JP4939849B2 - Generator and power supply system - Google Patents

Description

  The technical field to which the present invention belongs is that of an auxiliary power source for supplying electricity to an implantable medical device. Implantable medical devices are usually operated with a primary battery, which is consumed with use. Even with a generator with low power generation capacity, supplying power continuously or semi-persistently suppresses further consumption of the temporarily consumed primary battery, and reduces the time until the primary power supply is completely consumed. It can be extended.

  Normal when the enzymes and hormones necessary for life activities cannot be supplied regularly or when needed due to diseases or organ diseases, or when the organs that should operate at a constant rhythm are disturbed by the electrical signals that move the organs May not work. Many of these illnesses and diseases are difficult to conceive, and there are an increasing number of treatment methods that can be substituted with artificial organs or signal generators. For example, the device that delivers insulin in a timely manner is an insulin pump, and it is the cardiac pacemaker that calibrates the arrhythmia. Such life support devices function independently so as not to be inconvenient for living a normal life, and implantable types have become widespread.

  Many of these artificial organs and signal generators require a power source, and in the case of an implantable type, they need mobility, so many batteries, particularly primary batteries, are used as a power source. When this device is implanted in the body, it is necessary to implant the device by incising the body and replacing the battery by performing the operation again just because the battery is exhausted. Given the heavy burden, it is not easy. However, the space that can be secured in the body is limited, and there is a limit in embedding a large, high-performance battery in the body. On the other hand, it is well known that high reliability is required for an implantable device for the above reason. It is also true that there is a phenomenon that the more the fail-safe mechanism is installed to increase the reliability, the more burden is placed on the power supply.

For this reason, an in-vivo electronic device is disclosed that combines a magnetic field generator that generates magnetic field fluctuations and a magnet that mechanically displaces, generates power in a non-contact manner, and supplies power to the in-vivo device (patent). Reference 1).
See JP-A-11-215802

  If the primary power supply is used, it is inevitable that it will be consumed. However, as a result of giving priority to function and performance in an implantable device, there is a limit to achieving power consumption using an element with low power consumption. In particular, when the patient is a young person, it is often the case that the patient survives for a long period of time, and it is difficult to continue to operate the device until the patient reaches the death stage without replacing the battery.

  On the other hand, there is a power supply with a secondary battery in the power generation mechanism, but in general, a self-supporting power generator is inefficient and cannot generate power unless the conditions necessary for power generation are met. It is strict to demand power generation type power and stable power supply. Since this implantable device has a risk of human life if it does not operate, it is not preferable as a medical practice to operate this device with only a power generation type power source.

  Further, the in-vivo electronic device described in Patent Document 1 cannot generate electric power by itself in the body, and must supply a magnetic field generated outside the body to a magnet or the like embedded in the body.

  The power generator of the present invention is a container, a magnet inside the container, and inside the container, with one end connected to the magnet, the other end connected to the container, and the magnet connected to the container And an elastic elastic body that is held in a hollow state, and a coil wound around the outside of the container.

  In the power generator of the present invention, the magnet moves in the container by the movement of the wearer.

  Moreover, the power supply system of this invention has these power generators, and has a secondary battery which stores the electric power generated by the power generator.

  The power generator of the present invention further includes a primary battery, and the secondary battery is used as an auxiliary power source for the primary battery. The primary battery is stable and can supply a relatively large current at any time, but has the disadvantage of being consumed. A secondary battery can supply a current though it is relatively small semipermanently if power generation conditions are met. Therefore, the current supplied from the secondary battery is preferentially used, and the insufficient current is compensated by the primary battery.

  By using a power source that combines a primary battery and a secondary battery equipped with a position and kinetic energy conversion generator as a power source for an implantable medical device, the period of time when the primary battery is consumed is extended. By reducing the frequency of battery replacement surgery, the patient's financial and physical burden can be reduced.

  In the present invention, an apparatus configuration was attempted by a method of changing the rotational motion to electricity for a generator-mounted secondary battery. High power generation efficiency was obtained in the exercise of the arm and the exercise of the foot. In other parts of the body, only low power generation was obtained. From this result, it was judged that the movement of the human body was not a circular movement, and at the same time the movement was assumed to be a linear movement, and a power generation mechanism that converts the linear movement into electricity was adopted.

  The primary battery is a commonly used lithium battery. An electromagnetic induction method using a combination of dual-station permanent magnets and coils was adopted as a power generation method to convert line motion to electricity.

  In this embodiment, the structure and function of an electromagnetic induction power generation device that converts linear motion into electricity and a secondary battery will be described. FIG. 1 is a schematic diagram for explaining the principle of a so-called hollow suspension generator in which a permanent magnet is suspended in a hollow state by a spring-like wire so that the permanent magnet can freely move. The permanent magnet 100 is fixed to the diagonal corner of the storage box 130 by four spring-like wires 110a, 110b, 110c, and 110d. The permanent magnet 100 is preferably made of a small material that emits strong magnetic field lines. In this embodiment, the permanent magnet 100 made of samarium cobalt is used. As the spring material suspenders 110a, 110b, 110c, and 110d for suspending the permanent magnet 100, a material used for a mainspring of a mechanical timepiece, in this embodiment, a spron material processed into a coil spring shape was used. The mainspring metal is one of the best materials to satisfy the reliability required for medical devices because of its high durability against repeated bending and stress. The storage box 130 is preferably made of a metal material that is hard to be magnetized. In this embodiment, a non-magnetized soft iron material is used as the material of the storage box 130. The storage box 130 has the effect of an iron core that increases the lines of magnetic force emitted from the permanent magnet 100, and higher power generation efficiency is obtained with a material that is less magnetized than a dielectric material. The spring material suspenders 110a, 110b, 110c, and 110d adjust the length and the spring constant so that the permanent magnet 100 does not hit the side wall of the storage box 130 as much as possible. In this embodiment, since the shape of the storage box 130 is a rectangular parallelepiped, in order to prevent the permanent magnet 100 from being destroyed by colliding with one wall, the wall in the X direction as shown in FIG. 4, as shown in FIG. The protective plates 120a, 120b, 120c, and 120d were attached to the four surfaces of the permanent magnet 100. The material of the protective plate is preferably a material that easily absorbs impact, and in this embodiment, a soft vinyl material was used.

  FIG. 2 is a schematic diagram showing an electric circuit of the generator, a secondary battery, and a voltage control circuit. An electric wire 210 serving as a power generation coil 200 is wound around the storage box 130. In the present embodiment, the power generating coil 200 uses an enameled wire and is wound twice in a single direction. The electromotive force generated in the power generating coil 200 is connected to the secondary battery 230 through the smoothing circuit 220 of the bridge diode because the direction of the current is determined by the direction of movement of the permanent magnet 100. As a secondary battery 230, a nickel-hydrogen battery or a nickel-cadmium battery has been studied. However, if charging and discharging are repeated, the service life becomes extremely short. Therefore, in this embodiment, an electric double layer capacitor having a large charge capacity is used. Using. However, since a small electric double layer capacitor has a low absolute withstand voltage, a voltage controller (VR) 240 with a variable voltage control mechanism is mounted in order to avoid a surge voltage due to excessive power generation. The voltage controller 240 has both the function of keeping the output voltage from the secondary battery 230 constant and the two effects of preventing the surge voltage and keeping the voltage not exceeding the absolute withstand voltage of the secondary battery 230. As the standard of the electric double layer capacitor used in this example, a capacitor having a capacity of 0.47 F (Farad) and an absolute withstand voltage of 5.5 V was used. Accordingly, the control voltage range of the voltage controller 230 is set to 0 to 5V.

  FIG. 3 is a voltage diagram showing the absolute withstand voltage of the electric double layer capacitor, the set voltage of the voltage controller, and the generated voltage. It can be seen that the generated voltage value does not exceed the absolute withstand voltage value of the electric double layer capacitor 230 by the voltage drop function of the voltage controller 240. An electrolytic capacitor 250 (see FIG. 2) having 500 μF and a withstand voltage of 6 V was connected to the outlet of the voltage controller 240 to obtain a load buffer.

  Next, conditions for the power generator to generate power efficiently will be described. When the power generator 400 is embedded in the body, particularly in the human torso 410 together with the implantable medical device, power generation efficiency can be improved by embedding in the direction shown in FIG. The basics of human behavior are walking and standing and sitting. The walking motion is obtained by adding a vertical motion in the Z direction to a motion close to a constant velocity straight line in the Y direction shown in FIG.

  FIG. 5 is a schematic diagram showing the vertical movement and the position of the permanent magnet when a human walks. The movement necessary for power generation is movement accompanied by acceleration. Since walking motion and standing and sitting motion are acceleration motions in the Z direction, it is assumed that motions with acceleration among human motions often move in the Z direction. Must be maximized. The permanent magnet 100 is held hollow by spring-like suspenders 110a to 110d. However, since the permanent magnet 100 moves differently from the storage box 130 embedded in the body due to its inertia, the magnetic flux density passing through the power generating coil 200 is low. Change. When the magnetic flux density changes, a current flows through the power generation coil 210 and power generation is performed. Similarly, the standing and sitting movement is a vertical movement in the Z direction, and thus power generation occurs. However, since the movement is not continuous, the power generation efficiency is low. The Y direction shown in FIG. 4 is the traveling direction when a person walks, that is, the forward direction. Walking is accompanied by a slight acceleration motion in the Y direction, but the difference is large compared to the Z direction as in the X direction in FIG.

  Therefore, the maximum power generation efficiency can be obtained by embedding the power generator 400 in the body in the direction shown in FIG.

  In general, the secondary power supply is often used as an auxiliary power supply for the primary power supply, but here the power supplied by the secondary power supply is usually used to minimize the consumption of the primary power supply. A method of using the primary power supply only when the electricity required by the power supply cannot be supplied will be described.

  FIG. 6 shows a minimum necessary circuit for carrying out this method. First, the voltage required in the load portion is applied to the set voltage of the voltage control element (VR) 602. When sufficient electricity is stored in the electric double layer capacitor 604 that is a secondary battery in the secondary power supply 600, that is, when the voltage indicated by the electric double layer capacitor 604 exceeds the control voltage, the backflow prevention diode 610 Power is supplied to the load through. At point A in FIG. 6, the same voltage as the control voltage appears. Therefore, at point C, which is the output point of the comparator 620, the comparator 620 obtains power from the primary power source 630. The same voltage as the power supply 630 appears. Since the voltage appearing at the point C is supplied to the power transistor 640 via the inverter 620, the voltage is 0V at the output point D of the inverter 650. Therefore, the power transistor 640 does not operate, and power supply from the primary power supply 630 is not performed.

  However, when the voltage indicated by the electric double layer capacitor 604 is lower than the control voltage, the voltage does not appear at the point A in FIG. 6 and becomes 0V at the point A. Therefore, the voltage at the point C is 0V. It becomes. Since the voltage at the point C is 0V, at the point D which is the output point of the inverter 650, the voltage is the same as the primary power source 630, the power transistor 640 is activated, and the current of the primary power source 630 to the point B Is supplied. However, since there is a backflow prevention diode 610 on the secondary power source side at point B, the current of the primary power source 630 is supplied only to the load side.

  Therefore, by using this circuit, a circuit that uses the secondary power source 604 preferentially and uses the primary power source 630 only when the secondary power source 604 is exhausted can be realized.

  Although this invention was developed as a power source for an implantable medical device, it can be used outside the medical field by replacing the power generator with another power generation method.

It is a figure which shows the principle of a hollow fishing power generator, and a protection board, FIG. 1 (a) is a front view, FIG.1 (b) is a three-dimensional view, FIG.1 (c) is a three-dimensional view which shows the attachment state of a protection board. The figure which shows the shape and smoothing circuit of the coil for power generation Voltage diagram showing how the overvoltage protection circuit operates Schematic diagram showing the direction of movement of the permanent magnet Schematic diagram showing walking movement and position displacement Circuit diagram using primary power supply as auxiliary power supply for secondary power supply

Explanation of symbols

100 Magnet 110a, 110b, 110c, 110d Wire 120a, 120b Guard plate 130 Storage box 200 Power generation coil 210 Electric wire 230, 604 Secondary battery 400 Generator

Claims (4)

A container,
A magnet inside the container;
Inside the container, one end is connected to the magnet, and the other end is connected to a pair of diagonal corners on the inner top surface of the container and a pair of diagonal corners on the bottom surface inside the container. A plurality of elastic elastic bodies that hold the magnet in a suspended state in the container,
A coil wound around the outside of the container;
A generator consisting of   The power generator according to claim 1, wherein the magnet moves in the container by a movement of a wearer.   A power supply system comprising: the power generator according to claim 1 or 2; and a secondary battery that stores power generated by the power generator.   The power supply system according to claim 3, further comprising a primary battery, wherein the secondary battery is used as an auxiliary power source for the primary battery.

Images