JPH1014139A - Power transmission device - Google Patents

Abstract

(57) [Summary] Even if a load fluctuates, an optimum power can always be supplied to a power receiver by following the fluctuation. SOLUTION: On the power receiver 5 side, when the power consumption (load) on the secondary side becomes large and supply power becomes insufficient, a voltage status signal generator 54 detects a drop in the power supply voltage Vdd. By doing so, a voltage status signal VST indicating that "supply power is insufficient" is generated. The signal transmission / reception circuit 55 wirelessly transmits the generated voltage status signal VST to the power transmitter 3. The voltage status signal VST transmitted wirelessly is received by the signal transmitter / receiver 41 of the power transmitter 3. PWM control circuit 33
Performs control to increase the amount of power supplied to the power receiver 5 based on the voltage status signal VST input via the transmission / reception circuit 41.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission apparatus for transmitting electric power from a primary power transmitter to a secondary power receiver using electromagnetic induction in a non-contact manner, and more particularly to an external power supply. By supplying power from a transmitter to a power receiver implanted in the body, FES (Functional Electrical Stimulation; Functi) that provides electrical stimulation to muscles or nerves and moves paralyzed muscles
The present invention relates to a power transmission device suitable for application to an on-electrical-timing device.

[0002]

2. Description of the Related Art Conventionally, as this type of power transmission device,
For example, Japanese Patent Application Laid-Open No. 61-271806,
The devices described in JP-A-205955 and JP-A-4-334975 are known. In these conventional devices, the primary-side power transmitter 1 includes, as shown in FIG. 6, a power transmission coil 11, which is connected in series with the power transmission coil 11, and a series resonance circuit together with the power transmission coil 11. , An oscillation circuit 13 for driving the power transmission coil 11, and a control circuit 14 for driving the oscillation circuit 13. As shown in the figure, the power receiver 2 on the secondary side includes a power receiving coil 21 electromagnetically coupled to the power transmitting coil 11 of the power transmitter 1, and a power receiving coil 21. And a diode 22 connected in parallel with the power receiving coil 21 to form a parallel resonance circuit with the power receiving coil 21 and a diode 2 connected in series with the parallel resonance circuit and applying a DC voltage to a load 23.
4 and a smoothing capacitor 25 connected in parallel with the load 23 to smooth the rectified output of the diode 24. In this case, the resonance frequency of a series resonance circuit composed of the power transmission coil 11 and the capacitor 12;
The resonance frequency of the parallel resonance circuit composed of the power receiving coil 21 and the capacitor 22
3 output frequency.

In operation, the frequency of the AC voltage induced (transmitted) to the power receiving coil 21 by the electromagnetic energy of the power transmitting coil 11 driven by the oscillation circuit 13 is different from the resonance frequency of the parallel resonance circuit. Since they match, a large resonance current flows through the parallel resonance circuit, and a large voltage is generated on both sides of the capacitor 22. Then, the AC voltage is rectified by the diode 24 and smoothed by the smoothing capacitor 25 to become a DC voltage.

[0004]

However, in the above-described conventional power transmission device, it is impossible to adjust the transmission power by following a variation in distance between the two coils 11 and 21 and a variation in load on the power receiver 2 side. There were drawbacks. For this reason, when the above-mentioned conventional power transmission device is applied to a device that handles a load that fluctuates rapidly and greatly, for example, an FES device that moves a muscle of a human body, there is a problem that the usability is poor. Therefore, in order to cope with the maximum load, it is one idea to adopt a method in which the transmitter 1 constantly supplies the power corresponding to the maximum consumption to the receiver 2. However, in this system, even when a large amount of power is not required, the power transmitter 1 attempts to supply a large amount of power. Excessive current flows in the resonance circuit and the like, and as a result, unnecessary heat is generated in the circuit, and the life of the circuit element is shortened. There is also a problem that an excessive voltage is supplied to the load 23. As a countermeasure, a constant voltage element may be interposed between the smoothing capacitor 25 and the load 23 to keep the voltage of the load 23 constant. However, the problem of wasteful power consumption is still not solved at all. Particularly, in a constant voltage element absorbing unnecessary voltage, excessive power loss and heat generation become a problem.

The present invention has been made in view of the above-described circumstances, and even if a load or a distance between coils changes, an optimum power can always be supplied to the secondary side by following the change. It is an object of the present invention to provide a power transmission device capable of generating the transmission power on the primary side.

[0006]

In order to solve the above-mentioned problems, the invention according to claim 1 is achieved by magnetic coupling between a power transmitting coil on a power transmitter side and a power receiving coil on a power receiver side. According to a power transmission device that transmits power from the power transmitter on the primary side to the power receiver on the secondary side in a non-contact manner,
Status information generating means for detecting the state of power consumption on the secondary side and generating status information on the power consumption; and supplying the power to the power receiver based on the status information generated by the status information generating means. Power control means for controlling the amount of power.

According to a second aspect of the present invention, the power transmission coil on the power transmitter side and the power reception coil on the power receiver side are magnetically coupled to each other so that the power transmission coil on the primary side is connected to the power transmission coil on the secondary side. A power transmission device for transmitting power to the power receiver in a contactless manner, wherein the power receiver detects a state of power consumption on a secondary side and generates status information on the power consumption. Generating means, and status information transmitting means for wirelessly transmitting the status information generated by the receiver-side status information generating means to the power transmitter, wherein the power transmitter transmits the status information. Status information receiving means for wirelessly receiving the status information sent from the information transmitting means; and the status information input via the status information receiving means. Based on Tasu information, characterized by comprising a power control means for controlling the amount of power supplied to the power receiver.

According to a third aspect of the present invention, the power transmission coil provided in the power transmitter and the power reception coil provided in the power receiver are magnetically coupled to each other so that the power transmission coil on the primary side is separated from the power transmitter coil. The present invention relates to a power transmission device for transmitting power to the power receiver on a secondary side in a non-contact manner, wherein the power receiver detects a state of power consumption on a secondary side and generates status information on the power consumption. And a status information transmitting means for wirelessly transmitting the status information generated by the receiver-side status information generating means to the power transmitter. A status information receiving means for wirelessly receiving the status information sent from the status information transmitting means, and a current flowing through the power transmitting coil. Transmitter-side status information generating means for detecting a state and generating status information relating to the current amount, and based on the status information input via the status information receiving means or from the transmitter-side status information generating means And power control means for controlling the amount of power supplied to the power receiver.

According to a fourth aspect of the present invention, there is provided the power transmission device according to the second or third aspect, wherein the status information generating means on the receiver side is configured such that the secondary power supply voltage is higher than a preset reference voltage. When the power is also low, status information indicating that power supply is insufficient is generated.

According to a fifth aspect of the present invention, there is provided the power transmission apparatus according to the second or third aspect, wherein the status information generating means on the receiver side comprises a first power supply voltage on a secondary side which is set in advance. When the power supply voltage is lower than the reference voltage, status information indicating that the power supply is insufficient is generated. When the power supply voltage on the secondary side is higher than the second reference voltage set in advance, the power supply is excessive. It is characterized by generating status information indicating that

According to a sixth aspect of the present invention, there is provided the power transmission apparatus according to the third aspect, wherein the transmitter-side status information generating means determines that a current amount flowing through the power transmitting coil is a reference value set in advance. When the number is larger than the threshold value, status information indicating that the coil current amount is excessive is generated.

[0012] The invention according to claim 7 is based on claim 2,
3. The power transmission device according to 3, 4, 5 or 6, wherein the power control unit performs a pulse on the basis of the status information input via the status information reception unit or from the transmitter-side status information generation unit. Generating a width-modulated AC generation signal and outputting the generated signal to a power transmission coil driving unit, wherein the power transmission coil driving unit drives the power transmission coil based on the input AC generation signal; It is characterized by.

[0013] The invention described in claim 8 is the second invention.
The power receiver according to any one of 3, 4, 5, 6 and 7, wherein the power receiver includes a stimulus generator for electrically stimulating muscles or nerves.

[0014]

According to the structure of the present invention, on the power receiver side,
When the power consumption (load) on the secondary side becomes large and the power supply is insufficient, the status information generating means on the receiver side detects this and the status indicating "power supply is insufficient". Generate information. The status information transmitting means wirelessly transmits the generated status information to the power transmitter. The status information transmitted wirelessly is received by status information receiving means of the power transmitter. The power control means performs control to increase the amount of power supplied to the power receiver based on the status information input via the status information receiving means. next,
On the power receiver side, when the power consumption (load) on the secondary side becomes small and the supply power becomes excessive, the status information generation means on the receiver side detects this, and “the supply power becomes low. Generate status information indicating "excessive". The status information transmitting unit wirelessly transmits the generated status information to the power transmitter. The status information transmitted wirelessly is received by status information receiving means of the power transmitter. The power control means performs control to reduce the amount of power supplied to the power receiver based on the status information input via the status information receiving means. On the other hand, when the distance between the two coils is too large, the resonance frequency greatly deviates from the set value. As a result, when the amount of current flowing through the primary side power transmission coil becomes excessive, the transmitter side status information generation is performed. The means detects this and generates status information indicating that "the coil current amount is excessive". The power control means performs control to reduce the coil current amount based on the input status information.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. The description will be specifically made using an embodiment. FIG. 1 is a block diagram showing an electric configuration of an FES (functional electrical stimulation) device to which a power transmission device according to an embodiment of the present invention is applied, and FIG. 2 is a part of transmission power control of the FES device. And FIG. 3 is a time chart for explaining the operation of the shift register, and FIG. 4 is a flowchart showing an operation processing procedure (PWM control algorithm) of the FES device. FIG. 5 is a time chart for explaining the control operation of the FES device. FES in this example
The device is a device that exercises paralyzed muscles by applying electrical stimulation to muscles or nerves, from a primary power transmitter 3 placed outside the body to a secondary power receiver 4 implanted inside the body.
The power is transmitted wirelessly using electromagnetic induction. As shown in FIG. 1, the power transmitter 3
PU (central processing unit) 31, memory 32, PWM control circuit 33, D latch circuit 34, clock generator 3
5, a frequency divider 36, a shift register 37, a full bridge circuit 38, a series resonance circuit 39, a current status signal generator 40, and a signal transmission / reception circuit 41. Further, as shown in FIG.
Parallel resonance circuit 51 and full-wave rectifier 5 composed of a diode
2, a smoothing capacitor 53, a voltage status signal generator 54, a signal transmission / reception circuit 55, and a stimulus generation circuit 56.

First, the components of the power transmitter 3 will be described.
The CPU 31 controls each unit of the apparatus by executing a processing program stored in a ROM constituting the memory 32 by using a work RAM constituting the memory 32. In this example, if the control of the CPU 31 is particularly important, the CPU 31 sends the power transmission permission signal DRV to the PW
The control signal is sent to the M control circuit 33 to start / continue the supply of power to the power receiver 5 and the control signal C
The TL is wirelessly transmitted to the stimulus generation circuit 56 of the power receiver 5 to control the start, stop, and change of the stimulus output STM. When an abnormal situation occurs in the apparatus, the CPU 31 stops outputting the power transmission permission signal DRV. Further, the change control of the stimulus output STM accompanied by the change of the load is performed by, for example, instructing the stimulus generation circuit 56 to increase or decrease the number of channels (the number of muscle fibers or nerves) for applying the stimulus and to change the stimulus voltage and the stimulus frequency. Done.

The PWM control circuit 33 includes a CPU 31
While receiving the power transmission permission signal DRV from the power status signal generator 40, based on the current status signal AST given from the current status signal generator 40 and the voltage status signal VST given from the voltage status signal generator 54, PWM (described later) A pulse width modulation) control algorithm (FIG. 2) generates and outputs a PWM control signal DAT used for controlling the amount of transmission power to the D latch circuit 34,
A write signal (latch enable signal) ENA is supplied to the D latch circuit 34 as necessary. PW in this example
In the M control circuit 33, TYPE0 (= 00000000000), TYPE1
(= 10000000), TYPE2 (= 1110,000)
00), TYPE3 (= 11100000), TYPE
4 (= 11111000), TYPE5 (= 111111)
111) can generate six types of PWM control signals DAT, whereby the amount of transmission power is controlled stepwise within a range of six steps. That is, the PWM control signal D of TYPE0
If the AT is generated, the transmission power amount is set to zero, if the PWM control signal DAT of TYPE 5 is set to the maximum power amount,
For a PWM control signal DAT from E1 to TYPE4,
The transmission power amount is controlled stepwise in the increasing direction in the order of TYPE1, TYPE2, TYPE3, and TYPE4. At the input timing of the write signal ENA output from the PWM control circuit 33, the D latch circuit 34 changes the PWM control signal DAT existing on the input side at that time until the next write signal ENA is supplied. Temporarily hold output regardless of input.

The shift register 37 has, for example, a 16-bit configuration obtained by cascading D flip-flops. The shift register 37 has a clock CLK output from the clock generator 35 (in this example, the frequency is 16 times the power transmission frequency). Clock) and a frequency-divided signal D output from the frequency divider 36.
CK (in this example, the frequency is 1/16 of the clock frequency
The divided signal DCK is input, and while the state of the inputted divided signal DCK is at the level “0”, the clock CLK is output on the output side.
(Shift mode)
When the frequency-divided signal DCK of “1” is input, that is, when the frequency-divided signal DCK of the positive pulse is input, the PWM control signal DAT (the output signal of the D-latch circuit 34) existing on the input side at that time. ) Is loaded on the output side (load mode). In this shift register 37, the input D0
To D7 are grounded, so that "0" is always loaded to the inputs D0 to D7, while the inputs D8 to D1
5 is loaded with an 8-bit PWM control signal DAT (output signal of the D latch circuit 34) in parallel. further,
Referring to FIG. 2 in detail, since a pulse 16 times as large as the input terminal SH / LD is input to the input terminal CK, first, while the state of the input frequency-divided signal DCK is “0”, In the outputs S15 to S0, 16 "ripple" shifts S15 → S15 → S1
4... S3 → S2 → S1 are performed, and then the frequency-divided signal D of “1”
When CK is input, an 8-bit PWM control signal DAT existing in parallel with the inputs D15 to D8 is loaded to the outputs S15 to S8 (D15 → S15, D14 → S14,..., D8 → S8),
"0" existing in each of the inputs D7 to D0 is loaded into the outputs S7 to S0 (D7 → S7, D6 → S6,..., D1 → S1). Again, with the loaded outputs S15-S0, 16 "ripple" shifts S1
5 → S14 → S13... S3 → S2 → S1 are performed. Thereafter, the 8-bit P existing in parallel to the inputs D15 to D8 is again input.
The WM control signal DAT is loaded to the outputs S15 to S8 (D1
5 → S15, D14 → S14,..., D8 → S8) and “0” present at each input D7-D0 are loaded into outputs S7-S0 (D7 → S7, D6 → S6,..., D1 → S1). . Hereinafter, the above operation is repeated. It should be noted that the output S15 of the shift register 37 is set to "0" after the "ripple" has passed and until it is loaded next time.

In the shift register 37 of this example, the output S
Of the 15 to S8, the output S8 is input to the full bridge circuit 38 as the switching signal SW +, and the output S0 is input to the full bridge circuit 38 as the switching signal SW-. Now, at the input timing of the frequency-divided signal DCK of the positive pulse (see FIG. 3B), the outputs S15 to S8
PWM control signal DA of YPE0 (= 0000000000)
When T is loaded in parallel, the outputs S8 to S15 are all loaded with "0". Therefore, even if the shift operation is performed 16 times at the input timing of the clock CLK ((a) in the figure), No pulse waveform is output from the outputs S8 and S0 ((c) in the figure). Next, at the input timing of the frequency-divided signal DCK of the positive pulse, TYPE1 (=
When the PWM control signal DAT (10000000) is loaded in parallel, "1" is output only to the output S8,
Since "0" is loaded into S15, the shift operation is performed 16 times at the input timing of the clock CLK, and as a result, as shown in FIG.
A pulse waveform (switching signals SW +, SW−) having a duty ratio of 1/16 is obtained. This time, at the input timing of the frequency-divided signal DCK of the positive pulse, T15 is output to the outputs S15 to S8.
PWM control signal DA of YPE2 (= 11000000)
Assuming that T is loaded in parallel, "1" is loaded into the outputs S8 and S9, and "0" is loaded into S10 to S15, so that the shift operation is performed 16 times at the input timing of the clock CLK. As a result, a pulse waveform (switching signals SW +, SW-) having a duty ratio of 2/16 is obtained from the outputs S8 and S0 as shown in FIG. Similarly, TYPE3 (= 111) is output to outputs S15 to S8.
When the PWM control signal DAT (00000) is loaded in parallel, the pulse waveforms (switching signals SW + and SW−) having a duty ratio of 3/16 are output from the respective outputs S8 and S0 as shown in FIG. ) Is output S15 ~
When the PWM control signal DAT of TYPE4 (= 11111000) is loaded in parallel to S8, the respective outputs S8 and S0 output a pulse waveform with a duty ratio of 5/16 (switching) as shown in FIG. Signal SW
+, SW-), and outputs S15 to S8 are TYPE5.
When the PWM control signal DAT of (= 11111111) is loaded in parallel, the duty ratio of 8/16 is obtained from the respective outputs S8 and S0 as shown in FIG.
(The switching signals SW + and SW−) are obtained.

The full bridge circuit 38 is an inverter for converting a direct current into an alternating current to drive a series resonance circuit 39, and determines whether the series resonance circuit 39 is on or off by dividing a frequency by a divided signal D.
It is composed of two sets of analog switching elements (for example, FETs) that are alternately performed at the cycle of CK. That is, the output S8 of the shift register 37 (the switching signal SW
+) Is input to one set of analog switching elements, and the output S0 (switching signal SW−) of the shift register 37 is input to the other set of analog switching elements. By the switching operation that alternately turns on and off, alternating-current transmission power is generated in the series resonance circuit 39 according to the pulse width (duty ratio) of the switching signals SW + and SW−. The series resonance circuit 39 includes a power transmission coil 391 which is a planar coil and a capacitor 392 connected in series with the power transmission coil 391. The resonance frequency of the series resonance circuit 39 is a full bridge circuit 38.
Is set to be equal to the driving frequency. The current status signal generator 40 includes a current detector (not shown) that detects a current flowing through the power transmission coil 391, and a comparator that compares a coil current amount detected by the current detector with a predetermined reference current amount. When the coil current amount exceeds the reference current amount, "the coil current amount is excessive"
If the coil current amount does not exceed the reference current amount, various current status signals AST indicating that "the coil current amount is not excessive" are generated and sent to the PWM control circuit 33.

The signal transmitting / receiving circuit 41 includes an antenna 41
a control signal CTL output from the CPU 31
To the power receiver 5 to transmit an instruction (start, stop, change instruction of the stimulus output STM) from the CPU 31 to the stimulus generation circuit 56, and a voltage status signal radiated from the power receiver 5 as a radio wave. The VST is received, and the detected and demodulated voltage status signal VST is supplied to the PWM control circuit 33.

Next, each part of the power receiver 5 will be described. As shown in FIG. 1, the parallel resonance circuit 41 includes a power receiving coil (plane coil) 511 magnetically coupled to the power transmitting coil 391 of the power transmitter 3 and two ends of the power receiving coil 511. And a capacitor 512 connected in parallel. The resonance frequency of the parallel resonance circuit 41 is also set to match the drive frequency of the full bridge circuit 38. The parallel resonance circuit 51 is connected in parallel with the parallel resonance circuit 51 and has a DC power supply voltage Vdd.
And a full-wave rectifier 52 for generating the
2 together with a smoothing capacitor 53 for smoothing the rectified output of
It constitutes the secondary power supply. During operation, the frequency of the AC voltage induced (transmitted) to the secondary-side power receiving coil 511 by the electromagnetic energy of the power-transmitting coil 391 driven by the primary-side full-bridge circuit 38 changes the parallel resonance frequency. Since the resonance frequency matches the resonance frequency of the circuit 39, a large resonance current flows through the parallel resonance circuit 39,
Therefore, a large AC voltage is generated on both sides of the capacitor 512. The AC voltage is subjected to full-wave rectification by a full-wave rectifier 52 and smoothed by a smoothing capacitor 53 to become a DC power supply voltage Vdd. The DC power supply voltage is applied to loads such as muscles, nerves, and a stimulus generation circuit 56. Given.

The voltage status signal generator 53 includes a voltage detector (not shown) for detecting the power supply voltage Vdd of the secondary power supply, and a lower limit for comparing the detected power supply voltage Vdd with a predetermined lower limit reference voltage value. A comparator and an upper-limit comparator for comparing the detected power supply voltage Vdd with a predetermined upper-limit reference voltage value. When the power supply voltage Vdd is lower than the lower-limit reference voltage value, the power supply voltage Vdd becomes insufficient. If the power supply voltage Vdd exceeds the upper-limit reference voltage value, the power supply voltage Vdd exceeds the lower-limit reference voltage value and the upper-limit reference voltage value. In some cases, various voltage status signals VST indicating that “the power supply voltage Vdd is appropriate” are generated and sent to the signal transmitting / receiving circuit 55. Further, the signal transmission / reception circuit 55 transmits the input voltage status signal VST to the power transmitter 3 via the antenna 55a, supplies the voltage status signal VST to the PWM control circuit 33, and receives the control signal CTL output from the CPU 31. Then, the detected and demodulated control signal CTL is supplied to the stimulus generation circuit 56. The stimulus generation circuit 56 is a circuit for applying an AC signal of about 20 Hz to a muscle or a nerve to perform electrical stimulation, and the CPU 31 of the power transmitter 3
Thus, the number of channels (the number of muscle fibers or nerves) to be stimulated, the stimulation voltage and the stimulation frequency are controlled.

Next, the operation of this example will be described with reference to the flowchart (PWM control algorithm) of FIG. When the power is turned on to the apparatus by the operator, first, the CPU 31 initializes each section of the apparatus.
This initialization includes, for example, clearing various registers set in the memory 32, resetting various flags, and initializing various variables that are initial settings for peripheral circuits. P
In the WM control circuit 33, TY
PWM control signal DAT of PE0 (= 0000000000)
Is generated and output (step SP
1). In the output of TYPE0, the power transmission coil 3
No transmission power is generated at 91 yet. When the initialization of each unit of the device is completed, the CPU 31 sends a power transmission permission signal DRV to the PWM control circuit 33 to perform control for starting supply of power to the power receiver 5 and
The control signal CTL is transmitted wirelessly to the stimulus generation circuit 56 of the power receiver 5 so as to start the stimulus output STM.

The PWM control circuit 33 outputs the power transmission permission signal DR from the CPU 31 even after completing the initialization.
Until V is supplied, the standby state (steps SP2, S
P1), while the power transmission permission signal D
When the RV is input, power transmission control is started. First, the current output of the PWM control circuit 33 is TY
It is determined whether the signal is the PWM control signal DAT of PE0 (step SP3). In this case, since the power transmission control has just started, the current output is the PW of TYPE0.
This is the M control signal DAT. Output is PWM of TYPE0
When it is the control signal DAT, the PWM control circuit 33
TYPE1 (= 100) which is one stage higher than the output of TYPE0
0000) and outputs the PWM control signal DAT to the D latch circuit 34 (step SP4), and supplies the write signal ENA to the D latch circuit 34 (step SP9). The D latch circuit 34 receives the write signal ENA output from the PWM control circuit 33 at the input timing.
At this time, the PWM control signal DAT of TYPE1 existing on the input side is held at the output. The output of the D latch circuit 34 (in this case, the PWM control signal DAT of TYPE1) is
Until the next write signal ENA is applied, it is held regardless of subsequent inputs. As a result, as shown in FIG.
Are supplied to the full-bridge circuit 38, and the full-bridge circuit 38 starts switching at the input timing of the switching signals SW +, SW-. Flow and power transfer begin.

The above-described determination (steps SP2 and SP3) is repeated again in the PWM control circuit 33, but this time the output of the PWM control circuit 33 at this time is TYPE0
Is not the PWM control signal DAT, but the PWM of TYPE1.
Since this is the control signal DAT (step SP3), this time, the content of the current status signal AST given from the current status signal generator 40 indicates that the coil current amount (the current amount flowing through the power transmission coil 391) is excessive. It is determined whether or not there is (step SP5). Here, if the distance between the two coils 391 and 511 is equal to the set value, the mutual resonance frequency relationship is maintained, so that the coil current amount does not become excessive. 391,
If the distance between 511 is too far from the set value, the resonance frequency greatly deviates from the set value, and as a result, the coil current amount becomes excessive and the power transmitter 3 may be damaged. But,
Since the power transmission control has just started and the amount of generated power is not large, there are few cases where it is determined that the coil current amount is excessive. In many cases, it is determined that the coil current amount is not excessive. If it is determined that the amount of coil current is not excessive (step SP5), then the voltage status signal VST provided from the voltage status signal generator 54
It is determined whether or not the power supply voltage value Vdd on the power receiver 5 side is insufficient by looking at the contents of (2) (step SP6).

Immediately after startup, the power supply voltage Vdd often does not yet reach the lower-limit side reference voltage value. Therefore, if it is determined that the power supply voltage value Vdd is insufficient, the process proceeds to step SP4 and the power Increase the control amount one step. In this case,
Because it is the output of TYPE1, TYPE one level higher than this
2 (= 110000000) PWM control signal DAT is generated and output to the D latch circuit 34 (step SP4).
At the same time, the write signal ENA is given to the D latch circuit 34 (step SP9). At the input timing of the write signal ENA output from the PWM control circuit 33, the D latch circuit 34 holds the PWM control signal DAT of TYPE2 existing on the input side as an output at this time. The output of the D latch circuit 34 (in this case, the PWM control signal D of TYPE2)
AT) until the next write signal ENA is given.
It is retained regardless of subsequent inputs. Accordingly, FIG.
As shown in (e), the switching signals SW + and SW− pulse-width-modulated to a duty ratio of 2/16 are supplied from the shift register 37 to the full bridge circuit 38, so that the power is transmitted to the power transmitting coil 391. As a result, the supplied power increases on the power receiver 5 side, and the power supply voltage Vdd is further increased.

The above processing is repeated, and as a result of the second determination (step SP6) as to whether the power supply voltage value Vdd on the power receiver 5 side is insufficient, the power supply voltage value Vdd is still obtained.
If dd is insufficient, the control amount is further increased by one step (step SP4). In this case, since the output is TYPE2, TYPE3 (= 1110000) which is one level higher than this is output.
0) and generates a PWM control signal DAT to
4 (step SP4), and also provides the write signal ENA to the D latch circuit 34 (step SP4).
9). At the input timing of the write signal ENA output from the PWM control circuit 33, the D latch circuit 34 receives the PWM control signal D of TYPE2 existing on the input side at this time.
Hold AT at output. The output of the D latch circuit 34 (in this case, the PWM control signal DAT of TYPE3) is held until the next write signal ENA is supplied, irrespective of subsequent inputs. Accordingly, as shown in FIG. 3F, the switching signals SW + and SW− pulse-width-modulated to a duty ratio of 3/16 are supplied from the shift register 37 to the full bridge circuit 38. An alternating current whose power has been further increased flows through 391, and as a result, the power supplied to the power receiver 5 further increases, and the power supply voltage Vdd is further increased.

The above-described processing is repeated, and the third determination (step SP6) as to whether the power supply voltage value Vdd on the power receiver 5 side is insufficient is also applied to the load on the secondary side.
If the power supply is still insufficient and the power supply voltage value Vdd is still insufficient, the control amount is further increased by one step (step SP4). The CPU 31 drives the stimulus generation circuit 56 with the control signal CTL to apply stimulus to muscles and nerves. However, since the stimulus is an electric current, the power consumption of the power receiver 5 increases. Then, the current increases, but the supply power is limited, so that the power supply voltage Vdd of the power receiver 5 decreases. In this case, since the output is TYPE3, the PWM control signal DAT of TYPE4 (= 11111000) one level higher than this is generated and output to the D latch circuit 34 (step SP4), and the write signal ENA is output to the D latch circuit 34. (Step SP9). D latch circuit 3
Reference numeral 4 denotes an input timing of the write signal ENA output from the PWM control circuit 33. At this time, the PWM control signal DAT of TYPE2 existing on the input side is held at the output. Output of D latch circuit 34 (in this case, TYPE4
PWM control signal DAT) is the next write signal ENA.
Is held irrespective of subsequent inputs until is given (see FIG. 5). Accordingly, as shown in FIG.
The switching signals SW + and SW− pulse-width-modulated to a duty ratio of 5/16 are supplied from the shift register 37 to the full bridge circuit 38, so that an AC current whose power is further increased flows through the power transmission coil 391. As a result, the amount of transmission power increases, and the power supply voltage Vdd is further increased.

On the other hand, a third determination is made as to whether or not the power supply voltage value Vdd on the power receiver 5 side is insufficient (step SP6).
At this time, when it is determined that the power supply voltage Vdd exceeds the lower-limit reference voltage value because the supply power to the secondary-side load has increased, and as a result, the power supply voltage value Vdd is not insufficient. This time, it is determined whether or not the power supply voltage value Vdd on the power receiver 5 side has exceeded (step SP7). If it is determined that the power consumption is not exceeded, the power consumption and the transmission power are balanced.
The above processing is repeated without changing the current holding state of.
On the other hand, in step SP7, when it is determined that the power supply voltage value Vdd of the power receiver 5 has exceeded the power supply to the load on the secondary side because the power supply has become excessive, The control amount is reduced by one step (step SP8). In this case, since the output is TYPE3, the TYPE one level lower than this is
PWM control signal DAT of PE3 (= 11100000)
Is generated and output to the D latch circuit 34 (step SP
8), the write signal ENA is supplied to the D latch circuit 34 (step SP9). The D latch circuit 34 has a PW
At the input timing of the write signal ENA output from the M control circuit 33, the TYPE existing on the input side at this time is
3 is held at the output. The output of the D latch circuit 34 (in this case, the PWM control signal DAT of TYPE3) is held until the next write signal ENA is supplied, irrespective of subsequent inputs. Accordingly, as shown in FIG. 3F, the switching signals SW + and SW− pulse-width-modulated to have a duty ratio of 3/16.
Is supplied from the shift register 37 to the full bridge circuit 38, so that the power-down AC current flows through the power transmission coil 391, and as a result, the amount of transmission power decreases, and the power supply voltage Vdd also drops.

In step SP5, if the distance between the coils 391 and 511 is too far from the set value, the resonance frequency greatly deviates from the set value. As a result, even when the coil current amount becomes excessive, Is adjusted by one step (step SP8). When stopping the operation of the power receiver 5, the CPU 31 stops sending the power transmission permission signal DRV. Then, the PWM control circuit 33 immediately stops the power transmission (steps SP2 and SP1).

As described above, according to the above configuration, even if the load or the distance between the coils fluctuates, it always follows the fluctuation,
The optimum power can be supplied to the power receiver, and the optimum transmission power can be generated by the power transmitter. Therefore, a very convenient device can be provided. The durability of the device and parts can be significantly improved. In addition, unnecessary heat generation can be prevented, and waste of power can be eliminated.

Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and there are design changes and the like that do not depart from the gist of the present invention. Is also included in the present invention. For example, the resonance circuit is not limited to the primary side and the secondary side of the device, and may be a series resonance circuit or a parallel resonance circuit. The number of PWM control signals is not limited to six, and can be increased or decreased as necessary. The shift register is not limited to a 16-bit shift register. Further, each unit of the apparatus including the PWM control circuit may have a hardware configuration or a software configuration. Further, the reference value such as the lower-limit side reference voltage value may be changed according to the magnitude of the electric energy.

[0034]

As described above, according to the configuration of the present invention, even if the load or the distance between the coils fluctuates, the optimum power can always be supplied to the power receiver while following the fluctuation. Optimal transmission power can be generated by the power transmitter. Therefore, a very convenient device can be provided. The durability of the device and parts can be significantly improved. In addition, unnecessary heat generation can be prevented, and waste of power can be eliminated.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of an FES (Functional Electrical Stimulation) device to which a power transmission device according to an embodiment of the present invention is applied.

FIG. 2 is a diagram illustrating in detail input / output terminals of a shift register that performs a part of transmission power control of the FES device.

FIG. 3 is a time chart for explaining the operation of the shift register.

FIG. 4 is a flowchart showing an operation processing procedure (PWM control algorithm) of the FES device.

FIG. 5 is a time chart for explaining a control operation of the FES device.

FIG. 6 is a block diagram illustrating an electrical configuration of a conventional power transmission device.

[Explanation of symbols]

3 Power Transmitter 31 CPU 33 PWM Control Unit (Power Control Unit) 34 D Latch Circuit 36 Divider 37 Shift Register 38 Full Bridge Circuit (Power Transmission Coil Driving Unit) 39 Series Resonant Circuit 391 Power Transmission Coil 392 Capacitor 40 Current status signal generator (status information generating means on transmitter side) 41 Signal transmission / reception circuit (status information receiving means) 5 Power receiver 51 Parallel resonance circuit 511 Power receiving coil 512 Capacitor 54 Voltage status signal generator (status on receiver side) Information generation means) 55 Signal transmission / reception circuit (Status information transmission means) 56 Stimulation generation circuit (Stimulation generation means) DRV Power transmission permission signal CTL Control signal STM Stimulation output DAT PWM control signal (pulse width modulated AC generation signal) ENA Write Signal AST current Status signal (status information) VST voltage status signal (status information)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication location H02M 7/21 8726-5H H02M 7/21 Z (71) Applicant 392013648 Matsuki Hidetoshi Taishiro, Sendai City, Miyagi Prefecture (72) Inventor Kotaro Sato 5-7-1 Shiba, Minato-ku, Tokyo Within NEC Corporation

Claims (8)

[Claims] 1. A magnetic coupling between a power transmitting coil on a power transmitter side and a power receiving coil on a power receiver side allows the power transmitter on the primary side to contact the power receiver on the secondary side in a non-contact manner. In a power transmission device that transmits power, a status information generating unit that detects a state of power consumption on the secondary side and generates status information related to the power consumption, based on the status information generated by the status information generating unit And a power control unit for controlling an amount of power supplied to the power receiver. 2. A magnetic coupling between a power transmitting coil on a power transmitter side and a power receiving coil on a power receiver side allows the primary side power transmitter to contact the secondary side power receiver in a non-contact manner. In a power transmission device for transmitting power, the power receiver detects a state of power consumption on a secondary side and generates status information related to the power consumption. Status information transmitting means for wirelessly transmitting the status information generated by the information generating means to the power transmitter, and the power transmitter transmits the status transmitted from the status information transmitting means. Status information receiving means for receiving information wirelessly, based on the status information input via the status information receiving means, Serial power transmission apparatus characterized by comprising a power control means for controlling the amount of power supplied to the power receiver. 3. The power transmitter on the primary side and the power receiver on the secondary side by magnetic coupling between a power transmission coil provided in the power transmitter and a power reception coil provided in the power receiver. In a power transmission device that transmits power in a non-contact manner, the power receiver detects a state of power consumption on the secondary side and generates status information related to the power consumption, and receiver-side status information generation means, Status information transmitting means for wirelessly transmitting the status information generated by the receiver-side status information generating means to the power transmitter, and the power transmitter transmits the status information from the status information transmitting means. Status information receiving means for wirelessly receiving the received status information, and detecting the state of the current flowing through the power transmission coil to detect the current Transmitter-side status information generating means for generating status information relating to the status information input to the power receiver via the status information receiving means or from the transmitter-side status information generating means. A power control unit for controlling the amount of power to be transmitted. 4. The receiver-side status information generating means, when the secondary-side power supply voltage is lower than a preset reference voltage, generates status information indicating that power supply is insufficient. The power transmission device according to claim 2 or 3, wherein 5. The receiver status information generating means generates status information indicating that power supply is insufficient when the secondary power supply voltage is lower than a first reference voltage set in advance. 4. The method according to claim 2, wherein when the power supply voltage on the secondary side is higher than a second reference voltage set in advance, status information indicating that the supplied power is excessive is generated. Power transmission device. 6. The transmitter-side status information generating means generates status information indicating that the coil current amount is excessive when the amount of current flowing through the power transmission coil is larger than a preset reference value. The power transmission device according to claim 3, wherein 7. The power control means, based on the status information input via the status information receiving means or from the transmitter side status information generating means,
A pulse width modulated AC generation signal is generated and output to the power transmission coil driving means, and the power transmission coil driving means drives the power transmission coil based on the input AC generation signal. The power transmission device according to claim 2, 3, 4, 5, or 6, wherein 8. The electric power according to claim 2, wherein the electric power receiver is provided with a stimulus generating means for electrically stimulating a muscle or a nerve. Transmission equipment.