JP2001112104A - Noncontact power feeding apparatus for mobile unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a simple noncontact power feeding apparatus for a mobile unit which shows little unbalance of on-loss. SOLUTION: A noncontact power feeding apparatus has a plurality of pickup coils 5 and 105 in which electromotive forces are induced by a line 3 and resonance capacitors 7 and 107 for the parallel resonance with the coils 5 and 105 on a mobile unit in order to supply a power to a load 30. A plurality of constant voltage means 250 and 350, which keep the terminal voltage of the load 30 at a constant value by switching devices 15 and 115 in accordance with powers extracted by the pickup coils 5 and 105, a voltage detection means 100, which detects the terminal voltage of the load 30 and a control unit 100 which controls the switching devices 15 and 115, so as to keep the voltage detected by the voltage detection means 100 at the predetermined constant value are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact power supply apparatus for a mobile body, which transmits electric power in a non-contact manner using an induced electromotive force generated in a coil by a magnetic field.

[0002]

2. Description of the Related Art A conventional non-contact power supply apparatus for a moving body will be described with reference to Japanese Patent Application Laid-Open No. 9-130905. According to the publication, as shown in FIG. 6, the non-contact power supply device includes a line 3 which also has a function as a power supply line for flowing a resonance current from a primary power supply unit 1 along a guide rail of a vehicle body (moving body). The moving body includes a pickup unit (coil) 5 that is fed from the line 3 in a non-contact manner and a resonance capacitor 7 that resonates at the same frequency as the frequency of the resonance current of the pickup coil 5 and the line 3. Secondary power supply unit 5 for supplying a constant voltage to load 30 by a voltage circuit
0 is disclosed. In the constant voltage circuit, the output of the full-wave rectifier bridge 9 is connected to a switching element 15 via a reactor 11, and a capacitor 1 is connected to both ends of the switching element 15 via a diode 13.
7 is connected. The switching element 15 is connected between both ends of the capacitor 17 in order to make the voltage VDc between both ends constant.
Is connected to a voltage control unit 40 that controls on / off of the voltage.

[0003]

However, the load 3
The capacity of the secondary side power supply unit 50
It is not desirable from the standpoint of work efficiency and the like to design and manufacture each time according to the capacity of the load 30. Therefore, a plurality of secondary power supply units 50, 150... Having the same predetermined rated capacity are manufactured, and the outputs of the plurality of secondary power supply units 50, 150 are connected in parallel as shown in FIG. It is conceivable that the connection is made to correspond to the capacity of the load 30.

In such a case, the secondary power supply units 50 and 150 are arranged along the line 3 (vertically) in order to extract power from the line 3 on the moving body.
The pickup coils 5 and 105 of each of the secondary-side power supply units 50 and 150 extract power using a constant current source. This is because, if a constant voltage source is used, the input voltage of each of the secondary power supply units 50 and 150 fluctuates due to a voltage fluctuation or the like. Further, each secondary-side power supply unit 50, 15
The output of 0 is connected to a capacitor 160 via diodes 155 and 159 for preventing backflow in order to avoid mutual interference.

[0005] The operation of the non-contact power supply device configured as described above will be described with reference to FIG. Now, the secondary side power supply unit 50 (150) extracts power from the primary side with a constant current by a resonance circuit including the pickup coil 5 (105) and the resonance capacitor 7 (107),
(109) and rectified by the capacitor 11 (11) via the reactor 11 (111) and the diode 13 (113).
7), and a backflow prevention diode 155 (15
Power is supplied to the capacitor 160 and the load 30 via 9). On the other hand, the voltage control unit 40 (140) detects the voltage V11 (V21) across the capacitor 17 (117), and controls the switching element 15 (115) to turn on / off the voltage V11 (V21) to be constant.

Here, when two moving bodies are traveling on a straight line and the voltage VDC across the capacitor 160 is controlled to be constant at 300 V, if the resistance value of the load 30 is 10Ω, the current IR0 flowing through the load is 30A. Becomes This load current IR0 is borne by each of the secondary-side power supply units 50 and 150. If the burden currents are IR1 and IR2, IR1 = IR22 = 15A, and the switching elements 15 and 115 are connected to each other as shown in FIG. As shown in (5), it is turned on and off with a 50% duty. In such a case, the ON loss of each of the switching elements 15 and 115 is substantially the same.

However, as shown in FIG. 9A, assuming that the secondary power supply unit 150 provided on the moving body is in a straight section and the secondary power supply unit 50 is traveling in a curved section. In the secondary power supply unit 50, as shown in FIG. 9B, the line 3 is located outside the center of the pickup coil 5 as indicated by a dashed line.
Here, the resonance capacitors 7 and 107 are set so that the line 3 has a desired resonance frequency at the center of the pickup coil 5. The coupling degree decreases, the inductance value of the pickup coil 5 changes, and the resonance frequency deviates from the desired frequency as shown in FIG. Therefore, the resonance current I21 of the secondary power supply unit 50 running on the curved portion decreases. It should be noted that even if it is outside the pickup coil 5,
Although it is conceivable to wind the pickup coil 5 around the core many times so that the degree of magnetic coupling between the pickup coil 5 and the pickup coil 5 does not decrease, this is not practical because the secondary-side current decreases in inverse proportion to the number of turns.

In such a case, the resonance current I21 of the secondary-side power supply unit 50 drops from 30A to 20A, and the resonance current I22 of the secondary-side power supply unit 150 remains at 30A because it runs on a straight line. Each secondary-side power supply unit 50,
150 outputs a constant voltage source to drive the load 30,
The same output current flows, and the load current IRo becomes 3
Since the power is 0 A, the secondary power supply units 50 and 150 supply 15 A while halving the load.

Therefore, as shown in FIG. 8B, the output currents IR1 and IR2 of the secondary power supply units 50 and 150 are
The relationship between the resonance currents I21 and I22 and the on / off times of the switching elements 15 is as follows.
When 15 is on (on time), the current is cut off,
Since the current flows when the switch is off (off time), the following expression is obtained. IR1 (IR2) = I21 (I22) × {off time / (off time + on time)} (1) On the other hand, duty (on time / (on time + off time) of switching elements 15 and 115) duty) has the following relationship: OFF time / (OFF time + ON time) = 1−duty (2) Therefore, rearranging equation (1) using the duty gives the following equation. duty = 1− (IR1 / I21) (3) By substituting IR1 = 15A and I21 = 20A into the above equation (3), the duty is obtained as follows. duty = 1− (15/20) = 0.25 That is, the duty is 25%. In addition, since the secondary-side power supply unit 150 runs on a straight line portion, the resonance current I22 remains at 30A. Therefore, the duty remains at 50%.

The loss when the switching elements 15 and 115 are on, and the on-loss Loss per cycle is determined by the following equation. Loss ≒ ID × VCE (ON) × duty (4) where ID: current flowing through the switching elements 15 and 115 (A) VCE (ON): saturation voltage (V) when the switching elements 15 and 115 are on According to the above equation (4), the ON loss Lo of the switching element 15 is obtained.
Ss1 is obtained by substituting VCE (ON) at the current value of 2.5 V for a current of 20 A and substituting a duty of 0.25. Loss1 ≒ 20 × 2.5 × 0.25 = 12.5 W Similarly, a current of 30 A flows through the on-loss Loss2 of the switching element 115, VCE (ON) at the current value is set to 3.0V, and the duty (duty) is set. Substitute 0.5 and find. Loss2 ≒ 30 × 3.0 × 0.5 = 45W Comparing the on-losses of both, the following equation is obtained. Loss2 / Loss1 = 45 / 12.5 = 3.6 That is, an imbalance as large as 3.6 times occurs.

[0011] Based on the unbalance, the capacity of each of the secondary power supply units 50 and 150 is not properly applied, and the efficient operation of each of the secondary power supply units 50 and 150 is hindered. Can be Further, in order to operate the secondary power supply units 50 and 150 in parallel, reverse current prevention diodes 155 and 159 are required to prevent the current from flowing into each of the secondary power supply units 50 and 150. In addition, since the secondary power supply units 50 and 150 are set to a constant voltage because of the voltages V11 and V21 across the capacitors 17 and 117, voltage fluctuation due to a voltage drop of the reverse current prevention diodes 155 and 159 is suppressed. However, there is a problem that a capacitor 160 having a relatively large capacitance may be required after the diodes 155 and 159 for preventing reverse current.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a simple non-contact power supply device for a mobile body, which has a small imbalance in on-loss.

[0013]

According to a first aspect of the present invention, there is provided a non-contact power supply apparatus for a moving body, in which a line for passing an alternating current is laid along a traveling path on which the moving body travels. A non-contact power supply device for a moving body that supplies a load with a plurality of pickup coils in which induced electromotive force is generated from the line and a resonance capacitor that resonates in parallel with the pickup coil, and includes a pickup coil from each of the pickup coils. A plurality of constant voltage means for maintaining the terminal voltage of the load at a constant voltage value by switching means based on the extracted power;
A voltage detecting means for detecting a terminal voltage of the load, and a common controlling means for controlling on / off of the switching means so that a voltage value detected by the voltage detecting means becomes a predetermined constant value. It is.

According to a second aspect of the present invention, the control means in the contactless power supply apparatus for a mobile body controls on / off all the switching means at the same timing.

According to a third aspect of the present invention, the control means in the non-contact power supply apparatus for a mobile body turns on or off all the switching means when the detected voltage of the voltage detecting means is equal to or higher than the first voltage value, and the detected voltage is equal to the first voltage. At least a second voltage value lower than the above voltage value is pulse-modulated in at least one of the switching means.

According to a fourth aspect of the present invention, the switching means in the mobile contactless power supply device is connected in parallel with the resonance capacitor.

According to a fifth aspect of the present invention, in the mobile contactless power supply apparatus, the switching means is connected in series with the resonance capacitor.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 One embodiment of the present invention will be described with reference to FIG. FIG. 1 is an electrical connection diagram of a non-contact power supply device that controls a plurality of secondary-side power supply units with one voltage control unit. 1, the same reference numerals as those in FIG. 7 denote the same or corresponding parts, and a description thereof will be omitted. In FIG. 1, secondary-side power supply units 250 and 350 as constant voltage means include:
A separate voltage control unit is omitted, and the switching elements 15 and 115 are turned on and off by a common common voltage control unit 100 to make the voltage VDc (output voltage) across the capacitor 160 constant. Note that the common voltage control unit 100 also has a function as voltage detection means for detecting the terminal voltage of the load 30.

Each of the secondary side power supply units 250 and 350
The output is directly connected to the capacitor 160 and the load 30, and as shown in FIG.
159 and the capacitors 17 and 117 are omitted. This is because the control target of the common control unit 100 is the capacitor 16
Since the voltage value of 0 (load 30) is set to a predetermined constant value, each secondary-side power supply unit 250, 350
Have the same output voltage value. In contrast, FIG.
As shown in (1), the capacitors 17 and 117 for suppressing the sudden change of the voltage value are required in order to individually make the output voltage values of the respective secondary-side power supply units 50 and 150 constant. However, this is not required. Further, each secondary-side power supply unit 50, 1
Since there is no voltage difference between the outputs of the output 50, the backflow prevention diodes 155 and 155 for preventing the current from flowing around based on the voltage difference.
159 is also unnecessary.

The operation of the non-contact power feeding device configured as described above will be described with reference to FIG. Now, the secondary side power supply unit 250 (350) is the pickup coil 5 (105).
A constant current is taken out from the primary side by a resonance circuit consisting of a capacitor and a resonance capacitor 7 (107), rectified by a full-wave rectification bridge 9 (109), and rectified by a capacitor 160 via a reactor 11 (111) and a diode 13 (113). And power to the load 30. On the other hand, the common voltage control unit 1
00 detects the voltage VDC across the capacitor 160 and controls the switching elements 15 and 115 with the same on and off times to keep the voltage VDC constant.

Here, two moving bodies are running on the straight portion of the line 3 and the voltage VDC across the capacitor 160 is 30
In the case of constant control at 0 V, if the resistance value of the load 30 is 10Ω, the current IR0 flowing through the load is 30A. In such a case, the switching elements 15, 115 of each of the secondary-side power supply units 250, 350 are turned on and off at 50% as in the conventional case.

Next, as shown in FIG. 9A, assuming that the secondary power supply unit 350 provided on the moving body is running in a straight line portion and the secondary power supply unit 250 is running in a curved portion. In the secondary side power supply unit 250, the resonance current I21
Drops from 30A to 20A, and the secondary side power supply unit 35
The resonance current I22 of 0 is 30 A
Will remain. The switching elements 15 and 115 of each of the secondary power supply units 250 and 350 are connected to the common voltage control unit 10.
Since the on / off control is performed by 0, the operation is performed with the same duty. Therefore, the following equation is obtained using the above equation (3). duty = 1− {IR0 / (I21 + I22)} (5) In the above equation (5), IR0 = 30A, I21 = 20A, I22 = 3
0A is substituted to obtain a duty. duty = 1−30 / (30 + 20) = 0.4 Therefore, the duty is 40%, and the current waveforms of the switching elements 15 and 115 are as shown in FIG.
According to the above equation (4), the ON loss Lo of the switching element 15 is obtained.
Ss1 is obtained by substituting VCE (ON) at the current value of 2.5 V for a current of 20 A and substituting a duty of 0.4. Loss1Ａ20 × 2.5 × 0.4 = 20 W Similarly, a current of 30 A flows through the on-loss Loss2 of the switching element 115, VCE (ON) at the current value is set to 3.0 V, and the duty (duty) is set to 0. Substitute 4 and find. Loss2 ≒ 30 × 3.0 × 0.4 = 36W Comparing the on-loss of both, the result is as follows. Loss2 / Loss1 = 36/20 = 1.8

Therefore, the ratio of the on-loss is 3.
What was 6 times increased to 1.8, and each switching element 1
The balance of 5,115 is good. According to the above configuration, conventionally, as shown in FIG.
Although the voltage control units 40 and 140 are required for 0 and 150, one common voltage control unit 100 may be used according to this embodiment. Moreover, the conventional large-capacity capacitor 1
7, 117 and diodes 155, 159 for preventing reverse current
Can be omitted. Thereby, the diode 155
As a result, no voltage drop occurs due to 159 and no power loss occurs.

Embodiment 2 FIG. Another embodiment of the present invention will be described with reference to FIG. FIG. 3 is a connection diagram for changing the control means of the switching element according to the output voltage. 3, the same reference numerals as those in FIG. 1 denote the same or corresponding parts, and a description thereof will be omitted. In FIG. 3, three secondary power supply units 2
50, 350, and 450 are connected in parallel, a voltage detector 200 as voltage detecting means for detecting a DC voltage VDc across the capacitor 160, and a detection voltage value of the voltage detector 200 divided into five stages. And a control unit 300 for changing the control means of the switching elements 15, 115, 215 at each stage.

The control unit 300 includes an input circuit 302 for taking in the detected voltage value of the voltage detector 200, a logic circuit 304 for controlling the switching elements 15, 115, 215 according to the taken-in voltage value, and a logic circuit 304 And an output circuit 306 for inputting the output of the switching element 15 to the switching elements 15, 115, 215.

The logic circuit 304 includes, for example, the capacitor 1
When the terminal voltage VDC of the 60 is controlled to 300V ± 10V, the detected voltage value is controlled in five stages.
The five steps are as follows. First, when the first voltage value is 306 V or more, all the switching elements 15, 115, 21
5 is turned on, and secondly, 302V is determined as a second voltage value lower than the first voltage value 306V.
At 06V, only the switching element 15 is pulse-modulated, for example, pulse width modulated, and the other switching elements 11
5 and 215, and thirdly, at 298 V to 302 V, the switching element 15 is turned off.
15 is pulse width modulated, and the switching element 215 is turned on. Fourth, the switching element 15 is turned off at 294 V to 298 V, the switching element 115 is turned off, and the switching element 215 is pulse width modulated. 29
At 4 V or less, the switching elements 15, 115,
215 is turned off.

According to the non-contact power supply device configured as described above, the detected voltage value of the voltage detector 200 is 294V to 3V.
06V, one switching element 15
Since pulse modulation of (15, 215) is sufficient, loss (iron loss) due to ripple current in reactors 11, 111, 211 is reduced. In addition, switching element 1
5,115,215, reactor 11,111,211
Loss due to switching is reduced, and the output voltage VDC
Is also reduced.

In the non-contact power supply device as shown in FIG. 4, the switches 21, 121, 221 are connected in parallel with the resonance capacitors 7, 107, 207, and the control unit 300
Switches 21, 121, 22 as in the logic circuit 304 of FIG.
1 is turned on / off or pulse width controlled. Logic circuit 3
When any of the switches 21, 121, 221 is turned on based on the current signal 04, the current value I0 of the line 3 returns to the line 3 again through any of the turned on switches 21, 121, 221. Since the load is not transmitted, the full-wave bridges 9, 109, and 20 are maintained while the load 30 is maintained at a constant voltage.
9, reactor 11, 111, 211, diode 1
The power loss due to 3,113,213 is reduced.

In the non-contact power supply device as shown in FIG. 5, the switches 21, 121 and 221 are connected in series with the resonance capacitors 7, 107 and 207, and the switch 21 is connected like the logic circuit 404 of the control unit 300. , 121, 221
May be turned on and off. Note that the logic circuit 404 corresponds to FIG.
Is turned on and off in a logic opposite to that of the logic circuit 304 shown in FIG. Therefore, first, as the first voltage value, 3
06V or more, all the switching elements 15,
115, 215, and second, the first voltage value 30
302V is determined as a second voltage value lower than 6V, and in the range of 302V to 306V, only the switching element 215 is subjected to, for example, pulse width modulation as pulse modulation, and the other switching elements 15 and 115 are turned off. Logic circuit 404
When the switches 21, 121 and 221 are turned off based on
The resonance capacitors 7, 107, 207 are no longer connected to the pickup coils 5, 105, 205, and the full-wave bridges 9, 109, 20 are maintained while the load 30 is maintained at a constant voltage.
9, reactor 11, 111, 211, diode 1
The power loss due to 3,113,213 is reduced.

Although the second embodiment has been described with the three secondary power supply units 250, 350 and 450, it is sufficient to provide two or more secondary power supply units.

[0031]

According to the first aspect of the present invention, a plurality of constant voltage means for maintaining the terminal voltage of the load at a constant voltage value by the switching means based on the power extracted from each pickup coil, and the terminal voltage of the load. A voltage detecting means for detecting and a common control means for controlling ON / OFF of the switching means so that the voltage value detected by the voltage detecting means is constant, so that one common voltage means is provided for a plurality of constant voltage means. There is an effect that the configuration is simple because common control means is sufficient.

According to the second aspect, in addition to the effect of the first aspect, since the control means controls on / off of all the switching means at the same timing, there is little imbalance in the on-loss of the switching means. effective.

According to the third invention, in addition to the effect of the first invention, the control means turns on or off all the switching means when the detected voltage is equal to or higher than the first voltage value, and the control voltage is equal to the first voltage. At least the second voltage value lower than the voltage value, at least one of the switching means is pulse-modulated, so that there is an effect that power loss of a pickup coil or the like can be reduced.

According to the fourth aspect, in addition to the effect of the third aspect, since the switching means is connected in parallel with the resonance capacitor, when the voltage of the voltage detection means is higher than the reference value, the load is fixed. There is an effect that the loss of the reactor and the like can be reduced while maintaining the voltage.

According to the fifth aspect, in addition to the effect of the third aspect, since the switching means is connected in series with the resonance capacitor, when the voltage of the voltage detection means is higher than the reference value, the load is fixed. There is an effect that the loss of the reactor and the like can be reduced while maintaining the voltage.

[Brief description of the drawings]

FIG. 1 is an electrical connection diagram of a non-contact power supply device according to an embodiment of the present invention, in which a plurality of secondary-side power supply units are controlled by a single voltage control unit.

FIG. 2 is a current waveform of the switching element shown in FIG.

FIG. 3 shows another embodiment of the present invention, and is an electrical connection diagram of a non-contact power supply device that changes on / off control of a switching element according to an output voltage.

FIG. 4 shows another embodiment of the present invention, and is an electrical connection diagram of a non-contact power supply device in which a switch is provided in parallel with a resonance capacitor to change on / off control.

FIG. 5 shows another embodiment of the present invention, and is an electrical connection diagram of a non-contact power supply device that changes on / off control by providing a switch in series with a resonance capacitor.

FIG. 6 is an electrical connection diagram of a conventional contactless power supply device.

FIG. 7 is an electrical connection diagram of a non-contact power supply device that controls a plurality of secondary units by each voltage control unit.

8 is a waveform of a current flowing through a switching element of the wireless power supply device shown in FIG.

FIG. 9 is a plan view of a moving body moving on a track and a front view of an electromagnetic coupling unit.

FIG. 10 is a gain-frequency characteristic curve of a resonance circuit.

[Explanation of symbols]

3 lines, 5,105,205 pickup coil,
7, 107, 207 resonance capacitors, 15, 115, 2
15 Switching element (switching means), 21,
121, 221 switch (switching means), 5
0, 150, 250, 350, 450 Secondary power supply unit (constant voltage means), 100 common voltage control unit (control means, voltage detection means), 200 voltage detector (voltage detection means), 300 control unit (control means) ).

Continued on the front page (72) Inventor Toshiharu Adachi 2-3-3 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) in Mitsubishi Electric Corporation 5G065 DA01 DA06 GA09 HA04 JA01 LA01 MA01 MA03 MA10 NA01 NA02 NA03 NA05 NA09 5H105 AA20 BA01 CC02 CC19 DD10 GG04 5H730 AA15 AS00 BB21 BB61 EE01 EE24 EE30 EE59 EE75

Claims (5)

[Claims] 1. A line through which an alternating current flows is laid along a traveling path on which a moving body travels. The moving body has a plurality of pickup coils generating induced electromotive force from the line, and a parallel connection with the pickup coil. And a resonance capacitor that resonates and supplies power to the load by supplying a power to the load, wherein the terminal voltage of the load is set to a constant voltage value by switching means based on the power extracted from each of the pickup coils. A plurality of constant voltage means, a voltage detection means for detecting a terminal voltage of the load, and a switching means for controlling on / off such that a voltage value detected by the voltage detection means becomes a predetermined constant value. A non-contact power supply device for a mobile body, comprising: common control means; 2. The non-contact power supply apparatus for a mobile body according to claim 1, wherein the control means controls on / off of all the switching means at the same timing. 3. The control means turns on or off all of the switching means when the detection voltage of the voltage detection means is equal to or higher than a first voltage value, and the second detection means detects that the detection voltage is lower than the first voltage value. The non-contact power supply device for a mobile object according to claim 1, wherein at least one of the switching means is pulse-modulated when the voltage value is equal to or higher than the voltage value. 4. The non-contact power supply device for a moving body according to claim 3, wherein the switching means is connected in parallel with the resonance capacitor. 5. The non-contact power supply device for a moving body according to claim 3, wherein the switching means is connected in series with the resonance capacitor.