JP2006060941A - Brushless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brushless motor capable of obtaining high output by driving its rotation even with a power supply of low voltage. <P>SOLUTION: For the brushless motor 50 of which the number P of poles in a magnetic rotor 54 is ≤16 and the output is ≤400 W and the efficiency is ≥70%, the number of turns of a three-phase armature winding 52 is set at two or less when a rotational speed of ≤4,000 and >2,000, three or less when the rotational speed is ≤2,000 and >1,000, and four or less when the rotational speed is below 1,000, thus stably driving the brushless motor 50. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to optimization of drive control when detecting and driving a rotational position of a magnet rotor of a brushless motor.

  A brushless motor is known as a motor without a brush and a commutator. This brushless motor is suitable for long-term driving because the brushed motor is in contact with the commutator and the brush is free from frictional wear. For this reason, it is widely used in environments where the frequency of use is high and maintenance is not performed regularly, such as water pumps for cooling vehicles and drive motors for various home appliances.

  The brushless motor is composed of a plurality of armature windings and a magnet rotor having N-pole and S-pole magnetic poles, and applies a voltage from a power source to each armature winding to pass a current. The magnet rotor is rotated by generating a rotating magnetic field in the armature winding. In addition, the armature winding has a self-induced back electromotive force due to a change in the flowing current when the voltage application is turned off during the period when the voltage application by the power supply is turned off and the next voltage application is turned on. After that, an induced voltage is generated due to the rotation of the magnet rotor.

By the way, since the brushless motor generates the rotating magnetic field in the armature winding, it is necessary to detect the rotational position of the magnet rotor and energize the armature winding at an appropriate timing. A method of detecting the induced voltage generated by the rotation of the magnet rotor is known for detecting the rotational position. In Patent Document 1, a magnet (so-called zero cross point) is detected by detecting a point (so-called zero-cross point) where an induced voltage detected after the occurrence of a self-induced counter electromotive voltage and a half of a power supply voltage (neutral point potential) coincide with each other. It describes that the rotational position of the rotor is detected. With this method of detecting the rotational position based on the induced voltage, the brushless motor does not need to be provided with a sensor or the like for detecting the rotational position of the magnet rotor, and the configuration of the drive circuit can be simplified.
Japanese Patent Laid-Open No. 2003-102191

  However, a brushless motor that rotates with a high voltage power source (for example, 100V power source) such as a home appliance and obtains a high output (for example, 400W output) is replaced with a low voltage power source (for example, 12V (actually for vehicles) The voltage value of 13.5V) may not be rotated even if it is rotated. The reason is as follows. With a low voltage power supply, it is necessary to pass more current through the armature winding than with a high voltage power supply in order to drive the brushless motor to rotate at the same output as the high voltage power supply. For this reason, when the voltage application from the low-voltage power supply is turned off, a larger amount of current flows in the armature winding than in the case of the high-voltage power supply. It is detected after the zero cross point at which the induced voltage due to the rotation of the rotor becomes 1/2 of the power supply voltage. As a result, the rotational position of the magnet rotor cannot be detected, and the timing for applying a voltage to the armature winding cannot be determined appropriately.

  As described above, a brushless motor that obtains a high output needs to flow as much as a low-voltage power supply, and the amount of current that flows through the armature winding depends on the efficiency of the brushless motor with respect to the power supplied from the power supply and the electric machine. It changes according to the number of turns of the conductor of the child winding.

  Also, since the induced voltage is generated by the rotation of the magnet rotor, the period from when the voltage application to the armature winding is turned off until the induced voltage becomes ½ of the power supply voltage is the rotational speed of the magnet rotor. And the number of poles (N pole, S pole). For example, if the number of poles of the magnet rotor is 4 even if the number of rotations is the same, if the magnet rotor rotates once, a sine wave of the induced voltage is generated for two cycles, so the number of poles of the magnet rotor is large. The period from when the voltage application is turned off until the induced voltage becomes 1/2 of the power supply voltage is shortened.

  For this reason, in a brushless motor, it is necessary to determine an appropriate number of poles, number of turns, and the like according to conditions such as required output, brushless motor efficiency, rotation speed, power supply voltage, and the like.

  In consideration of the above facts, an object of the present invention is to provide a brushless motor that can be rotationally driven even with a low-voltage power source and obtain a high output.

  According to the first aspect of the present invention, when the switch element is turned ON / OFF, a voltage from a power source is applied to the armature winding to pass a current, and the magnet rotor is rotated by the rotating magnetic field generated in the armature winding. A current due to a self-induced back electromotive voltage generated in the armature winding due to the switch element changing from ON to OFF flows through a diode provided so as to short-circuit the switch element, and the switch The neutral point of the voltage applied from the power supply and the induced voltage generated in the armature winding by the rotation of the magnet rotor after a current due to the self-induced counter electromotive voltage flows during the OFF period of the element Brushless for determining the next timing of turning on and off the switch element based on the rotational position information by detecting the point at which the potential coincides to obtain the rotational position information of the magnet rotor The power supply voltage is 13.5 V, the voltage drop due to the diode is 0.8 V, the number of magnetic poles of the magnet rotor is 16 poles or less, and the output obtained by the rotation of the magnet rotor is 400 W. When the efficiency of the brushless motor with respect to the electric power supplied from the power source is 70% or more, the armature winding in the case where the rotation number per unit of the magnet rotor is 4000 or less and greater than 2000 The armature when the number of turns of the conductor is 2 or less, the number of turns of the armature winding when the number of revolutions is 2000 or less and greater than 1000, and the number of revolutions is 1000 or less The number of turns of the conducting wire of the winding is 4 or less.

  According to the first aspect of the present invention, the power source voltage is a low voltage power source of 13.5 V, the voltage drop due to the diode is 0.8 V, the number of magnetic poles of the magnet rotor is 16, and the rotation of the magnet rotor Even if the output obtained by the above is 400 W and the efficiency with respect to the power supplied from the power source of the brushless motor is 70%, if the rotational speed per unit of the magnet rotor is 4000 or less and greater than 2000, the armature winding When the number of turns of the conducting wire is 2 or less, the number of turns of the armature winding is 3 or less when the number of revolutions is 2000 or less and greater than 1000, and the number of windings of the armature winding when the number of revolutions is 1000 or less Is set to 4 turns or less, it is possible to detect a point at which the induced voltage generated by the rotation of the magnet rotor matches the neutral point potential of the voltage applied from the power source. Therefore, the brushless motor can be stably rotated at a high output even with a low voltage power source.

  The invention according to claim 2 applies a voltage from a power source to the armature winding by turning on and off the switch element to flow current, and rotates the magnet rotor by the rotating magnetic field generated in the armature winding. A current due to a self-induced back electromotive voltage generated in the armature winding due to the switch element changing from ON to OFF flows through a diode provided so as to short-circuit the switch element, and the switch The neutral point of the voltage applied from the power supply and the induced voltage generated in the armature winding by the rotation of the magnet rotor after a current due to the self-induced counter electromotive voltage flows during the OFF period of the element Brushless for determining the next timing of turning on and off the switch element based on the rotational position information by detecting the point at which the potential coincides to obtain the rotational position information of the magnet rotor The power supply voltage is 13.5 V, the voltage drop due to the diode is 0.8 V, the number of magnetic poles of the magnet rotor is 16 poles or less, and the output obtained by the rotation of the magnet rotor is 300 W. When the efficiency of the brushless motor with respect to the electric power supplied from the power source is 70% or more, the armature winding in the case where the number of rotations per unit of the magnet rotor is 4000 or less and greater than 3000 The armature when the number of turns of the conductor is 2 or less, the number of turns of the armature winding when the number of revolutions is 3000 or less and greater than 1000, and the number of revolutions is 1000 or less The number of turns of the conducting wire of the winding is 5 or less.

  According to the invention described in claim 2, the power supply voltage is a low voltage power supply of 13.5V, the voltage drop due to the diode is 0.8V, the number of magnetic poles of the magnet rotor is 16, and the rotation of the magnet rotor Even if the output obtained by the above is 300 W and the efficiency of the brushless motor with respect to the electric power supplied from the power source is 70%, the armature winding is used when the rotational speed per unit of the magnet rotor is 4000 or less and greater than 3000 When the number of turns of the armature winding is 2 or less, the number of turns of the armature winding is 3 or less when the number of rotations is 3000 or less and greater than 1000, and when the number of rotations is 1000 or less, the number of turns of the armature winding By setting the number of turns to 5 or less, it is possible to detect a point at which the induced voltage generated by the rotation of the magnet rotor matches the neutral point potential applied from the power source. Therefore, the brushless motor can be stably rotated.

  The invention according to claim 3 applies a voltage from a power source to the armature winding by turning on and off the switch element to flow current, and rotates the magnet rotor by the rotating magnetic field generated in the armature winding. A current due to a self-induced back electromotive voltage generated in the armature winding due to the switch element changing from ON to OFF flows through a diode provided so as to short-circuit the switch element, and the switch The neutral point of the voltage applied from the power supply and the induced voltage generated in the armature winding by the rotation of the magnet rotor after a current due to the self-induced counter electromotive voltage flows during the OFF period of the element Brushless for determining the next timing of turning on and off the switch element based on the rotational position information by detecting the point at which the potential coincides to obtain the rotational position information of the magnet rotor The power supply voltage is 13.5 V, the voltage drop due to the diode is 0.8 V, the number of magnetic poles of the magnet rotor is 16 poles or less, and the output obtained by the rotation of the magnet rotor is 200 W. When the efficiency of the brushless motor with respect to the electric power supplied from the power source is 70% or more, the armature winding in the case where the rotation number per unit of the magnet rotor is 4000 or less and greater than 2000 The armature when the number of turns of the conductor is 3 or less, the number of turns of the armature winding when the number of revolutions is 2000 or less and greater than 1000, and the number of revolutions is 1000 or less The number of turns of the conducting wire of the winding is 6 or less.

  According to the invention described in claim 3, the power supply voltage is a low voltage power supply of 13.5V, the voltage drop due to the diode is 0.8V, the number of poles of the magnetic pole of the magnet rotor is 16, and the rotation of the magnet rotor is Even if the output obtained by the above is 200 W and the efficiency of the brushless motor with respect to the power supplied from the power source is 70%, if the rotational speed per unit of the magnet rotor is 4000 or less and greater than 2000, the armature winding When the number of turns of the conductor is 3 or less, the number of turns of the armature winding is 4 or less when the number of revolutions is 2000 or less and greater than 1000, and the number of turns of the armature winding when the number of revolutions is 1000 or less Is set to 6 or less, it is possible to detect a point where the induced voltage generated by the rotation of the magnet rotor matches the neutral point potential of the voltage applied from the power source. Therefore, the brushless motor can be stably rotated.

  The invention according to claim 4 applies a voltage from a power source to the armature winding by turning on and off the switch element to flow a current, and rotates the magnet rotor by the rotating magnetic field generated in the armature winding. A current due to a self-induced back electromotive voltage generated in the armature winding due to the switch element changing from ON to OFF flows through a diode provided so as to short-circuit the switch element, and the switch The neutral point of the voltage applied from the power supply and the induced voltage generated in the armature winding by the rotation of the magnet rotor after a current due to the self-induced counter electromotive voltage flows during the OFF period of the element Brushless for determining the next timing of turning on and off the switch element based on the rotational position information by detecting the point at which the potential coincides to obtain the rotational position information of the magnet rotor The power supply voltage is 13.5 V, the voltage drop due to the diode is 0.8 V, the number of magnetic poles of the magnet rotor is 16 poles or less, and the output obtained by the rotation of the magnet rotor is 400 W. When the efficiency of the brushless motor with respect to the power supplied from the power source is 80% or more, the armature winding of the magnet rotor when the number of rotations per unit of the magnet rotor is 4000 or less and greater than 3000 The armature when the number of turns of the conductor is 2 or less, the number of turns of the armature winding when the number of revolutions is 3000 or less and greater than 1000, and the number of revolutions is 1000 or less The number of turns of the conducting wire of the winding is 5 or less.

  According to the invention described in claim 4, the power supply voltage is a low voltage power supply of 13.5V, the voltage drop due to the diode is 0.8V, the number of magnetic poles of the magnet rotor is 16, and the rotation of the magnet rotor Even if the output obtained by the above is 400 W and the efficiency of the brushless motor with respect to the power supplied from the power source is 80%, if the rotational speed per unit of the magnet rotor is 4000 or less and greater than 3000, the armature winding When the number of turns of the conducting wire is 2 or less, the number of turns of the armature winding is 3 or less when the number of rotations is 3000 or less and greater than 1000, and the number of windings of the armature winding when the number of revolutions is 1000 or less Is set to 5 or less, it is possible to detect a point at which the induced voltage generated by the rotation of the magnet rotor matches the neutral point potential of the voltage applied from the power source. Therefore, the brushless motor can be stably rotated at a high output even with a low voltage power source.

  The invention according to claim 5 applies a voltage from the power source to the armature winding by turning on and off the switch element to flow current, and rotates the magnet rotor by the rotating magnetic field generated in the armature winding. A current due to a self-induced back electromotive voltage generated in the armature winding due to the switch element changing from ON to OFF flows through a diode provided so as to short-circuit the switch element, and the switch The neutral point of the voltage applied from the power supply and the induced voltage generated in the armature winding by the rotation of the magnet rotor after a current due to the self-induced counter electromotive voltage flows during the OFF period of the element Brushless for determining the next timing of turning on and off the switch element based on the rotational position information by detecting the point at which the potential coincides to obtain the rotational position information of the magnet rotor The power supply voltage is 13.5 V, the voltage drop due to the diode is 0.8 V, the number of magnetic poles of the magnet rotor is 16 poles or less, and the output obtained by the rotation of the magnet rotor is 300 W. When the efficiency of the brushless motor with respect to the power supplied from the power source is 80% or more, the armature winding of the armature winding when the number of rotations per unit of the magnet rotor is 4000 or less and greater than 2000 The armature when the number of turns of the conductor is 3 or less, the number of turns of the armature winding when the number of revolutions is 2000 or less and greater than 1000, and the number of revolutions is 1000 or less The number of turns of the conducting wire of the winding is 6 or less.

  According to the invention described in claim 5, the power supply voltage is a low voltage power supply of 13.5V, the voltage drop due to the diode is 0.8V, the number of magnetic poles of the magnet rotor is 16, and the rotation of the magnet rotor Even if the output obtained by the above is 300 W and the efficiency of the brushless motor with respect to the power supplied from the power source is 80%, if the rotational speed per unit of the magnet rotor is 4000 or less and greater than 2000, the armature winding When the number of turns of the conductor is 3 or less, the number of turns of the armature winding is 4 or less when the number of revolutions is 2000 or less and greater than 1000, and the number of turns of the armature winding when the number of revolutions is 1000 or less Is set to 6 or less, it is possible to detect a point where the induced voltage generated by the rotation of the magnet rotor matches the neutral point potential of the voltage applied from the power source. Therefore, the brushless motor can be stably rotated at a high output even with a low voltage power source.

  The invention described in claim 6 applies a voltage from a power source to the armature winding by turning on and off the switch element to flow current, and rotates the magnet rotor by the rotating magnetic field generated in the armature winding. A current due to a self-induced back electromotive voltage generated in the armature winding due to the switch element changing from ON to OFF flows through a diode provided so as to short-circuit the switch element, and the switch The neutral point of the voltage applied from the power supply and the induced voltage generated in the armature winding by the rotation of the magnet rotor after a current due to the self-induced counter electromotive voltage flows during the OFF period of the element Brushless for determining the next timing of turning on and off the switch element based on the rotational position information by detecting the point at which the potential coincides to obtain the rotational position information of the magnet rotor The power supply voltage is 13.5 V, the voltage drop due to the diode is 0.8 V, the number of magnetic poles of the magnet rotor is 16 poles or less, and the output obtained by the rotation of the magnet rotor is 200 W. When the efficiency of the brushless motor with respect to the power supplied from the power source is 80% or more, the armature winding of the magnet rotor when the number of rotations per unit of the magnet rotor is 4000 or less and greater than 3000 When the number of turns of the conductor is 3 or less, the number of turns of the conductor of the armature winding when the number of revolutions is 3000 or less and more than 2000, and the number of turns is 2000 or less and more than 1000 The number of turns of the conductor of the armature winding is 5 or less, and the number of turns of the conductor of the armature winding when the number of rotations is 1000 or less, That.

  According to the invention described in claim 6, the power supply voltage is a low voltage power supply of 13.5V, the voltage drop due to the diode is 0.8V, the number of magnetic poles of the magnet rotor is 16, and the rotation of the magnet rotor Even if the output obtained by the above is 200 W and the efficiency of the brushless motor with respect to the power supplied from the power source is 80%, if the rotational speed per unit of the magnet rotor is 4000 or less and greater than 3000, the armature winding When the number of turns of the conducting wire is 3 or less, the number of turns of the armature winding is 4 or less when the number of revolutions is 3000 or less and more than 2000, and when the number of revolutions is 2000 or less and more than 1000, When the number of turns of the conducting wire is 5 or less and the number of revolutions is 1000 or less, the number of turns of the conducting wire of the armature winding is 6 or less so that the induced voltage generated by the rotation of the magnet rotor Can detect the point at which the neutral point potential of the voltage applied from the power source, it is consistent. Therefore, the brushless motor can be stably rotated.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a brushless motor 50 and a brushless motor driving apparatus 10 according to the present embodiment.

  The brushless motor 50 includes a magnet rotor 54 and a three-phase armature winding 52 in which U, V, and W armature windings are star-connected.

  The brushless motor driving apparatus 10 is connected to a power source (not shown), detects the rotational position of the inverter unit 14 that switches the energization of the three-phase armature winding 52 in response to a driving signal to be described later, and the magnet rotor 54. Based on a rotor position detection unit 16 that outputs a phase rotation position signal, a delay unit 20 that delays a three-phase rotation position signal and outputs a three-phase energization switching timing signal, and a three-phase energization switching timing signal A motor energization switching control unit 22 that outputs a drive signal, a rotation speed detection unit 24 that detects the rotation speed of the magnet rotor 54 from the U phase of the three-phase rotation position signal, and outputs a rotation speed signal; The delay unit 20 includes a delay amount adjusting unit 34 that adjusts a delay amount for delaying the rotational position signal based on the signal, a CPU, a RAM, a ROM, and a bus that connects them. It has been.

  Each phase of the three-phase armature winding 52 is connected to the output terminal of the inverter unit 14 and the rotor position detection unit 16. The three-phase armature winding 52 is switched in energization by a drive signal to generate a rotating magnetic field of 120 ° square wave energization.

  The magnet rotor 54 rotates by receiving torque from the rotating magnetic field generated in the three-phase armature winding 52. In addition, when the magnet rotor 54 rotates, an induced voltage is generated in each phase of the three-phase armature winding 52. Note that the magnet rotor 54 shown in FIG. 1 has two poles (N pole and S pole are one pole each).

  The inverter unit 14 is composed of a circuit in which three pairs (a total of six) switching elements U +, U−, V +, V−, W +, and W− are connected in a three-phase bridge. Is connected to each phase of the unit 22 and the three-phase armature winding 52, receives a drive signal (see the drive signal in FIG. 2) from the motor energization switching control unit 22, and the three-phase armature winding 52 is energized with a 120 ° square wave. The energization switching is performed. Each switching element has a diode 17 that connects (short-circuits) both ends in parallel, and one end side of each of the switching elements U−, V−, and W− is GND.

  The rotor position detection unit 16 is connected to each phase of the three-phase armature winding 52 and the delay unit 20, and extracts a pseudo-induced voltage from the terminal voltage of the three-phase armature winding 52 through a low-pass filter. Detects a zero cross point at which ½ of the power supply voltage (neutral point potential) is detected, and a three-phase rotational position signal (U phase, V phase, W phase) (see the rotational position signal in FIG. 2) is a delay unit 20 Output to.

  The delay unit 20 is connected to the rotor position detection unit 16, the motor energization switching control unit 22, and the delay amount adjustment unit 34. The delay unit 20 calculates the delay amount calculated by the delay amount adjustment unit 34 described later with respect to the three-phase rotation position signal. Delay is performed, and a three-phase energization switching timing signal (U phase, V phase, W phase) (see the energization switching timing signal in FIG. 2) is output.

  The motor energization switching control unit 22 is connected to the delay unit 20 and the inverter unit 14 and outputs a drive signal (see the drive signal in FIG. 2) based on the timing at which the value of the energization switching timing signal changes. Further, the drive signals U +, V +, W +, U−, V−, and W− output from the motor energization switching control unit 22 are pulse width modulated, but in FIG. 2, the drive signals are shown as rectangular waves. . Furthermore, one end side of the switching elements U +, V−, and W− is GND.

  The rotational speed detection unit 24 is connected to the U phase of the rotational position signal and the delay amount adjusting unit 34, detects the rotational speed of the magnet rotor 54 from the U phase of the rotational position signal, and converts the rotational speed signal into the delay amount adjusting unit. 34.

  The delay amount adjustment unit 34 is connected to the delay unit 20 and the rotation speed detection unit 24, calculates a delay amount for delaying the three-phase rotation position signal based on the rotation speed signal sent from the rotation speed detection unit 24, and delays the delay amount adjustment unit 34. To the unit 20. In the present embodiment, the delay amount calculated by the delay amount adjusting unit 34 is a period corresponding to an electrical angle of 30 °.

  Next, the flow of each signal for driving the brushless motor 50 and the voltage generated in the three-phase armature winding 52 will be described.

  When a drive signal for 120 ° square wave energization (see the drive signal in FIG. 2) is output from the motor energization switching control unit 22 to each phase of the three-phase armature winding 52, energization is turned on at an electrical angle of 120 °. The energization OFF with an electrical angle of 60 ° is repeated, and a rotating magnetic field is generated. The magnet rotor 54 receives torque from the rotating magnetic field and rotates.

  FIG. 3 shows the voltage generated at the V-phase terminal of the three-phase armature winding 52. The voltage generated in the three-phase armature winding 52 oscillates at a short timing because the drive signal is pulse-width modulated, but in FIG. 3, the voltage waveform is shown as a rectangular wave.

  As shown in FIG. 3, the voltage from the power source is applied to the V phase of the three-phase armature winding 52 when the drive signal V + is ON (see period t1 in FIG. 2) (period t2 in FIG. 3). reference). Further, when the drive signal V- is turned ON (refer to a period t3 in FIG. 2), the voltage of the GND is set (refer to a period t4 in FIG. 3). Further, when V + or V− of the drive signal is turned OFF, the current flowing in the V phase changes, so that a self-induced counter electromotive voltage is generated in the V phase (see period t5 in FIG. 3). The self-inducted counter electromotive voltage causes a current to flow, and energy accumulated in the V phase of the three-phase armature winding 52 is released by energization while the switch element V + or V− is ON. When the release of the stored energy ends, the induced voltage (see period t6 in FIG. 3) is exposed.

  The rotor position detector 16 detects a point (see zero cross point in FIG. 3) where the terminal voltage of each phase of the three-phase armature winding 52 becomes 1/2 (neutral point potential) of the voltage from the power source. The three-phase rotational position signal (see the rotational position signal (V phase) in FIG. 2) is output to the delay unit 20. Therefore, the rotor position detector 16 detects the zero cross point where the voltage crosses the neutral point potential during the period in which the induced voltage is exposed in the V phase (see the period t6 in FIG. 3). The value changes at the zero cross point (see the rotational position signal (V phase) in FIG. 2).

  The delay unit 20 delays the detected three-phase rotational position signal (see the rotor position signal in FIG. 2) for a period corresponding to an electrical angle of 30 ° calculated by the delay amount adjusting unit 34. A phase energization switching timing signal (see the energization switching timing signal in FIG. 2) is output to the motor energization switching control unit 22.

  The motor energization switching control unit 22 outputs a 120 ° square wave energization drive signal (see the drive signal in FIG. 2) for rotating the magnet rotor 54 to the inverter unit 14 based on the three-phase energization switching timing signal. Thus, in the inverter unit 14, the switch elements U +, U−, V +, V−, W +, and W− are turned on and off based on the drive signal, and the energization ON with an electrical angle of 120 ° and the energization OFF with an electrical angle of 60 ° are performed. Repeatedly, a rotating magnetic field is generated in each phase of the three-phase armature winding 52.

  Here, in FIG. 4A, during the period t8 in FIG. 3, and in FIG. 4B during the period t7 in FIG. Show the flow.

  In the period t8 in FIG. 3, the drive signals U + and V− are ON (see the period t9 in FIG. 2), and as shown by the broken line in FIG. A current flows to the switching element V− through the U phase and the V phase of 52. When the period t8 in FIG. 3 elapses, the drive signal V− is turned off and the drive signal W− is turned on (see arrow t10 in FIG. 2), so that the current from the power source is as shown in FIG. 4B. A current flows from the switch element U + to the switch element W− through the U phase and the W phase of the three-phase armature winding 52. At this time, the current flowing in the period t8 in FIG. 3 (current indicated by the broken line in FIG. 4A) does not flow in the V phase of the three-phase armature winding 52. Electric power is generated, and the back electromotive force causes the diode 17 connected in parallel with the switch element V + from the V phase of the three-phase armature winding 52, the switch element U +, and the three-phase armature winding, as shown by a one-dot chain line. A current passing through the U phase of the wire 52 flows, and energy stored by the electrical resistance of the three-phase armature winding 52 is released. Since the diode 17 has a larger voltage drop in the reverse direction than in the forward direction, the current in the reverse direction is prevented from flowing. Further, a voltage drop (0.8 V in the diode 117 of the present embodiment) is also generated when a current flows in the forward direction.

  Here, in the brushless motor 50, as shown in FIG. 3, the detection of the zero cross point between the induced voltage (see period 6 in FIG. 3) and the neutral point potential is performed in the middle of an electrical angle of 60 ° when the energization is turned off. It is detected at the 30 ° portion of the point. The period corresponding to the electrical angle of 30 ° becomes shorter as the number of rotations of the brushless motor increases. Further, since the induced voltage is generated by one cycle of a sine wave of the induced voltage due to a pair of N poles and S poles when the magnet rotor rotates, the period corresponding to an electrical angle of 30 ° becomes shorter as the number of poles increases. Become. That is, even if the magnet rotor has the same number of revolutions, for example, in the case of a 4-pole magnet rotor 54, two cycles of the sine wave of the induced voltage are generated while the magnet rotor 54 makes one rotation, so one cycle The period during which the induced voltage can be detected between the sine waves is shortened.

  Therefore, in the period T in which one electrical period (electrical angle 360 °) is an electrical angle 30 °, when the number of poles of the magnet rotor is P and the rotational number (rpm) is N,

となり、変換することにより
Ｔ＝１０／（Ｐ×Ｎ）・・・（２）
となる。なお、（１）式では、極数Ｐが磁石回転子５４のＮ極とＳ極の磁極の数をカウントしたもので必ず偶数となり、１対のＮ極とＳ極により正弦波が1周期検出されるために極数Ｐを２で割っており、また、回転数Ｎ［ｒｐｍ］は、１分間にあたりに回転数する数であるため、１分間の秒数６０で割ることにより１秒当たり回転数としている。

And T = 10 / (P × N) (2)
It becomes. In equation (1), the number P of poles is the number of N poles and S poles of the magnet rotor 54, which is always an even number, and a pair of N poles and S poles detects one cycle of a sine wave. Therefore, the number of poles P is divided by 2, and the number of revolutions N [rpm] is the number of revolutions per minute. Therefore, the number of revolutions per second is obtained by dividing by the number of seconds 60 per minute. It is a number.

  In order to detect the zero-cross point, it is necessary to make the period in which the above-described self-induced back electromotive force is generated smaller than the period T obtained by the equation (2).

  Since the period during which this self-inducted counter electromotive force is generated varies depending on the magnetic field generated in the three-phase armature winding 52, the amount of current flowing in the three-phase armature winding 52 and the three-phase armature winding Depends on the number of turns of the 52 conductors.

  Therefore, the applicant of the present application has experimentally changed the number of poles of the magnet rotor 54 from 6 poles to 16 poles as shown in FIG. 5 to FIG. (Period during which self-induced back electromotive force is generated) was measured.

  5A to 5H show measurement results when the number of poles P of the magnet rotor 54 is six.

  5A to 5C measure the cases where the efficiency of the brushless motor 50 is 70% and the output of the brushless motor 50 is 200 W, 300 W, and 400 W, respectively.

  5D to 5F measure the cases where the efficiency of the brushless motor 50 is 80% and the output of the brushless motor 50 is 200 W, 300 W, and 400 W, respectively.

  FIGS. 5G to 5I measure the cases where the efficiency of the brushless motor 50 is 85% and the output of the brushless motor 50 is 200 W, 300 W, and 400 W, respectively.

  5A to 5H, the applied voltage by the power source is 13.5 V, and the voltage drop Vf is 0.8 V by the diode 17 (the same applies to FIGS. 6 to 10 described later). In addition, this applied voltage assumes the case where the 12V battery for vehicles is used as a power supply.

  5A to 5H, for each number of rotations of the brushless motor 50, an actual measurement value of a period during which a current flows in the diode 17, an allowable value of the period T obtained from the equation (2), Judgment is shown.

  The allowable value is calculated from the equation (2). When the number of poles P of the magnet rotor 54 is six, T = 1.667 [ms] when the rotation speed N is 1000 rpm, and T = when the rotation speed N is 2000 rpm. 0.833 [ms], T = 0.556 [ms] when the rotational speed N is 3000 rpm, and T = 0.417 [ms] when the rotational speed N is 4000 rpm.

  The determination is “◯” when the measured value is smaller than the allowable value (actual value <allowable value), and “X” when the measured value is equal to or greater than the allowable value (actual value ≧ allowable value).

  On the other hand, on the horizontal axis of FIGS. 5A to 5H, the number of turns of the conductive wire of each phase of the three-phase armature winding 52 is changed from 1 to 6.

  At the number of rotations and the number of turns at which this determination is “◯”, the period during which the self-induced counter electromotive voltage is generated is less than 30 °, so that the zero cross point between the induced voltage and the neutral point potential can be detected. Since the rotational position of the magnet rotor 54 can be detected, the brushless motor 50 can be driven to rotate.

  Therefore, as shown in FIG. 5C, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 6 poles or less, the output is 400 W or less, and the efficiency is 70% or more, the rotational speed is 4000 or less and 2000 When the number is large, the number of turns of the three-phase armature winding 52 is 4 or less, and when the number of rotations is 2000 or less and greater than 1000, the number of turns of the three-phase armature winding 52 is 5 or less and the number of rotations is 1000 or less. In this case, by setting the number of turns of the three-phase armature winding 52 to 6 or less, the brushless motor 50 can be driven stably.

  As shown in FIG. 5 (B), in the case of the brushless motor 50 having the magnetic rotor 54 having a pole number P of 6 poles or less, an output of 300 W or less, and an efficiency of 70% or more, the rotation speed is 4000 or less and greater than 3000. In the case where the number of turns of the three-phase armature winding 52 is 4 or less, the number of turns of the three-phase armature winding 52 is 5 or less when the number of revolutions is 3000 or less and greater than 2000, and the number of revolutions is 2000 or less. By setting the number of turns of the three-phase armature winding 52 to 6 or less, the brushless motor 50 can be driven stably.

  As shown in FIG. 5A, in the case of the brushless motor 50 in which the number P of the magnet rotor 54 is 6 poles or less, the output is 200 W or less, and the efficiency is 70% or more, the rotational speed is 4000 or less and greater than 3000. In addition, the number of turns of the three-phase armature winding 52 is set to 5 or less, and when the number of rotations is 3000 or less, the number of turns of the three-phase armature winding 52 is set to 6 or less to drive the brushless motor 50 stably. Can be made.

  As shown in FIGS. 5F and 5I, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 6 poles or less, the output is 400 W or less, and the efficiency is 80% or more, the rotational speed is 4000 or less and When the number is greater than 3000, the number of turns of the three-phase armature winding 52 is 4 or less, and when the number of rotations is 3000 or less and greater than 2000, the number of turns of the three-phase armature winding 52 is 5 or less. By setting the number of turns of the three-phase armature winding 52 to 6 or less in the following cases, the brushless motor 50 can be driven stably.

  As shown in FIG. 5E, in the brushless motor 50 in which the number P of the magnetic rotor 54 is 6 poles or less, the output is 300 W or less, and the efficiency is 80% or more, the rotation speed is 4000 or less and greater than 2000. In addition, the number of turns of the three-phase armature winding 52 is set to 5 or less, and when the number of rotations is 2000 or less, the number of turns of the three-phase armature winding 52 is set to 6 or less to drive the brushless motor 50 stably. Can be made.

  As shown in FIG. 5H, in the case of the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 6 poles or less, the output is 300 W or less, and the efficiency is 85% or more, the rotation speed is 4000 or less and greater than 3000. In addition, the number of turns of the three-phase armature winding 52 is set to 5 or less, and when the number of rotations is 3000 or less, the number of turns of the three-phase armature winding 52 is set to 6 or less to drive the brushless motor 50 stably. Can be made.

  Next, FIGS. 6A to 6H show measurement results when the number of poles P of the magnet rotor 54 is eight.

  6A to 6C measure the cases where the efficiency of the brushless motor 50 is 70% and the output of the brushless motor 50 is 200 W, 300 W, and 400 W, respectively.

  6D to 6F measure the cases where the efficiency of the brushless motor 50 is 80% and the output of the brushless motor 50 is 200 W, 300 W, and 400 W, respectively.

  6 (G) to 6 (I) measure the cases where the efficiency of the brushless motor 50 is 85% and the output of the brushless motor 50 is 200 W, 300 W, and 400 W, respectively.

  The allowable values of (A) to (H) in FIG. 6 are calculated from the equation (2). When the number of poles P of the magnet rotor 54 is eight, T = 1.25 [ms when the number of revolutions N is 1000 rpm. When the rotational speed N is 2000 rpm, T = 0.625 [ms], when the rotational speed N is 3000 rpm, T = 0.417 [ms], and when the rotational speed N is 4000 rpm, T = 0.313 [ms]. Become.

  The vertical axis of (A) to (H) in FIG. 6 is provided with an actual measurement value, the allowable value, and the determination, similarly to the vertical axis of FIG. 5, and (A) to (H) in FIG. The horizontal axis of FIG. 5 changes the number of turns of the conducting wire of each phase of the three-phase armature winding 52 from 1 to 6 as in the horizontal axis of FIG.

  Therefore, as shown in FIG. 6C, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 8 poles or less, the output is 400 W or less, and the efficiency is 70% or more, the rotational speed is 4000 or less and 3000 When the number is large, the number of turns of the three-phase armature winding 52 is 3 or less, and when the number of rotations is 3000 or less and greater than 1000, the number of turns of the three-phase armature winding 52 is 4 or less and the number of rotations is 1000 or less. In this case, by setting the number of turns of the three-phase armature winding 52 to 6 or less, the brushless motor 50 can be driven stably.

  As shown in FIG. 6B, in the case of the brushless motor 50 having the pole number P of the magnet rotor 54 of 8 poles or less, an output of 300 W or less, and an efficiency of 70% or more, the rotation speed is 4000 or less and greater than 3000. When the number of turns of the three-phase armature winding 52 is 3 or less, and the number of rotations is 3000 or less and greater than 2000, the number of turns of the three-phase armature winding 52 is 4 or less, and the number of rotations is 2000 or less and 1000 The brushless motor 50 is stabilized by setting the number of turns of the three-phase armature winding 52 to 5 or less when the number is large and setting the number of turns of the three-phase armature winding 52 to 6 or less when the rotation speed is 1000 or less. Can be driven.

  As shown in FIG. 6A, in the case of the brushless motor 50 in which the number P of the magnetic rotor 54 is 8 poles or less, the output is 200 W or less, and the efficiency is 70% or more, the rotation speed is 4000 or less and greater than 3000. In the case where the number of turns of the three-phase armature winding 52 is 4 or less, the number of turns of the three-phase armature winding 52 is 5 or less when the number of revolutions is 3000 or less and greater than 2000, and the number of revolutions is 2000 or less. By setting the number of turns of the three-phase armature winding 52 to 6 or less, the brushless motor 50 can be driven stably.

  As shown in FIGS. 6F and 6I, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 8 poles or less, the output is 400 W or less, and the efficiency is 80% or more, the rotational speed is 4000 or less and If it is greater than 3000, the number of turns of the three-phase armature winding 52 is 3 or less, and if the number of revolutions is 3000 or less and greater than 2000, the number of turns of the 3-phase armature winding 52 is 4 or less and the number of revolutions is 2000. The number of turns of the three-phase armature winding 52 is set to 5 or less when the number is less than 1000 and the number of turns of the three-phase armature winding 52 is set to 6 or less when the number of rotations is 1000 or less. 50 can be driven stably.

  As shown in FIGS. 6E and 6H, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 8 poles or less, the output is 300 W or less, and the efficiency is 80% or more, the rotational speed is 4000 or less and When the number is greater than 3000, the number of turns of the three-phase armature winding 52 is 4 or less, and when the number of rotations is 3000 or less and greater than 2000, the number of turns of the three-phase armature winding 52 is 5 or less. By setting the number of turns of the three-phase armature winding 52 to 6 or less in the following cases, the brushless motor 50 can be driven stably.

  As shown in FIGS. 6D and 6G, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 8 poles or less, the output is 200 W or less, and the efficiency is 80% or more, the rotational speed is 4000 or less and When the rotational speed is 3000 or less, the number of turns of the three-phase armature winding 52 is set to 5 or less when the rotational speed is 3000 or less. It can be driven stably.

  Next, FIGS. 7A to 7H show measurement results when the number of poles P of the magnet rotor 54 is 10 poles.

  7A to 7C measure the cases where the efficiency of the brushless motor 50 is 70% and the output of the brushless motor 50 is 200 W, 300 W, and 400 W, respectively.

  7D to 7F measure the cases where the efficiency of the brushless motor 50 is 80% and the output of the brushless motor 50 is 200 W, 300 W, and 400 W, respectively.

  FIGS. 7G to 7I measure the cases where the efficiency of the brushless motor 50 is 85% and the output of the brushless motor 50 is 200 W, 300 W, and 400 W, respectively.

  The allowable values of (A) to (H) in FIG. 7 are calculated from the equation (2). When the number of poles P of the magnet rotor 54 is 10, the T = 1.00 [ms when the number of revolutions N is 1000 rpm. When the rotational speed N is 2000 rpm, T = 0.500 [ms], when the rotational speed N is 3000 rpm, T = 0.333 [ms], and when the rotational speed N is 4000 rpm, T = 0.250 [ms]. Become.

  The vertical axis of (A) to (H) in FIG. 7 is provided with an actual measurement value, the allowable value, and the determination, similarly to the vertical axis of FIG. 5, and (A) to (H) in FIG. The horizontal axis of FIG. 5 changes the number of turns of the conducting wire of each phase of the three-phase armature winding 52 from 1 to 6 as in the horizontal axis of FIG.

  Therefore, as shown in FIGS. 7C and 7F, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 10 poles or less, the output is 400 W or less, and the efficiency is 70% or more, the rotational speed is 4000. If the number is less than 2000 and greater than 2000, the number of turns of the three-phase armature winding 52 is 3 or less. If the number of revolutions is 2000 or less and greater than 1000, the number of turns of the three-phase armature winding 52 is 4 or less. The brushless motor 50 can be driven stably by setting the number of turns of the three-phase armature winding 52 to 6 or less when is less than 1000.

  As shown in FIGS. 7B, 7E, and 7H, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 10 poles or less, the output is 300 W or less, and the efficiency is 70% or more, the rotational speed Is less than 4000 and greater than 3000, the number of turns of the three-phase armature winding 52 is 3 or less, and when the rotational speed is less than 3000 and greater than 2000, the number of turns of the 3-phase armature winding 52 is 4 or less, When the rotation speed is 2000 or less and greater than 1000, the number of turns of the three-phase armature winding 52 is 5 or less, and when the rotation speed is 1000 or less, the number of turns of the 3-phase armature winding 52 is 6 or less. Thus, the brushless motor 50 can be driven stably.

  As shown in FIG. 7A, in the case of the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 10 poles or less, the output is 200 W or less, and the efficiency is 70% or more, the rotation speed is 4000 or less and greater than 2000. In addition, the number of turns of the three-phase armature winding 52 is set to 4 or less, and when the number of rotations is 2000 or less, the number of turns of the three-phase armature winding 52 is set to 6 or less to drive the brushless motor 50 stably. Can be made.

  As shown in FIGS. 7D and 7G, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 10 poles or less, the output is 200 W or less, and the efficiency is 80% or more, the rotational speed is 4000 or less and When the number is greater than 3000, the number of turns of the three-phase armature winding 52 is 4 or less, and when the number of rotations is 3000 or less and greater than 2000, the number of turns of the three-phase armature winding 52 is 5 or less. By setting the number of turns of the three-phase armature winding 52 to 6 or less in the following cases, the brushless motor 50 can be driven stably.

  As shown in FIG. 7 (I), in the case of the brushless motor 50 having the pole number P of the magnet rotor 54 of 10 poles or less, an output of 400 W or less, and an efficiency of 85% or more, the rotation speed is 4000 or less and greater than 3000. In the case where the number of turns of the three-phase armature winding 52 is 3 or less, the number of turns of the three-phase armature winding 52 is 4 or less when the number of revolutions is 3000 or less and greater than 1000, and the number of revolutions is 1000 or less. By setting the number of turns of the three-phase armature winding 52 to 6 or less, the brushless motor 50 can be driven stably.

  Next, FIGS. 8A to 8H show measurement results when the number of poles P of the magnet rotor 54 is 12 poles.

  8A to 8C measure the cases where the efficiency of the brushless motor 50 is 70% and the output of the brushless motor 50 is 200 W, 300 W, and 400 W, respectively.

  8D to 8F measure the cases where the efficiency of the brushless motor 50 is 80% and the output of the brushless motor 50 is 200 W, 300 W, and 400 W, respectively.

  FIGS. 8G to 8I measure the cases where the efficiency of the brushless motor 50 is 85% and the output of the brushless motor 50 is 200 W, 300 W, and 400 W, respectively.

  The allowable values of (A) to (H) in FIG. 8 are calculated from the equation (2). When the number of poles P of the magnet rotor 54 is 12, the rotation number N is 1000 rpm and T = 0.833 [ms]. When the rotational speed N is 2000 rpm, T = 0.417 [ms], when the rotational speed N is 3000 rpm, T = 0.278 [ms], and when the rotational speed N is 4000 rpm, T = 0.208 [ms]. Become.

  The vertical axis of (A) to (H) in FIG. 8 is provided with an actual measurement value, the allowable value, and the determination, similarly to the vertical axis of FIG. 5, and (A) to (H) in FIG. The horizontal axis of FIG. 5 changes the number of turns of the conducting wire of each phase of the three-phase armature winding 52 from 1 to 6 as in the horizontal axis of FIG.

  Therefore, as shown in FIG. 8C, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 12 poles or less, the output is 400 W or less, and the efficiency is 70% or more, the rotational speed is 4000 or less and 3000 When the number is large, the number of turns of the three-phase armature winding 52 is 2 or less, and when the number of rotations is 3000 or less and greater than 2000, the number of turns of the three-phase armature winding 52 is 3 or less, and the number of rotations is 2000 or less and When the number is larger than 1000, the number of turns of the three-phase armature winding 52 is 4 or less, and when the number of rotations is 1000 or less, the number of turns of the three-phase armature winding 52 is 5 or less. It can be driven stably.

  As shown in FIG. 8B, in the case of the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 12 poles or less, the output is 300 W or less, and the efficiency is 70% or more, the rotation speed is 4000 or less and greater than 2000. In the case where the number of turns of the three-phase armature winding 52 is 3 or less, the number of turns of the three-phase armature winding 52 is 4 or less when the number of revolutions is 2000 or less and greater than 1000, and the number of revolutions is 1000 or less. By setting the number of turns of the three-phase armature winding 52 to 6 or less, the brushless motor 50 can be driven stably.

  As shown in FIG. 8A, in the case of the brushless motor 50 in which the number P of the magnetic rotor 54 is 12 poles or less, the output is 200 W or less, and the efficiency is 70% or more, the rotation speed is 4000 or less and greater than 3000. When the number of turns of the three-phase armature winding 52 is 3 or less, and the number of rotations is 3000 or less and greater than 2000, the number of turns of the three-phase armature winding 52 is 4 or less, and the number of rotations is 2000 or less and 1000 The brushless motor 50 is stabilized by setting the number of turns of the three-phase armature winding 52 to 5 or less when the number is large and setting the number of turns of the three-phase armature winding 52 to 6 or less when the rotation speed is 1000 or less. Can be driven.

  As shown in FIG. 8F, in the case of the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 12 poles or less, the output is 400 W or less, and the efficiency is 80% or more, the rotation speed is 4000 or less and greater than 2000. In the case where the number of turns of the three-phase armature winding 52 is 3 or less, the number of turns of the three-phase armature winding 52 is 4 or less when the number of revolutions is 2000 or less and greater than 1000, and the number of revolutions is 1000 or less. By setting the number of turns of the three-phase armature winding 52 to 5 or less, the brushless motor 50 can be driven stably.

  As shown in FIGS. 8E and 8H, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 12 poles or less, the output is 300 W or less, and the efficiency is 80% or more, the rotational speed is 4000 or less and If it is greater than 3000, the number of turns of the three-phase armature winding 52 is 3 or less, and if the number of revolutions is 3000 or less and greater than 2000, the number of turns of the 3-phase armature winding 52 is 4 or less and the number of revolutions is 2000. The number of turns of the three-phase armature winding 52 is set to 5 or less when the number is less than 1000 and the number of turns of the three-phase armature winding 52 is set to 6 or less when the number of rotations is 1000 or less. 50 can be driven stably.

  As shown in FIGS. 8D and 8G, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 12 or less, the output is 200 W or less, and the efficiency is 80% or more, the rotation speed is 4000 or less and When the number of turns of the three-phase armature winding 52 is less than 4, the number of turns of the three-phase armature winding 52 is set to 4 or less. When the number of rotations is 2000 or less, the number of turns of the three-phase armature winding 52 is set to 6 or less. It can be driven stably.

  As shown in FIG. 8I, in the case of the brushless motor 50 in which the number P of the magnetic rotor 54 is 12 poles or less, the output is 400 W or less, and the efficiency is 85% or more, the rotation speed is 4000 or less and greater than 2000. In the case where the number of turns of the three-phase armature winding 52 is 3 or less, the number of turns of the three-phase armature winding 52 is 4 or less when the number of revolutions is 2000 or less and greater than 1000, and the number of revolutions is 1000 or less. By setting the number of turns of the three-phase armature winding 52 to 6 or less, the brushless motor 50 can be driven stably.

  Next, FIGS. 9A to 9H show measurement results when the number of poles P of the magnet rotor 54 is 14 poles.

  9A to 9C measure the cases where the efficiency of the brushless motor 50 is 70% and the output of the brushless motor 50 is 200 W, 300 W, and 400 W, respectively.

  9D to 9F measure the cases where the efficiency of the brushless motor 50 is 80% and the output of the brushless motor 50 is 200 W, 300 W, and 400 W, respectively.

  FIGS. 9G to 9I measure the cases where the efficiency of the brushless motor 50 is 85% and the output of the brushless motor 50 is 200 W, 300 W, and 400 W, respectively.

  The allowable values of (A) to (H) in FIG. 9 are calculated from the formula (2). When the number of poles P of the magnet rotor 54 is 14, the rotation number N is 1000 rpm, and T = 0.714 [ms]. When the rotational speed N is 2000 rpm, T = 0.357 [ms], when the rotational speed N is 3000 rpm, T = 0.238 [ms], and when the rotational speed N is 4000 rpm, T = 0.179 [ms]. Become.

  The vertical axis of (A) to (H) in FIG. 9 is provided with an actual measurement value, the allowable value, and the determination, similarly to the vertical axis of FIG. 5, and (A) to (H) in FIG. 9, the number of turns of each phase of the three-phase armature winding 52 is changed from 1 to 6 as in the horizontal axis of FIG. 9.

  Therefore, as shown in FIG. 9C, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 14 poles or less, the output is 400 W or less, and the efficiency is 70% or more, the rotational speed is 4000 or less and 3000 When the number is large, the number of turns of the three-phase armature winding 52 is 2 or less, and when the number of rotations is 3000 or less and greater than 1000, the number of turns of the three-phase armature winding 52 is 3 or less and the number of rotations is 1000 or less. In this case, by setting the number of turns of the three-phase armature winding 52 to 5 or less, the brushless motor 50 can be driven stably.

  As shown in FIG. 9B, in the case of the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 14 poles or less, the output is 300 W or less, and the efficiency is 70% or more, the rotation speed is 4000 or less and greater than 3000. If the number of turns of the three-phase armature winding 52 is 2 or less, and the number of rotations is 3000 or less and greater than 2000, the number of turns of the three-phase armature winding 52 is 3 or less, and the number of rotations is 2000 or less and 1000 The brushless motor 50 is stabilized by setting the number of turns of the three-phase armature winding 52 to 4 or less when the number is large, and setting the number of turns of the three-phase armature winding 52 to 6 or less when the rotation speed is 1000 or less. Can be driven.

  As shown in FIGS. 9A and 9D, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 14 or less, the output is 200 W or less, and the efficiency is 70% or more, the rotation speed is 4000 or less and If it is greater than 3000, the number of turns of the three-phase armature winding 52 is 3 or less, and if the number of revolutions is 3000 or less and greater than 2000, the number of turns of the 3-phase armature winding 52 is 4 or less and the number of revolutions is 2000. The number of turns of the three-phase armature winding 52 is set to 5 or less when the number is less than 1000 and the number of turns of the three-phase armature winding 52 is set to 6 or less when the number of rotations is 1000 or less. 50 can be driven stably.

  As shown in FIG. 9F, in the case of the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 14 poles or less, the output is 400 W or less, and the efficiency is 80% or more, the rotation speed is 4000 or less and greater than 3000. If the number of turns of the three-phase armature winding 52 is 2 or less, and the number of rotations is 3000 or less and greater than 2000, the number of turns of the three-phase armature winding 52 is 3 or less, and the number of rotations is 2000 or less and 1000 The brushless motor 50 is stabilized by setting the number of turns of the three-phase armature winding 52 to 4 or less when the number is large, and setting the number of turns of the three-phase armature winding 52 to 5 or less when the number of rotations is 1000 or less. Can be driven.

  As shown in FIGS. 9E and 9H, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 14 or less, the output is 300 W or less, and the efficiency is 80% or more, the rotation speed is 4000 or less and When the rotational speed is greater than 2000, the number of turns of the three-phase armature winding 52 is 3 or less, and when the rotational speed is 2000 or less and greater than 1000, the number of turns of the 3-phase armature winding 52 is 4 or less. By setting the number of turns of the three-phase armature winding 52 to 6 or less in the following cases, the brushless motor 50 can be driven stably.

  As shown in (I) of FIG. 9, in the case of the brushless motor 50 having a pole number P of the magnet rotor 54 of 14 poles or less, an output of 400 W or less, and an efficiency of 85% or more, the rotation speed is 4000 or less and greater than 3000. If the number of turns of the three-phase armature winding 52 is 2 or less, and the number of rotations is 3000 or less and greater than 2000, the number of turns of the three-phase armature winding 52 is 3 or less, and the number of rotations is 2000 or less and 1000 The brushless motor 50 is stabilized by setting the number of turns of the three-phase armature winding 52 to 4 or less when the number is large, and setting the number of turns of the three-phase armature winding 52 to 6 or less when the rotation speed is 1000 or less. Can be driven.

  As shown in FIG. 9G, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 14 poles or less, the output is 200 W or less, and the efficiency is 85% or more, the rotational speed is 4000 or less and greater than 2000. In the case where the number of turns of the three-phase armature winding 52 is 4 or less, the number of turns of the three-phase armature winding 52 is 5 or less when the number of revolutions is 2000 or less and greater than 1000, and the number of revolutions is 1000 or less. By setting the number of turns of the three-phase armature winding 52 to 6 or less, the brushless motor 50 can be driven stably.

  Next, FIGS. 10A to 10H show measurement results when the number of poles P of the magnet rotor 54 is 16 poles.

  10A to 10C measure the cases where the efficiency of the brushless motor 50 is 70% and the output of the brushless motor 50 is 200 W, 300 W, and 400 W, respectively.

  10D to 10F measure the cases where the efficiency of the brushless motor 50 is 80% and the output of the brushless motor 50 is 200 W, 300 W, and 400 W, respectively.

  10G to 10I measure the cases where the efficiency of the brushless motor 50 is 85% and the output of the brushless motor 50 is 200 W, 300 W, and 400 W, respectively.

  The allowable values of (A) to (H) in FIG. 10 are calculated from the equation (2). When the number of poles P of the magnet rotor 54 is 16, the rotation number N is 1000 rpm and T = 0.625 [ms. When the rotational speed N is 2000 rpm, T = 0.125 [ms], when the rotational speed N is 3000 rpm, T = 0.208 [ms], and when the rotational speed N is 4000 rpm, T = 0.156 [ms]. Become.

  The vertical axis of (A) to (H) in FIG. 10 is provided with an actual measurement value, the allowable value, and the determination, similarly to the vertical axis of FIG. 5, and (A) to (H) in FIG. 9, the number of turns of each phase of the three-phase armature winding 52 is changed from 1 to 6 as in the horizontal axis of FIG. 9.

  Therefore, as shown in FIG. 10C, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 16 poles or less, the output is 400 W or less, and the efficiency is 70% or more, the rotational speed is 4000 or less and 2000 When the number is large, the number of turns of the three-phase armature winding 52 is 2 or less, and when the number of rotations is 2000 or less and greater than 1000, the number of turns of the three-phase armature winding 52 is 3 or less and the number of rotations is 1000 or less. In this case, by setting the number of turns of the three-phase armature winding 52 to 4 or less, the brushless motor 50 can be driven stably.

  As shown in FIG. 10B, in the case of the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 16 poles or less, the output is 300 W or less, and the efficiency is 70% or more, the rotation speed is 4000 or less and greater than 3000. In the case where the number of turns of the three-phase armature winding 52 is 2 or less, the number of turns of the three-phase armature winding 52 is 3 or less when the number of revolutions is 3000 or less and greater than 1000, and the number of revolutions is 1000 or less. By setting the number of turns of the three-phase armature winding 52 to 5 or less, the brushless motor 50 can be driven stably.

  As shown in FIG. 10A, when the number of poles P of the magnet rotor 54 is 16 poles or less, the output is 200 W or less, and the efficiency is 70% or more, the rotation speed is 4000 or less and greater than 2000. In the case where the number of turns of the three-phase armature winding 52 is 3 or less, the number of turns of the three-phase armature winding 52 is 4 or less when the number of revolutions is 2000 or less and greater than 1000, and the number of revolutions is 1000 or less. By setting the number of turns of the three-phase armature winding 52 to 6 or less, the brushless motor 50 can be driven stably.

  As shown in FIGS. 10F and 10I, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 16 poles or less, the output is 400 W or less, and the efficiency is 80% or more, the rotational speed is 4000 or less and When the number is greater than 3000, the number of turns of the three-phase armature winding 52 is 2 or less, and when the number of rotations is 3000 or less and greater than 1000, the number of turns of the three-phase armature winding 52 is 3 or less. By setting the number of turns of the three-phase armature winding 52 to 5 or less in the following cases, the brushless motor 50 can be driven stably.

  As shown in FIGS. 10E and 10H, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 16 poles or less, the output is 300 W or less, and the efficiency is 80% or more, the rotational speed is 4000 or less and When the number is greater than 2000, the number of turns of the three-phase armature winding 52 is 3 or less, and when the number of rotations is 200 or less and greater than 1000, the number of turns of the three-phase armature winding 52 is 4 or less. By setting the number of turns of the three-phase armature winding 52 to 6 or less in the following cases, the brushless motor 50 can be driven stably.

  As shown in FIGS. 10D and 10G, in the brushless motor 50 in which the number of poles P of the magnet rotor 54 is 16 poles or less, the output is 200 W or less, and the efficiency is 80% or more, the rotational speed is 4000 or less and If it is greater than 3000, the number of turns of the three-phase armature winding 52 is 3 or less. If the number of revolutions is 3000 or less and greater than 2000, the number of turns of the 3-phase armature winding 52 is 4 or less, and the number of revolutions is 200. The number of turns of the three-phase armature winding 52 is set to 5 or less when the number is less than 1000 and the number of turns of the three-phase armature winding 52 is set to 6 or less when the number of rotations is 1000 or less. 50 can be driven stably.

  As described above, the brushless motor 50 can be driven to rotate even with a low-voltage power supply by appropriately determining an appropriate number of poles, number of turns, and the like according to the required output, the efficiency of the brushless motor, and the number of rotations. Obtainable.

It is a schematic block diagram of a brushless motor and a brushless motor drive device. It is a wave form diagram of various signals. It is a voltage waveform figure which generate | occur | produces in the V phase of a three-phase armature winding. The flow of the electric current from an inverter part to a three-phase armature winding is shown. It is the result of having determined the measured value when the number of poles of the magnet rotor is 6 with an allowable value. It is the result of determining the measured value when the number of poles of the magnet rotor is 8 with an allowable value. It is the result of having determined the measured value when the number of poles of the magnet rotor is 10 with an allowable value. It is the result of having determined the measured value when the number of poles of the magnet rotor is 12 with an allowable value. It is the result of having determined the measured value when the number of poles of the magnet rotor is 14 with an allowable value. It is the result of determining the measured value when the number of poles of the magnet rotor is 16 with an allowable value.

Explanation of symbols

Brushless motor driving device 10, inverter unit 14, rotor position detection unit 16, diode 17, delay unit 20, control unit 22, rotation speed detection unit 24, delay amount adjustment unit 34, brushless motor 50, three-phase armature winding 52 (armature winding), magnet rotor 54

Claims (6)

When the switch element is turned ON / OFF, a voltage from a power source is applied to the armature winding to cause a current to flow. The magnet rotor is rotated by the rotating magnetic field generated in the armature winding, and the switch element is turned from ON to OFF. The current due to the self-inductive counter electromotive voltage generated in the armature winding flows through a diode provided to be short-circuited to the switch element, and the self-induction during the OFF period of the switch element After the current due to the back electromotive voltage flows, the point where the induced voltage generated in the armature winding due to the rotation of the magnet rotor coincides with the neutral point potential of the voltage applied from the power source is detected. A rotational position information of the magnet rotor, and a brushless motor that determines the next timing for turning on and off the switch element based on the rotational position information,
The power supply voltage is 13.5 V, the voltage drop due to the diode is 0.8 V, the number of magnetic poles of the magnet rotor is 16 poles or less, and the output obtained by the rotation of the magnet rotor is 400 W or less and supplied from the power supply When the efficiency of the brushless motor with respect to the generated electric power is 70% or more, the number of turns of the conductor of the armature winding is 2 when the rotational speed per unit of the magnet rotor is 4000 or less and larger than 2000 The number of turns of the conductor of the armature winding when the number of revolutions is 2000 or less and greater than 1000 is 3 or less, and the number of turns of the conductor of the armature winding when the number of revolutions is 1000 or less Is a brushless motor, characterized in that the number is 4 or less. When the switch element is turned ON / OFF, a voltage from a power source is applied to the armature winding to cause a current to flow. The magnet rotor is rotated by the rotating magnetic field generated in the armature winding, and the switch element is turned from ON to OFF. The current due to the self-inductive counter electromotive voltage generated in the armature winding flows through a diode provided to be short-circuited to the switch element, and the self-induction during the OFF period of the switch element After the current due to the back electromotive voltage flows, the point where the induced voltage generated in the armature winding due to the rotation of the magnet rotor coincides with the neutral point potential of the voltage applied from the power source is detected. A rotational position information of the magnet rotor, and a brushless motor that determines the next timing for turning on and off the switch element based on the rotational position information,
The power supply voltage is 13.5 V, the voltage drop due to the diode is 0.8 V, the number of magnetic poles of the magnet rotor is 16 poles or less, and the output obtained by the rotation of the magnet rotor is 300 W or less and supplied from the power supply When the efficiency of the brushless motor with respect to the generated electric power is 70% or more, the number of windings of the armature winding is 2 when the rotational speed per unit of the magnet rotor is 4000 or less and greater than 3000 The number of turns of the conductor of the armature winding when the number of revolutions is 3000 or less and greater than 1000 is 3 or less, and the number of turns of the conductor of the armature winding when the number of revolutions is 1000 or less A brushless motor characterized by having 5 or less rolls. When the switch element is turned ON / OFF, a voltage from a power source is applied to the armature winding to cause a current to flow. The magnet rotor is rotated by the rotating magnetic field generated in the armature winding, and the switch element is turned from ON to OFF. The current due to the self-inductive counter electromotive voltage generated in the armature winding flows through a diode provided to be short-circuited to the switch element, and the self-induction during the OFF period of the switch element After the current due to the back electromotive voltage flows, the point where the induced voltage generated in the armature winding due to the rotation of the magnet rotor coincides with the neutral point potential of the voltage applied from the power source is detected. A rotational position information of the magnet rotor, and a brushless motor that determines the next timing for turning on and off the switch element based on the rotational position information,
The power supply voltage is 13.5 V, the voltage drop due to the diode is 0.8 V, the number of magnetic poles of the magnet rotor is 16 poles or less, and the output obtained by the rotation of the magnet rotor is 200 W or less and supplied from the power supply When the efficiency of the brushless motor with respect to the generated electric power is 70% or more, the number of turns of the conductor of the armature winding is 3 when the rotational speed per unit of the magnet rotor is 4000 or less and larger than 2000 The number of turns of the conductor of the armature winding when the number of revolutions is 2000 or less and greater than 1000 is 4 or less, and the number of turns of the conductor of the armature winding when the number of revolutions is 1000 or less. Is a brushless motor characterized by having 6 or less rolls. When the switch element is turned ON / OFF, a voltage from a power source is applied to the armature winding to cause a current to flow. The magnet rotor is rotated by the rotating magnetic field generated in the armature winding, and the switch element is turned from ON to OFF. The current due to the self-inductive counter electromotive voltage generated in the armature winding flows through a diode provided to be short-circuited to the switch element, and the self-induction during the OFF period of the switch element After the current due to the back electromotive voltage flows, the point where the induced voltage generated in the armature winding due to the rotation of the magnet rotor coincides with the neutral point potential of the voltage applied from the power source is detected. A rotational position information of the magnet rotor, and a brushless motor that determines the next timing for turning on and off the switch element based on the rotational position information,
The power supply voltage is 13.5 V, the voltage drop due to the diode is 0.8 V, the number of magnetic poles of the magnet rotor is 16 poles or less, and the output obtained by the rotation of the magnet rotor is 400 W or less and supplied from the power supply When the efficiency of the brushless motor with respect to the generated electric power is 80% or more, the number of windings of the armature winding is 2 when the rotational speed per unit of the magnet rotor is 4000 or less and larger than 3000 The number of turns of the conductor of the armature winding when the number of revolutions is 3000 or less and greater than 1000 is 3 or less, and the number of turns of the conductor of the armature winding when the number of revolutions is 1000 or less Is a brushless motor characterized by having 5 or less. When the switch element is turned ON / OFF, a voltage from a power source is applied to the armature winding to cause a current to flow. The magnet rotor is rotated by the rotating magnetic field generated in the armature winding, and the switch element is turned from ON to OFF. The current due to the self-inductive counter electromotive voltage generated in the armature winding flows through a diode provided to be short-circuited to the switch element, and the self-induction during the OFF period of the switch element After the current due to the back electromotive voltage flows, the point where the induced voltage generated in the armature winding due to the rotation of the magnet rotor coincides with the neutral point potential of the voltage applied from the power source is detected. A rotational position information of the magnet rotor, and a brushless motor that determines the next timing for turning on and off the switch element based on the rotational position information,
The power supply voltage is 13.5 V, the voltage drop due to the diode is 0.8 V, the number of magnetic poles of the magnet rotor is 16 poles or less, and the output obtained by the rotation of the magnet rotor is 300 W or less and supplied from the power supply When the efficiency of the brushless motor with respect to the generated electric power is 80% or more, the number of turns of the conductor of the armature winding is 3 when the rotational speed per unit of the magnet rotor is 4000 or less and greater than 2000 The number of turns of the conductor of the armature winding when the number of revolutions is 2000 or less and greater than 1000 is 4 or less, and the number of turns of the conductor of the armature winding when the number of revolutions is 1000 or less. Is a brushless motor characterized by having 6 or less rolls. When the switch element is turned ON / OFF, a voltage from a power source is applied to the armature winding to cause a current to flow. The magnet rotor is rotated by the rotating magnetic field generated in the armature winding, and the switch element is turned from ON to OFF. The current due to the self-inductive counter electromotive voltage generated in the armature winding flows through a diode provided to be short-circuited to the switch element, and the self-induction during the OFF period of the switch element After the current due to the back electromotive voltage flows, the point where the induced voltage generated in the armature winding due to the rotation of the magnet rotor coincides with the neutral point potential of the voltage applied from the power source is detected. A rotational position information of the magnet rotor, and a brushless motor that determines the next timing for turning on and off the switch element based on the rotational position information,
The power supply voltage is 13.5 V, the voltage drop due to the diode is 0.8 V, the number of magnetic poles of the magnet rotor is 16 poles or less, and the output obtained by the rotation of the magnet rotor is 200 W or less and supplied from the power supply When the efficiency of the brushless motor with respect to the generated electric power is 80% or more, the number of windings of the armature winding is 3 when the rotation number of the magnet rotor is 4000 or less and greater than 3000 The number of turns of the conductor of the armature winding when the rotation number is 3000 or less and greater than 2000 is 4 or less, and the armature winding when the rotation number is 2000 or less and greater than 1000 A brushless motor, wherein the number of turns of the conductor is 5 or less and the number of turns of the armature winding when the number of revolutions is 1000 or less. Data.

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