JP5044258B2 - DC power distribution system - Google Patents

Description

  The present invention relates to a DC distribution system that distributes DC through a power supply line from a DC power source to a DC device as a load device in a house or a building.

In general, when power is supplied to an electrical device, AC power is supplied via a power supply line that is wired in advance in a building. On the other hand, DC power is often supplied to internal circuits except when power and heat are used in electrical equipment. In electrical equipment that mainly handles information such as sound, video, and communication, AC power is used. Many are equipped with a power conversion adapter for converting to DC power. As a result, a large number of power conversion adapters are connected to the outlet in order to handle this type of electric equipment, and there is a problem that the periphery of the electric equipment tends to be messy. In order to solve such a problem, it is considered to supply DC power through a preceding wiring (for example, see Patent Document 1). If DC power is supplied using a power supply line wired in advance, the power conversion adapter becomes unnecessary, and the surroundings of the electrical equipment can be prevented from becoming messy.
JP 2003-274542 A

  By the way, when AC power is supplied by preceding wiring, the current supplied to the power supply line is limited as a rated value using a breaker or the like arranged in the distribution board, and the power supply line connected to the breaker When the current flowing through the capacitor becomes larger than the rated value, the breaker is cut off at a timing according to the current value, thereby protecting the power supply line and the electric equipment and preventing the overload from affecting the power source.

  On the other hand, electrical equipment using DC power (hereinafter referred to as “DC equipment”) has many functions for handling information as described above. For example, there are DC equipment used for crime prevention and disaster prevention. If some types of direct current equipment stop operating, the purpose of crime prevention and disaster prevention cannot be achieved. In addition, a DC device (for example, a linked operation of a switch and a load) that operates in cooperation through a communication network such as a home network or a wide area network becomes inoperable unless DC power can be secured.

  Therefore, except for cases where there is a danger such as overheating of the power supply line such as a short circuit of the power supply line, operation of all DC devices can be performed by adopting a configuration that cuts off the power supply due to overload, such as a breaker. It is desirable that the protection operation that stops is not functioning. Furthermore, if the DC device is always connected to the power supply line, the maximum current supplied to the power supply line is already known, so the wiring design can be performed so that no overload occurs in the power supply line. When a DC device that can be attached to and detached from the power supply line is used, an overload of the power supply line cannot be predicted in advance, and cannot be handled depending on the wiring design. That is, some protection against overload is required.

  The present invention has been made in view of the above-mentioned reasons, and the object thereof is to control the supply from the DC power supply to meet the demand from the power supply line with respect to at least one of the current and the voltage within the limit range. Thus, it is to provide a DC power distribution system that protects against overload.

The invention of claim 1 includes a DC power supply for outputting a DC power, a DC device driven by DC power supplied via a power supply line from the DC power source, between the DC devices and the DC power supply and limiting means provided for limiting at least one of the current and the voltage supplied to the power supply line, and the line state detecting means for detecting as a single load information at least one of the current and voltage of the power supply line, power to detect and control means for controlling the limiting means in response to at least one for the load information of the current and the voltage supplied to the power supply line, the supply capacity with respect to one of at least the current and the voltage for the DC power supply as a power source information A state detection unit, and the control unit uses the power supply information in addition to the load information, so that the DC power supply can be supplied. Oite, it controls the limiting means so that at least one of the current and the voltage supplied to the power supply line is limited to a specified range.

  According to a second aspect of the present invention, in the first aspect of the present invention, the DC power supply includes the restriction unit and the line state detection unit at a connection site with the power supply line.

  According to a third aspect of the present invention, in the second aspect of the present invention, the power supply line branches into a plurality of systems, and the limiting means and the line state detecting means are a branch point for each system and each output end of the DC power supply. It is characterized by being provided between.

  According to a fourth aspect of the invention, in the first aspect of the invention, the control means and the DC device are communicable, and the load information is notified by communication from the DC device regarding at least one of current and voltage. It is a request.

The invention of claim 5 includes a DC power source that outputs DC power, a DC device driven by DC power supplied from the DC power source via a power supply line, and between the DC power source and the DC device. Limiting means for limiting at least one of current and voltage supplied to the power supply line, line state detection means for detecting at least one of the current and voltage of the power supply line as one of load information, Control means for controlling the limiting means according to the load information for at least one of a current and a voltage supplied to the power supply line, the limiting means limiting a current supplied to the power supply line consists limiting means, said control means, on the basis of the load information indicating the current supplied to the power supply line, the current limiting and supply current reaches the limit current value of the defined Stage by and performs limit operation to maintain a small holding current value than the limiting current value the current flowing in the power supply line. The limit current value and the sustain current value are set to values smaller than the allowable current value (current upper limit value) in the power supply line. For example, the limit current value is 95% of the allowable current value, and the sustain current value is allowable. It is set to 90% of the current value.

The invention of claim 6 includes a DC power source that outputs DC power, a DC device driven by DC power supplied from the DC power source via a power supply line, and the DC power source and the DC device. Limiting means for limiting at least one of current and voltage supplied to the power supply line, line state detection means for detecting at least one of the current and voltage of the power supply line as one of load information, Control means for controlling the limiting means according to the load information for at least one of a current and a voltage supplied to the power supply line, and the limiting means is a voltage for limiting a voltage applied to the power supply line. consists limiting means, said control means, on the basis of the load information indicating the current supplied to the power supply line, said voltage limiting and supply current reaches the limit current value of the defined Stage by and performs limit operation to lower the voltage applied to the power supply line to maintain the voltage value of the specified. The limit current value is set to a value (for example, 95% of the allowable current value) smaller than the allowable current value (the upper limit value of the current) for the power supply line, and the sustain voltage value is constantly applied to the power supply line. It is set to a value lower than the current voltage value (for example, 80% of the normal voltage value).

In the invention of claim 7, in the invention of claim 5 or claim 6, wherein the said DC device control means a communicable, the DC device, at least one of the voltage and current supplied to the internal circuit includes a apparatus-side limiting means for limiting the said control means, said DC device by said device-side limiting means and the voltage applied to the DC device is lowered to a specified voltage while said limiting means is performing limited operations It is characterized by reducing the amount of power used in the system.

In the invention of claim 8, in the invention of claim 7, wherein the power supply line branches into a plurality of systems, the power supply line communication inside said DC power supply between said control means and the DC device It performed using wired communication path branches in the same strain as the information filter for selecting and passing the blocking of carrier waves transporting the information, the communication path between the branch point of the communication path and the DC device characterized in that it comprises for each system integration.

According to a ninth aspect of the present invention, in the eighth aspect of the invention, the DC device includes a detecting unit that detects at least one of a supplied current and a voltage, and the control unit passes a carrier wave for each of the information filters. and recognizes the load information the DC device is detected by the detection means by selecting the blocking with each line of the power supply line.

  According to the configuration of the first aspect of the invention, at least one of the current and voltage of the power supply line is detected as one of the load information, and the voltage and current supplied from the DC power source to the power supply line according to the load information Therefore, when an overload is detected from the load information, the DC power supply can be protected by limiting the power supply from the DC power supply. Moreover, by limiting the current and / or voltage supplied from the DC power supply according to the current and / or voltage of the power supply line, the DC power supply can be protected while supplying power to the DC equipment. Is possible.

For example, in the case of inconvenience when the operation of a part of the DC equipment is stopped, the voltage applied to the power supply line from the DC power supply should be operated at a lower voltage than the voltage that is always supplied. If the limiting means is controlled so as to pull down the power, it becomes possible to continue supplying power to what is necessary even when the operation of other DC devices is stopped. In addition, the DC power supply can be protected by limiting the upper limit of the current and lowering the voltage during overload. That is, it is possible to prevent the system from going down by continuously supplying power to some DC devices during an overload.
Moreover, since the supply capability of the DC power supply is used as the power supply information, even when a DC power supply (DC power supply, battery, etc. that obtains power from natural energy such as sunlight or wind power) whose supply capability changes with time is used. The DC power supply can be protected by limiting the power supply within the range of the power supply capability.

  According to the configuration of the invention of claim 2, since the limiting means and the line state detecting means are provided in the connection part of the power supply line in the DC power supply, load information is obtained for all DC devices connected to the power supply line. Can be detected in a batch.

  According to the configuration of the invention of claim 3, it is possible to monitor a request from the power supply line for each system of the power supply line and to limit at least one of current and voltage for each system. Even when the supply power is limited by the operation of the limiting means when an overload occurs in the system, it is possible to allow the DC device to maintain a normal operation without limiting the supply power for other systems.

  According to the configuration of the invention of claim 4, since the limiting means is controlled according to a request from the DC device, it is possible to adjust the power supplied from the DC power source according to the operating state of the DC device. For example, demand control is possible in which power corresponding to the operation of a DC device is supplied from a DC power supply.

According to the configuration of the invention of claim 5 , when the current flowing through the power supply line reaches a specified limit current value, the current supplied to the power supply line is maintained by maintaining the sustain current value smaller than the limit current value. And the DC power supply can be protected.

According to the configuration of the sixth aspect of the present invention, when the current flowing through the power supply line reaches a specified limit current value, the power supplied to the power supply line can be limited by reducing the current to the maintenance voltage value.

According to the configuration of the seventh aspect of the present invention, when the voltage applied to the DC device is reduced to the specified voltage during the limiting operation, the power consumption in the DC device is reduced by reducing the power consumption in the DC device. The power to be supplied can be reduced. The voltage applied to the DC device during the limit operation is usually reduced due to the increase in power consumption in the DC device, so when multiple DC devices are connected to the power supply line, By reducing the amount of power used in any of the DC devices, it becomes possible to maintain the operation of the other DC devices.

  For example, by providing device-side limiting means in DC devices, DC devices with lower priority when overloaded (for example, DC devices with priority over video and music compared to DC devices for crime prevention and disaster prevention purposes) The power received can be limited, and overload can be prevented while maintaining the operation of important DC equipment.

According to the configuration of the invention of claim 8 , when a plurality of power supply lines are provided, the wired communication path is branched into the same system as the power supply line, and the information filter is provided for each system of the communication paths. Since it is provided, it becomes possible to communicate with the DC device for each system of the power supply path.

According to the configuration of the invention of claim 9 , when a plurality of power supply lines are provided, the information filter is used to communicate with the DC device for each system, and the load information detected by the detecting means provided in the DC device is detected. It becomes possible to recognize for each system.

(Embodiment 1)
As shown in FIG. 1, the present invention basically includes a DC power source 1 arranged on a distribution board and a DC device 2 as a load driven by DC power, and the output of the DC power source 1. It has a configuration for supplying DC power to the DC device 2 through the power supply line Lp connected to the end. In the illustrated example, the power supply line Lp from the DC power source 1 to the DC device 2 is branched into a plurality of systems (three systems in the illustrated example), but only one system may be used. In the following, when it is necessary to distinguish each system, the power supply lines Lpa, Lpb, and Lpc are distinguished by adding symbols a, b, and c.

  An information line Ls for communication is provided together with a power supply line Lp for supplying DC power (when necessary, the information lines Lsa, Lsb, and Lsc are distinguished by adding symbols a, b, and c), Each DC device 2 can be connected to the information line Ls. The information line Ls may be provided independently of the power supply line Lp, or may also be used as the power supply line Lp. When the power supply line Lp and the information line Ls are used together, communication is performed by superimposing a high-frequency carrier wave used for information transmission on a DC voltage. In addition, a wireless communication path can be formed instead of the information line Ls. In the following, it is assumed that the power supply line Lp and the information line Ls are wired and are provided separately.

  The configuration for supplying power in the DC power supply 1 is based on a power converter 1a including an AC / DC converter that converts AC power AC such as commercial power into DC power. A distributed power source 1b using a power generator, a fuel cell, an engine-driven generator, or the like can be used in combination. When the distributed power source 1b is used in combination, the outputs of the power converter 1a and the distributed power source 1b are adjusted according to a request from the DC device 2. However, in the following description, the operation of the distributed power supply 1b is not particularly described, and the power supply in the DC power supply 1 is described as being performed by the power converter 1a.

  An information filter 3 is inserted in the information line Ls between the DC power source 1 and the DC device 2. In the illustrated example, the information filter 3 is disposed between the branch points of the information lines Lsa, Lsb, and Lsc and the DC device 2. The branch points of the information lines Lsa, Lsb, and Lsc are provided inside the DC power supply 1, and the information lines Lsa, Lsb, and Lsc branch to the same system as the power supply lines Lpa, Lpb, and Lpc. That is, it corresponds to providing the information filter 3 for each power supply line Lpa, Lpb, Lpc of each system.

  The information filter 3 has a function of selecting whether or not to pass a high-frequency carrier wave used for information transmission, and determines whether or not to transmit information between the DC power source 1 and the DC device 2 using the power supply line Lpa. , Lpb, and Lpc. Whether the information filter 3 passes or blocks the carrier wave is instructed by a control means 5 (described later) provided in the DC power supply 1.

  Further, the limiting means 4 is inserted in the power supply line Lp between the DC power source 1 and the DC device 2. The limiting means 4 is between the branch point that branches the power supply lines Lpa, Lpb, and Lpc in the DC power source 1 and the output connection port (output end) T1 that connects the power supply lines Lpa, Lpb, and Lpc. Placed in. Therefore, the limiting means 4 is provided for each system of the power supply lines Lpa, Lpb, and Lpc. Further, in the illustrated example, the limiting means 4 is also provided at the output end of the power converter 1a.

  Between the junction of the power converter 1a and the distributed power source 1b and the branch point of the power supply lines Lpa, Lpb, Lpc, a current sensor CT is disposed and the output of the current sensor CT is input to the current detection circuit 6a. Then, a current passing through this part is detected. Further, a voltage detection circuit 6b for detecting the voltage of this part is also provided. The current sensor CT uses a so-called DC CT in which a Hall element and a magnetic core are combined, or a current detection resistor connected in series to an electric circuit. The current sensor CT, the current detection circuit 6a, and the voltage detection circuit 6b constitute a line state detection unit that detects a request from the power supply line Lp for the DC power supply 1 with respect to current and voltage as load information. The load information may be information on one of current and voltage. If only one is required, the combination of the current sensor CT and the current detection circuit 6a or the voltage detection circuit 6b is omitted.

  The limiting means 4 inserted in each power supply line Lpa, Lpb, Lpc includes an information filter 3 between the branch points of the power supply lines Lpa, Lpb, Lpc, and these three information filters 3 Current sensors (not shown) for detecting the passing current are arranged between the three limiting means 4 and the three limiting means 4. The limiting means 4 in this part has a function of limiting currents flowing through the power supply lines Lpa, Lpb, and Lpc of each system. The output of each current sensor at this part is input to a current detection circuit (not shown) provided for each system of power supply lines Lpa, Lpb, and Lpc separately from the above-described current detection circuit 6a, and load information for each system is provided. Is obtained. That is, a line state detection unit for each power supply line Lpa, Lpb, Lpc is configured by a current sensor and a current detection circuit (not shown).

  The load information obtained by the line state detection means is input to the control means 5 and used for controlling the restriction means 4 arranged at each part. The limiting unit 4 has a function of limiting at least one of a current and a voltage supplied to the power supply line Lp. In the present embodiment, the limiting means 4 is provided with a current limiting means and a voltage limiting means, and one of the current limiting means and the voltage limiting means is selected according to the conditions described later, and the power supply line Lp is selected. The supplied current is limited to a specified range, or the voltage supplied to the power supply line Lp is limited to a specified range.

  The control unit 5 includes a microcomputer and includes a communication unit 5a that communicates with the DC device 2 through the information line Ls. The control means 5 also uses load information acquired from the DC device 2 as needed when controlling the limiting means 4, but here, the load information obtained from at least one of the current detection circuit 6a and the voltage detection circuit 6b is used. The case where the limiting means 4 is used to be controlled will be described, and the operation using the load information obtained from the DC device 2 will be described later.

  As the simplest configuration for limiting the current as the limiting means 4, as shown in FIG. 2, it is possible to adopt a configuration in which whether or not the current limiting resistor R is inserted into the power supply line Lp is selected by the switch element SW. it can. In this configuration, the state in which the current limiting resistor R is not inserted is selected at all times, and when it is necessary to limit the current, the switch element SW is switched to insert the current limiting resistor R. Note that after the current supplied to the power supply line Lp is reduced due to the insertion of the current limiting resistor R, the switch element SW is returned after the current value detected by the line state detecting means is reduced to a specified value or less. By this operation, chattering of the switch element SW can be prevented.

  As a current limiting means having the same function as the configuration shown in FIG. 2, for example, a current limiting circuit is formed by using a three-terminal active element such as a transistor or a MOSFET instead of the current limiting resistor R and the switch element SW. It is also possible to configure. If a transistor is used, a low resistance is connected in series to the collector-emitter and inserted into the power supply line Lp. The transistor is normally turned on in the saturation region, and when it is overloaded, the control means 5 passes the collector-emitter. What is necessary is just to employ | adopt the structure which restrict | limits an electric current. It is possible to use a configuration using a constant current diode or a configuration in which a positive temperature coefficient thermistor and a resistor are connected in parallel for constant current, but in these configurations, control by the control means 5 is not required. Use auxiliary.

  On the other hand, when the voltage limiting means for limiting the voltage is configured, the collector-emitter of the transistor is inserted into the power supply line Lp, and a smoothing capacitor is connected between the power supply lines Lp to detect the line state. A series control type constant voltage circuit configured in combination with the means and the control means 5 can be used. Alternatively, a chopper circuit consisting of an inductor, a smoothing capacitor, and a switching element or a switching element is connected in series to the primary winding of the transformer to form a DC-DC converter that rectifies and smoothes the secondary output to extract direct current, thereby detecting the line condition A switching power supply configured together with the means and the control means 5 can be used.

  Here, as a case where the current is limited to a specified range, a case where current exceeding the current that can be supplied by the DC power source 1 is prevented from flowing to the power supply line Lp (short circuit of the power supply line Lp or the inside of the DC device 2). There is a case where it is limited so that a current larger than the allowable current defined in the power supply line Lp does not flow. In the former case, a current limit is required to protect the DC power supply 1, and in the latter case, a current limit is required to comply with the restrictions on the wiring rules. Further, when the voltage is limited to the specified range, it basically means to secure a minimum voltage necessary for driving the DC device 2. Note that the current value and voltage value to be limited can be set as appropriate as long as they are within the limits of the rules.

  As described above, normally, the upper limit of the current supplied to the power supply line Lp is limited for the current, and the voltage is kept constant at the power converter 1a. However, when the lower limit is limited for the current (for example, When the current is smaller than the minimum current required for driving the DC device 2 and it is determined that there is a leakage, etc., or when the upper limit of the voltage is limited (for example, output due to a failure of the DC power supply 1) In some cases, such as when there is an abnormal increase in voltage).

  Thus, in the control means 5, the request from the power supply line Lp is monitored by the line state detection means (current sensor CT, current detection circuit 6a, voltage detection circuit 6b), and the DC power is supplied from the DC power source 1 to the DC device 2. Only when the request cannot be normally supplied, the limiting means 4 is operated to limit at least one of the current and voltage supplied to the power supply line Lp. In other words, if the DC power can be normally supplied from the DC power source 1 to the DC device 2, the limiting means 4 does not have to be operated.

  Hereinafter, a typical operation example will be described. Here, the line state detection means includes both the current detection circuit 6a and the voltage detection circuit 6b, detects both the current and voltage of the power supply line Lp, and the limiting means 4 limits the current of the power supply line Lp. One of current limiting means for limiting voltage and voltage limiting means for limiting the voltage is provided.

  Since DC power is supplied to the DC device 2 from between the power supply lines Lp, the power converter 1a normally maintains the voltage between the power supply lines Lp at a constant voltage.

  On the other hand, when the current flowing through the power supply line Lp reaches a limit current value (for example, 95% of the allowable current value) set with respect to the allowable current value (upper limit current value) of the power supply line Lp, the power supply line Lp. The constant current control (limit operation) is performed by the current limiting means provided in the limiting means 4 so that the current flowing in the current is maintained at a sustain current value smaller than the limit current value (for example, 90% of the allowable current value). Since this limiting operation is constant current control, the voltage between the lines varies depending on the amount of power used in the DC device 2 (that is, the impedance of the power supply line Lp), but when the voltage increases, the current decreases. As a result, the voltage between the lines does not rise because the constant voltage control state is restored.

  When the DC device 2 is newly operated during a period in which the constant current control is performed (in a state where the power supply line Lp is maintained at the maintenance current value), the demand for the current from the power supply line Lp becomes excessive. . At this time, since the impedance between the power supply lines Lp decreases, the line voltage of the power supply line Lp decreases.

  Therefore, among the DC devices 2, those that cause inconvenience when the operation stops, such as devices related to crime prevention and disaster prevention, are operated at a voltage lower than the voltage that is constantly supplied, and the power supply line Lp Operate even if the line voltage drops. By adopting such a configuration, in the event of an overload, it is possible to continue supplying DC power to the DC device 2 that is inconvenient to stop the operation while limiting the supplied current and protecting the DC power supply 1. It becomes possible. That is, it is possible to prevent the system from going down by continuously supplying power to some of the DC devices 2 while protecting the DC power supply 1 in the event of an overload.

  As the limiting operation when the current flowing through the power supply line Lp reaches the limit current value set with respect to the allowable current value of the power supply line Lp, the voltage limiting means provided in the limiting means 4 causes the power supply line Lp to You may make it pull down the voltage to apply rather than usual.

  In this limited operation, the DC device 2 that may be stopped stops operating due to a shortage of input voltage, and the DC device 2 that needs to operate can continue operation because the input voltage is secured. Become. As the DC device 2 that enables the above-described operation, a device in which a constant voltage circuit (a Zener diode may be used) is provided in a power receiving unit from the power supply line Lp, and an input voltage required for the constant voltage circuit is varied. Just keep it.

  In the configuration example shown in FIG. 1, the power converter 1a, the information filter 3, the limiting unit 4, the control unit 5, and the line state detection unit are housed in the body of the DC power source 1, and the DC output of the distributed power source 1b is obtained. One set of input connection ports T1 for receiving power and three sets of output connection ports T2 for connecting the three power supply lines Lpa, Lpb, and Lpc are provided.

  In contrast to the above-described configuration, the power converter 1a is housed in the first body having the input connection port T1, and the output is made into one system, and the electric circuit that receives this output and branches the system of the power supply line Lp is housed. You may employ | adopt the structure which provides the output connection port T2 in the made 2nd container. In this structure, since the 1st container which accommodated the power converter 1a which supplies direct-current power, and the 2nd container which accommodated the structure which branches the electric power supply line Lp into plurality are provided separately, branching The number of systems of the power supply line Lp can be changed only by exchanging the second vessel provided with the electric circuit corresponding to the number.

  Moreover, in this structure, when the number of systems is the same, the output current and output voltage of the DC power source 1 can be changed by changing the specifications of the power converter 1a. Since the limiting means 4 for limiting the output of the power converter 1a and the limiting means 4 for limiting the power supplied to the power supply lines Lpa, Lpb, and Lpc of each system are provided, each limiting means 4 is controlled. It is desirable that the control means 5 for doing so is divided into a first container and a second container.

  When the DC power supply 1 is housed in the distribution board, the power supply line system that supplies power to the DC equipment 2 that is the internal device of the distribution board and the power that is supplied to the DC equipment 2 installed outside the distribution board It is desirable to branch off from the supply line system.

  Incidentally, the DC device 2 shown in FIG. 1 communicates with the DC power source 1 via the information circuit Lp and the main circuit 20 as a functional unit that performs various operations according to the DC device 2 such as operation, monitoring, display, and notification. And communication means 21. The main circuit 20 includes a microcomputer, and the microcomputer controls the operation of the DC device 2.

  The communication means 21 communicates with other devices using either identification information (individual address) for individual communication or identification information (common address) for broadcast communication. Further, the DC device 2 includes detection means 22 for detecting at least one of current and voltage supplied to the main circuit 20 (that is, requested by the main circuit 20), and information detected by the detection means 22 is communication means. 21 is sent to the information line Ls, and is notified to the control means 5 of the DC power supply 1 as load information related to the request of the DC device 2.

  As shown in FIG. 3, the detection means 22 includes a current detection circuit 22 a that detects a current supplied to the main circuit 20 and a voltage detection circuit 22 b that detects a voltage applied to the main circuit 20. A temperature detection circuit 22c for detecting the temperature of the specific part and an abnormality detection circuit 22d for detecting an abnormality such as a short circuit of the main circuit 20 are provided. Further, the DC device 2 is provided with a device side restricting means 23 inserted in a power supply path to the main circuit 20 as an internal circuit, and the device side restricting means 23 receives an instruction from the control means 5 through the communication means 21. And has a function of limiting at least one of current and voltage used in the internal circuit of the DC device 2.

  As in the above-described operation example, when the DC device 2 is newly operated in a state in which the DC device 2 is shifted to the limiting operation in accordance with an increase in power usage, the voltage between the power supply lines Lp decreases. To do. In this case, it is desirable to monitor the voltage applied to the DC device 2 by the detecting means 22 and notify the DC power source 1 of the voltage drop as load information by communication when the voltage drops. In the DC power source 1, when a voltage drop is notified from the DC device 2, the device-side restricting means 23 is controlled to control the power on the DC device 2 with a low priority set in advance among the operating DC devices 2. Instruct them to limit their usage. By this operation, it is possible to suppress the impedance drop between the power supply lines Lp and maintain the operation of the DC device 2 having a high priority.

  This operation will be described with reference to FIG. The illustrated example illustrates the case where the current is limited by the current limiting means as the limiting operation. As shown in FIG. 4A, a constant voltage Vc is always applied between the power supply lines Lp. As shown in FIG. 4B, when the current flowing through the power supply line Lp increases and reaches the limit current value It (time t1), the current limiter (limiter 4) operates, and the limit current value It The constant current control is performed so that the sustain current value is low. In this state, when the current used in the DC device 2 increases, the line voltage of the power supply line Lp decreases (time t1-t2, t2-t3). When the line voltage of the power supply line Lp is thus notified as load information to the DC power supply 1 that the voltage of the DC supply line Lp has decreased to the lower limit voltage value Vi of the DC device 2 having a high priority that needs to be maintained ( At time t3), the low-priority DC device 2 is instructed to control the device-side limiting means 23, and the high-priority DC device 2 is restored to a voltage that can continue to operate (t4). With such an operation, it is possible to maintain the power supply to the DC device 2 having a high priority that cannot be stopped.

  The same configuration as that of the detection unit 2 can be provided as the power supply state detection unit 10 in the power converter 1a. That is, as shown in FIG. 5, a current detection circuit 10a that detects a current output from the power converter 1a, a voltage detection circuit 10b that detects a voltage output from the power converter 1a, and a specific part of the power converter 1a A temperature detection circuit 10c for detecting the temperature of the power converter 1a and an abnormality detection circuit 10d for detecting an abnormality such as a short circuit of the power converter 1a. The power supply information acquired by the power supply state detection means 10 of the power converter 1a can be directly given to the control means 5, but may be notified to the control means 5 through the communication line Ls. When the power supply state detection unit 10 communicates with the control unit 5, identification information (individual address) for individual communication is used. The power supply state detection means 10 may be provided on the same circuit board as the power converter 1a, or may be provided on a circuit board different from the power converter 1a.

  Load information obtained from the line state detection means such as the current sensor CT and the detection means 22 provided in the DC device 2 serves as an index of power consumption of the DC device 2 and is detected by the power supply state detection means 10 of the power converter 1a. Therefore, the control unit 5 controls the limiting unit 4 using the load information and the power source information so that the demand amount of the DC power exceeds the supply amount. There can be no restriction.

  Note that if there is information on the output power of the power converter 1a and the power consumption of the DC device 2, it becomes a guideline for determining the relationship between the demand amount and the supply amount of the DC power. It is desirable to have the power converter 1a have information on the rated output power and the DC device 2 have information on the rated power consumption so that it can be acquired.

  As described above, the control unit 5 can recognize load information for each system of the power supply lines Lpa, Lpb, and Lpc, and the control unit 4 can limit at least one of current and voltage for each system. Therefore, even when an overload occurs in any of the systems and the supply power is limited by the operation of the limiting unit 4, the DC device 2 can be operated without limiting the supply power in the other systems.

  Further, since the control means 5 can give an instruction to the device-side limiting means 23, at the time of overload, the device-side limiting means 23 of the DC device 2 having a low priority is sent from the control means 5 to at least one of current and voltage. By instructing the usage amount to be limited, the current and voltage supplied from the DC power supply 1 are not changed, and the current required for the power supply line Lp is reduced. It becomes possible to maintain the operation. For example, DC devices 2 that are inconvenient to stop power supply, such as those intended for crime prevention and disaster prevention, have a higher priority, and it is safe to stop power supply, such as those related to video and music For DC devices 2 that are not related to securing the power supply, etc., when the priority is set low, the DC device 2 with high priority is preferentially used with DC power while maintaining the operation of important DC devices. Overload can be prevented.

  Regarding the control of the information filter 3, when acquiring electrical information from the DC device 2 for each power supply line Lpa, Lpb, Lpc, one information filter 3 inserted in each power supply line Lpa, Lpb, Lpc. Alternatively, the remaining information filter 3 may be set in the blocking state by alternately passing it. Alternatively, it is possible to start from a state where all the information filters 3 of each system are passed or blocked, and to reduce the number of information filters 3 that are passed or blocked one by one. By operating the information filter 3 as described above, it becomes possible to recognize the load information from the DC device 2 for each system of the power supply lines Lpa, Lpb, and Lpc. In other words, when a plurality of systems of power supply lines Lpa, Lpb, and Lpc are provided, by enabling communication for each system, when receiving a request from the DC device 2 or giving an instruction to the DC device 2, An increase in traffic is suppressed, and transmission delay due to collision can be suppressed. Also, when the control unit 5 acquires the individual address held by the DC device 2, the individual address can be acquired separately for each system.

It is a block diagram which shows embodiment. It is a circuit diagram which shows an example of the limiting means used for the same as the above. It is a principal part block diagram of the direct current | flow apparatus used for the same as the above. It is operation | movement explanatory drawing same as the above. It is a principal part block diagram of DC power supply used for the same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 DC power supply 2 DC equipment 3 Information filter 4 Limiting means 5 Control means 5a Communication means 6a Current detection means 6b Voltage detection means 10 Power supply state detection means 20 Main circuit 21 Communication means 22 Detection means 23 Equipment side restriction means CT Current sensor Lp Power Supply line Lpa Power supply line Lpb Power supply line Lpc Power supply line Ls Information line Lsa Information line Lsb Information line Lsc Information line

Claims (9)

A DC power source for outputting a DC power, a DC device driven by DC power supplied via a power supply line from the DC power source, the power supply line provided between the DC devices and the DC power supply and limiting means for limiting at least one of the current and voltage supplied, and the line state detecting means for detecting as a single load information at least one of the current and voltage of the power supply line is supplied to the power supply line and control means for controlling the limiting means in response to at least one for the load information of the current and voltage, and a power source state detecting means for detecting a power information supply capacity with respect to one of the at least current and voltage for the DC power supply The control means uses the power supply information in addition to the load information, so that it can be supplied from the DC power supply, Serial DC distribution system and to control said limiting means such that at least one is limited to a specified range of current and voltage supplied to the power supply line.   2. The DC power distribution system according to claim 1, wherein the DC power source includes the restriction unit and the line state detection unit at a connection site with the power supply line.   The power supply line branches into a plurality of systems, and the limiting means and the line state detection means are provided between the branch point and each output end of the DC power supply for each system. Item 3. A DC power distribution system according to item 2.   2. The direct current according to claim 1, wherein the control means and the DC device are communicable, and the load information is a request notified by communication from the DC device regarding at least one of current and voltage. Power distribution system. A direct current power source that outputs direct current power; a direct current device driven by direct current power supplied from the direct current power source via a power supply line; and the power supply line provided between the direct current power source and the direct current device. Limiting means for limiting at least one of current and voltage to be supplied; line state detecting means for detecting at least one of current and voltage of the power supply line as one of load information; and supplying to the power supply line Control means for controlling the limiting means according to the load information for at least one of current and voltage, the limiting means comprising current limiting means for limiting the current supplied to the power supply line, and the control When the supply current reaches a predetermined limit current value based on the load information indicating the supply current to the power supply line, the current limiting means causes the power DC distribution system and performing a limiting operation to maintain the current flowing through the feed line to a small holding current value than the limit current value. A direct current power source that outputs direct current power; a direct current device driven by direct current power supplied from the direct current power source via a power supply line; and the power supply line provided between the direct current power source and the direct current device. Limiting means for limiting at least one of current and voltage to be supplied; line state detecting means for detecting at least one of current and voltage of the power supply line as one of load information; and supplying to the power supply line Control means for controlling the limiting means according to the load information for at least one of current and voltage, the limiting means comprising voltage limiting means for limiting the voltage applied to the power supply line, and the control means, on the basis of the load information indicating the current supplied to the power supply line, the power by the voltage limiting means and the supply current reaches the limit current value of the defined DC distribution system and performing a limiting operation to lower the voltage applied to the supply line to maintain the voltage value of the specified. The control unit and the DC device can communicate with each other, and the DC device includes a device-side limiting unit that limits at least one of a voltage and a current supplied to an internal circuit, and the control unit includes the limiting unit. 6. The power consumption in the DC device is reduced by the device-side limiting means when the voltage applied to the DC device drops to a specified voltage while the device is performing the limiting operation. Item 7. A DC power distribution system according to item 6 . The power supply line is branched into a plurality of systems, and communication between the control means and the DC device is performed using a wired communication path branched into the same system as the power supply line inside the DC power supply. The information filter for selecting passage and blocking of a carrier wave for transmitting information is provided for each system of the communication path between a branch point of the communication path and the DC device . DC power distribution system. The DC device includes a detecting unit that detects at least one of a supplied current and voltage, and the control unit selects whether the DC device detects or passes a carrier wave for each information filter. DC distribution system of claim 8, wherein the recognizing the load information detected by the means for each line of the power supply line.

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