JP2015018383A - Power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small power supply system achieving efficient power supply regardless of the position of a feeder line.SOLUTION: A feeder line 2 is formed in a bus shape and includes a feeding point 41 for supplying electric power with an apparatus 5 consuming electric power using electromagnetic induction. A power supply section 31 supplies an AC signal having a preset power supply frequency with the feeder line. Electric length changeover sections 6 and 33 include: inductors 61 and 331 connected with the feeder line; bypass tracks bypassing the inductors; and switches 62, 332 for connecting and disconnecting the bypass lines, respectively. A control section 34 controls the state of the switches configuring the electric length changeover sections such that the electric length of the feeder line is periodically switched over.

Description

  The present invention relates to a power supply system that performs power supply from a power supply line to a terminal in a contactless manner.

  2. Description of the Related Art Conventionally, a power feeding system that superimposes an AC signal on a power supply line and uses a primary coil provided on the power supply line side and a secondary coil provided on the terminal side to supply power to the terminal in a non-contact manner is known (for example, , See Patent Document 1).

International Publication WO2007 / 029438

  By the way, if the frequency of the AC signal superimposed on the feeder line is lowered, it is necessary to increase the size of the coil. Therefore, in order to reduce the size of the device, it is necessary to increase the frequency. However, by increasing the frequency of the AC signal, if the wavelength of the AC signal becomes smaller than several times the line length of the feed line, the current distribution on the feed line becomes non-uniform and the feed efficiency on the feed line is greatly reduced. There was a problem that some parts occurred.

  In order to solve the above problems, an object of the present invention is to provide a small power supply system that realizes efficient power supply regardless of the position of the power supply line.

The power supply system of the present invention includes a power supply line, a power supply unit, one or more electrical length switching units, and a control unit.
The power supply line is formed in a bus shape and has a power supply point that supplies power to a device that consumes power using electromagnetic induction. The power supply unit supplies an AC signal having a preset power supply frequency to the power supply line. The electrical length switching unit includes an inductor connected to the power supply line, a detour path that bypasses the inductor, and a switch that intermittently connects the detour path. A control part controls the state of the switch which comprises an electrical length switching part so that the electrical length of a feeder may switch periodically.

  According to such a configuration, the control unit performs on / off control of the switch, so that the state in which the inductor is connected to the power supply line and the state in which the inductor is disconnected from the power supply line can be set. The electrical length of the feeder line changes according to the state.

  As a result, depending on the state of the switch, the current distribution on the feeder line, and hence the location corresponding to the node of the current distribution where the feeding efficiency is greatly reduced, changes. Therefore, efficient power supply can be realized at all locations on the power supply line by appropriately switching the switch state by the control unit. In addition, since the power supply frequency can be set to a high frequency (a frequency at which the wavelength is several times less than the line length), the coil formed at the power supply point, the coil provided in the power supply target device, and the system can be downsized. Can be

  In addition, the code | symbol in the parenthesis described in the claim shows the correspondence with the specific means as described in embodiment mentioned later as one aspect, Comprising: The technical scope of this invention is limited is not.

1 is an overall configuration diagram of an in-vehicle power line communication system according to a first embodiment. (A) is explanatory drawing which shows the system configuration used for the measurement of the power transfer characteristic from a master node to a slave node, (b) is a graph which shows a measurement result. (A) is explanatory drawing which shows the system structure used for the measurement of the current distribution on a feeder, (b) is a graph which shows a measurement result. It is a whole block diagram of the vehicle-mounted power line communication system of 2nd Embodiment. It is a whole block diagram of the vehicle-mounted power line communication system of 3rd Embodiment. It is a whole block diagram of the vehicle-mounted power line communication system of 4th Embodiment. It is a whole block diagram of the vehicle-mounted power line communication system of 5th Embodiment.

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
<Overall configuration>
As shown in FIG. 1, an in-vehicle power line communication system 1 to which the present invention is applied is directly connected to a bus-like power supply line (power line) 2 composed of a twisted pair line and a power supply line 2, and power is supplied to the power supply line Connected to the power supply line 2 and a plurality of slave nodes 5 that are connected to the power supply line 2 through the coupling unit 4 in a contactless manner via the coupling unit 4 and operate by contactless power supply through the power supply line 2. The electrical length switching unit 6 is provided. Then, the master node 3 and the slave node 5 execute master-slave communication using the feeder line 2 as a transmission medium.

  A power supply signal PS that is an AC signal having a preset frequency (hereinafter referred to as “power supply frequency”) is used for power supply via the power supply line 2, and a predetermined frequency (hereinafter “ A communication signal CM which is an AC signal having a “communication frequency” is used.

  However, the communication signal CM may be a signal modulated using the power supply signal PS as a carrier wave (that is, the power supply signal PS and the communication signal CM are the same), or a frequency different from the power supply signal PS (“power supply frequency” ≠ “ It may be obtained by modulating a carrier wave of “communication frequency”.

<Coupling part>
The coupling unit 4 includes a feeding line side coupling unit (feeding point) 41 and a node side coupling unit 42, and is configured to transmit signals of a feeding frequency and a communication frequency to each other using electromagnetic induction. belongs to.

  For example, the feeder line side coupling portion 41 is formed by unwinding a part of the twisted pair wire constituting the feeder line 2 and is formed of a ring-shaped portion that acts as an inductor. On the other hand, the node-side coupling portion 42 is configured integrally with the slave node 5 and is formed of a spiral-shaped inductor that is disposed to face the ring-shaped portion of the feeder line-side coupling portion 41.

<Electrical length switching unit>
The electrical length switching unit 6 is provided at the end of the feeder line 2 and includes an inductor 61, a switch 62, and a capacitor 63.

  The inductor 61 is inserted between a pair of signal lines (outward / return) constituting the feeder line 2. The switch 62 is connected so as to cut off the bypass line connecting both ends of the inductor 61. The capacitor 63 is inserted into one signal line of the feeder line 2 and cuts a DC signal (that is, a second control signal C2 described later) superimposed on the feeder line 2, and an AC signal (that is, the feeder signal PS / communication). Only the signal CS) is supplied to the detour line provided with the inductor 61 and the switch 62. The switch 62 is connected so that the on / off state is controlled according to the signal level of the DC signal extracted at the end of the capacitor 63 on the power supply line 2 side.

  That is, when the switch 62 is in the off state, the inductor 61 is inserted in the power supply line 2, and when the switch 62 is in the on state, the inductor 61 is not inserted in the power supply line 2.

<Slave node>
The slave node 5 includes a power receiving circuit 51 and a communication circuit 52.
The power receiving circuit 51 rectifies and smoothes the power supply signal PS received through the coupling unit 4 to generate a constant voltage power output for driving each unit of the slave node 5.

  The communication circuit 52 operates when there is a power output from the power receiving circuit 51, and executes master-slave communication by transmitting / receiving a communication signal CM to / from the master node 3 via the coupling unit 4.

<Master node>
The master node 3 includes a power feeding circuit 31, a communication circuit 32, an electrical length switching circuit 33, and a control circuit 34.

  The power supply circuit 31 generates a power supply signal PS and supplies it to the power supply line 2. The communication circuit 32 performs master-slave communication by transmitting / receiving a communication signal CM obtained by modulating a carrier wave to / from the slave node 5.

  The electrical length switching circuit 33 is provided in a bypass line connecting both ends of the inductor 331 and the inductor 331 inserted in series in the path from the feed circuit 31 to the feed line 2, and a switch 332 that conducts and blocks the bypass path. Consists of.

  The control circuit 34 generates a first control signal C <b> 1 for turning on / off the switch 332 and a second control signal C <b> 2 that is a DC signal applied to the power supply line 2 to control the electrical length switching unit 6. Here, a first state in which the switch 332 is turned off by the first control signal C1 (input end side inductor insertion) and the switch 62 is turned on by the second control signal C2 (termination side short-circuit), and the first control The switch 332 is turned on by the signal C1 (input end side inductor not inserted) and the second state in which the switch 62 is turned off by the second control signal C2 (termination side inductor inserted) is periodically switched. The first control signal C1 and the second control signal C2 are generated.

  For example, the switching cycle of the first state and the second state may be switched every time necessary for the power receiving circuit 51 of the slave node 5 to store power necessary for transmission / reception of signals for one frame. The switching timing between the first state and the second state may be any timing when the power supply frequency and the communication frequency are different, and when both frequencies are the same, it is necessary to switch in synchronization with frame transmission / reception. is there.

As described above, the switching cycle and the switching timing may be appropriately set according to the system specifications such as the power consumption in the slave, the power supply frequency, and the communication frequency.
<Effect>
In the in-vehicle power line communication system 1 configured as described above, power is supplied from the master node 3 to the slave node 5 through the power supply line 2 and between the master node 3 and the slave node 5 through the power supply line 2. Execute master-slave communication.

  However, when the relationship between the wavelength λ of the AC signal used for power supply and communication and the reciprocation length L of the twisted pair wire constituting the power supply line 2 is λ ≦ 10L, the current distribution of the AC signal on the line is uneven. Thus, there are locations where the current intensity is reduced by 3 dB or more compared to locations where the maximum intensity is present, that is, locations where the power supply efficiency is reduced.

  In contrast, in the in-vehicle power line communication system 1, the control circuit 34 switches the first state and the second state to change the electrical length of the feeder line 2, thereby changing the current distribution in the feeder line 2. Yes. As a result, the location where the power supply efficiency is maximized and the location where the power supply efficiency is reduced also change, so that at any location of the power supply line 2 at least one of the first state and the second state, efficient power supply is realized. Can do.

  In the in-vehicle power line communication system 1, the above effect can be obtained even if the frequency of the AC signal used for power supply and communication is set high (that is, the wavelength λ is set small). A small physique can be used, and the system can be reduced in size and weight.

<Experiment>
FIG. 2 (b) shows the result of measuring the received power at the slave node 5 by changing the position of the coupling unit 4 on the feed line 2. It can be confirmed that the value is exceeded.

  However, as shown in FIG. 2A, the length of the feeder line 2 is 5 m (round trip length L = 10 m), the inductances of the inductors 331 and 61 are 2.7 μH, and the frequency of the AC signal used for feeding or communication is It was measured as 13.56 MHz.

For comparison, FIG. 3B shows the result of measuring the current distribution on the feeder line 2 under the same conditions except that the inductors 331 and 61 are removed, as shown in FIG.
It can be seen that in the comparative example that does not have a configuration for switching the electrical length, the power supply efficiency is greatly reduced, and there is a place where the slave node 5 cannot be substantially connected.

[Second Embodiment]
Next, a second embodiment will be described.
Since the in-vehicle power line communication system 1a of the present embodiment has the same basic configuration as that of the first embodiment, the description of the common configuration will be omitted, and differences will be mainly described.

  In the first embodiment, the electrical length switching unit 6 is provided at the end of the feeder line 2. On the other hand, in this embodiment, as shown in FIG. 4, instead of wiring the feeder 2 in a loop shape so that both ends thereof are connected to the master node 3a and omitting the electrical length switching unit 6, It differs from the first embodiment in that a configuration corresponding to the electrical length switching unit 6 is added to the master node 3a.

<Master node>
The master node 3a includes a power feeding circuit 31, a communication circuit 32, a first electrical length switching circuit 33 (the same as the electrical length switching circuit 33 of the first embodiment), a control circuit 34, and a second electrical length switching circuit. 35.

  The second electrical length switching circuit 35 is obtained by omitting the capacitor 63 from the electrical length switching unit 6 in the first embodiment, and receives the second control signal C2 directly from the control circuit 34a without passing through the feeder line 2. It is configured.

<Effect>
According to the present embodiment, not only can the same effect as in the first embodiment be obtained, but also the second control signal C2 does not need to be transmitted via the feeder line 2, so that the apparatus configuration is simplified accordingly. Can be

[Third Embodiment]
Next, a third embodiment will be described.
Since the basic configuration of the in-vehicle power line communication system 1b of the present embodiment is the same as that of the first embodiment, description of common configurations will be omitted, and differences will be mainly described.

  In the first embodiment, the electrical length switching unit 6 is provided at the end of the feeder line 2. In contrast, the present embodiment is different from the first embodiment in that the configuration relating to the generation and transmission of the electrical length switching unit 6 and the second control signal C2 is omitted as shown in FIG.

Specifically, at the end of the feed line 2, a pair of signal lines constituting the feed line 2 is short-circuited (termination-side short).
In the master node 3b, the control circuit 34b generates only the first control signal C1, and the first control signal C1 turns off the switch 332 (input end side inductor insertion), and the first control. It is configured to periodically switch the second state in which the switch 332 is turned on (input end side inductor not inserted) by the signal C1.

According to the present embodiment configured as described above, the same effect as that of the first embodiment can be obtained with a simpler configuration.
[Fourth Embodiment]
Next, a fourth embodiment will be described.

Since the in-vehicle power line communication system 1c of the present embodiment has the same basic configuration as that of the first embodiment, the description of the common configuration will be omitted, and differences will be mainly described.
In the first embodiment, an electrical length switching circuit 33 is provided in the master node 3. On the other hand, this embodiment is different from the first embodiment in that the configuration relating to the generation of the electrical length switching circuit 33 and the first control signal C1 is omitted as shown in FIG.

  Specifically, in the master node 3c, the control circuit 34c generates only the second control signal C2, and the first state in which the switch 62 is turned on (termination-side short) by the second control signal C2, The control signal C2 is configured to periodically switch between a second state in which the switch 62 is turned off (termination-side inductor insertion).

According to the present embodiment configured as described above, the same effect as that of the first embodiment can be obtained with a simpler configuration.
[Fifth Embodiment]
Next, a fifth embodiment will be described.

Since the basic configuration of the in-vehicle power line communication system 1d of the present embodiment is the same as that of the second embodiment, the description of the common configuration will be omitted, and differences will be mainly described.
In the second embodiment, an electrical length switching circuit 33 is provided in the master node 3a. On the other hand, the present embodiment is different from the second embodiment in that the configuration relating to the generation of the electrical length switching circuit 33 and the first control signal C1 is omitted as shown in FIG.

  Specifically, in the master node 3d, as in the case of the fourth embodiment, the control circuit 34d generates only the second control signal C2, and the switch is turned on by the second control signal C2 (terminal-side short). And the second state in which the switch is turned off (termination-side inductor insertion) by the second control signal C2.

According to the present embodiment configured as described above, the same effect as that of the second embodiment can be obtained with a simpler configuration.
[Other Embodiments]
As mentioned above, although embodiment of this invention was described, it cannot be overemphasized that this invention can take a various form, without being limited to the said embodiment.

  (1) In the first and second embodiments, the control circuit 34 switches between the first state and the second state. However, the switch 332 and the switch 62 are switched by the first control signal C1 and the second control signal C2. You may comprise so that two or more arbitrary states may be used among the four states which added the 3rd state to which all are ON states, and the 4th state to which all are OFF states.

  (2) In the above embodiment, a configuration for changing the electrical length of the feed line 2 is provided at the input end or the end of the feed line 2, but these configurations may be provided anywhere on the feed line 2, In particular, the electrical length can be changed efficiently by providing it at a position corresponding to the antinode of the current distribution on the feeder line.

  (3) Although the example applied to the power line communication system that performs both power supply and communication using an AC signal has been described in the above embodiment, the present invention may be applied to a power supply system that performs only contactless power supply using an AC signal.

  (4) In the above embodiment, the present invention is applied to the in-vehicle power line communication system. However, the present invention is not limited to this. The wavelength λ of the AC signal used for power feeding and communication and the round trip line length L of the power feeding line An effect can be obtained if the system is set so that the relationship satisfies λ ≦ 10L.

  (5) Each component of the present invention is conceptual and is not limited to the above embodiment. For example, the functions of one component may be distributed to a plurality of components, or the functions of a plurality of components may be integrated into one component. Further, at least a part of the configuration of the above embodiment may be replaced with a known configuration having the same function. Further, at least a part of the configuration of the above embodiment may be loaded, replaced, or the like with respect to the configuration of another embodiment.

  DESCRIPTION OF SYMBOLS 1,1a-1d ... In-vehicle power line communication system 2 ... Feed line 3, 3a-3d ... Master node 4 ... Coupling part 5 ... Slave node 6 ... Electric length switching part 31 ... Feeding circuit 32 ... Communication circuit 33 ... Electric length switching circuit (First electrical length switching circuit) 33 ... electric length switching circuit 34, 34a to 34d ... control circuit 35 ... second electrical length switching circuit 41 ... feed line side coupling unit 42 ... node side coupling unit 51 ... power receiving circuit 52 ... communication Circuit 61,331 ... Inductor 62,332 ... Switch 63 ... Capacitor

Claims (10)

A feeding line (2) having a feeding point (41) that is formed in a bus shape and feeds power using electromagnetic induction to a device (5) that consumes power;
A power supply unit (31) for supplying an AC signal having a preset power supply frequency to the power supply line;
One or more electrical length switching units (6, 33, 35) each including an inductor (61, 331) connected to the feeder line, a detour path that bypasses the inductor, and a switch (62, 332) that interrupts the detour path )When,
A control unit (34, 34a to 34d) for controlling the state of the switch constituting the electrical length switching unit so that the electrical length of the feeder line is periodically switched;
A power supply system comprising: The control unit and the electrical length switching unit are provided at different locations on the feeder line,
The control unit superimposes a DC signal on the feeder line as a signal for controlling the state of the switch,
The electrical length switching unit includes a capacitor (63) connected in series with the inductor on a line to be detoured by the detour path, and the switch is switched according to a signal level of a DC signal superimposed on the feeder line. The power supply system according to claim 1, wherein on / off control is performed. A plurality of the electrical length switching units are provided,
The power supply system according to claim 1, wherein the control unit individually controls the state of the switch for each electrical length switching unit.   The power supply system according to any one of claims 1 to 3, wherein the electrical length switching unit (33) is provided at an input end of the power supply line to which the power supply unit is connected.   The power supply system according to any one of claims 1 to 3, wherein the electrical length switching unit (6, 35) is provided at a terminal end of the power supply line.   The power supply system according to any one of claims 1 to 3, wherein the electrical length switching unit is provided at a position corresponding to an antinode of a current distribution generated in the power supply line when the switch is in an on state. .   7. The power feeding system according to claim 1, wherein a line length of the power feeding line is 1/10 or more of a wavelength of the AC signal.   The power feeding system according to claim 1, wherein the power feeding line is a twisted pair wire.   The power supply system according to any one of claims 1 to 8, further comprising a communication circuit (32) that performs communication with the device via the power supply line.   The power feeding system according to claim 1, wherein the power feeding system is mounted on a vehicle.