JP3661395B2 - Power generator and electric washing machine using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a power generation device such as a motor or a linear motor used for home or industry, and an electric washing machine using the power generation device.
[0002]
[Prior art]
  Hereinafter, a conventional power generation device will be described with reference to the drawings. FIG. 11 is a circuit diagram showing a configuration of a conventional power generator. In FIG. 11, the stator which comprises the 1st object 1 and the rotor which comprises the 2nd object 2 rotatably provided inside the 1st object 1 are provided.
[0003]
  The first object 1 includes a three-phase winding 3 including a winding 3a, a winding 3b, and a winding 3c wound in three phases on an iron core in which silicon steel plates or the like are laminated, a hall IC 4a, a hall IC 4b, and a hall And position detecting means 4 constituted by an IC 4c. The second object 2 is provided with a two-pole permanent magnet 5. Reference numeral 6 denotes an inverter circuit that switches or cuts off the input / output of the current flowing through the three-phase winding 3, and corresponds to the inverter circuit 6a corresponding to the winding 3a, the inverter circuit 6b corresponding to the winding 3b, and the winding 3c. And an inverter circuit 6c. The inverter circuit 6a includes a series circuit of a first switching element 7a and a second switching element 8a, and a driver 9a that opens and closes the first switching element 7a and the second switching element 8a. . The common connection point of the first switching element 7a and the second switching element 8a is connected to the winding 3a. The driver 9a includes a first drive circuit 10a that opens and closes the first switching element 7a and a second drive circuit 11a that opens and closes the second switching element 8a. Reference numeral 12a denotes a second DC power source that supplies power to the second drive circuit 11a, and reference numeral 13a denotes a third DC power source that supplies power to the first drive circuit 10a.
[0004]
  Although not shown, the configurations of the inverter circuit 6b and the inverter circuit 6c are the same as those of the inverter circuit 6a. The inverter circuit 6b includes a series circuit of a first switching element 7b and a second switching element 8b. And a driver 9b including a first drive circuit 10b and a second drive circuit 11b, and a second DC power supply 12b and a third DC power supply 13b are connected to the inverter circuit 6c. A switching circuit 7c and a second switching element 8c, and a driver 9c including a first driving circuit 10c and a second driving circuit 11c, and a second DC power supply 12c and a third DC A power source 13c is connected.
[0005]
  Reference numeral 14 denotes a first DC power source for supplying current to the three-phase winding 3 via the inverter 6.
[0006]
  Reference numeral 15 denotes a three-phase distribution circuit that generates timing for energizing the windings 3a to 3c. The signal is input from the position detection means 4 and the signals a to f are output by logical expressions. Here, the signal a is a signal for opening and closing the first switching element 7a of the inverter circuit 6a, and the signal b is a signal for opening and closing the second switching element 8a. The same applies to the signals c and d for the inverter circuit 6b and the signals e and f for the inverter circuit 6c. Reference numerals 16a, 16b and 16c are AND circuits. The AND circuit 16a receives the signal a, the signal b, and the PWM signal from the PWM circuit 17, outputs a logical product of the signal a and the PWM signal to the first drive circuit 10a, and outputs the signal b as it is to the second circuit. Output to the drive circuit 11a. The same applies to the AND circuit 16b and the AND circuit 16c. The PWM circuit 17 includes an oscillation circuit 18 that outputs a triangular wave voltage signal and a comparator 19.
[0007]
  The operation in the above configuration will be described. The position detection means 4 detects the relative rotation angle of the second object 2 with respect to the first object 1, and the three-phase distribution circuit 15 corresponds to the rotation angle and includes three first switching elements. The target to be turned on is determined among 7a to 7c and the three second switching elements 8a to 8c, and the corresponding signals a to f are set to HIGH and output to the AND circuits 16a to 16c. The AND circuit 16a outputs a logical product with the PWM signal to the first drive circuit 10a if the signal a is HIGH, and outputs it to the second drive circuit 11a as it is if the signal b is HIGH. The same applies to the AND circuit 16b and the AND circuit 16c. The first drive circuit 10a that receives a logical product with the PWM signal and the second drive circuit 11a that receives a HIGH signal b output an output of about 15V with respect to the HIGH to the first switching element 7a. The second switching element 8a is applied and turned on. The same applies to the first drive circuits 10b to 10c and the second drive circuits 11b to 11c.
[0008]
  At this time, the third DC power supply 13a and the second DC power supply 12a operate by supplying power to the first drive circuit 10a and the second drive circuit 11a, respectively. The same applies to the third DC power supplies 13b to 13c and the second DC power supplies 12b to 12c.
[0009]
  By the above operation, the current corresponding to the rotation angle of the second object 2 detected by the position detection means 4 is supplied from the first DC power source 14 to the windings 3a to 3c. As a result, the second object 2 Torque is generated and rotated to extract power.
[0010]
  Here, the PWM circuit 17 acts to adjust the voltage of the first DC power supply 14 to an arbitrary value equal to or less than 100%, and operates the variable resistor 20 to adjust the output voltage of the bias power supply 21. As a result, the voltage at the point g in the figure changes, and the comparator 19 outputs a PWM signal in which HIGH and LOW are switched at the intersection of the triangular wave voltage output from the oscillation circuit 18 and the voltage at the point g. When the voltage at the point g is increased, the ratio of the HIGH period of the PWM signal output from the comparator 19 is increased. Since the AND circuit 16a outputs a logical product of the PWM signal of the PWM circuit 17 and the signal a, the period during which the signal a is turned on for the first switching element 7a is increased or decreased within a range of 100% or less by PWM control. The value of the current flowing through the line 3a is controlled. The same applies to the AND circuit 16b and the AND circuit 16c.
[0011]
  FIG. 12 is a circuit diagram showing in detail the configuration of the first drive circuit 10a and the second drive circuit 11a in the power generation apparatus shown in FIG. The same applies to the other first drive circuits 10b to 10c and the second drive circuits 11b to 11c.
[0012]
  In FIG. 12, the first DC power supply 14 includes a commercial power supply 22 of 100 V 60 Hz, a rectifier bridge 23, a choke coil 24, and a smoothing capacitor 25. The first drive circuit 10a is composed of a photocoupler 26 composed of a light emitting diode and a phototransistor, an NPN transistor 27 and an NPN transistor 28, a PNP transistor 29, a resistor 30, and a resistor 31, and via a resistor 32. It is connected to the output of the AND circuit 16a. The second drive circuit 11a includes an NPN transistor 33, a PNP transistor 34, a resistor 35, and a resistor 36, and is directly connected to the output of the AND circuit 16a.
[0013]
  The switching power source 37 is a power source realizing the second DC power sources 12a to 12c and the third DC power sources 13a to 13c, and includes an NPN transistor 38, a drive circuit 39, a transformer 40, a snubber 41, a diode 42, The diode 43, the diode 44, the diode 45, the diode 46, the electrolytic capacitor 47, the electrolytic capacitor 48, the electrolytic capacitor 49, and the electrolytic capacitor 50 are configured. The snubber 41 is configured by a resistor 51 and a capacitor 52. The output from the electrolytic capacitor 47 acts as the third DC power source 13a, and the output from the electrolytic capacitor 50 acts as the second DC power source 12a. Further, although connection is not shown for the respective terminals j, k, l, and m, j and k are used as the third DC power source 13b of the inverter circuit 6b, and l and m are the third terminals of the inverter circuit 6c. Used as a DC power source 13c. The output from the electrolytic capacitor 50 is also used as the second DC power sources 12b to 12c.
[0014]
  As described above, the DC power supply for the second drive circuits 11a to 11c, that is, the second DC power supplies 12a to 12c can be made common, but the second drive circuits 10a to 10c can be shared. The third DC power supplies 13a to 13c may be a common DC power supply because the commonly used first switching elements 7a to 7c are N-channel IGBTs (MOSFETs) or NPN power transistors. As a result, three third DC power supplies 13a to 13c are required, and the configuration of the commonly used three-phase six-stone inverter requires at least four DC outputs.
[0015]
[Problems to be solved by the invention]
  In such a conventional power generation device, the third drive circuit 10a to 10c for opening and closing the first switching elements 7a to 7c connected to the plus side of the first DC power source 14 is provided. The DC power supplies 13a to 13c are electrically insulated from the second drive circuits 11a to 11c and other circuit parts, respectively. In general, this type of inverter uses a three-phase six-stone structure. Therefore, since the power source capable of outputting at least four independent direct currents by the switching power source 37 or the like is used, the power source is large, heavy, and expensive.
[0016]
  SUMMARY OF THE INVENTION The present invention solves the above-described problems, and a power generation device that operates stably at a low cost, at a low cost, by simplifying the configuration of a DC power source that operates the first drive circuit and the second drive circuit in each inverter circuit. An object is to provide an electric washing machine using the same.
[0017]
[Means for Solving the Problems]
  In order to achieve the above object, the power generation device of the present invention provides:A PWM circuit that PWM-controls the conduction period of the first switching element in each inverter circuit; and a duty limiting circuit that limits the duty in the PWM control, the dutyThe limit circuit changes the upper limit value that limits the duty according to the operating frequency of the inverter,The terminal voltage of the bootstrap capacitor is maintained so that the first driving circuit can operate.Is.
[0018]
  According to the present invention, a DC power source for operating the first drive circuit can be stably operated while being constituted only by a bootstrap capacitor, and a light-weight and low-cost power generation device can be realized.In addition, it is possible to realize a power generation device that can obtain sufficient torque and output at high speeds, and can obtain sufficient torque and output within a range in which a terminal voltage necessary for the bootstrap capacitor can be obtained even at low speeds.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
  Claim 1The invention described in 1 is a first object having at least one winding, a second object that is movably provided relative to the first object, a first DC power source, A series circuit connected to a first DC power source, in which a first switching element and a second switching element are connected in series, a first drive circuit for opening and closing the first switching element, and the second switching element A second drive circuit that opens and closes the second drive circuit, a second DC power source that operates the second drive circuit, and a charging current supplied from the second DC power source when the second switching element is turned on. An inverter provided with a bootstrap capacitor serving as a DC power source for operating one drive circuit for each of the windings; and an induction circuit for the first switching element in each inverter circuit. A PWM circuit that performs PWM control of a period; and a duty limit circuit that limits a duty in the PWM control, wherein the duty limit circuit changes an upper limit value that limits the duty in accordance with an operating frequency of the inverter, and the bootstrap The terminal voltage of the capacitor is maintained so that the first drive circuit can operate.
[0020]
  TheThe root strap capacitor is a capacitor that acts as a DC power source for the first drive circuit that opens and closes the first switching element, and can be realized by an electrolytic capacitor having a large electric capacity. Further, the second DC power source that operates the second drive circuit that drives the second switching element to open and close can be realized with a simple configuration that rectifies and smoothes the commercial power source, for example. Further, by connecting the bootstrap capacitor to the second DC power source through a diode and a resistor, a charging current is supplied during a period in which the second switching element is conductive. The diode is provided for preventing backflow, and the resistor is provided for suppressing an excessive charging current. The duty limiting circuit is a means for limiting the duty in PWM control. In the normal means, the voltage for increasing the duty corresponding to the operating frequency of the inverter is limited by a Zener diode or the like. The operating frequency of the inverter is detected by using a signal from a position detection means such as a Hall IC, but corresponds to the rotational speed in the rotational motion.
[0021]
As a result, the DC power source for operating the first drive circuit can be stably operated with only the bootstrap capacitor, and a light-weight and low-cost power generation device can be realized. In addition, it is possible to realize a power generation device that can obtain sufficient torque and output at high speeds, and can obtain sufficient torque and output within a range in which a terminal voltage necessary for the bootstrap capacitor can be obtained even at low speeds.
[0022]
  Claim 2In the invention described in claim 1, in the invention described in claim 1, the second object includes a permanent magnet, and the first drive circuit and the second drive circuit are provided from position detecting means for detecting the position of the permanent magnet. The first switching element and the second switching element are driven to open and close based on the signal. The permanent magnet is fixed to the second object, and the permanent magnet A mechanical force is generated by the field provided by the permanent magnet and the winding current in the first object, and a highly efficient power generating device can be realized.
[0023]
  Claim 3The invention according to claim 1 is an electric washing machine including the power generation device according to claim 1 or 2, and can realize a lightweight, low-cost, high-efficiency and highly reliable electric washing machine.
[0024]
【Example】
  Example 1
  Hereinafter, a first embodiment of the power generation device of the present invention will be described with reference to the drawings.To do.FIG. 1 is a circuit diagram showing a configuration of the present embodiment, and FIG. 2 is a circuit diagram showing configurations of a first drive circuit and a second drive circuit and their peripherals in the present embodiment. The same constituent elements as those in the conventional example shown in FIGS. 11 and 12 are given the same reference numerals, and detailed description thereof is omitted.
[0025]
  The main difference between the present embodiment and the conventional example is that the bootstrap capacitors 53a to 53c for supplying power to the first drive circuits 10a to 10c, respectively, instead of the third DC power supplies 13a to 13c in the conventional example. Is provided, and the duty limiting circuit 54 is provided. By limiting the duty, the terminal voltages of the bootstrap capacitors 53a to 53c are sufficient to drive the first driving circuits 10a to 10c. It is in keeping with.
[0026]
  In FIG. 1, a second DC power supply 12a supplies power to the second drive circuit 11a. A bootstrap capacitor 53a is provided for the first drive circuit 10a, and a resistor 55 and a diode 56 are connected in series. To the second DC power supply 12a. In FIG. 1, for the sake of simplicity, only the configuration of one-phase inverter circuit 6a of the three phases is shown, but the other two phases are configured in exactly the same manner, and each of them has a second DC power source. It is assumed that 12a is connected in common. The second DC power supply 12a is not shared and may be provided for each inverter circuit. However, in this embodiment, only one second DC power supply 12a is used. The bootstrap capacitor 53a is charged from the second DC power supply 12a through the resistor 55 and the diode 56 during a period in which the second switching element 8a is in a conductive state, and functions as a DC power supply for the first drive circuit 10a.
[0027]
  The output of the PWM circuit 17 is input to the AND circuit 16a, the AND circuit 16b, and the AND circuit 16c, and the PWM signal is output to the first drive circuits 10a to 10c at about 15 KHz equal to the oscillation frequency of the oscillation circuit 18, respectively. However, the duty limiting circuit 54 includes a resistor 57 and a Zener diode 58. By limiting the voltage value input to the PWM circuit 17 to a predetermined value or less, the duty limiting circuit 54 is controlled by the signals a, c, and e. The ratio of the period during which the one switching element 7a, the first switching element 7b, and the first switching element 7c are turned on, that is, the duty is limited to about 30% or less.
[0028]
  The speed detection circuit 59 detects the rotation speed of the second object 2 based on the signal from the position detection means 4 and outputs an analog voltage corresponding to the detected rotation speed. Further, the difference between the DC voltage value input from the error amplifier 60 and the reference voltage source 61 and the output voltage of the speed detection circuit 59 is amplified and output to the PWM circuit 17 via the duty limiting circuit 54. As a result, the power generation apparatus of this embodiment performs a feedback operation so that the input voltage difference of the error amplifier 60 is eliminated, and the rotational speed is controlled to be substantially constant.
[0029]
  FIG. 2 is a circuit diagram showing the configuration of the first drive circuit 10a and the second drive circuit 11a and their peripherals in the present embodiment. Note that the same components as those in the conventional example are assigned the same reference numerals and detailed description thereof is omitted.
[0030]
  In FIG. 2, the configuration of the first DC power supply 14 and the second drive circuit 11a is the same as that of the conventional example. The configuration of the first drive circuit 10a is almost the same as that of the conventional example. However, the signal from the AND circuit 16a is a withstand voltage by the NPN transistor 62, the resistor 63, and the resistor 64 instead of the photocoupler 26 in the conventional example. Input through the circuit. The second DC power supply 12a is simply configured by the transformer 65, the rectifier bridge 66, the constant voltage IC 67, the electrolytic capacitor 68, and the electrolytic capacitor 69. As described above, the output from the electrolytic capacitor 69 is the second. It is shared by the drive circuit 11b and the second drive circuit 11c. In the present embodiment, the first switching element 7a and the second switching element 8a are constituted by a diode and an IGBT provided for reverse conduction. The same applies to the inverter circuit 6b and the inverter circuit 6c.
[0031]
  The operation in the above configuration will be described. The second drive circuits 11a to 11c operate by being supplied with a common power supply from the second DC power supply 12a. The bootstrap capacitor 53a is charged from the second DC power supply 12a through the diode 56 and the resistor 55 during the period when the second switching element 8a is ON, and operates as a DC power supply for the first drive circuit 10a. . In this case, the terminal voltage of the bootstrap capacitor 53a is decreased by discharging by operating the first switching element 7a, and particularly when the power transistor having a large driving current is used as the first switching element 7a. Becomes larger. Therefore, in order to suppress the voltage drop, the ratio of the period during which the first switching element 7a is turned on, that is, the duty may be limited. In the present embodiment, the duty limiting circuit 54 limits the ratio of the period during which the first switching element 7a is turned on to suppress the voltage drop of the bootstrap capacitor 53a. The terminal voltage of the strap capacitor 53a is ensured to be equal to or higher than the voltage at which the first drive circuit 10a operates normally. The same applies to the bootstrap capacitors 53b to 53c.
[0032]
  As described above, generally used first switching elements 7a to 7c are N-channel IGBTs (MOSFETs), NPN power transistors that increase the current consumption of the first drive circuits 10a to 10c, and the like. However, all the power sources of the first drive circuits 10a to 10c can be constituted by the second DC power source 12a and the bootstrap capacitors 53a to 53c, thereby realizing the simplification of the device and the cost reduction. Can do.
[0033]
  As described above, according to the present embodiment, the first drive circuits 10a to 10c are each provided with the bootstrap capacitors 53a to 53c as a DC power supply, respectively supplied with a charging current from the second DC power supply 12a, and the first The first drive circuits 10a to 10c are driven by securing the terminal voltages of the bootstrap capacitors 53a to 53c by limiting the duty related to the conduction period of the switching elements 7a to 7c to a predetermined value or less. Therefore, it is possible to simplify the power supply for the operation and to operate the power supply reliably.
[0034]
  In the present embodiment, the second object 2 includes the permanent magnet 5, but there is no particular limitation on the configuration thereof. For example, the configuration including the short-circuited winding or the excitation winding includes the first object 2. A configuration in which a DC power source is connected, a configuration using a ferromagnetic material having magnetic unevenness, or a configuration using a magnetic material having a large magnetic hysteresis may be used. Also, the configuration of the winding and the inverter circuit is not limited to three phases, but may be a single-phase four-stone system or the number of phases such as 2, 4, 5, 6, 7. Needless to say.
[0035]
  (Example 2)
  Hereinafter, Example 2 of the power generation device of the present invention will be described with reference to the drawings.To do.FIG. 3 is a circuit diagram showing the configuration of this embodiment. In addition, the same number is attached | subjected to the same component as Example 1, and detailed description is abbreviate | omitted. The present embodiment is different from the first embodiment in that the duty limiting circuit 54 limits the duty only when the operating frequency of the inverter 6 is equal to or lower than a predetermined value. This is intended to prevent the torque and output from being reduced at high speeds due to duty limitations.
[0036]
  In FIG. 3, the duty limiting circuit 54 includes a voltage selector 70, a reference voltage source 71, a reference voltage source 72, and a frequency determination circuit 73. In this embodiment, the reference voltage source 71 uses a voltage source that outputs a voltage of 7V, the reference voltage source 72 uses a voltage source that outputs a voltage of 14V, and the frequency determination circuit 73 uses the Hall ICs 4a to 4c in the position detection means 4. The frequency of the signal input from one of the two is detected, and when it is lower than 24 Hz, it is connected to the α terminal side of the voltage selector 70, and when it is 24 Hz or more, the β terminal side of the voltage selector 70 is connected To connect to. The oscillation circuit 18 outputs a triangular wave voltage of about 15 KHz. However, in this embodiment, the peak value is 9.5 V, so that the input voltage of the PWM circuit 17 exceeds 9.5 V. The output of the PWM circuit 17 has a duty of 100%, that is, it is HIGH at all times.
[0037]
  The operation in the above configuration will be described. FIG. 4 is a characteristic diagram showing the operation of the duty limiting circuit 54 shown in FIG. In FIG. 4, the horizontal axis indicates the frequency f of the signal from the Hall IC 4b, and the vertical axis indicates the duty of the output signal of the PWM circuit 17, that is, the ratio of the HIGH period. As shown in FIG. 4, when the voltage of 7 <V is output from the duty limiting circuit 54 under the condition of f <24 Hz, the duty is 80%, and the voltage of 14V is output from the duty limiting circuit 54 under the condition of f ≧ 24 Hz. The duty is 100%, that is, it is HIGH at the same time.
[0038]
  With the above operation, the duty is forcibly limited to 80% during low-speed rotation, so that a sufficient charging current is supplied to the bootstrap capacitors 53a to 53c, and the first switching elements 7a to 7c are supplied. Can be reliably turned on. In this embodiment, the second object 2 is configured to have two poles with respect to the windings 3a to 3c, so that the bootstrap capacitor is driven by PWM whose duty is limited to 80% at a rotational speed lower than 1440 rpm. 53a to 53c are charged. Further, the duty is not limited under the condition of 1440 rpm or more, and therefore, the bootstrap capacitors 53a to 53c are charged at the fundamental frequency of the motor, that is, the signal frequency of the Hall IC 4b, while ensuring sufficient torque and acceleration. As a result, a sufficient DC voltage is supplied to the first drive circuits 10a to 10c under any rotation speed condition. In addition, since the duty is not limited in the high speed range, sufficient torque and output can be obtained.
[0039]
  As described above, according to the present embodiment, the duty is limited only in the low speed region where the operating frequency of the inverter 6 is equal to or lower than the predetermined value, so that the terminal voltages of the bootstrap capacitors 53a to 53c are secured, and In the high speed range, sufficient torque and output can be obtained without limiting the duty.
[0040]
  (Example 3)
  Hereinafter, Example 3 of the power generation device of the present invention will be described with reference to the drawings.To do.FIG. 5 is a circuit diagram showing the configuration of this embodiment. In addition, the same number is attached | subjected to the same component as Example 1 thru | or Example 1, and detailed description is abbreviate | omitted. This embodiment is different from the second embodiment in that the duty limit in the low speed range is changed in accordance with the operating frequency of the inverter. This is intended to obtain sufficient torque and output while limiting the duty even in the low speed range.
[0041]
  FIG. 6 is a characteristic diagram showing the operation of the duty limiting circuit 54 of FIG. In FIG. 6, the horizontal axis represents the frequency of the signal from the Hall IC 4b, and the vertical axis represents the duty of the output signal from the PWM circuit 17, that is, the ratio of the HIGH period.
[0042]
  In this embodiment, the duty is 67% under the condition of f = 0, the duty is 100% under the condition of f = 40 Hz, and the duty is 100% under the condition of f> 40 Hz. It is trying to become.
[0043]
  With the above configuration, in this embodiment, the terminal voltages of the bootstrap capacitors 53a to 53c are ensured to be equal to or higher than a predetermined value under any frequency f condition, that is, the rotational speed condition, and the first drive circuits 10a to 10c. By preventing the duty from being excessively limited while ensuring sufficient operation, the output and torque of the power generator can be fully exerted, ensuring high reliability while ensuring reliability. A generator can be realized.
[0044]
  In this embodiment, the duty relationship with respect to the frequency f is a straight line under the condition of 0 <f <40 Hz. However, the present invention is not limited to a straight line, and a curve may be used. By optimizing the curve, it becomes possible to minimize the duty limit while ensuring the terminal voltages of the bootstrap capacitors 53a to 53c at any rotational speed, and the capability as a power generation device is sufficient. Can be demonstrated.
[0045]
  As described above, according to this embodiment, the duty limit in the low speed range is suppressed as much as possible in accordance with the operating frequency of the inverter 6, and sufficient torque is ensured in the low speed range while ensuring the terminal voltages of the bootstrap capacitors 53a to 53c. And output can be obtained.
[0046]
  Example 4
  Hereinafter, Example 4 of the power generator of the present invention will be described with reference to the drawings.To do.The difference of the present embodiment from the third embodiment is that the duty limiting circuit 54 includes a boot voltage detection circuit 74 and performs feedback control so that the terminal voltage of the bootstrap capacitor 53a does not become a predetermined value or less. Other configurations are the same as those in FIG.
[0047]
  FIG. 7 is a circuit diagram showing the configuration of the boot voltage detection circuit 74 in this embodiment. In FIG. 7, the boot voltage detection circuit 74 connects a series circuit of the Zener diode 75 and the light emitting diode side of the photocoupler 76 between both ends of the bootstrap capacitor 53 a, and outputs the photocoupler 76 via a resistor 77. A voltage of the DC power supply 78 is applied and connected to an operational amplifier 80 through a resistor 79 so as to be compared and amplified with the voltage of the reference voltage source 81. The voltage of the DC power supply 78 is 15 V in this embodiment, but it can be supplied from the output of the second DC power supply 12a shown in FIG.
[0048]
  The output of the operational amplifier 80 is input to the PWM circuit 17, and the terminal voltage of the bootstrap capacitor 53 a causes the Zener voltage of the Zener diode 75 and the forward voltage drop of the light emitting diode constituting the photocoupler 76 (about 1.. 7V), the output voltage decreases. When the output voltage decreases below the voltage of the reference voltage source 81, the output voltage of the operational amplifier 80 increases and the duty of the PWM signal of the PWM circuit 17 increases. As a result, the feedback operation is performed so that the terminal voltage of the bootstrap capacitor 53a becomes a substantially constant value.
[0049]
  When the rotation speed is high, the bootstrap capacitor 53a is frequently charged at the fundamental frequency, so that the output voltage of the operational amplifier 80 rises to approximately 15V and the duty becomes 100%. Here, in this embodiment, the boot voltage detection circuit 74 is provided only for the bootstrap capacitor 53a of one of the three phases. However, the charge and discharge under the same conditions are applied to the other two phases. A sufficient effect can be obtained without detection. However, it goes without saying that operation compensation can be made for variations in the capacitance of the bootstrap capacitors 53a to 53c by providing them in other phases if necessary.
[0050]
  As described above, according to this embodiment, the first drive circuits 10a to 10c can be reliably operated by limiting the duty so that the terminal voltages of the bootstrap capacitors 53a to 53c do not become a predetermined value or less. it can.
[0051]
  (Example 5)
  Hereinafter, Example 5 of the power generation device of the present invention will be described with reference to the drawings.To do.The present embodiment is different from the fourth embodiment in that the duty limiting circuit 54 includes a boot voltage arithmetic circuit (not shown), and the first drive circuits 10a to 10c operate with the terminal voltages of the bootstrap capacitors 53a to 53c. The duty is limited so as to maintain a predetermined value which is sufficient and minimum for the purpose. Other configurations are the same as those in FIG.
[0052]
  The operation in the above configuration will be described. FIG. 8 is a characteristic diagram showing the rotation speed and the terminal voltage Vs of the bootstrap capacitor 53a (however, the ripple bottom value) under each duty condition in this embodiment. As shown in the figure, the value of the terminal voltage Vs with respect to the rotational speed of the power generator is greatly influenced by the duty particularly in the low speed region.
[0053]
  The boot voltage calculation circuit calculates a duty necessary to maintain the terminal voltage Vs of the bootstrap capacitor 53a at a predetermined value with respect to the current rotation speed based on the characteristics of FIG. Feedback. Thereby, the terminal voltage Vs of the bootstrap capacitor 53a can be controlled to be maintained at a predetermined value.
[0054]
  In this embodiment, if the duty is 90% and 500 rpm, the estimated value of the terminal voltage Vs is 8V. Even if the duty is 100% and 800 rpm, the estimated value of the terminal voltage Vs is 8V. In the present embodiment, the voltage at which the first drive circuits 10a to 10c operate reliably is 8V, so that the terminal voltage Vs is maintained at 8V by performing the above feedback operation.
[0055]
  Note that the boot voltage calculation circuit may have the characteristics shown in FIG. 8 in a mathematical formula, or may be stored in a memory as a data table.
[0056]
  As described above, according to the present embodiment, by limiting the duty so as to maintain the terminal voltages of the bootstrap capacitors 53a to 53c at a predetermined minimum value, the duty is optimally limited, Torque and output can be obtained to the maximum.
[0057]
  (Example 6)
  Hereinafter, Example 6 of the power generation device of the present invention will be described with reference to the drawings.To do.FIG. 9 is a circuit diagram showing the configuration of this embodiment. In addition, the same number is attached | subjected to the same component as Example 1 thru | or Example 5, and detailed description is abbreviate | omitted.
[0058]
  The configuration of this embodiment includes a 75 kΩ charging resistor 82 connected to both ends of the second switching element 8a, and the other configurations are the same as those of any of the first to fifth embodiments.
[0059]
  This embodiment is different from the first to fifth embodiments in that a charging resistor 82 is provided so that the bootstrap capacitors 53a to 53c are charged even before the second switching elements 8a to 8c are opened and closed. There is. This is related to ensuring the operation of the inverter 6 at the time of startup.
[0060]
  In FIG. 9, when the operation is stopped,IeFor example, when the signals a to f are all LOW, all the second switching elements 8a to 8c (there are three phases in this embodiment) are in an OFF state. . At this time, in order to charge the bootstrap capacitor 53a from the second DC power supply 12a, it is necessary to draw the charging current of the bootstrap capacitor 53a from the emitter terminal of the first switching element 7a. Since the charging resistor 82 is provided to secure the path of the charging current and the bootstrap capacitor 53a is charged, the first driving circuit 10a operates reliably when the device is started up. The turn-on of the first switching element 7a is reliably performed.
[0061]
  In the present embodiment, since it has a three-phase configuration, the other two phases are also provided with bootstrap capacitors 53b to 53c, which are supplied through winding 3a, winding 3b, and winding 3c. As a result, all the three bootstrap capacitors 53a to 53c can be charged by only one charging resistor 82. Two or more charging resistors may be connected, in which case the charging current increases, charging is sufficiently performed even when the charging time is short, and charging currents of a plurality of bootstrap capacitors are equalized. The effects such as being able to plan can be expected.
[0062]
  In the present embodiment, the voltage of the first DC power supply 14 is 140 V, the electrostatic capacitances of the bootstrap capacitors 53a to 53c are 47 μf, and the resistance value of the charging resistor 82 is 75 kΩ, so that the charging current is about 0. When the power generator of this embodiment is used for an electric washing machine, the time required to charge the bootstrap capacitors 53a to 53c (three in total) for three phases to about 8V is about 7 seconds. A sufficiently short waiting time from power-on to startup is sufficient.
[0063]
  Further, when the power generation device is driven from the load side during the stop, the permanent magnet 5 provided in the second object 2 generates induced power proportional to the speed in the windings 3a to 3c. Then, since the resistance value of the charging resistor 82 is a large value of 75 kΩ, the current due to the induced power is as small as 1.8 mA or less, and therefore the windings 3a to 3c are not burned out. Note that the configuration of the second object 2 is not limited to that using the permanent magnet 5, and may be other configurations. In this case, the bootstrap is simply configured by providing the charging resistor 82. Capacitors 53a to 53c can be charged, and a low-cost power generation device can be realized.
[0064]
  As described above, according to the present embodiment, the bootstrap capacitors 53a to 53c are charged even before the second switching elements 8a to 8c start the opening / closing operation, thereby reliably Can be activated.
[0065]
  (Example 7)
  Hereinafter, an embodiment of an electric washing machine using the power generation device of the present invention will be described with reference to the drawings.To do.
[0066]
  FIG. 9 is a cross-sectional view showing the configuration of this embodiment. In FIG. 9, a washing machine outer frame 83 suspends a water receiving tank 85 by four suspension rods 84, and a washing / dehydrating tank 86 is rotatably disposed in the water receiving tank 85 so that washing / demounting is performed. A stirring blade 87 is rotatably disposed at the bottom of the water tank 86. The power generation device 88 including the first object 1 and the second object 2 and the inverter 6 described in the first to sixth embodiments includes a stirring blade 87 and a laundry through a V belt 89 and a speed reduction mechanism 90. The cum dewatering tank 86 is driven. In addition, 91 is a drain valve and 92 is a water supply valve. The control device 93 controls each step of washing, rinsing, and dehydration based on information input from the input means, for example, and controls the power generation device 88.
[0067]
  The operation in the above configuration will be described. When the power generation device 88 is driven by a command from the control device 93 with clothes in the washing and dewatering tub 86, the power generation device 88 rotates the stirring blade 87 via the V belt 89 and the speed reduction mechanism 90. Execute washing by letting. In addition, the washing / dehydrating tub 86 rotates during dehydration. Switching between washing and dewatering is performed in conjunction with the drain valve 91 according to a command from the control device 93 and in conjunction with turning on and off of the planetary gear provided in the speed reduction mechanism 90.
[0068]
【The invention's effect】
  As described above, the invention described in claim 1 of the present invention isA first object having at least one winding, a second object that is movably provided relative to the first object, a first DC power source, and both ends of the first DC power source A series circuit that is connected and has a first switching element and a second switching element connected in series, a first driving circuit that opens and closes the first switching element, and a second that opens and closes the second switching element. Drive circuit, a second DC power supply for operating the second drive circuit, and a charging current supplied from the second DC power supply when the second switching element is turned on to operate the first drive circuit An inverter circuit having a bootstrap capacitor serving as a direct current power source for each winding and a conduction period of the first switching element in each inverter circuit by PWM control. A PWM circuit for, and a duty limiting circuit for limiting the duty in the PWM control, the dutyThe limit circuit changes the upper limit value that limits the duty according to the operating frequency of the inverter,The terminal voltage of the bootstrap capacitor is maintained so that the first driving circuit can operate.FromA DC power source for operating the first drive circuit can be stably operated while being constituted only by a bootstrap capacitor, and a light-weight and low-cost power generation device can be realized.In addition, it is possible to realize a power generation device that can obtain sufficient torque and output at high speeds, and can obtain sufficient torque and output within a range in which a terminal voltage necessary for the bootstrap capacitor can be obtained even at low speeds.
[0069]
  Claim 2In the described invention, the second object includes a permanent magnet, and each of the first drive circuit and the second drive circuit is based on a signal from a position detection unit that detects the position of the permanent magnet. Since the switching element and the second switching element are driven to open and close, a highly efficient power generation device can be realized.
[0070]
  Claim 3Since the described invention includes the power generation device according to claim 1 or 2, it is possible to realize an electric washing machine that is lightweight, low-cost, highly efficient, and highly reliable.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing a configuration of a first embodiment of a power generation apparatus according to the present invention.
FIG. 2 is a circuit diagram showing a configuration of a first drive circuit and a second drive circuit and their peripherals in the embodiment;
FIG. 3 is a circuit diagram showing a configuration of a power generator according to a second embodiment of the present invention.
FIG. 4 is a characteristic diagram showing the operation of the embodiment.
FIG. 5 is a circuit diagram showing the configuration of a power generator according to Embodiment 3 of the present invention.
FIG. 6 is a characteristic diagram showing the operation of the embodiment.
FIG. 7 is a circuit diagram showing a configuration of a boot voltage detection circuit in Embodiment 4 of the power generation device of the present invention.
FIG. 8 is a characteristic diagram showing the relationship among the duty used by the boot voltage calculation circuit in the fifth embodiment of the power generation device of the present invention, the terminal voltage of the bootstrap capacitor, and the rotation speed;
FIG. 9 is a circuit diagram showing the configuration of Embodiment 6 of the power generating device of the present invention;
FIG. 10 is a sectional view showing the configuration of an embodiment of the electric washing machine of the present invention.
FIG. 11 is a circuit diagram showing a configuration of a conventional power generation device.
FIG. 12 is a circuit diagram showing a configuration of a first drive circuit and a second drive circuit and their peripherals in the conventional example
[Explanation of symbols]
  1 First object
  2 Second object
  3 Three-phase winding
  3a, 3b, 3c winding
  4 Position detection means
  4a, 4b, 4c Hall IC
  5 Permanent magnet
  6 Inverter
  6a, 6b, 6c Inverter circuit
  7a, 7b, 7c first switching element
  8a, 8b, 8c Second switching element
  9a, 9b, 9c driver
  10a, 10b, 10c first drive circuit
  11a, 11b, 11c Second drive circuit
  12a, 12b, 12c Second DC power supply
  13a, 13b, 13c Third DC power supply
  14 First DC power supply
  15 Three-phase distribution circuit
  16a, 16b, 16c AND circuit
  17 PWM circuit
  18 Oscillator circuit
  19 Comparator
  20 Variable resistance
  21 Bias power supply
  22 Commercial power supply
  23 Rectifier bridge
  24 Choke coil
  25 Smoothing capacitor
  26 Photocoupler
  27, 28, 33, 38 NPN transistor
  29, 34 PNP transistors
  30, 31, 32, 35, 36, 51 Resistance
  37 Switching power supply
  39 Drive circuit
  40 transformer
  41 Snubber
  42, 43, 44, 45, 46 Diode
  47, 48, 49, 50 Electrolytic capacitors
  52 capacitors
  53a, 53b, 53c Bootstrap capacitor
  54 Duty limit circuit
  55, 57 resistance
  56 diodes
  58 Zener diode
  59 Speed detection circuit
  60 Error amplifier
  61 Reference voltage source
  62 NPN transistor
  63, 64 resistance
  65 transformer
  66 Rectifier Bridge
  67 Constant voltage IC
  68, 69 Electrolytic capacitor
  70 voltage selector
  71, 72 Reference voltage source
  73 Frequency judgment circuit
  74 Boot voltage detection circuit
  75 Zener diode
  76 Photocoupler
  77, 79 resistance
  78 DC power supply
  80 operational amplifier
  81 Reference voltage source
  82 Charging resistance
  83 Outer frame of washing machine
  84 Hanging rod
  85 water tank
  86 Washing and dewatering tank
  87 Stirring blade
  88 Power generator
  89 V belt
  90 Reduction mechanism
  91 Drain valve
  92 Water supply valve
  93 Controller

Claims (3)

A first object having at least one winding, a second object that is movably provided relative to the first object, a first DC power source, and both ends of the first DC power source A series circuit in which the first switching element and the second switching element are connected in series, a first drive circuit that opens and closes the first switching element, and a second that opens and closes the second switching element. Drive circuit, a second DC power source for operating the second drive circuit, and a charging current supplied from the second DC power source when the second switching element is turned on to operate the first drive circuit An inverter circuit having a bootstrap capacitor serving as a direct current power source for each winding and a conduction period of the first switching element in each inverter circuit by PWM control. A PWM circuit for, and a duty limiting circuit for limiting the duty in the PWM control, the duty limiting circuit, an upper limit value for limiting the duty, changed in correspondence to the operating frequency of the inverter, the terminal of the bootstrap capacitor A power generation device configured to maintain a voltage such that the first drive circuit is operable. The second object includes a permanent magnet, and the first drive circuit and the second drive circuit are respectively based on a signal from a position detection means for detecting the position of the permanent magnet, and the first switching element and the second drive circuit. power generating device according to claim 1, wherein the switching element so as to open and close drive. An electric washing machine comprising the power generation device according to claim 1 .

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