• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The present invention relates to a particularly advantageous, process technology stable, simple in construction and energy-saving device for generating a magnetic field of alternating polarity by means of a current-carrying coil (10) for demagnetizing ferromagnetic materials. About power switch (23, 24), the coil (10) is energized.
    公开号:CH713865A2
    申请号:CH00750/17
    申请日:2017-06-09
    公开日:2018-12-14
    发明作者:Meyer Urs；Maurer Albert
    申请人:Maurer Albert；
    IPC主号:
    专利说明:

    DESCRIPTION [0001] Demagnetizing ferromagnetic materials uses magnetic fields of alternating polarity with degressive amplitude. These magnetic fields are generated by conductor coils, hereinafter referred to as coils, through which an electric current flows according to the desired strength of the magnetic field. The degressive amplitude of the magnetic field is generated by suitable control of the current. This creates a temporally variable magnetic field to which the body to be demagnetized is exposed. Alternatively, a temporally constant, the polarity continues changing magnetic field is used, the demagnetizing body is moved from the zone of maximum field strength out into the field-free environment.
    The present invention relates to a particularly advantageous, process technology stable, simple in construction and energy-saving device for generating a magnetic field by means of a current-carrying coil.
    Fig. 1 shows schematically a system of known type for feeding a magnetic coil with a fixed frequency and variable voltage.
    Fig. 2 shows schematically the supply of a magnetic coil with a voltage source in a serial resonant circuit.
    Fig. 3 shows schematically the supply of a magnetic coil with a pulsed switched capacitor in a parallel resonant circuit.
    Fig. 4 shows the circuit for feeding a magnetic coil in the resonant frequency with bipolar feed.
    Fig. 5 shows the circuit for automatic control in the resonant frequency.
    Fig. 6 shows the circuit for feeding a magnetic coil in the resonant frequency with unipolar supply, Ma gnetspule with center tap.
    Fig. 7 shows the circuit for feeding a magnetic coil in the resonant frequency with unipolar supply, via a bridge circuit for the switching elements.
    A known device for generating a magnetic field, as it is used for demagnetizing ferromagnetic material is shown schematically in Fig. 1. The mains voltage 1 is fed to a rectifier 2, which feeds a DC intermediate circuit 3. A power amplifier 4 generates the voltage 9 for feeding the coil 10. The power amplifier, a setpoint signal 8 is supplied, which comes in an oscillator circuit 7. This generates a sinusoidal signal of fixed frequency and adjustable amplitude. The envelope with adjustable This system is identical to a frequency converter according to known technology. It is already functional for demagnetization with temporally constant magnetic field of predetermined frequency and amplitude. In order to demagnetize with a time-variable magnetic field, a sinusoidal setpoint signal 8 for the voltage 9 is supplied to the power amplifier 4. This setpoint signal 8 is generated in an oscillator circuit 7. The amplitude of the setpoint signal 8 follows in pulses over the course of time of an envelope which is generated in the controller 5 as an amplitude desired value 6.
    Such a system can be implemented with an industrial frequency converter or inverter for drives with induction motors by a purpose-adapted control is attached.
    The disadvantages of this solution are on the one hand in the lack of process control, given by the according to the charging of the coil different inductance. The current flowing through the coil and the magnetic field generated thereby are determined by the applied frequency and voltage only inaccurate. But even more important is the reactive power demand of such a circuit. The power unit must supply this reactive current, and thus be designed for the apparent power of the coil. This is expressed by correspondingly large losses in the circuit. Finally, commercially available frequency converters are generally designed to provide a three-phase voltage as required by industrial motors. However, only one phase is used to supply a demagnetizing coil. Commercially available frequency converters are equipped for this purpose in a superfluous manner and unnecessarily complex in structure. They are used for demagnetization purposes, as is apparent from the publication "Demagnetization of large-scale objects as a process preparation before welding process", pages 3 and 9, published by Maurer Magnetic AG.
    The associated with the reactive power demand of the coil disadvantage of bad exploited circuit can be solved by this reactive current is generated by a capacitor. A corresponding basic configuration is shown in FIG. 2. A capacitor 11 is arranged in series with the coil 10 and thus forms a series resonant circuit. A voltage source 12, usually a frequency converter, fed by a DC intermediate circuit 3, supplies the operating voltage in the Serieschwingkreis. It is in turn inserted into the series connection of coil 10 and capacitor 11. The resulting current 13 depends on the known manner from the vote of supply frequency and resonant frequency of the resonant circuit. This must be considered as a disadvantage, because this resonance frequency is dependent on the loading of the coil 10 with ferromagnetic material. This effect is exploited in a process described in CH698521. By tuning the feeding frequency on an edge of the resonant circuit, it is possible to the operating point in
    Dependence on the amount of ferromagnetic material targeted to move in the direction of the resonance point. This improves the efficiency of the whole device as the amount of ferromagnetic material increases.
    Such a solution requires a targeted deviation of the feeding frequency of the resonant frequency of the resonant circuit and causes a loss of efficiency of the entire circuit.
    In principle, it is also possible to operate the built-up from the coil 10 and the capacitor 11 resonant circuit as a parallel resonant circuit. This is shown in Fig. 3. A current source 14 fed by the DC intermediate circuit 3 charges the capacitor when the switch 16 is turned off. When the voltage 15 has reached its target value, the current source 14 turns off and the switch 16 is closed. The resonant circuit formed by the coil 10 and the capacitor 11 now oscillates in its resonant frequency. As a typical application of this circuit is the degaussing of color picture tubes for television sets, as described for example in US 4,599,673. This circuit concept, which is also described in EP 0 021 274, is used in various ways. However, its performance is not enough for demagnetizing industrial components and products made of modern steels. The fall in the current amplitude takes place in a free oscillating resonant circuit too fast for a qualitatively satisfactory demagnetization result. In EP 0 282 290 a circuit for demagnetizing television picture tubes is described, which slows down this decay by periodically connecting a second capacitor. As can be seen from this patent, this is associated with an asymmetry in the amplitude characteristic of the demagnetizing current. However, such an asymmetry precludes process reliability in the demagnetization process.
    The device described below has the concept that the resonant circuit described is not supplied with a source of AC or AC, but that its energy losses are covered by a circuit that acts as a negative resistance. Such a resonant circuit operates basically at the resonance point. The resonance frequency thus follows continuously and directly the currently present inductance of the coil. The influence of the amount of ferromagnetic material in the coil is compensated directly by adjusting the frequency. The circuit always works with the optimum efficiency. This also means the best possible utilization of the required components of the circuit and is an optimum in terms of effect in the demagnetization.
    Fig. 4 shows the structure of such a circuit. The mains voltage 1 is converted in a bipolar feed circuit 40 into a positive DC voltage 42 and a negative DC voltage 43 with a common center 41. This center is connected to a pole of the resonant circuit formed from coil 10 and capacitor 11. The other pole of the resonant circuit is connected to two power switches 23 and 24, which are shown here with a transistor symbol. The voltage at the oscillating circuit is measured at both poles as measured value 27 (actual value for the oscillating circuit voltage on the supply side) or 28 (actual value for the oscillating circuit voltage on the switch side). The current flowing in the resonant circuit is tapped with a shunt 21 as a current actual value signal 22. The N-circuit breaker 23 connects the oscillating circuit with the negative supply voltage 42, the P-circuit breaker 24 also with the positive supply voltage 43. The semiconductor elements used in the two line switches bipolar transistors, Darlington transistors, Insulated Gate bipolar transistors or field effect Be transistors. The control in the sense of switching on and off via the signals 25 and 26. The control circuit 20 generates these two signals 25 and 26 in accordance with the resonant circuit voltage resulting from the measured values 27 and 28, the resonant circuit current from the measured value 22, and the set value 6 for the amplitude of the resonant circuit voltage.
    The function of the control circuit 20 of FIG. 4 is shown in FIG. 5. A differential amplifier 30 determines from the measured values 27 and 28 an actual value signal 31 for the resonant circuit voltage 31. The threshold value switch 32 forms a digital signal 33 with the two values 1 for positive resonant circuit voltage and 0 for negative resonant circuit voltage. A threshold value switch 34 forms from the current actual value signal 22 a digital signal 35 with the two values 1 for positive current flow and 0 for negative current flow. A voltage regulator 37 forms from the desired amplitude value 6 and the actual value signal 31 a digital, clocked actuating signal 38. The switching logic 36 determines from the states of the signals 33, 35 and 38 the control signals 25 and 26 for the two power switches. This is done as follows: The P-power switch 24 is turned on when the tank circuit voltage exceeds the zero value in the positive direction (digital signal 33 goes from 0 to 1). It then follows the clock given by the signal 38 until it turns off at the zero crossing of the current in the negative direction (digital signal 35 goes from 1 to 0). The N-power switch 23 is turned on when the tank circuit voltage exceeds the zero value in the negative direction (digital signal 33 goes from 1 to 0). It then follows the clock given by the signal 38 until it turns off at the zero crossing of the current in the positive direction (digital signal 35 goes from 0 to 1). In this way, the losses in the resonant circuit are compensated by a phase-dependent, regulated metered power supply. The effect of the circuit corresponds to a negative resistance, which is arranged parallel to the resonant circuit. The resulting frequency of the oscillation corresponds to the natural resonant frequency, given by the values of inductance of the coil and capacitance of the capacitor. The amplitude of the resonant circuit voltage can be controlled with the amplitude setpoint 6.
    Fig. 6 shows the circuit for feeding a magnetic coil in the resonant frequency with unipolar supply, magnetic coil with center tap. The mains voltage 1 is converted in a feed circuit 44 into a DC voltage having a positive pole 45 and a negative pole 46. The positive pole 45 is connected to the center of the coil 51, which forms the resonant circuit with the capacitor 11. The two poles of the resonant circuit are each connected to one of the similar circuit breaker 52, which are shown here with a transistor symbol. The voltage at the resonant circuit is tapped at both poles as measured value 27 or 28 as the actual value. The current flowing in the resonant circuit is tapped with a shunt 21 as a current actual value signal 22. The two power switches 52 connect the resonant circuit to the negative pole 46 of the supply voltage. The semiconductor elements used in the two line switches may be bipolar transistors, Darlington transistors, insulated gate bipolar transistors or field effect transistors. The activation in the sense of switching on and off takes place via the signals 53, generated by the control circuit 50 in analogy to the mode of operation shown in FIG. The unipolar supply and the similarity of the two circuit breakers represent the particular advantages of this design.
    Fig. 7 shows the circuit for feeding a magnetic coil in the resonant frequency with unipolar supply and control via a bridge circuit. The mains voltage 1 is converted in a feed circuit 44 into a DC voltage having a positive pole 45 and a negative pole 46. This supply voltage is supplied to a known from frequency converters and servo amplifiers bridge circuit consisting of the circuit breakers 62, 63, 64, 65, the coil 10 and the capacitor 11 form the resonant circuit. The two poles of the resonant circuit are in the diagonal of said bridge circuit. The resonant circuit voltage is transmitted to the control circuit with the two voltage taps 61. The current flowing in the resonant circuit is tapped with a shunt 21 as a current actual value signal 22. The entire bridge circuit is preferably designed as an integrated module. The control in the sense of switching on and off of the individual bridge arms via the signals 66, 67, 68, 69 generated by the control circuit 60 in analogy to the shown in Fig. 5 mode of action. The use of a constructed as an integrated module power unit represents the particular advantage of this design.
    权利要求:
    Claims (10)
    [1]
    claims
    1. An apparatus for demagnetizing ferromagnetic materials, consisting of an inductance in the form of a magnetic coil and a capacitance, both together forming an electrical resonant circuit, and a circuit for supplying electrical energy, characterized in that the oscillating circuit of voltage and current prevailing in the resonant circuit selbsttätig and is built up and maintained exclusively in the resonant frequency.
    [2]
    2. Device according to 1, characterized in that the circuit for supplying electrical energy is controlled by the variables prevailing in the resonant circuit voltage and current in time,
    [3]
    3. Device according to 2, characterized in that the circuit for supplying electrical energy to the resonant circuit is regulated to a predetermined desired value of the AC voltage in the resonant circuit.
    [4]
    4. Device according to 2, characterized in that the circuit for supplying electrical energy to the resonant circuit is regulated to a predetermined desired value of the alternating current in the resonant circuit.
    [5]
    5. Device according to 1 or 2, characterized in that the supply of energy to the resonant circuit is effected by clocked connection of an external voltage source.
    [6]
    6. Device according to 1 or 2, characterized in that the supply of energy to the resonant circuit is effected by clocked connection of an external power source.
    [7]
    7. Device according to 5 or 6, characterized in that the energy supplying voltage source is switched alternately in two polarities.
    [8]
    8. Device according to 5 or 6, characterized in that the energy supplying circuit operates with a bipolar voltage source, wherein the two polarities are alternately switched by two switching elements.
    [9]
    9. Device according to 5 or 6, characterized in that the resonant circuit forming coil is provided with a center tap, wherein the energy supplying circuit operates with a monopolar voltage source and alternately feeds to the two end terminals of the coil.
    [10]
    10. Device according to 5 or 6, using a monopolar voltage source, characterized in that the energy supplying circuit is designed as a bridge circuit, so that the supplied current is alternately fed in both directions in the resonant circuit.
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    同族专利:
    公开号 | 公开日
    CH713865B1|2021-02-15|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    法律状态:
    2020-06-30| NV| New agent|Representative=s name: SCHNEIDER FELDMANN AG PATENT- UND MARKENANWAEL, CH |
    2020-10-15| PFA| Name/firm changed|Owner name: ALBERT MAURER, CH Free format text: FORMER OWNER: ALBERT MAURER, CH |
    优先权:
    申请号 | 申请日 | 专利标题
    CH00750/17A|CH713865B1|2017-06-09|2017-06-09|Device for demagnetizing ferromagnetic materials.|CH00750/17A| CH713865B1|2017-06-09|2017-06-09|Device for demagnetizing ferromagnetic materials.|
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