next, the operation of the control circuit 9 in the above-described configuration will be described with reference to FIGS. FIG. 2 is a diagram illustrating a current path when the power supply to the first load is not necessary in the power supply system according to the first embodiment when the commercial power supply is not powered (normal time). FIG. 3 shows a case where power supply to the first load is necessary in the power supply system according to the first embodiment at the time of a power failure of the commercial power source and at the time of a non-power failure of the commercial power source (normal time). It is a figure which shows an electric current path | route.

  As shown in FIG. 2, when it is not necessary to supply power to the first load 21 when the commercial power source 1 is not powered (normal time), the control circuit 9 causes the first power converter 3 and the second power to be supplied. The output of the conversion unit 4 is on-controlled and the switch circuit 10 is off-controlled. At this time, a current flows through a path indicated by a broken-line arrow in FIG. 2, and the output of the rectifier circuit 2 is converted to the first predetermined voltage Va by the first power conversion unit 3 and supplied to the DC common unit 8 (DC Voltage Vs1 = Va of common unit 8). In addition, a current flows through a path indicated by a one-dot chain line arrow in FIG. The power storage unit 5 is charged.

  In addition, as shown in FIG. 3, when power supply to the first load 21 is necessary at the time of a power failure of the commercial power source 1 and at the time of a non-power failure of the commercial power source 1 (normal time), the control circuit 9 Thus, the outputs of the first power conversion unit 3 and the second power conversion unit 4 are turned off. At this time, the output voltages of the first power conversion unit 3 and the second power conversion unit 4 are substantially zero, and the DC common unit 8 and the power storage unit 5 are changed from the first power conversion unit 3 and the second power conversion unit 4. 3 is not supplied, current flows through a path indicated by a two-dot chain line arrow in FIG. 3, and DC power charged in the power storage unit 5 is supplied to the DC common unit 8 via the diode 6 (DC common unit). 8 voltage Vs2 = Vbtt−α).

  FIG. 4 is a diagram illustrating the relationship between the control state of the first power conversion unit and the voltage of the DC common unit when the power supply system according to the first embodiment is not in a power outage (normal time).

  When the first power conversion unit 3 and the second power conversion unit 4 are on-controlled by the control circuit 9 at the time of non-power failure (normal time), the voltage Vs1 of the DC common unit 8 is as shown in FIG. The first predetermined voltage Va output from the first power conversion unit 3 (Vs1 = Va).

  Here, when the first power conversion unit 3 and the second power conversion unit 4 are turned off by the control circuit 9, the voltage Vs 2 of the DC common unit 8 is output from the power storage unit 5 as shown in FIG. The voltage obtained by subtracting the voltage drop α of the diode 6 from the storage unit voltage Vbtt to be performed (Vs2 = Vbtt−α).

  When power storage unit 5 is in a fully charged state, power storage unit voltage Vbtt is equal to second predetermined voltage Vb that is the output voltage of second power conversion unit 4 (Vbtt = Vb), and voltage of DC common unit 8 The maximum voltage of Vs2 is a voltage obtained by subtracting the voltage drop α of the diode 6 from the second predetermined voltage Vb (Vs2 = Vb−α). That is, the voltage Vs2 of the DC common unit 8 is in a voltage range in which Vb−α is the maximum voltage (Vs2 = Vbtt−α ≦ Vb−α).

  Therefore, as shown in FIG. 4, the voltage of the DC common unit 8 is changed to the first voltage conversion unit 3 when the first power conversion unit 3 and the second power conversion unit 4 are on / off controlled at the time of non-power failure (normal time). In a state where the power conversion unit 3 and the second power conversion unit 4 are on-controlled, the first predetermined voltage Va (Vs1 = Va), and the first power conversion unit 3 and the second power conversion unit 4 are off. In a controlled state, Vbtt−α (≦ Vb−α) is satisfied (Vs2 = Vbtt−α ≦ Vb−α).

  Here, in the present embodiment, the upper limit voltage V1 of the first load 21, the upper limit voltage V2 of the second load 22, the first power conversion unit 3 and the second power conversion at the time of non-power failure (normal time). The voltage Vs1 (= Va) of the DC common unit 8 when the unit 4 is on-controlled, and the first power conversion unit 3 and the second power conversion unit 4 are off-controlled during a non-power failure (normal time) Assume that the magnitude relationship of the upper limit value (= Vb−α) of the voltage Vs2 of the direct current common unit 8 is Vs2 (= Vb−α) <V1 <Vs1 (= Va) <V2.

  That is, the voltage of the DC common unit 8 at the time of non-power failure (normal time) is less than the upper limit voltage V2 of the second load 22 regardless of the on / off control state of the first power converter 3 and the second power converter 4. (Vs1 = Va or Vs2 = Vbtt−α ≦ Vb−α), and is lower than the upper limit voltage V1 of the first load 21 in a state where the first power conversion unit 3 and the second power conversion unit 4 are off-controlled. (Vs2 = Vbtt−α ≦ Vb−α).

  In the present embodiment, when the switch circuit 10 is provided in the power supply path to the first load 21 having the upper limit voltage V1, and the power supply to the first load 21 is unnecessary, the first power conversion unit The first power conversion unit 3 and the second power conversion unit 3 and the second power conversion unit 4 are turned on and the switch circuit 10 is turned off, and only when the power supply to the first load 21 is necessary. The unit 4 is turned off and the switch circuit 10 is turned on.

  By controlling in this way, a voltage less than the upper limit voltage V1 is applied to the first load 21 only when power supply to the first load 21 is necessary (Vo1 = Vo2 = Vs2 = Vbtt−α ≦ Vb). -Α) When the power supply to the first load 21 is unnecessary, the power supply to the first load 21 is stopped (Vo1 = 0, Vo2 = Vs1 = Va).

  Next, the operation of the power supply system according to the first exemplary embodiment will be described with reference to FIGS. FIG. 5 is a time chart of the power supply system according to the fourth embodiment.

  FIG. 5A shows the control state of the switch circuit 10, and FIG. 5B shows the control state of the first power converter 3. 5C shows the voltage of the DC common unit 8, and FIG. 5D shows the voltage Vo1 output to the first load 21.

  First, state 1 shown in FIG. 5 will be described. When the first power conversion unit 3 and the second power conversion unit 4 are on-controlled, the voltage of the DC common unit 8 is the first output from the first power conversion unit 3 as described above. It becomes a predetermined voltage Va (Vs1 = Va). At this time, the switch circuit 10 is off-controlled, and the voltage Vo1 applied to the first load 21 becomes zero (Vo1 = 0).

  Next, the state 2 shown in FIG. 5 will be described. When the first power conversion unit 3 and the second power conversion unit 4 are off-controlled, the voltage of the DC common unit 8 is Vbtt−α (≦ Vb−α) (Vs2 = Vbtt−α ≦ Vb−α). At this time, the switch circuit 10 is ON-controlled, and the voltage Vo1 applied to the first load 21 is a voltage obtained by subtracting the voltage drop α of the diode 6 from the second predetermined voltage Vb (Vo1). = Vs2 = Vbtt−α ≦ Vb−α).

  As described above, when power is supplied to the first load 21, the control to be in the state 2 shown in FIG. 5, that is, the first power conversion unit 3 and the second power conversion unit 4 are simultaneously turned off. By turning on the switch circuit 10, the voltage Vo1 applied to the first load 21 having a small upper limit voltage V1 is set to be equal to or lower than the upper limit voltage V1.

  Further, when the first power conversion unit 3 and the second power conversion unit 4 are controlled to be turned on / off, when the state 2 shown in FIG. 5 is reached, the first power conversion unit 3 and the second power conversion unit 4 are switched from the power storage unit 5 via the diode 6 and the DC common unit 8. DC power is supplied to the first load 21 and the second load 22. For this reason, the time to be in the state 2, that is, the first power conversion unit 3 and the first power conversion unit 3 and the second power conversion unit 4 is longer than the time to be in the state 1, that is, the first power conversion unit 3 and the second power conversion unit 4. When the off control time of the second power conversion unit 4 becomes longer, the discharge energy of the power storage unit 5 exceeds the charging energy supplied from the second power conversion unit 4, and the power storage unit voltage Vbtt gradually decreases and discharges. Below the limit.

  Therefore, in the present embodiment, the time when the state 2 is set, that is, the time when the state 1 is set longer than the off control time of the first power conversion unit 3 and the second power conversion unit 4, that is, the first power conversion unit. 3 and the second power conversion unit 4 are set so that the ON control time becomes longer.

  As described above, according to the power supply system of the first embodiment, from the DC common unit to the first load having a lower upper limit voltage than the output voltage (first predetermined voltage Va) of the first power conversion unit. When the commercial power supply is not out of power (normal time) and power supply to the first load is not necessary, the first power conversion unit and the second power conversion are provided. The first power conversion unit and the second power only when the power supply to the first load is necessary by stopping the power supply to the first load. Since the converter is turned off and the switch circuit is turned on to supply power from the power storage unit, the voltage applied to each load can be applied to each load without newly providing a power supply circuit such as a linear regulator or a switching regulator. On the load Can be a voltage or less, it is possible to suppress the influence of the size and cost increases of the circuit.

  In addition, by setting the on-control time of the first power conversion unit and the second power conversion unit to be longer than the off control time of the first power conversion unit and the second power conversion unit, It is possible to suppress the voltage (power storage unit voltage Vbtt) applied from the unit to each load from being lowered to be equal to or lower than the discharge limit value.

  In the first embodiment described above, one first load and one second load are shown in FIG. 1, but each may be two or more, and each upper limit voltage and first load As long as the relationship between the output voltage of each of the power conversion unit and the power storage unit satisfies the relationship described in the first embodiment.

Embodiment 2. FIG.
In the first embodiment described above, when it is not necessary to supply power to the first load whose upper limit voltage is lower than the output voltage Va of the first power conversion unit when the commercial power supply is not powered (normal time). The first power conversion unit and the second power conversion unit are turned on and the switch circuit is turned off, and only when the power supply to the first load is necessary, the first power conversion unit and the second power conversion unit In the present embodiment, the power conversion unit is turned off as in the case of a power failure and the switch circuit is turned on to supply power from the power storage unit to the first load and the second load. A control example for suppressing the discharge of the power storage unit when power is supplied to the first load and the second load at the time of non-power failure of the commercial power supply will be described. The configuration of the power supply system according to the second embodiment is the same as that of the power supply system according to the first embodiment, and thus the description thereof is omitted here.

  FIG. 6 is a diagram illustrating a current path of the power supply system according to the second embodiment when power supply to the first load is not required when the commercial power supply is not powered (normal time).

  In the present embodiment, as shown in FIG. 6, when power supply to the first load 21 is necessary when the commercial power supply 1 is not powered (normal time), the control circuit 9 The power converter 3 is turned off, the second power converter 4 is turned on, and the switch circuit 10 is turned on.

  By controlling in this way, when it is necessary to supply power to the first load 21 when the commercial power source 1 is not out of power, current flows along a path indicated by a one-dot chain line in FIG. The output is converted to the second predetermined voltage Vb by the second power conversion unit 4 and supplied to the power storage unit 5 to charge the power storage unit 5, and a current flows along a path indicated by a two-dot chain line arrow. The DC power charged in the unit 5 is supplied to the DC common unit 8 through the diode 6 (voltage Vs2 = Vbtt−α of the DC common unit 8). When power storage unit 5 is fully charged, power storage unit voltage Vbtt is equal to second predetermined voltage Vb that is the output voltage of second power conversion unit 4 (Vbtt = Vb), and power storage unit 5 Is not charged.

  Therefore, in the present embodiment, when the commercial power supply is not powered (normally), the output of the rectifier circuit 2 is converted to the second predetermined voltage Vb by the second power converter 4 and the power storage unit 5 is charged. Since the discharge is performed simultaneously, the discharge of the power storage unit 5 is suppressed.

  As described above, according to the power supply system of the second embodiment, when power is supplied to the first load when the commercial power supply is not interrupted, the first power is different from when the commercial power supply is interrupted. Since the power storage unit is charged and discharged at the same time by turning off the conversion unit and turning on the second power conversion unit, discharge of the power storage unit can be suppressed.

  Note that the configuration shown in the above embodiment is an example of the configuration of the present invention, and can be combined with another known technique, and a part thereof is omitted without departing from the gist of the present invention. Needless to say, it is possible to change the configuration.

  DESCRIPTION OF SYMBOLS 1 Commercial power supply, 2 Rectifier circuit, 3 1st power converter, 4 2nd power converter, 5 Power storage part, 6 Unidirectional element (diode), 7 Voltage detection circuit, 8 DC common part, 9 Control circuit DESCRIPTION OF SYMBOLS 10 Switch circuit, 11 Electric power branch part, 20 Load group, 21 1st load, 22 2nd load, 100 Power supply system.

Claims (3)

A power supply system for converting AC power supplied from a commercial power source into DC power and supplying the first load and a second load having a higher upper limit voltage than the first load,
A rectifier circuit for rectifying the output voltage of the commercial power supply;
First power for converting the output of the rectifier circuit into a first predetermined voltage that is larger than the upper limit voltage of the first load and smaller than the upper limit voltage of the second load and supplies DC power to the DC common unit A conversion unit;
The output of the rectifier circuit is converted to a second predetermined voltage so that the voltage applied to the DC common unit is smaller than the upper limit voltage of the first load, and DC power is supplied to the DC common unit. A second power conversion unit;
A power storage unit that is charged with the second predetermined voltage and supplies DC power to the DC common unit through a unidirectional element that blocks current from the first power conversion unit;
A power branching unit configured to be capable of supplying DC power from the DC common unit to the first load and the second load, and provided with a switch circuit in a power supply path to the first load;
Wherein during the non power failure of the commercial power supply, in case of no power supply to the first load, while on controlling the output of said first power conversion unit, and off control of the switching circuit, the commercial during the non power failure of the power supply, the case where the electricity is supplied to the first load, while off control of the output of the first power conversion unit, and a control circuit for turning on controlling the switch circuit,
A power supply system comprising:   2. The control circuit according to claim 1, wherein an ON control time of the first power conversion unit during a non-power failure of the commercial power supply is set longer than an OFF control time of the first power conversion unit. The power supply system according to 1. During the non power outage of the commercial power source, wherein when performing the power supply to the first load, according to claim 1 or 2, characterized in that on controlling the output of said second power conversion unit Power supply system.

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