JP2008054456A - Ac power source direct-coupling brushless dc motor and electric apparatus equipped therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an AC power source direct-coupling burshless motor capable of realizing an air capacity-static pressure characteristic having less change in air capacity due to a change in static pressure, after lower power consumption, miniaturization, high quality, and long service life are realized and rotation variation is suppressed. <P>SOLUTION: A commercial AC voltage supply is subjected to full-wave rectification, a high-voltage containing a ripple after full-wave rectification is converted in a low DC voltage of not more than 45V. A supplied current value control means 16 controls a low DC voltage value changing means 14, so that a mean current value to an inverter circuit 6 to be detected in a current value detecting means 21 on the basis of a correlation indicating means 13 may be the same as a current value indicated by a current value indicating means 19, and performs feedback control while varying an output voltage of a low DC voltage converting means 8. The current value indicating means 19 indicates a current to be supplied to the inverter circuit 6 by adding/subtracting it to a reference set value depending on an output voltage of the low DC voltage converting means 8. With this configuration for ROM-torque characteristics, the characteristics can be obtained in which an axial torque becomes larger as RPM increases. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention mainly relates to a brushless DC for driving a fan such as a pipe fan, a ceiling-embedded ventilator for exhaust and air supply, a fan, a humidifier, a dehumidifier, a refrigeration apparatus, an air conditioner, a water heater, etc. The present invention relates to a motor and an electric device equipped with the brushless DC motor.

  In recent years, there has been a strong demand for low-price, high-efficiency, low-noise, and standardization in motors for driving fans mounted on electrical equipment such as ventilation devices, and it is difficult to achieve significant increases in efficiency with induction motors. For this reason, brushless DC motors using permanent magnets are increasing. In addition, since a brushless DC motor is mounted, there is an increasing number of devices that control the air volume of a ventilator or the like with a predetermined air volume. On the other hand, there is also a demand for an electric motor that is easy to use, such as simply rotating by connecting to an AC power source.

  Conventionally, the thing of the structure disclosed by patent document 1 is known for this kind of electric motor.

  Hereinafter, the electric motor will be described with reference to FIGS.

As shown in the figure, 101 is a current detection means for detecting the current supplied to the switching element 102, 106 is a current setting means that is exposed in the recess 107, and is generated by the low-voltage DC voltage conversion means 105. The low-voltage DC voltage is reduced by a resistance voltage dividing circuit or the like and converted to a supply current value indicating voltage. Reference numeral 103 denotes a supply current value control means, which is a low voltage DC voltage value so that the average current value supplied to the switching element 102 detected by the current detection means 101 is equal to the current value set by the current setting means 106. By controlling the changing means 104, a configuration of a brushless DC motor directly connected to an AC power source that performs feedback control while varying the voltage output from the low-voltage DC voltage converting means 105 is adopted.
JP 2004-236488 A

  According to such a conventional electric motor, feedback control is performed so that the current supplied to the switching element 102 becomes a current value set by the current setting means 106 exposed in the concave portion 107. Since the output torque is almost constant, when a brushless DC motor with this characteristic is installed in a device with a centrifugal fan such as a sirocco fan such as a duct type ventilation device, the air volume of the device decreases as the pressure loss increases. There is a need for a fan motor that can achieve constant air volume control without using a microcomputer even if static pressure changes, such as pressure loss, without using a microcomputer. As the rotational speed increases, it is required that the rotational speed-torque characteristic that increases the shaft torque can be obtained arbitrarily. That.

  The present invention solves such a conventional problem, and it is possible to obtain an air flow-static pressure characteristic with a very small air flow change amount even if the static pressure changes such as pressure loss without using a microcomputer. An object of the present invention is to provide a brushless DC motor directly connected to an AC power source.

  In order to achieve the above object, the AC power source direct-coupled brushless DC motor of the present invention converts the low-voltage DC voltage into a low-voltage DC voltage and applies it to the inverter circuit, and supplies it to the inverter circuit. The supply current value control means for controlling the average current to be substantially constant, the current value instruction means for instructing the average current value to be controlled substantially constant by the supply current value control means, and the low-voltage DC voltage conversion means Correlation indicating means for indicating the correlation between the voltage value of the low-voltage DC voltage and the average current value indicated by the current value indicating means according to the resistance value to be connected, and the reference current setting indicated by the current value indicating means Supply current reference set value indicating means for determining a value according to a resistance value to be connected, the current value indicating means determined by the supply current reference set value indicating means The instruction current is increased or decreased so that the quasi-current set value becomes the correlation indicated by the correlation instruction means, and the resistance connected to the correlation instruction means and the resistance connected to the supply current reference set value indication means Either or both of them are variable, and either or both of these variable resistors are exposed to provide a configuration of an AC power supply direct-coupled brushless DC motor.

  Specification adjustment can be made by changing and adjusting the resistance value of the resistor connected to the supply current reference set value indicating means and the resistance value connected to the correlation indicating means by this means, and the man-hour required for the specification adjustment can be greatly reduced. Since the rotation speed-torque characteristics that increase the shaft torque further as the rotation speed increases can be obtained arbitrarily, the fan volume does not change even if the static pressure changes, such as pressure loss. If the pressure characteristics can be realized and the resistance connected to the correlation indication means is exposed, the airflow slope can be changed even if the in-flight pressure loss state of the device changes from the initial state, and the supply current standard set value indication When the resistance connected to the means is exposed, a brushless DC motor and an electric device directly connected to an AC power source that can arbitrarily adjust the change in the air volume to be controlled are obtained.

  Further, in order to achieve the above object, the AC power source directly connected brushless DC motor of the present invention is formed by a chopper circuit that converts the high voltage obtained by the rectifying means into a substantially constant low voltage DC voltage and applies it to the inverter circuit. Low-voltage DC voltage conversion means, duty instruction voltage generation means for reducing the low-voltage DC voltage generated by the low-voltage DC voltage conversion means and indicating the ON / OFF duty when the switching element is PWM-controlled, Supply current value control means for controlling the average current supplied to the inverter circuit substantially constant, current value instruction means for indicating the average current value controlled substantially constant by the supply current value control means, and the duty instruction voltage generation Depending on the resistance value connecting the correlation between the voltage value generated by the means and the average current value indicated by the current value indicating means Correlation indicating means for indicating, and supply current reference setting value indicating means for determining a reference current setting value specified by the current value indicating means according to a resistance value to be connected, wherein the current value indicating means is the supply The reference current set value determined by the current reference set value indicating means is increased or decreased so that the correlation indicated by the correlation indicating means is reached, the resistance connected to the correlation indicating means, and the supply current One or both of the resistors connected to the reference set value indicating means are variable, and either or both of the variable resistors are exposed so as to be provided. The configuration is as follows.

  Specification adjustment can be made by changing and adjusting the resistance value of the resistor connected to the supply current reference set value indicating means and the resistance value connected to the correlation indicating means by this means, and the man-hour required for the specification adjustment can be greatly reduced. Since the rotation speed-torque characteristics that increase the shaft torque further as the rotation speed increases can be obtained arbitrarily, the fan volume does not change even if the static pressure changes, such as pressure loss. If the pressure characteristics can be realized and the resistance connected to the correlation indication means is exposed, the airflow slope can be changed even if the in-flight pressure loss state of the device changes from the initial state, and the supply current standard set value indication When the resistance connected to the means is exposed, a brushless DC motor and an electric device directly connected to an AC power source that can arbitrarily adjust the change in the air volume to be controlled are obtained.

  Further, in order to achieve the above object, the AC power source direct-coupled brushless DC motor of the present invention has a low voltage DC voltage conversion means formed by a chopper circuit that converts the voltage into a low voltage DC voltage and applies it to the inverter circuit, and a magnetic flux density distribution. Drive logic control means for sequentially energizing the drive coil in a predetermined direction and order through the inverter circuit with the low-voltage DC voltage generated by the low-voltage DC voltage conversion means based on the signal of the detection means; The magnetic flux density distribution detecting means is arranged so that the magnetic flux density distribution waveform detected by the magnetic flux density distribution detecting means is substantially similar to the induced voltage waveform induced in the drive coil by rotation of the magnet rotor. Current waveform control means for passing a current substantially similar to the waveform detected by the magnetic flux density distribution detection means to the drive coil and the inverter circuit. The supply current value control means for controlling the average current to be substantially constant, the current value instruction means for instructing the average current value to be controlled substantially constant by the supply current value control means, and the low-voltage DC voltage conversion means Correlation indicating means for indicating the correlation between the voltage value of the low-voltage DC voltage and the average current value indicated by the current value indicating means according to the resistance value to be connected, and the reference current setting indicated by the current value indicating means Supply current reference set value indicating means for determining a value according to a resistance value to which the value is connected, wherein the current value indicating means determines the reference current set value determined by the supply current reference set value indicating means as the correlation indicating means. The indicated current is increased or decreased so that the correlation indicated in (1) is established, and either the resistance connected to the correlation indicating means or the resistance connected to the supply current reference set value indicating means Both the variable is obtained by this variable and the AC power source directly connected brushless DC motor to either or both of the resistors characterized by providing the exposed configuration.

  Specification adjustment can be made by changing and adjusting the resistance value of the resistor connected to the supply current reference set value indicating means and the resistance value connected to the correlation indicating means by this means, and the man-hour required for the specification adjustment can be greatly reduced. Since the rotation speed-torque characteristics that increase the shaft torque further as the rotation speed increases can be obtained arbitrarily, the fan volume does not change even if the static pressure changes, such as pressure loss. If the pressure characteristics can be realized and the resistance connected to the correlation indication means is exposed, the airflow slope can be changed even if the in-flight pressure loss state of the device changes from the initial state, and the supply current standard set value indication When the resistance connected to the means is exposed, a brushless DC motor and an electric device directly connected to an AC power source that can arbitrarily adjust the change in the air volume to be controlled are obtained.

  Further, in order to achieve the above object, the AC power source directly connected brushless DC motor of the present invention is formed by a chopper circuit that converts the high voltage obtained by the rectifying means into a substantially constant low voltage DC voltage and applies it to the inverter circuit. Low-voltage DC voltage conversion means, duty instruction voltage generation means for reducing the low-voltage DC voltage generated by the low-voltage DC voltage conversion means and indicating the ON / OFF duty when the switching element is PWM-controlled, The magnetic flux density distribution detecting means is arranged such that the magnetic flux density distribution waveform detected by the magnetic flux density distribution detecting means is substantially similar to the induced voltage waveform induced in the drive coil by rotation of the magnet rotor, Current waveform control means for causing a current substantially similar to the waveform detected by the magnetic flux density distribution detection means to flow through the drive coil; Supply current value control means for controlling the average current supplied to the circuit substantially constant, current value instruction means for indicating the average current value controlled substantially constant by the supply current value control means, and duty instruction voltage generation means Correlation indicating means for instructing the correlation between the voltage value generated by the current value indicating means and the average current value specified by the current value indicating means according to the resistance value to be connected, and the reference current setting value specified by the current value indicating means Supply current reference set value indicating means determined according to a resistance value for connecting the reference current set value determined by the supply current reference set value indicating means to the correlation indicating means. The indicated current is increased / decreased so as to obtain the indicated correlation, and there is either a resistor connected to the correlation indicating means or a resistor connected to the supply current reference set value indicating means Is both a variable, is obtained by this variable and the AC power source directly connected brushless DC motor to either or both of the resistors characterized by providing the exposed configuration.

  Specification adjustment can be made by changing and adjusting the resistance value of the resistor connected to the supply current reference set value indicating means and the resistance value connected to the correlation indicating means by this means, and the man-hour required for the specification adjustment can be greatly reduced. Since the rotation speed-torque characteristics that increase the shaft torque further as the rotation speed increases can be obtained arbitrarily, the fan volume does not change even if the static pressure changes, such as pressure loss. If the pressure characteristics can be realized and the resistance connected to the correlation indication means is exposed, the airflow slope can be changed even if the in-flight pressure loss state of the device changes from the initial state, and the supply current standard set value indication When the resistance connected to the means is exposed, a brushless DC motor and an electric device directly connected to an AC power source that can arbitrarily adjust the change in the air volume to be controlled are obtained.

  According to the present invention, the specification can be adjusted by changing and adjusting the resistance connected to the supply current reference set value indicating means and the resistance connected to the correlation indicating means, so that the man-hours required for the specification adjustment can be greatly reduced. Since the motor can be standardized and the rotational speed-torque characteristics can be obtained as the shaft torque increases further as the rotational speed increases, the fan volume can be obtained even if the static pressure such as pressure loss changes. If the resistance connected to the correlation indicating means is exposed, the airflow-static pressure characteristics with almost no change can be realized without using a microcomputer. The AC power supply direct-coupled type can be adjusted to change the air volume to be controlled at will when the inclination can be changed and the resistance connected to the supply current reference set value indicating means is exposed. It can provide Rashiresu DC motors and electrical equipment.

  Further, according to the present invention, the specification can be adjusted by changing and adjusting the resistance value of the resistor connected to the supply current reference setting value indicating means and the resistance value connected to the correlation indicating means. The motor can be reduced and the motor can be standardized, and as the rotational speed increases, the rotational speed-torque characteristics that increase the shaft torque can be obtained arbitrarily. However, if the airflow-static pressure characteristics with almost no change in airflow can be realized without using a microcomputer, and the resistance connected to the correlation instruction means is exposed, the in-machine pressure loss state of the device may change from the initial state. If it is possible to respond to changes in the airflow inclination and the resistance connected to the supply current reference set value indicating means is exposed, the AC power supply can be directly adjusted to change the airflow for constant control. It provides type brushless DC motors and electrical equipment.

  Further, according to the present invention, the specification can be adjusted by changing and adjusting the resistance value of the resistor connected to the supply current reference setting value indicating means and the resistance value connected to the correlation indicating means. The motor can be reduced and the motor can be standardized, and as the rotational speed increases, the rotational speed-torque characteristics that increase the shaft torque can be obtained arbitrarily. However, if the airflow-static pressure characteristics with almost no change in airflow can be realized without using a microcomputer, and the resistance connected to the correlation instruction means is exposed, the in-machine pressure loss state of the device may change from the initial state. If the airflow slope change can be accommodated and the resistor connected to the supply current reference set value indicating means is exposed, the change in the airflow to be controlled at will can be arbitrarily adjusted. Since the voltage waveform of the electromotive force and the current waveform are substantially similar, the current ripple of the current supplied to the switching element can be reduced, so that a brushless DC motor and an electric device directly connected to an AC power source that can widen the setting range of the correlation are provided. it can.

  Further, according to the present invention, the specification can be adjusted by changing and adjusting the resistance value of the resistor connected to the supply current reference setting value indicating means and the resistance value connected to the correlation indicating means. The motor can be reduced and the motor can be standardized, and as the rotational speed increases, the rotational speed-torque characteristics that increase the shaft torque can be obtained arbitrarily. However, if the resistance connected to the correlation indicator is exposed, the in-flight pressure loss state of the device will change with respect to the initial value. If the resistance connected to the supply current reference set value indicating means is exposed, the change in the air volume to be controlled can be arbitrarily adjusted, Since the induced voltage waveform and the current waveform are substantially similar, the current ripple of the current supplied to the switching element can be reduced, so that a brushless DC motor and an electric device directly connected to an AC power source capable of widening the correlation setting range are provided. it can.

  According to the first aspect of the present invention, low voltage DC voltage conversion means formed by a chopper circuit that converts a low voltage DC voltage and applies it to an inverter circuit, and an average current supplied to the inverter circuit are controlled to be substantially constant. Supply current value control means, current value indicating means for indicating an average current value controlled substantially constant by the supply current value control means, voltage value of the low-voltage DC voltage generated by the low-voltage DC voltage conversion means, Correlation indicating means for indicating the correlation with the average current value indicated by the current value indicating means according to the connected resistance value, and according to the resistance value for connecting the reference current set value indicated by the current value indicating means Supply current reference set value indicating means for determining the reference current set value determined by the supply current reference set value indicating means at the correlation indicating means. The indicated current is increased or decreased so that the indicated correlation is obtained, and either or both of the resistor connected to the correlation indicating means and the resistor connected to the supply current reference set value indicating means are made variable, and this variable This is a configuration of a brushless DC motor with direct connection to an AC power supply characterized in that either one or both of the resistors formed are exposed, and the shaft torque increases further as the rotational speed increases. It has the effect that the rotational speed-torque characteristic can be obtained arbitrarily.

  According to a second aspect of the present invention, there is provided a low-voltage DC voltage converting means formed by a chopper circuit for converting a high-voltage voltage obtained by the rectifying means into a substantially constant low-voltage DC voltage and applying it to the inverter circuit, and the low-voltage DC voltage. Duty indication voltage generation means for indicating ON / OFF duty when PWM control of the switching element is performed by reducing the low-voltage DC voltage generated by the conversion means, and the average current supplied to the inverter circuit is substantially constant Supply current value control means for controlling, current value instruction means for instructing an average current value controlled substantially constant by the supply current value control means, voltage value generated by the duty instruction voltage generation means, and current value indication Correlation indicating means for indicating the correlation with the average current value indicated by the means according to the connected resistance value, and the current value indicating means Supply current reference set value indicating means for determining a reference current set value to be indicated according to a resistance value to be connected, wherein the current value indicating means determines the reference current set value determined by the supply current reference set value indicating means. The instruction current is increased or decreased so as to achieve the correlation instructed by the correlation instruction means, and either or both of the resistance connected to the correlation instruction means and the resistance connected to the supply current reference set value instruction means Is a variable type, and either one or both of the variable type resistors are exposed to provide a configuration of an AC power supply direct-coupled brushless DC motor. As the rotational speed increases, The rotation speed-torque characteristic that increases the shaft torque can be obtained arbitrarily.

  According to a third aspect of the present invention, the low-voltage direct current voltage is converted into a low-voltage direct-current voltage and applied to the inverter circuit. Drive logic control means for sequentially energizing the drive coil in a predetermined direction and order through the inverter circuit with the low-voltage DC voltage generated by the conversion means, and magnetic flux detected by the magnetic flux density distribution detection means The magnetic flux density distribution detecting means is arranged so that the density distribution waveform is substantially similar to the induced voltage waveform induced in the drive coil by the rotation of the magnet rotor, and the waveform detected by the magnetic flux density distribution detecting means. Current waveform control means for supplying a current substantially similar to the drive coil, and supply current value control means for controlling the average current supplied to the inverter circuit substantially constant A current value indicating means for indicating an average current value controlled substantially constant by the supply current value control means; a voltage value of the low voltage DC voltage generated by the low voltage DC voltage converting means; and an average indicated by the current value indicating means Correlation indicating means for indicating the correlation with the current value according to the connected resistance value, and the supply current reference setting value for determining the reference current set value indicated by the current value indicating means according to the connected resistance value An instruction means, wherein the current value instruction means increases or decreases the instruction current so that the reference current set value determined by the supply current reference set value instruction means becomes the correlation indicated by the correlation instruction means, Either one or both of the resistor connected to the correlation indicating means and the resistor connected to the supply current reference set value indicating means is variable, and one of the variable resistors is selected. Alternatively, the AC power supply direct-coupled brushless DC motor is characterized in that both are exposed, and the induced voltage waveform and the current waveform are substantially similar, so that the current supplied to the switching element While the current ripple is suppressed, the rotational speed-torque characteristic in which the shaft torque further increases as the rotational speed increases can be obtained arbitrarily.

  According to a fourth aspect of the present invention, there is provided a low-voltage DC voltage converting means formed by a chopper circuit for converting a high-voltage voltage obtained by the rectifying means into a substantially constant low-voltage DC voltage and applying it to the inverter circuit, and the low-voltage DC voltage. Duty indication voltage generation means for indicating ON / OFF duty when PWM control of the switching element is performed by reducing the low-voltage DC voltage generated by the conversion means, and magnetic flux density distribution detected by the magnetic flux density distribution detection means The magnetic flux density distribution detecting means is arranged so that the waveform is substantially similar to the induced voltage waveform induced in the drive coil by the rotation of the magnet rotor, and substantially similar to the waveform detected by the magnetic flux density distribution detecting means. Current waveform control means for supplying a current of a shape to the drive coil, and a supply current value for controlling the average current supplied to the inverter circuit to be substantially constant Control means, current value instruction means for instructing an average current value controlled substantially constant by the supply current value control means, voltage value generated by the duty instruction voltage generation means, and average indicated by the current value instruction means Correlation indicating means for indicating the correlation with the current value according to the connected resistance value, and the supply current reference setting value for determining the reference current set value indicated by the current value indicating means according to the connected resistance value An instruction means, wherein the current value instruction means increases or decreases the instruction current so that the reference current set value determined by the supply current reference set value instruction means becomes the correlation indicated by the correlation instruction means, Either one or both of the resistor connected to the correlation indicating means and the resistor connected to the supply current reference set value indicating means is variable, and either of these variable resistors The AC power supply direct connection type brushless DC motor is characterized in that one or both of them are exposed. Since the induced voltage waveform and the current waveform are substantially similar, the current supplied to the switching element Current ripple is suppressed, and the rotational speed-torque characteristic in which the shaft torque is further increased as the rotational speed increases can be obtained arbitrarily.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
As shown in FIGS. 1 to 7, reference numeral 1 denotes a brushless DC motor directly connected to an AC power source, and 10 denotes a drive coil 2 via an insulator 11 formed of an insulating material on a stator core 10a having a plurality of slots. The stator 10 is a wound stator, and the stator 10 is molded with a thermosetting resin 27 containing a filler such as aluminum hydroxide or calcium carbonate to form a jacket. keeping. Reference numeral 3 denotes a magnet rotor, which is formed by integrally orienting a plastic magnet with the shaft 24 during the injection molding, and the main magnetic pole portion is a polar anisotropic magnet 3a. A hall element 4 serves as a magnetic flux density distribution detecting means for detecting the magnetic flux density distribution of the polar anisotropic magnet 3a. A waveform detected by the magnetic flux density distribution detecting means 4 is induced in the drive coil 2 by the polar anisotropic magnet 3a. The gap between the magnetic flux density distribution detecting means 4 and the polar anisotropic magnet 3a is set and arranged so as to be substantially similar to the induced voltage waveform. 4a is a magnetic flux density distribution waveform synthesizing unit that subtracts the v phase waveform from the u phase waveform of the magnetic flux density distribution detection unit 4 in order to remove harmonic components of the current waveform supplied to the u phase of the drive coil 2. The w phase waveform is subtracted from the v phase waveform of the magnetic flux density distribution detecting means 4 for the v phase of the driving coil 2, and the u phase waveform is derived from the w phase waveform of the magnetic flux density distribution detecting means 4 for the w phase of the driving coil 2. Subtracting. Q1, Q3, and Q5 are upper-stage switching elements, and Q2, Q4, and Q6 are lower-stage switching elements. The inverter circuit 6 is formed by bridge connection. 5 is a drive logic control means for controlling ON / OFF of the upper switching elements Q1, Q3, Q5 and the lower switching elements Q2, Q4, Q6 so that the drive coil 2 is sequentially full-wave energized in a predetermined direction and order. The current waveform control means 7 then switches the upper switching elements Q1, Q3, Q5 so that each phase current waveform of the drive coil 2 is substantially similar to the waveform from which the harmonic component has been removed by the magnetic flux density distribution waveform synthesis means 4a. The output bias current is adjusted while performing feedback so that the lower-stage switching elements Q2, Q4, and Q6 are in a non-saturated state close to saturation. 15 is an AC power supply connecting means for connecting a commercial AC power supply, 9 is a rectifying means for full-wave rectification of the AC power supply, and 8 is a high voltage having ripples rectified by the full-wave rectification by the rectifying means 9 to 45 V or less. The low-voltage DC voltage conversion means configured by a chopper circuit for converting to a low-voltage DC voltage, and the low-voltage DC voltage converted by the low-voltage DC voltage conversion means 8 is supplied to the drive coil 2 via the inverter circuit 6. A polymer capacitor is disposed between the low-voltage DC voltage converting means 8 and the rectifying means 9 as a small-capacity smoothing capacitor 18 that compensates for a voltage of 45 V or less when full-wave rectification of AC 100 V 50 Hz is performed. Reference numeral 21 denotes current detection means for detecting the current supplied to the inverter circuit 6, and reference numeral 16 denotes supply current value control means. The supply current value control means 16 changes the low-voltage DC voltage so that the average current value supplied to the inverter circuit 6 detected by the current value detection means 21 is equivalent to the current value indicated by the current value indication means 19. By controlling the means 14, feedback control is performed while varying the voltage output from the low voltage DC voltage converting means 8. Reference numeral 20 denotes a supply current reference set value indicating means, which indicates a reference set value of the current value indicated by the current value indicating means 19, and includes a variable resistor 17a exposed in the recess 12a and a supply current reference set value indicating means. The reference set value is determined according to the combined resistance value with the 20 internal resistances. Reference numeral 13 denotes correlation indicating means, which feeds back the change in the output voltage so that the output voltage-current characteristic of the low-voltage DC voltage conversion means 8 becomes a characteristic as shown in FIG. Depending on the magnitude of the voltage value to be output, the current supplied to the inverter circuit 6 is added to or subtracted from the reference set value, and the current value indicating means 19 is instructed. At this time, the addition / subtraction ratio with respect to the reference set value is determined according to the resistance value of the variable resistor 17b exposed to the recess 12b and connected to the correlation instruction means 13. Further, in consideration of the withstand voltage of the inverter circuit 6 and the kickback voltage, an upper limit is provided for the low-voltage DC voltage applied to the inverter circuit 6, and a section for operating at a constant voltage without controlling the current is provided. 1 except for the smoothing capacitor 18 and the coil that is one of the components constituting the low-voltage DC voltage converting means 8 and the secondary smoothing capacitor (not shown). Thus, the integrated circuit 22 is formed by mounting and wiring connection on an alumina substrate. Reference numeral 28 denotes a ventilator equipped with the AC power source directly connected brushless DC motor 1 and a centrifugal blower 23 built therein.

  According to the brushless DC motor 1 directly connected to the AC power source of the present invention, the current supplied to the inverter circuit 6 according to the magnitude of the voltage value output from the low voltage DC voltage converting means 8 by the correlation indicating means 13. Is added to and subtracted from the reference set value, so that the supply current increases as the rotational speed increases, and conversely the supply current decreases as the rotational speed decreases. As the rotational speed-torque characteristic, a characteristic in which the shaft torque increases as the rotational speed increases is obtained. With this characteristic, in the ventilation device 28 equipped with the centrifugal blower 23, as shown in FIG. Even if the pressure loss such as the duct length changes, the air volume-static pressure characteristic is obtained in which the air volume does not change greatly. Here, the amount of change to be added or subtracted may be appropriately set from the load amount such as a fan load so as to have an optimum inclination of the characteristic curve of the rotational speed-torque characteristic.

  Further, by changing the resistance value of the exposed variable resistor 17a connected to the supply current reference set value indicating means 20 from Ra to Rb, as shown in FIG. 4, the torque in the rotational speed-torque characteristic of the motor can be arbitrarily set. Therefore, in the ventilator 28 equipped with the centrifugal blower 23, as shown in FIG. 6, the AC power source directly connected brushless DC motor and the ventilator equipped with the same can be adjusted easily. Equipment is obtained.

  Further, in the brushless DC motor 1, the resistance value of the exposed variable resistor 17b connected to the correlation indicating means 13 can be arbitrarily set. Therefore, the rotational speed-torque characteristic of the motor has a shaft torque as the rotational speed increases. Since the inclination in the characteristic of increasing the air pressure can be arbitrarily adjusted, the ventilation device 28 equipped with the centrifugal blower 23 can adjust the outside air pressure, the duct length, etc. as shown in FIG. An air volume-static pressure characteristic in which the air volume does not change greatly even if the pressure loss changes can be easily obtained. Further, as shown in FIG. 7, an air volume-static pressure characteristic in which the air volume slightly increases as the pressure loss increases becomes possible. Here, since the correlation is determined at the exposed portion of the brushless DC motor 1, all of the brushless DC motor 1 including the winding specification and the magnet specification can be made the same and standardized.

  Further, in the brushless DC motor 1, since the resistance value of the variable resistor 17a connected to the supply current reference set value indicating means 20 can be arbitrarily set, the torque in the rotation speed-torque characteristic of the motor can be arbitrarily adjusted. In the ventilator 28 equipped with the type blower 23, an electric device such as an AC power source directly connected brushless DC motor that can easily adjust the set air volume and a ventilator equipped with the same is obtained. Here, since the reference set value of the supply current is determined at the exposed portion of the brushless DC motor 1, all the brushless DC motors 1 including the winding specifications and the magnet specifications can be made the same and standardized.

  Further, the high voltage having ripples rectified by the rectifying means 9 for full-wave rectification is converted into a low voltage DC voltage of 45 V or less by the low voltage DC voltage converting means 8 and supplied to the drive coil 2 as a drive power source. Since the smoothing capacitor 18 after wave rectification can be kept low enough to compensate for a very short period of voltage shortage, the capacitor can be reduced in size and space, and an electrolytic capacitor impregnated with an electrolytic solution can be used. Without using it, it is possible to use solid capacitors such as polymer capacitors, ceramic capacitors, and film capacitors, so it is possible to use a brushless AC power source directly connected to achieve high quality and long life, such as significant downsizing and no change in temperature characteristics. A DC motor is obtained.

  Further, even if the capacity of the smoothing capacitor 18 is small, the current supplied to the inverter circuit 6 by the supply current value control means 16 is controlled to be substantially constant, so that an AC power supply directly connected brushless DC motor that suppresses torque ripple and rotation unevenness is achieved. Is obtained. And even if it uses for fan drive, stabilization of ventilation volume is realizable. Here, even if the secondary side smoothing capacitor used in the low-voltage DC voltage converting means 8 has a small capacity, the same effect can be obtained.

  Further, the gap between the magnetic flux density distribution detecting means 4 and the magnet is set so that the waveform detected by the magnetic flux density distribution detecting means 4 is substantially similar to the induced voltage waveform induced in the drive coil 2 by the polar anisotropic magnet 3a. The current waveform control means 7 causes the induced voltage waveform and the current waveform to be substantially similar by passing a current substantially similar to the magnetic flux density distribution waveform detected by the magnetic flux density distribution detection means 4 to the drive coil 2. The torque ripple and torque change rate can be further reduced, and the motor efficiency is greatly improved. Therefore, the noise and the efficiency can be reduced, and the current ripple of the current supplied to the inverter circuit 6 can be reduced. Thus, a brushless DC motor directly connected to an AC power source capable of expanding the correlation setting range can be obtained.

  Further, by making the main magnetic pole portion of the magnet rotor 3 the polar anisotropic magnet 3a, both the induced voltage waveform and the current waveform become sinusoidal waves, so that the torque ripple and the torque change rate can be further reduced. In addition, since the motor efficiency is greatly improved, a brushless DC motor directly connected to an AC power source can be obtained that realizes quietness, high efficiency, and further expansion of the correlation setting range by further suppressing current ripple.

  Further, the magnetic flux density distribution waveform synthesizing unit 4a synthesizes the u-phase, v-phase, and w-phase waveforms detected by the magnetic flux density distribution detecting unit 4, so that the influence of variations in the magnetic flux density distribution detecting unit 4 of each phase is affected. As the magnetic flux density distribution waveform of each of the u-phase, v-phase, and w-phase is basically a waveform that is simply shifted in phase, the detected magnetic flux is obtained by subtracting and synthesizing the two phases. Since harmonic components contained in the density distribution waveform are removed, rotation irregularity can be suppressed, and torque ripple and torque change rate can be further reduced. The brushless DC motor is obtained.

  Further, since the molding is integrally performed with the thermosetting resin 27, the smoothing capacitor 18 can simplify structural measures such as moisture absorption deterioration, and the switching elements, diodes, and coils constituting the low-voltage DC voltage conversion means 8 can be simplified. Since the temperature rise of the heat generating parts such as can be suppressed, further downsizing and cost reduction can be realized.

  In the first embodiment, the current waveform supplied to the drive coil 2 is configured to be substantially similar to the induced voltage waveform. However, the current waveform supplied to the drive coil 2 has a rectangular shape of 120 degrees depending on the use and the noise level required for the product. Wide-angle energization methods such as wave energization and 140-degree and 150-degree energization are also possible, and the motor rotation speed-torque characteristics are such that the shaft torque increases as the rotation speed increases, and after full-wave rectification The capacity of the smoothing capacitor is kept low, the rotation unevenness is suppressed, and the copper loss in the high output area is reduced, resulting in drastic downsizing, high quality, long life, and wide range of usable load torque. There is no difference in that a brushless DC motor directly connected to an AC power source capable of realizing low power consumption even in the output region can be obtained.

  In the first embodiment, the magnetic flux density distribution detecting means 4 is used. However, a method of determining an energization phase for a magnet rotor by detecting an induced voltage or current induced in a non-energization phase, A system using magnetic pole detection means for determining the N pole and S pole of a magnet such as an IC may be used, and there is no difference in the effect.

  Further, in the first embodiment, the output bias current is adjusted while feedbacking so that the upper switching elements Q1, Q3, Q5 and the lower switching elements Q2, Q4, Q6 are close to saturation. The current waveforms may be controlled by PWM control of the side switching elements Q1, Q3, Q5 and the lower stage switching elements Q2, Q4, Q6. In that case, the upper stage switching elements Q1, Q3, Q5, the lower stage switching elements Since the loss of Q2, Q4, Q6 can be reduced, the AC power supply that can suppress the heat generation of the upper switching elements Q1, Q3, Q5, the lower switching elements Q2, Q4, Q6 and further expand the range of usable load torque A directly connected brushless DC motor will be obtained.

  In the first embodiment, the resistors connected to the correlation indicating unit 13 and the supply current reference set value indicating unit 20 are both variable resistors 17a and 17b, and both are exposed, but only one of them is exposed. May be configured to be variable, or only one of them may be exposed, and may be selected as appropriate in consideration of the degree of freedom in setting the rotational speed-torque characteristics in the motor and standardization.

  In the first embodiment, the variable resistors 17a and 17b are exposed. However, a switch for switching the resistance such as a dip switch may be exposed to change the resistance value internally. The setting of the rotational speed-torque characteristic at is only stepwise, and there is no difference in other operational effects.

  In the first embodiment, the substrate constituting the integrated circuit 22 is made of alumina. However, the substrate may be made of aluminum or copper, and there is no difference in the function and effect.

(Embodiment 2)
As shown in FIGS. 8 to 12, reference numeral 36 denotes a ventilation device including a centrifugal blower 37 and a brushless DC motor 30 directly connected to an AC power source that rotates a sirocco fan of the centrifugal blower 37. The same parts are denoted by the same reference numerals, and detailed description thereof is omitted. A brushless DC motor 30 directly connected to an AC power source formed by molding a jacket with a thermosetting resin 27 containing aluminum hydroxide or calcium carbonate includes a rectifying means 9, a small-capacity smoothing capacitor 18, a low-voltage DC voltage converter. Means 35, magnetic flux density distribution detection means 4, magnetic flux density distribution waveform synthesis means 4a, drive logic control means 34, inverter circuit 6, current value detection means 21, supply current value control means 16, current value indication means 19, supply current setting The value changing means 20 and the correlation instruction means 29 are mounted on the same printed circuit board and incorporated in a brushless DC motor 30 directly connected to an AC power source. Then, the supply current reference set value instruction means 20 determines the reference set value according to the combined resistance value of the variable resistor 17a exposed to the recess 12a and the internal resistance, as in the first embodiment, and indicates the correlation instruction. Similarly to the first embodiment, the means 29 also determines the addition / subtraction ratio with respect to the reference set value according to the resistance value of the variable resistor 17b exposed in the recess 12b. The drive logic control unit 34 includes a PWM control unit 32 that performs PWM control of the lower switching elements Q2, Q4, and Q6, and a waveform in which each phase current waveform of the drive coil 2 is removed from the harmonic component by the magnetic flux density distribution waveform synthesis unit 4a. Is mounted with current waveform control means 33 for adjusting the ON / OFF duty of the lower switching elements Q2, Q4, Q6 while feedback control so that the low voltage DC voltage conversion means 35 is a chopper circuit. Reference numeral 31 is a configured constant voltage output, and 31 is a duty indicating voltage generating means for reducing the low voltage DC voltage converted by the low voltage DC voltage converting means 35 and indicating the ON / OFF duty of the PWM control means 32. The instruction unit 29 has a relationship between the generated voltage of the duty instruction voltage generation unit 31 and the current of the low-voltage DC voltage conversion unit 35. By controlling the duty instruction voltage generation means 31 so as to have the characteristics shown in FIG. 9, feedback control is performed while varying the ON / OFF duty of the PWM control means 32, and the generated voltage of the duty instruction voltage generation means 31 is controlled. The current supplied to the inverter circuit 6 is added or subtracted with respect to the reference set value in accordance with the magnitude of. At this time, considering the allowable power consumption of the inverter circuit 6, an upper limit is set for the current supplied to the inverter circuit 6, and the ON duty in the PWM control is set at that point so that the current is not controlled beyond the upper limit current. Is set to be 100%, and a section for constant operation at an ON duty of 100% is provided. Other configurations of the magnet rotor 3 and the stator 10 are the same as those in the first embodiment.

  According to the brushless DC motor 30 directly connected to the AC power source of the present invention, the current value indicating unit 19 controls the duty indicating voltage generating unit 31 in accordance with the magnitude of the generated voltage of the duty indicating voltage generating unit 31. Since the current supplied to the inverter circuit 6 is added to or subtracted from the reference set value while changing the ON / OFF duty of the PWM control means 32, the supplied current increases as the rotational speed increases. Since the supply current decreases as the rotational speed decreases, the rotational speed-torque characteristic of the motor is obtained such that the shaft torque increases further as the rotational speed increases, as in the first embodiment. As for the air volume-static pressure characteristics of the ventilation device 36 equipped with the air volume, even if the pressure loss such as the external wind pressure or the duct length changes, the air volume does not change greatly. Here, the amount of change to be added or subtracted may be appropriately set from the load amount such as a fan load so as to have an optimum inclination of the characteristic curve of the rotational speed-torque characteristic.

  Further, since the low voltage direct current voltage generated by the low voltage direct current voltage conversion means 35 is reduced in pressure by the duty instruction voltage generation means 31 and set to the ON / OFF duty of the PWM control means 32, the characteristics can be adjusted. Since significant specification adjustments such as changes in wire specifications are not required, the characteristic adjustment of the brushless DC motor 30 directly connected to the AC power source can be simplified.

  Further, by changing the resistance value of the exposed variable resistor 17a connected to the supply current reference set value indicating means 20 from Ra to Rb, as shown in FIG. 10, the torque in the rotational speed-torque characteristic of the motor can be arbitrarily set. Therefore, in the ventilator 36 equipped with the centrifugal blower 37, as shown in FIG. 11, the AC power source directly connected brushless DC motor and the ventilator equipped with the AC power source can easily adjust the set air volume. Equipment is obtained.

  Further, in the brushless DC motor 30, since the resistance value of the exposed variable resistor 17b connected to the correlation indicating means 29 can be arbitrarily set, the motor rotational speed-torque characteristic is obtained by increasing the shaft torque as the rotational speed increases. In the ventilator 28 equipped with the centrifugal blower 23, even if the in-machine pressure loss is greatly changed, as shown in FIG. 12, the outside wind pressure, the duct length, etc. An air volume-static pressure characteristic in which the air volume does not change greatly even if the pressure loss changes can be easily obtained. Here, since the correlation is determined by the exposed portion of the brushless DC motor 30, the brushless DC motor 30 can be all the same including the winding specification and the magnet specification, and can be standardized.

  Further, in the brushless DC motor 30, since the resistance value of the variable resistor 17a connected to the supply current reference set value indicating means 20 can be arbitrarily set, the torque in the rotation speed-torque characteristic of the motor can be arbitrarily adjusted. In the ventilator 36 equipped with the blower 37, an electric device such as a brushless DC motor directly connected to an AC power source that can easily adjust the set air volume and a ventilator equipped with the brush is obtained. Here, since the reference set value of the supply current is determined at the exposed portion of the brushless DC motor 30, all the brushless DC motors 30 including the winding specifications and the magnet specifications can be made the same and standardized.

  Although the current value detection means 21 is provided on the GND side in the second embodiment, it may be provided on the power supply side, and there is no difference in the operational effect.

  In addition, there is no difference in the operational effect in the configuration similar to the configuration shown in the first embodiment.

  In the second embodiment, the resistors connected to the correlation indicating unit 29 and the supply current reference set value indicating unit 20 are both variable resistors 17a and 17b, and both are exposed, but only one of them is exposed. May be configured to be variable, or only one of them may be exposed, and may be selected as appropriate in consideration of the degree of freedom in setting the rotational speed-torque characteristics in the motor and standardization.

  In the second embodiment, the variable resistors 17a and 17b are exposed. However, a switch for switching a resistor such as a dip switch may be exposed to change the resistance value internally. The setting of the rotational speed-torque characteristic at is only stepwise, and there is no difference in other operational effects.

  As described above, the AC power supply direct-coupled brushless DC motor according to the present invention has a characteristic that the shaft torque increases as the rotational speed increases in the rotational speed-torque characteristics. Air conditioners such as ventilators, water heaters, air conditioners, air purifiers, dehumidifiers, dryers, fan filter units that are required to have no significant air flow changes even when there is a change in static pressure It is useful to install on.

The block diagram which shows the alternating current power supply direct connection type brushless DC motor in Embodiment 1 of this invention Sectional view showing the brushless DC motor The graph which shows the output voltage-current characteristic of the low voltage direct current voltage conversion means of the same brushless DC motor Graph showing rotation speed-torque characteristics of the brushless DC motor Three views showing a ventilator equipped with the brushless DC motor ((a) Front view of ventilator, (b) Side view of ventilator, (c) Plan view of ventilator) Graph showing the airflow-static pressure characteristics of a ventilator equipped with the brushless DC motor A graph showing other airflow-static pressure characteristics of a ventilator equipped with the brushless DC motor The block diagram which shows the alternating current power supply direct connection type brushless DC motor in Embodiment 2 of this invention Graph showing duty command voltage-current characteristics of the brushless DC motor Graph showing rotation speed-torque characteristics of the brushless DC motor Three views showing a ventilator equipped with the brushless DC motor ((a) Front view of ventilator, (b) Side view of ventilator, (c) Plan view of ventilator) Graph showing the airflow-static pressure characteristics of a ventilator equipped with the brushless DC motor Block diagram showing a conventional DC motor Sectional view showing the DC motor Graph comparing airflow-static pressure characteristics in a ventilator equipped with the DC motor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Brushless DC motor 2 Drive coil 3 Magnet rotor 4 Magnetic flux density distribution detection means 4a Magnetic flux density distribution waveform synthesis means 5 Drive logic control means 6 Inverter circuit 7 Current waveform control means 8 Low voltage DC voltage conversion means 9 Rectification means 10 Stator 10a Stator core 11 Insulator 12a Recess 12b Recess 13 Correlation indicating means 14 Low voltage DC voltage changing means 15 AC power source connecting means 16 Supply current value control means 17a Variable resistance 17b Variable resistance 18 Smoothing capacitor 19 Current value indicating means 20 Supply current Reference set value indicating means 21 Current value detecting means 22 Integrated circuit 23 Centrifugal blower 24 Shaft 25 Bracket 26 Bearing 27 Thermosetting resin 28 Ventilator 29 Correlation indicating means 30 Brushless DC motor 31 Duty indicating voltage generating means 32 PWM control means 33 Current waveform control means 34 Drive logic control means 35 Low voltage DC voltage conversion means 36 Ventilator 37 Centrifugal blower Q1 Upper stage switching element Q2 Lower stage switching element Q3 Upper stage switching element Q4 Lower stage switching element Q5 Upper stage switching Element Q6 Lower stage switching element

Claims (6)

A brushless DC motor that is directly connected to an AC power source, and includes a stator having a stator core wound with a drive coil via an insulator, and a magnet rotation provided with a permanent magnet rotatably disposed opposite the stator. A magnetic pole position detecting means for detecting the magnetic pole position of the magnet rotor, a rectifying means for full-wave rectifying the AC power supply, and an inverter circuit comprising an upper stage and a lower stage, each bridged by a plurality of switching elements. The low voltage DC voltage converting means formed by a chopper circuit that converts the high voltage obtained by the rectifying means into a low voltage DC voltage and applied to the inverter circuit, and the signal of the magnetic pole position detecting means, Drive logic for sequentially energizing the drive coil with a low voltage DC voltage generated by the DC voltage conversion means in a predetermined direction and order through the inverter circuit. Control means, supply current value control means for controlling the average current supplied to the inverter circuit substantially constant, current value instruction means for indicating the average current value controlled substantially constant by the supply current value control means, Correlation indicating means for instructing the correlation between the voltage value of the low voltage DC voltage generated by the low voltage DC voltage converting means and the average current value indicated by the current value indicating means according to the resistance value, and the current value A supply current reference set value indicating means for determining a reference current set value indicated by the indicating means according to a resistance value to be connected, wherein the current value indicating means is a reference determined by the supply current reference set value indicating means The current setting value is increased or decreased so as to be the correlation indicated by the correlation indicating means, the resistance connected to the correlation indicating means, and the supply current reference setting value indicating means Either one or both of the resistor connected to the variable AC power source directly connected brushless DC motor is characterized by providing exposed to either or both of the variable and the resistance. A brushless DC motor that is directly connected to an AC power source, and includes a stator having a stator core wound with a drive coil via an insulator, and a magnet rotation provided with a permanent magnet rotatably disposed opposite the stator. A magnetic pole position detecting means for detecting the magnetic pole position of the magnet rotor, an inverter circuit composed of an upper stage and a lower stage, each bridge-connected with a plurality of switching elements, and PWM control of the upper stage or the lower stage of the switching elements And a drive logic control means for sequentially energizing the drive coil in a predetermined direction and order based on a signal from the magnetic pole position detection means, a rectifying means for full-wave rectifying the AC power supply, and this rectification. Low voltage DC voltage converting means formed by a chopper circuit for converting the high voltage obtained by the means into a substantially constant low voltage DC voltage and applying it to the inverter circuit The low voltage direct current voltage generated by the low voltage direct current voltage conversion means is reduced in pressure and is supplied to the inverter circuit as duty instruction voltage generation means for indicating the ON / OFF duty when the switching element is PWM controlled. Supply current value control means for controlling the average current to be substantially constant, current value instruction means for instructing an average current value to be controlled to be substantially constant by the supply current value control means, and voltage generated by the duty instruction voltage generation means Correlation indicating means for indicating the correlation between the value and the average current value indicated by the current value indicating means according to the connected resistance value, and the resistor for connecting the reference current set value indicated by the current value indicating means Supply current reference set value indicating means determined according to the value, wherein the current value indicating means is determined by the supply current reference set value indicating means The instruction current is increased / decreased so that the reference current set value becomes the correlation instructed by the correlation instruction means, and the resistance connected to the correlation instruction means and the resistance connected to the supply current reference set value instruction means An AC power supply direct connection type brushless DC motor characterized in that either or both of them are made variable, and either or both of these variable resistors are exposed. A brushless DC motor that is directly connected to an AC power source, and includes a stator having a stator core wound with a drive coil via an insulator, and a magnet rotation provided with a permanent magnet rotatably disposed opposite the stator A magnetic flux density distribution detecting means for detecting the magnetic flux density distribution of the magnet rotor, a rectifying means for full-wave rectification of the AC power supply, and an inverter connected to each other by a plurality of switching elements. Based on a signal of a circuit, a low voltage DC voltage converting means formed by a chopper circuit for converting a high voltage obtained by the rectifying means into a low voltage DC voltage and applying it to the inverter circuit, and the magnetic flux density distribution detecting means The low-voltage direct-current voltage generated by the low-voltage direct-current voltage conversion means is used to sequentially carry out full-wave energization in a predetermined direction and order to the drive coil via the inverter circuit. The magnetic flux density distribution waveform detected by the dynamic logic control means and the magnetic flux density distribution detection means is substantially similar to the induced voltage waveform induced in the drive coil as the magnet rotor rotates. A density distribution detecting means is arranged, and a current waveform control means for supplying a current substantially similar to the waveform detected by the magnetic flux density distribution detecting means to the drive coil, and an average current supplied to the inverter circuit are controlled to be substantially constant. Supply current value control means, current value indicating means for indicating an average current value controlled substantially constant by the supply current value control means, voltage value of the low-voltage DC voltage generated by the low-voltage DC voltage conversion means and the current Correlation indicating means for indicating the correlation with the average current value indicated by the value indicating means according to the connected resistance value, and indicating with the current value indicating means A supply current reference set value indicating means for determining a reference current set value according to a resistance value to which the reference current set value is connected, and the current value indicating means determines the reference current set value determined by the supply current reference set value indicating means as the correlation Increase or decrease the command current so that the correlation instructed by the relationship indicating unit is obtained, and either or both of the resistor connected to the correlation indicating unit and the resistor connected to the supply current reference set value indicating unit can be varied A brushless DC motor with direct connection to an AC power source, characterized in that either one or both of the variable resistors are exposed. A brushless DC motor that is directly connected to an AC power source, and includes a stator having a stator core wound with a drive coil via an insulator, and a magnet rotation provided with a permanent magnet rotatably disposed opposite the stator A magnetic flux density distribution detecting means for detecting the magnetic flux density distribution of the magnet rotor, a rectifying means for full-wave rectification of the AC power supply, and an inverter connected to each other by a plurality of switching elements. Based on a signal of a circuit, a low voltage DC voltage converting means formed by a chopper circuit for converting a high voltage obtained by the rectifying means into a low voltage DC voltage and applying it to the inverter circuit, and the magnetic flux density distribution detecting means The low-voltage direct-current voltage generated by the low-voltage direct-current voltage conversion means is used to sequentially carry out full-wave energization in a predetermined direction and order to the drive coil via the inverter circuit. The magnetic flux density distribution waveform detected by the dynamic logic control means and the magnetic flux density distribution detection means is substantially similar to the induced voltage waveform induced in the drive coil as the magnet rotor rotates. A density distribution detecting means is arranged, and a current waveform control means for supplying a current substantially similar to the waveform detected by the magnetic flux density distribution detecting means to the drive coil, and an average current supplied to the inverter circuit are controlled to be substantially constant. Supply current value control means, current value indicating means for indicating an average current value controlled substantially constant by the supply current value control means, voltage value of the low-voltage DC voltage generated by the low-voltage DC voltage conversion means and the current Correlation indicating means for indicating the correlation with the average current value indicated by the value indicating means according to the connected resistance value, and indicating with the current value indicating means A supply current reference set value indicating means for determining a reference current set value according to a resistance value to which the reference current set value is connected, and the current value indicating means determines the reference current set value determined by the supply current reference set value indicating means as the correlation Increase or decrease the command current so that the correlation instructed by the relationship indicating unit is obtained, and either or both of the resistor connected to the correlation indicating unit and the resistor connected to the supply current reference set value indicating unit can be varied A brushless DC motor with direct connection to an AC power source, characterized in that either one or both of the variable resistors are exposed. An electric device equipped with the brushless DC motor directly connected to an AC power source according to any one of claims 1 to 4. 6. The electrical apparatus according to claim 5, wherein the electrical apparatus is any one of a ventilator, a blower, a dehumidifier, a humidifier, an air conditioner, a water heater, and a fan filter unit.

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