JP4393354B2 - Brushless motor control apparatus, brushless motor apparatus, and brushless motor control method - Google Patents

Description

  The present invention relates to a brushless motor control device, a brushless motor device, and a brushless motor control method, and more particularly to a brushless motor control device, a brushless motor device, and a brushless motor control method that control rotation of the brushless motor in a sensorless manner. .

  Conventionally, the rotational position of the rotor is detected not by using a rotational position detector such as a Hall element, but by detecting an induced voltage induced in the stator winding during the steady rotation of the rotor. A sensorless brushless motor control device is known (see, for example, Patent Documents 1 and 2).

  In this type of brushless motor control device, an energization signal is generally generated from a terminal voltage signal as follows. That is, U, V, and W three-phase terminal voltage signals obtained from the stator windings are detected, and each phase terminal voltage signal is integrated by a low-pass filter to generate a pseudo terminal voltage signal for each phase. To do.

  Then, a zero cross signal generated by comparing the pseudo terminal voltage signal with the reference voltage signal is used as a rotational position signal. Subsequently, the rotational position signal is delayed by a predetermined phase by a delay circuit to generate a delayed output signal, and an energization signal is generated based on the delayed output signal.

  Here, in the example described in Patent Document 1, a current flowing through the stator winding or a direct current supplied from a direct current power source is detected by a current detector, and delayed according to the current value detected by the current detector. A phase correction amount for correcting the delay phase of the output signal is determined. And it is comprised so that the electricity supply timing with respect to a stator winding | coil may become optimal by correct | amending the delay phase of a delay output signal based on this phase correction amount.

In the example described in Patent Document 2, the inverter return current period is determined from the terminal voltage of the non-energized phase and the DC power supply voltage, and the phase angle is determined from the terminal voltage after the end of the inverter return current period. It is configured. At this time, the relationship between the induced voltage value generated in the stator winding for each motor rotation speed and the phase angle is built in advance as a table map in the control unit, and the phase angle is determined by this table map. Yes. Based on this phase angle, the magnetic pole position of the rotor is detected, and based on this, an energization signal is generated.
Japanese Patent No. 3183071 JP 2002-95283 A

  However, as described in Patent Document 1, in the technique for determining the phase correction amount according to the current value detected by the current detector, there is a problem that the cost of the entire apparatus increases due to the provision of the current detector. is there.

  The technique described in Patent Document 2 determines the phase angle using a table map built in the control unit. Factors that affect the phase shift include terminal voltage, rotation speed, stator winding. There are various things such as the current flowing through, and it is difficult to create a table map that covers these factors.

  Furthermore, in order to secure the detection accuracy of the phase angle, it is necessary to set the table of the table map finely. On the other hand, if the table is set finely, the amount of work for building the table map in advance becomes enormous, There is a disadvantage that the memory capacity of the microcomputer necessary for storing the map increases.

  The present invention has been made in view of the above problems, and the object thereof is to reduce the cost as compared with the prior art and to exhibit high phase angle detection accuracy with a simple configuration. A brushless motor control device, a brushless motor device, and a brushless motor control method are provided.

In order to solve the above problem, the brushless motor control device according to claim 1 detects a terminal voltage waveform generated in each of a plurality of stator windings provided in the brushless motor and outputs a rotational position signal. A rotation position signal detection unit, a control unit for generating and outputting an energization signal based on the rotation position signal output from the rotation position signal detection unit, and a stator winding based on the energization signal output from the control unit And an inverter circuit unit that sequentially switches energization to the brushless motor control device, wherein the control unit terminates energization of at least one of the stator windings and the positive power source, and the negative power source. A terminal generated in at least one of the stator windings at a first timing when a predetermined electrical angle has elapsed since the start of the first non-energized section in the first non-energized section until the energization of Voltage V 1 is detected, and the second non-energized section in the second non-energized section until the energization of at least one of the stator windings and the negative power supply ends and the energization with the positive power supply is started. Terminal voltage detection means for detecting a terminal voltage Vf2 generated in at least one of the stator windings at a second timing when the same electrical angle as the predetermined electrical angle has elapsed since the start of the operation, and the first timing or Phase confirmation means for calculating the value of the phase angle θ or sin θ of the induced voltage generated in at least one of the stator windings of the second timing by any one of the following equations (1), (2), and (3) 51c).
Vf2−Vf1 = 3 Asin θ (1)
Vc / 2−Vf1 = 1.5 Asin θ (2)
Vf2-Vc / 2 = 1.5 Asin θ (3)
However, A is a product of a predetermined motor constant and a motor rotational speed determined from the rotational position signal, and Vc is a power supply voltage.

In order to solve the above-mentioned problem, the brushless motor control method according to claim 8 is characterized in that the rotational position signal is obtained based on the terminal voltage waveform generated in each of a plurality of stator windings provided in the brushless motor. And generating a delay output signal by correcting a predetermined delay phase with respect to the rotational position signal based on a predetermined amount of phase correction, and generating a stator winding by an energization signal generated based on the delay output signal Is a brushless motor control method for controlling the rotation of the brushless motor by sequentially switching the energization to the power supply, and the energization between at least one of the stator windings and the positive power supply is terminated and the energization with the negative power supply is started. The terminal voltage Vf1 generated in at least one of the stator windings at the first timing at which a predetermined electrical angle has elapsed after the start of the first non-energized period in the first non-energized period until is detected. And the second non-energization within the second non-energization section until the energization of at least one of the stator windings and the negative power supply is terminated and the energization of the positive power supply is started. A second step of detecting a terminal voltage Vf2 generated in at least one of the stator windings at a second timing when the same electrical angle as the predetermined electrical angle has elapsed since the start of the section; and the first timing or A value of the phase angle θ or sin θ of the induced voltage generated in at least one of the stator windings at the second timing is calculated by any one of the following formulas (1), (2), and (3). And a step.
Vf2−Vf1 = 3 Asin θ (1)
Vc / 2−Vf1 = 1.5 Asin θ (2)
Vf2-Vc / 2 = 1.5 Asin θ (3)
However, A is a product of a predetermined motor constant and a motor rotational speed determined from the rotational position signal, and Vc is a power supply voltage.

  In the first non-energized section and the second non-energized section in the present invention, an induced voltage induced in the stator winding is generated in the terminal voltage waveform. Therefore, as in the present invention, the terminal voltage Vf1 and the terminal voltage Vf2 detected at each of the first timing in the first non-energized section and the second timing in the second non-energized section are respectively the stator. This is the voltage value of the induced voltage induced in the winding.

  Therefore, according to the invention described in claim 1 or claim 8, the induced voltage generated in the stator winding at two predetermined first and second timings in the first and second non-energized sections. By detecting the terminal voltages Vf1 and Vf2 as values and substituting these terminal voltages Vf1 and Vf2 into any one of predetermined calculation formulas (1), (2) and (3), the predetermined voltages The phase angle θ or sin θ value of the induced voltage generated in the stator winding at the timing can be calculated. Accordingly, it is possible to determine a phase correction determination amount for correcting the delay phase of the delayed output signal based on the value of the phase angle θ or sin θ. Therefore, unlike the prior art, there is no need to determine the phase correction amount according to the current value detected by the current detector, so that the current detector can be made unnecessary.

  Further, as described above, the terminal voltages Vf1 and Vf2 generated in the stator winding at two predetermined first and second timings in the first and second non-energized sections are detected, and this terminal voltage is detected. By simply substituting Vf1 and Vf2 into any of predetermined calculation formulas (1), (2), and (3), the phase angle θ of the induced voltage generated in the stator winding at the predetermined timing or Since the value of sin θ can be calculated, a table map for determining the relationship between the induced voltage value generated in the stator winding and the phase angle for each motor rotation speed can be eliminated as in the prior art.

  As described above, according to the present invention, the current detector and the table map required in the prior art can be eliminated, so that the cost of the apparatus can be reduced as compared with the conventional configuration. it can. In addition, the delay phase of the delayed output signal can be corrected without using a current detector, a table map, or the like as in the past, so that a higher phase angle detection accuracy can be achieved with a simpler configuration than the conventional configuration. It can be demonstrated.

  At this time, as described in claim 2, the control unit more preferably includes a delay unit that delays the rotational position signal output from the rotational position signal detection unit and outputs a delayed output signal, and a delay unit. An energization signal generating means for generating and outputting an energization signal based on the output delayed output signal; and a phase correction means for determining a phase correction determination amount for correcting a delay phase angle of the delayed output signal output from the delay means; The phase correction means detects the rotational speed of the brushless motor based on the rotational position signal output from the rotational position signal detector, and determines the base phase correction amount according to the rotational speed of the brushless motor. Correction amount determining means, phase range setting storage means for setting and storing a predetermined range in advance for the value of the phase angle θ or sin θ of the induced voltage calculated by the phase confirmation means, Phase correction adjustment for gradually increasing or decreasing the phase correction determination amount so that the value of the phase angle θ or sin θ of the induced voltage calculated by the recognition means falls within the specified range stored in the phase range setting storage means Phase correction adjustment amount determining means for determining the amount, and a value obtained by adding the phase correction adjustment amount determined by the phase correction adjustment amount determining means to the base phase correction amount determined by the base phase correction amount determining means And a phase correction amount determination means.

  Further, according to the ninth aspect of the present invention, the brushless motor control method of the present invention more preferably determines the base phase correction amount according to the rotation speed of the brushless motor and calculates in the third step. A fourth step of determining a phase correction adjustment amount for gradually increasing or decreasing the phase correction determination amount so that the value of the phase angle θ or sin θ of the induced voltage falls within a predetermined specified range; And a fifth step in which a value obtained by adding the phase correction adjustment amount to the base phase correction amount determined in the four steps is used as the phase correction determination amount.

  According to the invention described in claim 2 or claim 9, the delay phase of the delayed output signal can be corrected without using a current detector, a table map, or the like as in the prior art. Compared with a simple configuration, high phase angle detection accuracy can be achieved. Further, the phase correction fixed amount is stepwise so that the value of the phase angle θ or sin θ of the induced voltage calculated using any one of the formulas (1), (2), and (3) is within a predetermined range. Therefore, the energization signal can be gradually converged to the set phase.

  According to a third aspect of the present invention, the control unit delays the rotational position signal output from the rotational position signal detection unit and outputs a delayed output signal, and the delayed output signal output from the delay unit. And a phase correction unit for determining a phase correction determination amount for correcting a delay phase angle of the delayed output signal output from the delay unit. The means detects the rotational speed of the brushless motor based on the rotational position signal output from the rotational position signal detector, and determines the base phase correction amount determining means according to the rotational speed of the brushless motor; Phase prescribed value storage means for presetting and storing a prescribed value for the value of the phase angle θ or sin θ of the induced voltage calculated by the phase confirmation means, and calculated by the phase confirmation means Phase correction adjustment amount determination for determining a phase correction adjustment amount for adjusting the phase correction determination amount so as to eliminate the difference between the phase angle θ or sin θ value of the induced voltage and the specified value stored in the phase specified value storage means And a phase correction amount determination unit that uses a value obtained by adding the phase correction adjustment amount determined by the phase correction adjustment amount determination unit to the base phase correction amount determined by the base phase correction amount determination unit; The structure which has this may be sufficient.

  According to a tenth aspect of the present invention, in the brushless motor control method according to the present invention, the base phase correction amount corresponding to the rotation speed of the brushless motor is determined, and the induced voltage calculated in the third step is determined. A fourth step of determining a phase correction adjustment amount for adjusting the phase correction determination amount so that there is no difference between the value of the phase angle θ or sin θ and the predetermined specified value, and the fourth step And a fifth step in which a value obtained by adding the phase correction adjustment amount to the base phase correction amount determined in this step is used as the phase correction determination amount.

  Even in the invention according to claim 3 or claim 10, since the delay phase of the delayed output signal can be corrected without using a current detector, a table map, or the like as in the prior art, High phase angle detection accuracy can be exhibited with a simple configuration compared to the configuration. Further, according to the invention described in claim 3 or claim 10, the value of the phase angle θ or sin θ of the induced voltage calculated using any one of the formulas (1), (2), and (3) is determined in advance. Since the phase correction determination amount is adjusted so as to fall within the specified range, the value of the phase angle θ or sin θ can quickly fall within the specified range.

  At this time, as described in claim 4, the control unit may be configured to detect the terminal voltage Vf2 at a timing having a phase difference that is an odd multiple of 180 degrees in phase angle with respect to the terminal voltage Vf1. .

  In the brushless motor control method of the present invention, the terminal voltage Vf2 is detected at a timing having an odd multiple of 180 degrees in phase angle with respect to the terminal voltage Vf1. Also good.

  In this case, for example, by applying PWM energization, when the PWM component exists in the induced voltage in the first and second non-energization sections, the terminal voltages Vf1 and Vf2 are accurately set every 180 electrical degrees. Even when the terminal voltage Vf2 cannot be detected, the terminal voltage Vf2 is detected at a timing having an odd multiple (for example, three times) of 180 degrees in phase angle with respect to the terminal voltage Vf1. It is possible to obtain the same result as when the terminal voltages Vf1 and Vf2 are detected every electrical angle 180 ° when no component is present.

  Furthermore, as described in claim 5, the control unit uses, as the terminal voltage Vf2, a terminal voltage generated in a stator winding of a phase different from that of the stator winding in which the terminal voltage Vf1 is detected. It may be a configuration.

  Further, in the brushless motor control method according to the twelfth aspect of the present invention, the terminal voltage generated in the stator winding of a phase different from that of the stator winding in which the terminal voltage Vf1 is detected among the stator windings. May be used as the terminal voltage Vf2.

  In this case, for example, when the terminal voltages Vf1 and Vf2 cannot be detected continuously from the same-phase stator windings, or when the terminal voltages Vf1 and Vf2 are detected from different-phase stator windings, respectively. Is preferable, the terminal voltage generated in the stator winding of a phase different from that of the stator winding in which the terminal voltage Vf1 is detected is set as the terminal voltage Vf2, thereby fixing the same phase. A result similar to the detection of the terminal voltages Vf1 and Vf2 from the child windings can be obtained.

  According to a sixth aspect of the present invention, when the PWM component is present in the terminal voltage waveform in the first non-energized section or the second non-energized section, the control unit is provided in the inverter circuit unit. Alternatively, the terminal voltage Vf1 or the terminal voltage Vf2 may be detected at the timing when the switching element that generates the PWM component among the switching elements is switched on.

  Further, as described in claim 13, in the brushless motor control method of the present invention, when a PWM component is present in the terminal voltage waveform in the first non-energized section or the second non-energized section, The terminal voltage Vf1 or the terminal voltage Vf2 may be detected at a timing at which a switching element that generates a PWM component among switching elements provided in the inverter circuit unit is switched on.

  Here, an induced voltage is generated in the terminal voltage waveform at the timing when the switching element that generates the PWM component among the switching elements provided in the inverter circuit section is switched on. Therefore, as described above, the induced voltage value is detected by detecting the terminal voltage Vf1 or the terminal voltage Vf2 when the switching element that generates the PWM component among the switching elements provided in the inverter circuit unit is switched on. Can be reliably detected as the terminal voltage Vf1 or the terminal voltage Vf2.

  A brushless motor comprising a plurality of phase stator windings and a permanent magnet rotor that is rotated by a magnetic field generated in the stator windings, and a controller that controls the rotation of the brushless motor. It is preferable that the controller of the brushless motor according to any one of claims 1 to 6 is used as a controller.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. It should be noted that members, arrangements, and the like described below do not limit the present invention, and it goes without saying that various modifications can be made in accordance with the spirit of the present invention.

  First, the configuration of a brushless motor device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4.

  FIG. 2 is a diagram showing a configuration of the brushless motor device according to the present embodiment, and FIG. 3 is a diagram showing various signal waveforms in the brushless motor device shown in FIG.

  A brushless motor device 1 according to an embodiment of the present invention shown in FIG. 2 is preferably used as a fan motor device in a vehicle (not shown), for example, and includes a brushless motor 10 and a controller 20 as a control device. , And is configured.

  The brushless motor 10 serves as a drive source for rotating a fan or the like (not shown), and includes a stator 11 that generates a drive magnetic field and a rotor 12 that is rotated by a drive magnetic field generated from the stator 11. It is configured. The stator 11 is provided with U-phase, V-phase, and W-phase stator windings 11u, 11v, and 11w that are Y-connected, and the rotor 12 has a hexapole permanent magnet ( 2 is omitted).

  The controller 20 receives power supply from the DC power supply device 60 and drives the brushless motor 10, and is configured by, for example, a small control device. The controller 20 of this example includes an inverter circuit unit 30, a rotational position signal detection unit 40, and a control unit 50.

  The inverter circuit unit 30 is configured by a so-called full-wave drive circuit in which an upper arm and a lower arm are bridge-connected. That is, the upper arm of the inverter circuit section 30 is configured by switching elements 31a, 31b, 31c and diodes 32a, 32b, 32c, and the lower arm is configured by switching elements 31d, 31e, 31f and diodes 32d, 32e, 32f. ing.

  The switching elements 31a to 31f are configured by n-channel MOSFETs, and are bridge-connected between the anode power supply line 33 and the cathode power supply line 34 in three phases of U phase, V phase, and W phase. The drains of the switching elements 31a, 31b, and 31c are connected to the anode power supply line 33, respectively, and the sources of the switching elements 31d, 31e, and 31f are connected to the cathode power supply line 34, respectively.

  The gates of the switching elements 31a to 31f are respectively connected to output terminals of energization signal generation circuits 55 of the control unit 50, which will be described later, and each bridge of the switching elements 31a, 31b, 31c and the switching elements 31d, 31e, 31f. The intermediate connection portions 35u, 35v, and 35w in the connection are connected to the stator windings 11u, 11v, and 11w, respectively.

  The switching elements 31a, 31b, and 31c flow currents from the anode power supply line 33 to the stator windings 11u, 11v, and 11w based on energization signals Sup, Svp, Swp, Sun, Svn, and Swn applied to the gates. Are sequentially switched. Further, the switching elements 31d, 31e, 31f flow current from the stator windings 11u, 11v, 11w to the cathode power supply line 34 based on energization signals Sup, Svp, Swp, Sun, Svn, Swn applied to the gates. Are sequentially switched.

  The diodes 32a to 32f are for releasing a surge voltage generated by switching of the switching elements 31a to 31f. The diodes 32a to 32f of this example are connected in parallel to the switching elements 31a to 31f, respectively, and are wired so as to be opposite to the current flow from the anode power supply line 33 to the cathode power supply line 34. . The diodes 32a to 32f are built in the switching elements 31a to 31f made of MOSFET, respectively.

  The rotational position signal detection unit 40 detects terminal voltage signals Su, Sv, Sw generated in the stator windings 11u, 11v, 11w according to the rotation of the rotor 12, and outputs rotational position signals Pu, Pv, Pw. It has a predetermined low-pass filter (integration circuit), a comparator, and the like. The rotational position signal detector 40 of this example integrates the terminal voltage signals Su, Sv, Sw of each phase to generate a pseudo terminal voltage signal of each phase, and generates it by comparing it with the reference voltage signal. The zero cross signal is output to the delay circuit 54 of the control unit 50 described later as the rotational position signals Pu, Pv, Pw.

  The control unit 50 generates energization signals Sup, Svp, Swp, Sun, Svn, Swn based on the rotational position signals Pu, Pv, Pw output from the rotational position signal detection unit 40, and outputs the energization signals Sup, Svp, Swp, Sun, Svn, Swn. 30 switching elements 31a to 31f (see FIG. 3 for detailed waveforms). In the control unit 50 of this example, a 120 ° energization method is adopted as an example. The control unit 50 of this example is configured by, for example, a one-chip microcomputer equipped with an arithmetic unit, a memory, and the like, and includes a phase check circuit 51, a rotation speed detection circuit 52, and phase correction as phase correction means. The circuit 53 includes a delay circuit 54 as delay means and an energization signal generation circuit 55 as energization signal generation means.

  As will be described in detail later, the phase check circuit 51 is for detecting the phase angle θ (see FIG. 1) of the induced voltage appearing in the terminal voltage signal Su at predetermined times t1 and t2. The phase confirmation circuit 51 of this example includes an A / D conversion start timing generation unit 51a, an A / D conversion unit 51b as a terminal voltage detection unit, and a phase confirmation unit 51c as a phase confirmation unit. Has been.

  Here, before describing the configuration of the phase check circuit 51, the terminal voltage signal of this example will be described with reference to FIG. FIG. 1 is a diagram showing a voltage waveform of a terminal voltage signal Su obtained from the stator winding 11u shown in FIG. The voltage waveform of the terminal voltage signal Su is a mixture of a drive voltage for rotating the brushless motor 10 and an induced voltage generated in the brushless motor 10.

  That is, the voltage waveform Su1 in the terminal voltage signal Su shown in FIG. 1 is a drive voltage applied to the stator winding 11u by energization with the anode terminal when the switching element 31a is turned on. A voltage waveform Su2 in the signal Su is a drive voltage applied to the stator winding 11u by energization with the cathode terminal when the switching element 31d is turned on.

  Further, a section T1 shown in FIG. 1 shows a non-energized state in which both the switching elements 31a and 31d are turned off after energization with the anode terminal, and a section T2 shows the switching elements 31a and 31d after energization with the cathode terminal. Both show the non-energized state that is turned off. That is, the first non-energized section T1 is a section from when the energization between the stator winding 11u and the positive power source is completed until the negative power supply is started, and the second non-conductive section T2 is This is a period from when the energization between the stator winding 11u and the negative power source is completed until the energization with the positive power source is started.

  Furthermore, the voltage waveform Su3 in the non-energized section T1 is generated by current flowing through the diode 32d during commutation, and the voltage waveform Su4 is an induced voltage generated in the stator winding 11u. Similarly, the voltage waveform Su5 in the non-energized section T2 is generated by a current flowing through the diode 32a during commutation, and the voltage waveform Su6 is an induced voltage generated in the stator winding 11u. In this example, since the 120 ° energization method is adopted, the first and second non-energization sections T1 and T2 are respectively set to an electrical angle of 60 °, and the motor energization start angle θm is set to an electrical angle of 30 °. Is set.

  Then, the A / D conversion start timing generation unit 51a of the present example has a timing (time t1; FIG. 5) after the U-phase stator winding 11u has been switched off from energization with the anode terminal. 1), the first A / D conversion start signal is output to the A / D converter 51b, and a predetermined electrical angle φ is applied after the U-phase stator winding 11u is switched off to the cathode terminal. The second A / D conversion start signal is output to the A / D converter 51b at the timing when the time elapses (time t2; see FIG. 1).

  In this example, the A / D converter at a timing (time t1, t2; see FIG. 3) at which a predetermined electrical angle φ has elapsed after the V-phase delayed output signal Dv output from the delay circuit 54 has changed. The first and second A / D conversion start signals are output to 51b. In this example, as an example, the predetermined electrical angle φ in the first and second non-energized sections T1, T2 is set to 50 °. In the case of this example, the predetermined electrical angle φ can be arbitrarily set within a range of 30 ° <φ <60 °.

  The A / D conversion unit 51b receives the first A / D conversion start signal output from the A / D conversion start timing generation unit 51a, so that the U-phase terminal voltage signal in the first non-energization section T1. The terminal voltage of Su is sampled, and digital terminal voltage data obtained by A / D converting the terminal voltage Vf1 at this time is output to the phase confirmation unit 51c. In addition, the A / D conversion unit 51b of this example samples the terminal voltage of the U-phase terminal voltage signal Su in the second non-energization period T2 by inputting the second A / D conversion start signal, Digital terminal voltage data obtained by A / D converting the terminal voltage Vf2 at this time is output to the phase confirmation unit 51c.

The phase confirmation unit 51c reads the digital voltage data corresponding to the terminal voltages Vf1 and Vf2 output from the A / D conversion unit 51b and inputs the rotation speed detection signal output from the rotation speed detection circuit 52. Based on (1), the phase angle (electrical angle) θ of the induced voltage (indicated by voltage waveforms Su3 and Su6 in FIG. 1) appearing in the terminal voltage signal Su is calculated.
Vf2−Vf1 = 3 Asin θ (1)

  In the above formula (1), the coefficient A is calculated by A = K × N. Here, K is a constant representing the level amount of the induced voltage generated per unit rotational speed, and is determined in advance by the motor characteristics of the brushless motor 10. N is the rotational speed of the brushless motor 10 and is calculated based on the rotational speed detection signal output from the rotational speed detection circuit 52. For example, if K = 1.1V / 1000 rpm, A = 5.5V when the rotational speed is 5000 rpm. The basis for deriving the theoretical formula shown in formula (1) will be described in detail later.

  The rotation speed detection circuit 52 calculates the rotation speed of the brushless motor 10 based on the U-phase rotation position signal Pu output from the rotation position signal detection unit 40, and outputs the rotation speed detection signal corresponding to the calculated value. It is configured to output to the confirmation unit 51c, the base phase correction amount determination unit 53a, and the phase correction amount determination unit 53e, respectively.

  The phase correction circuit 53 calculates the phase correction determination amount γ based on the phase angle θ calculated by the phase confirmation unit 51c and the rotation speed calculated by the rotation speed detection circuit 52, and the calculated result is A corresponding phase correction amount determination signal is output to the delay circuit 54. The phase correction circuit 53 of this example includes a base phase correction amount determination unit 53a as a base phase correction amount determination unit, a phase correction adjustment amount determination unit 53b as a phase correction adjustment amount determination unit, and a phase range setting storage unit. A phase range setting storage unit 53c, a step adjustment amount setting storage unit 53d, and a phase correction amount determination unit 53e as phase correction amount determination means are configured.

  Based on the rotational speed detection signal output from the rotational speed detection circuit 52, the base phase correction amount determination unit 53a determines the base phase correction amount α corresponding to the rotational speed of the brushless motor 10 when there is no load. . The base phase correction amount α determined by the base phase correction amount determination unit 53a mainly corrects the phase shift from the ideal delay phase angle due to the frequency characteristics of the low-pass filter provided in the rotational position signal detection unit 40. Is to do.

  FIG. 4 shows the relationship between the phase delay (electrical angle) by the low-pass filter and the motor rotation speed. As shown in FIG. 4, generally, the phase delay amount gradually decreases as the motor rotation speed increases. In this example, following the example shown in FIG. 4, the base phase correction amount α determined by the base phase correction amount determination unit 53a is set in advance so as to increase gradually as the motor speed increases. This base phase correction amount α is calculated based on the frequency characteristics of the low-pass filter. More specifically, a table map of the motor speed and the base phase correction amount α can be created by theoretical calculation using a filter constant, and this simple table map is stored in the base phase correction amount determination unit 53a. Yes.

  The phase correction adjustment amount determination unit 53b is mainly for correcting a phase shift caused by the load applied to the brushless motor 10. As will be described in detail later, the phase correction adjustment amount determination unit 53b of the present example calculates the phase angle θ calculated by the phase confirmation unit 51c and the phase range setting value θs stored in advance in the phase range setting storage unit 53c. When the differences are calculated and it is determined that these differences are outside a predetermined allowable range (in this example, an electrical angle ± 1 ° as an example), the phase correction adjustment amount β is set to 1 so that these differences are eliminated. It is configured to increase or decrease step by step. The one step amount at this time corresponds to the step adjustment amount σ stored in the step adjustment amount setting unit 53d.

  The phase range setting storage unit 53c includes the prescribed range of the phase angle θ of the induced voltage at the predetermined electrical angle φ in the first non-energized section T1, and the induced voltage at the predetermined electrical angle φ in the second non-energized section T2. The prescribed range of the phase angle θ is stored in advance. In this example, as an example, a 120 ° energized three-phase motor is adopted, and the first and second non-energized sections T1 and T2 are set to an electrical angle of 60 ° as described above, and the motor energization start angle is set. Is set to 30 °, and the predetermined electrical angle φ in the first and second non-energized sections T1 and T2 is set to 50 °. Accordingly, the phase range setting storage unit 53c stores the phase range set value θs = 20 ± 1 ° as the specified range of the phase angle θ of the induced voltage at the predetermined electrical angle φ in the first and second non-energized sections T1 and T2. Is preset.

  The step adjustment amount setting unit 53d stores a change amount for one step of the phase correction adjustment amount β determined by the phase correction adjustment amount determination unit 53b. In the step adjustment amount setting unit 53d of this example, an electrical angle of 0.5 ° is set as the step adjustment amount σ corresponding to the change amount for one step of the phase correction adjustment amount β.

  As described above, the phase correction amount determination unit 53e adds the phase correction adjustment amount β determined by the phase correction adjustment amount determination unit 53b to the base phase correction amount α determined by the base phase correction amount determination unit 53a. In addition, this is determined as the final phase correction determination amount γ. In addition, the phase correction amount determination unit 53e of this example is configured to generate a phase correction amount determination signal corresponding to the phase correction determination amount γ and output this to the delay circuit 54.

  The delay circuit 54 delays the rotational position signals Pu, Pv, and Pw output from the rotational position signal detection unit 40 by a predetermined phase, and outputs them to the energization signal generation circuit 55 as delayed output signals Du, Dv, and Dw. To do. The delay circuit 54 of this example is basically based on delaying the phase by a predetermined ideal delay phase angle with respect to the rotational position signals Pu, Pv, and Pw. When the phase correction amount determination signal is output from the determination unit 53e, the phase correction amount γ determined based on the phase correction amount determination signal is equal to the ideal delay phase angle of the delayed output signals Du, Dv, and Dw. It is configured to add correction.

  The energization signal generation circuit 55 inputs the delay output signals Du, Dv, Dw output from the delay circuit 54 to generate energization signals Sup, Svp, Swp, Sun, Svn, Swn, and outputs them to the inverter circuit unit 30. The switching elements 31a to 31f are output to the gates of the switching elements 31a to 31f, respectively, so that the switching elements 31a to 31f are sequentially driven.

Next, the basis for deriving the theoretical formula shown in the above formula (1) will be described with reference to FIGS.
FIG. 5 is a diagram showing an equivalent circuit when the U-phase stator winding 11u is in a non-energized state, and FIG. 6 is a diagram showing induced voltages generated in the stator windings 11u, 11, v, and 11w. .

First, derivation of the terminal voltage Vf1 in the first non-energization section T1 will be described.
FIG. 5 is a diagram showing an equivalent circuit at time t in FIG. 6 when a current flows from the W-phase upper arm to the V-phase lower arm. In FIG. 5, Veu, Vev, and Vew indicate induced voltages generated in the stator windings 11u, 11v, and 11w of the respective phases, and Ev and Ew indicate the V-phase stator winding 11v and the W-phase stator winding. This is the back electromotive force due to the current change of the line 11w. R is the winding resistance of the stator windings 11u, 11v, 11w.

The direction of the induced voltage generated in the stator windings 11u, 11v, 11w of each phase accompanying the rotation of the rotor 12 is as shown in FIG. 5 at time t1 in FIG.
Here, if 0 <θ <60 °,
Veu = Asin (180 + θ) = − Asinθ,
Vev = Asin [120+ (180 + θ)] = − Asin (60−θ),
Vew = Asin [240+ (180 + θ)] = Asin (60 + θ),
It becomes.

From FIG. 5, when the power supply voltage of the DC power supply device 60 is Vc and the current flowing as shown by the broken line is I,
Vc = Ew + Vew + | Vev | + Ev + 2IR,
Here, since Ew = Ev,
Vc = 2Ev + Asin (60 + θ) + Asin (60−θ) + 2IR,
Than this,
Vc / 2 = Ev + Asin (60 + θ) / 2 + Asin (60−θ) / 2 + IR (I
-1).

At this time, the terminal voltage Vf1 of the U-phase stator winding 11u, which is a non-conducting phase, is Vf1 = Vu, assuming that the potential Vu of the U-phase intermediate connection portion 35u is Vf1 = Vu.
Vf1 = IR + Ev + | Vev | + Veu,
Substituting Vev = −Asin (60−θ) and Veu = −Asinθ into this,
Vf1 = Ev + Asin (60−θ) −Asinθ + IR (I−2).

From formula (I-1) -formula (I-2):
Vc / 2−Vf1 = Asin (60 + θ) / 2−Asin (60−θ) / 2 + Asinθ.
Than this,
Vc / 2−Vf1 = A cos 60 sin θ + A sin θ.
Therefore, the following formula is established. That is,
Vc / 2−Vf1 = 1.5 Asin θ (I-3) is established.

Next, the derivation of the terminal voltage Vf2 in the second non-energization section T2 will be described.
FIG. 7 is a diagram showing an equivalent circuit at time t in FIG. 8 when current flows from the V-phase upper arm to the W-phase lower arm. In FIG. 7, Veu, Vev, and Vew indicate induced voltages generated in the stator windings 11u, 11v, and 11w of the respective phases, and Ev and Ew indicate the V-phase stator winding 11v and the W-phase stator winding. This is the back electromotive force due to the current change of the line 11w. R is the winding resistance of the stator windings 11u, 11v, 11w.

The direction of the induced voltage generated in the stator windings 11u, 11v, 11w of each phase accompanying the rotation of the rotor 12 is as shown in FIG. 7 at time t2 in FIG.
Here, if 0 <θ <60 °,
Veu = Asinθ,
Vev = Asin [120 + θ)] = Asin (60−θ),
Vew = Asin [240 + θ)] = − Asin (60 + θ),
It becomes.

From FIG. 7, when the power supply voltage of the DC power supply device 60 is Vc and the current flowing as shown by the broken line is I,
Vc = Ev + Vev + | Vew | + Ew + 2IR,
Here, since Ev = Ew,
Vc = 2Ew + Asin (60−θ) + Asin (60 + θ) + 2IR,
Than this,
Vc / 2 = Ew + Asin (60−θ) / 2 + Asin (60 + θ) / 2 + IR (II)
-1).

At this time, the terminal voltage Vf2 of the U-phase stator winding 11u, which is a non-conducting phase, is Vf2 = Vu, assuming that the potential Vu of the U-phase intermediate connection portion 35u is Vf2 = Vu.
Vf2 = IR + Ew + | Vew | + Veu,
Substituting Vew = −Asin (60 + θ) and Veu = Asinθ into this,
Vf2 = Ew + Asin (60 + θ) + Asinθ + IR (II-2).

From formula (II-1) -formula (II-2):
Vf1-Vc / 2 = Asin (60+ [theta]) / 2-Asin (60- [theta]) / 2 + Asin [theta].
Than this,
Vf2−Vc / 2 = Acos60sinθ + Asinθ.
Therefore, the following formula is established. That is,
Vf2−Vc / 2 = 1.5 Asin θ (II-3) is established.

And from Formula (II-3) -Formula (II-3),
The above-described Vf2−Vf1 = 3Asin θ (1) is derived.
That is, if the phase angle θ of the induced voltage is known from Equation (1), θ + (60−φ) that is the energization start angle can be obtained.

The formula (II-3) can also be derived from the formula (I-3). In other words, the phase angle of the induced voltage at the timing when the terminal voltage Vf1 is detected is θ, and the terminal voltage detected at the timing (180 ° + θ) when the electrical angle is 180 ° from the timing when the terminal voltage Vf1 is detected is Vf2. And substitute these into the formula (I-3).

Then, Vc / 2−Vf2 = 3 / 2Asin (180 + θ),
Vc / 2−Vf2 = −1.5 Asin θ.
Thus, Vf2−Vc / 2 = 1.5 Asin θ is derived, and the formula (II-3) can be derived.

Next, the operation of the brushless motor device 1 having the above configuration will be described.
When a control signal is input to the controller 20 from an upper controller (not shown), the energization signal generation circuit 55 performs energization signals Sup, Svp, Swp, Sun, Svn, Swn based on a synchronization signal output from a timer (not shown). Is generated. The energization signals Sup, Svp, Swp, Sun, Svn, and Swn are output to the inverter circuit unit 30.

  In this way, when the energization signals Sup, Svp, Swp, Sun, Svn, and Swn are output from the energization signal generation circuit 55 to the inverter circuit unit 30, the switching elements 31a to 31f are sequentially switched. When the switching elements 31a to 31f are sequentially switched, a current flows through the stator windings 11u, 11v, and 11w in a predetermined order, and the stator windings through which the current flows among the stator windings 11u, 11v, and 11w. A driving magnetic field is emitted from the wire, and the rotor 12 is forcibly rotated.

  As the frequency of the synchronization signal output from the timer increases, the rotational speed of the rotor 12 increases. When the rotational speed of the rotor 12 eventually reaches a predetermined rotational speed, the controller 20 moves from the forced drive state. Transition to the sensorless drive state. That is, in the controller 20, the energization signals Sup, Svp, Swp, based on the rotational position signals Pu, Pv, Pw output from the rotational position signal detector 40 and the terminal voltage signal Su obtained from the stator winding 11u. Sun, Svn, and Swn are generated.

  When the rotor 12 rotates in a sensorless manner as described above, the terminal voltage signals Su, Sv, Sw generated in the stator windings 11u, 11v, 11w according to the rotation of the rotor 12 are rotated. The signal is output to the signal detector 40. In the rotational position signal detection unit 40, the terminal voltage signals Su, Sv, Sw of each phase are integrated by a low-pass filter to be a pseudo terminal voltage signal, and then the pseudo terminal voltage signal and the reference voltage signal are compared and zero-crossed. Rotational position signals Pu, Pv, Pw consisting of signals are generated. The rotational position signals Pu, Pv, Pw are output to the delay circuit 54 of the control unit 50.

  In the delay circuit 54, the phases of the rotational position signals Pu, Pv, and Pw output from the rotational position signal detection unit 40 are delayed by a predetermined ideal delay phase angle. The delay output signals Du, Dv, Dw generated in this way are output to the energization signal generation circuit 55. At the same time, among the delayed output signals Du, Dv, and Dw output from the delay circuit 54, the V-phase delayed output signal Dv is output to the A / D conversion start timing generation unit 51a.

  The A / D conversion start timing generation unit 51a is a timing after a predetermined electrical angle φ after the V-phase delay output signal Dv output from the delay circuit 54 is changed (time t1, t2; see FIGS. 1 and 3). Thus, the first and second A / D conversion start signals are respectively output to the A / D converter 51b. In the A / D converter 51b, by inputting the first A / D conversion start signal, the U-phase terminal voltage in the first non-energization section T1 is sampled, and the terminal voltage Vf1 at this time is converted to A / D. The converted digital terminal voltage data is output to the phase confirmation unit 51c. Similarly, by inputting the second A / D conversion start signal, the U-phase terminal voltage in the second non-energized section T2 is sampled, and the digital terminal voltage obtained by A / D converting the terminal voltage Vf2 at this time is sampled. The data is output to the phase confirmation unit 51c.

  In parallel with these, the rotational speed detection circuit 52 calculates the rotational speed of the brushless motor 10 based on the U-phase rotational position signal Pu output from the rotational position signal detection unit 40. Then, a rotation speed detection signal corresponding to the calculated rotation speed is output to the phase confirmation unit 51c, the base phase correction amount determination unit 53a, and the phase correction amount determination unit 53e.

  In this way, when the rotation speed detection signal is output from the rotation speed detection circuit 52 to the base phase correction amount determination unit 53a, the base phase correction amount determination unit 53a performs the brushless operation under no load based on the rotation speed detection signal. A base phase correction amount α corresponding to the rotational speed of the motor 10 is determined. As described above, the base phase correction amount α determined by the base phase correction amount determination unit 53a causes a phase shift from an ideal delay phase angle due to the frequency characteristics of the low-pass filter provided in the rotational position signal detection unit 40. It is corrected.

  On the other hand, the digital voltage data corresponding to the terminal voltages Vf1 and Vf2 output from the A / D conversion unit 51b as described above is read into the phase confirmation unit 51c. The phase confirmation unit 51c reads digital voltage data corresponding to the terminal voltages Vf1 and Vf2 output from the A / D conversion unit 51b and inputs the rotation speed detection signal output from the rotation speed detection circuit 52. Then, in the phase confirmation unit 51c, the phase angle θ of the induced voltage is calculated based on the above formula (1) Vf2−Vf1 = 3Asinθ.

  The phase correction adjustment amount determination unit 53b reads the phase angle θ calculated by the phase confirmation unit 51c, and also reads the phase range setting value θs stored in advance in the phase range setting storage unit 53c. And the phase range set value θs are calculated. When the phase correction adjustment amount determination unit 53b determines that these differences are outside a predetermined allowable range (in this example, an electrical angle ± 1 ° as an example), such a difference is eliminated. The phase correction adjustment amount β is changed step by step step by step. One step amount at this time is a step adjustment amount σ (electrical angle 0.5 °) stored in the step adjustment amount setting unit 53d.

  The phase correction amount determination unit 53e reads the base phase correction amount α determined by the base phase correction amount determination unit 53a and the phase correction adjustment amount β adopted by the phase correction adjustment amount determination unit 53b. The final phase correction determination amount γ is determined by adding the base phase correction amount α and the phase correction adjustment amount β.

  Explaining with an example, in this example, as described above, a 120 ° energized three-phase motor is adopted, and as shown in FIG. 1, the first and second non-energized sections T1 and T2 are electrically connected. The angle is set to 60 °, the motor energization start angle is set to 30 °, and the predetermined electrical angle φ in the first and second non-energization sections T1 and T2 is set to 50 °. The phase range setting storage unit 53c stores a phase range set value θs (20 ± 1 °) as a specified range of the phase angle θ of the induced voltage at the predetermined electrical angle φ in the first and second non-energized sections T1 and T2. ) Is preset.

  Accordingly, when the phase angle θ calculated by the phase confirmation unit 51c is, for example, an electrical angle of 16 °, the phase angle θ is stored in the phase range setting storage unit 53c in advance as a phase range setting value θs (electrical angle 20 Since it is outside the range of ± 1 °), the energization start timing may be delayed. In this case, the phase correction adjustment amount β is increased stepwise by one step (electrical angle 0.5 °) each time the routine processing is repeated so that these differences are eliminated.

  Since the phase correction determination amount γ is the sum of the base phase correction amount α and the phase correction adjustment amount β, as a result, the phase correction determination amount γ is also step by step (electrical angle 0.5 °). Will increase. That is, the phase correction determination amount γ changes as the phase correction adjustment amount β changes. Then, a phase correction amount determination signal corresponding to the phase correction determination amount γ determined by the phase correction amount determination unit 53e is output from the phase correction amount determination unit 53e to the delay circuit 54.

  Thus, when the phase correction amount determination signal corresponding to the phase correction determination amount γ is output from the phase correction amount determination unit 53e to the delay circuit 54, the delay circuit 54 determines the phase correction amount determination signal based on the phase correction amount determination signal. Delay output signals Du, Dv, and Dw are generated by correcting the ideal delay phase angle by the phase correction determination amount γ. The delay output signals Du, Dv, Dw generated in this way are output to the energization signal generation circuit 55.

  In this way, in this example, even if a phase shift occurs in the rotational position signals Pu, Pv, Pw with respect to the terminal voltage signals Su, Sv, Sw due to the frequency characteristics of the low-pass filter in the rotational position signal detector 40, the delay circuit. At 54, the rotational position signals Pu, Pv, Pw are delayed by a predetermined phase, which are output to the energization signal generation circuit 55 as delayed output signals Du, Dv, Dw. As a result, accurate energization signals Sup, Svp, Swp, Sun, Svn, Swn having no phase shift corresponding to the magnetic pole position of the rotor 12 are generated. Therefore, the motor efficiency of the brushless motor 10 can be improved, and problems such as step-out can be prevented from occurring in the brushless motor 10.

  In this example, the phase correction determination amount γ is 1 so that there is no difference between the phase angle θ calculated by the phase confirmation unit 51c and the phase range setting value θs stored in advance in the phase range setting storage unit 53c. Since the step amount (electrical angle 0.5 °) increases step by step, the energization signals Sup, Svp, Swp, Sun, Svn, Swn can be gradually converged to the set phase.

  Furthermore, according to this example, the terminal voltage Vf1, generated in the stator winding 11u at two predetermined first and second timings t1, t2 in the first and second non-energizing sections T1, T2. By simply detecting Vf2 and substituting these terminal voltages Vf1 and Vf2 into a predetermined calculation formula, the value of the phase angle θ or sin θ of the induced voltage generated in the stator winding 11u at the predetermined timing is calculated. can do. Thereby, based on the value of the phase angle θ or sin θ, it is possible to determine the phase correction determination amount γ for correcting the delay phase of the delayed output signals Du, Dv, Dw. Therefore, unlike the prior art, there is no need to determine the phase correction amount according to the current value detected by the current detector, so that the current detector can be made unnecessary.

  Further, according to the present example, as described above, the stator winding 11u is applied to the stator winding 11u at two predetermined first and second timings t1 and t2 in the first and second non-energization sections T1 and T2. The detected terminal voltages Vf1 and Vf2 are detected, and the terminal voltages Vf1 and Vf2 are simply substituted into a predetermined calculation formula, so that the phase angle θ of the induced voltage generated in the stator winding 11u at the predetermined timing or Since the value of sin θ can be calculated, a table map for determining the relationship between the induced voltage value generated in the stator winding and the phase angle for each motor rotation speed can be eliminated as in the prior art.

  Thus, according to this example, the current detector and the table map required in the prior art can be made unnecessary, so that the cost of the apparatus can be reduced as compared with the conventional configuration. . In addition, the delay phase of the delayed output signals Du, Dv, and Dw can be corrected without using a current detector, a table map, or the like, so that a higher phase angle detection accuracy can be achieved with a simpler configuration than the conventional configuration. It can be demonstrated.

The embodiment of the present invention can be modified as follows.
(I) In the above embodiment, the terminal voltages Vf1 and Vf2 and the expression (1) Vf2−Vf1 = 3As
Although the phase correction adjustment amount β is determined by calculating the phase angle θ of the induced voltage from inθ, the present invention is not limited to this. In addition, the phase correction adjustment amount β may be determined by calculating the induced voltage sin θ from the terminal voltages Vf1 and Vf2 and the equation (1) Vf2−Vf1 = 3 Asin θ.

(Ii) In the above embodiment, the value of the phase angle θ of the induced voltage calculated by the phase confirmation unit 51c is within a predetermined allowable value range with respect to the phase range setting value θs stored in the phase range setting storage unit 53c. However, the present invention is not limited to this. In addition, for example, when the phase angle θ calculated by the phase confirmation unit 51c is, for example, an electrical angle of 16 °, the phase angle setting value θs is stored in the phase range setting storage unit 53c in advance. The phase correction adjustment amount β may be an electrical angle of 4 ° so that it falls within the range of (electrical angle 20 ± 1 °). In this way, as described above, the energization signals Sup, Svp, Swp, Sun, Svn, and Swn are converged to the set phase earlier than when the phase correction adjustment amount β is changed stepwise. Can do.

  (Iii) In the above embodiment, the terminal voltage Vf2 is detected at a timing having a difference of 180 ° in electrical angle with respect to the terminal voltage Vf1, but the present invention is not limited to this. In addition, for example, the terminal voltage Vf2 may be detected at a timing having a phase difference that is an odd multiple (for example, three times) of 180 degrees with respect to the terminal voltage Vf1. For example, even when PWM components are present in the induced voltages in the non-energized sections T1 and T2 by performing PWM energization, the terminal voltages Vf1 and Vf2 cannot be accurately detected every 180 ° of electrical angle. By detecting the terminal voltage Vf2 at a timing that has a phase difference that is an odd multiple (for example, three times) of 180 degrees in phase angle with respect to the terminal voltage Vf1, as a result, when there is no PWM component, the terminal A result similar to the detection of the voltages Vf1 and Vf2 every 180 ° electrical angle can be obtained.

(Iv) In the above embodiment, the terminal voltage Vf1, in the stator winding 11u of the same phase
Although it has been described that Vf2 is detected and the phase angle θ of the induced voltage is calculated from the terminal voltages Vf1 and Vf2 and the equation (1) Vf2−Vf1 = 3Asinθ, the present invention is not limited to this. In addition, the terminal voltages Vf1 and Vf2 detected from the stator windings of different phases are treated as the same phase, and the induced voltage is determined from the terminal voltages Vf1 and Vf2 and the expression (1) Vf2−Vf1 = 3Asin θ. The phase angle θ may be calculated.

(V) In the above embodiment, the rotation of the brushless motor 10 is controlled without performing PWM energization. However, the present invention is not limited to this, and the PWMless energization of the brushless motor 10 is performed. Of course, the rotation may be controlled. In this case, as shown in FIG. 9, when a PWM component is present in the first non-energized section T <b> 1 of the terminal voltage signal, the PWM among the switching elements 31 a to 31 f provided in the inverter circuit unit 30. When the first terminal voltage Vf1 is detected at the timing when the switching element that generates the component is switched on (ON interval), the induced voltage in the first non-energization interval T1 can be accurately detected. Although not particularly illustrated, the PWM component among the switching elements 31a to 31f provided in the inverter circuit unit 30 is also present when the PWM component is present in the second non-energized section T2 of the terminal voltage signal. When the second terminal voltage Vf2 is detected at the timing when the switching element to be generated is switched on, the induced voltage in the second non-energized section T2 can be accurately detected.

(Vi) In the above embodiment, the terminal voltages Vf1 and Vf2 at two electrical angles are detected, and the phase angle θ of the induced voltage from the terminal voltages Vf1 and Vf2 and the equation (1) Vf2−Vf1 = 3Asinθ or Although it has been described that sin θ is calculated, the present invention is not limited to this. In addition, as shown in FIG. 1, one of the terminal voltages Vf1 and Vf2 may be detected, and the phase angle θ or sin θ of the induced voltage may be calculated by the following equations (2) and (3). .
Vc / 2−Vf1 = 1.5 Asin θ (2)
Vf2-Vc / 2 = 1.5 Asin θ (3)
However, A is a product of a predetermined motor constant and a motor rotational speed determined from the rotational position signal Pu, and Vc is a power supply voltage.
The grounds for deriving the above formulas (2) and (3) are shown in the formulas (I-3) and (II-3).

  Next, technical ideas derived from the above formulas (2) and (3) and the above embodiments other than the invention described in the claims will be described.

That is, the first technical idea is to detect a terminal voltage waveform generated in each of a plurality of stator windings provided in a brushless motor and output a rotational position signal, and the rotational position A control unit that generates and outputs an energization signal based on the rotational position signal output from the signal detection unit, and an inverter circuit that sequentially switches energization to the stator winding based on the energization signal output from the control unit A controller for a brushless motor configured to include a power supply unit, wherein the control unit ends energization of at least one of the stator windings and the positive power supply and starts energization of the negative power supply. A terminal voltage detecting means for detecting a terminal voltage Vf1 generated in at least one of the stator windings at a timing when a predetermined electrical angle has elapsed since the start of the non-energized section in Control of a brushless motor, comprising: phase confirmation means for calculating the value of the phase angle θ or sin θ of the induced voltage generated in at least one of the stator windings of timing by the following equation (2) Device.
Vc / 2−Vf1 = 1.5 Asin θ (2)
However, A is a product of a predetermined motor constant and a motor rotational speed determined from the rotational position signal, and Vc is a power supply voltage.

The second technical idea is to detect a terminal voltage waveform generated in each of a plurality of stator windings provided in a brushless motor and output a rotational position signal, and the rotational position A control unit that generates and outputs an energization signal based on the rotational position signal output from the signal detection unit, and an inverter circuit that sequentially switches energization to the stator winding based on the energization signal output from the control unit A control unit for a brushless motor configured to include a power supply unit, wherein the control unit ends energization of at least one of the stator windings and the negative power supply and starts energization of the positive power supply. A terminal voltage detecting means for detecting a terminal voltage Vf2 generated in at least one of the stator windings at a timing when a predetermined electrical angle has elapsed since the start of the non-energized section in the non-energized section up to And a phase confirmation means for calculating the value of the phase angle θ or sin θ of the induced voltage generated in at least one of the stator stator windings according to the following equation (3): Device.
Vf2-Vc / 2 = 1.5 Asin θ (3)
However, A is a product of a predetermined motor constant and a motor rotational speed determined from the rotational position signal, and Vc is a power supply voltage.

The third technical idea is to generate a rotational position signal based on a terminal voltage waveform generated in each of a plurality of stator windings provided in a brushless motor, and to determine the rotational position signal in advance. The delayed phase is corrected based on a predetermined amount of phase correction to generate a delayed output signal, and the energization signal generated based on the delayed output signal is sequentially switched to energize the stator windings. A method for controlling a brushless motor for controlling rotation, wherein at least one of the stator windings and a positive power source are energized, and the non-energized section until the energization of the negative power source is started. A first step of detecting a terminal voltage Vf1 generated in at least one of the stator windings at a timing when a predetermined electrical angle has elapsed since the start of the energization section; and the stator at the timing The value of the phase angle θ or sinθ at least one to produce the induced voltage on the line is a control method for a brushless motor, characterized in that and a second step of calculating the following equation (2).
Vc / 2−Vf1 = 1.5 Asin θ (2)
However, A is a product of a predetermined motor constant and a motor rotational speed determined from the rotational position signal, and Vc is a power supply voltage.

Further, the fourth technical idea is that a rotational position signal is generated based on a terminal voltage waveform generated in each of a plurality of stator windings provided in a brushless motor, and the rotational position signal is determined in advance. The delayed phase is corrected based on a predetermined amount of phase correction to generate a delayed output signal, and the energization signal generated based on the delayed output signal is sequentially switched to energize the stator windings. A method of controlling a brushless motor for controlling rotation, wherein at least one of the stator windings and the negative power source are not energized until the energization of the positive power source is started and the non-energized section is not activated. A first step of detecting a terminal voltage Vf2 generated in at least one of the stator windings at a timing when a predetermined electrical angle has elapsed since the start of the energization section; and the fixing of the timing The value of the phase angle θ or sinθ of the induced voltage generated in at least one winding is a control method for a brushless motor, characterized in that and a second step of calculating the following equation (3).
Vf2-Vc / 2 = 1.5 Asin θ (3)
However, A is a product of a predetermined motor constant and a motor rotational speed determined from the rotational position signal, and Vc is a power supply voltage.

  Also according to this technical idea, the current detector and the table map required in the prior art can be made unnecessary as in the above embodiment, and the cost of the apparatus is reduced as compared with the conventional configuration. be able to. In addition, the delay phase of the delayed output signals Du, Dv, Dw can be corrected without using a current detector, table map, etc., and high phase angle detection accuracy is achieved with a simpler configuration than the conventional configuration. can do.

It is a figure which shows the terminal voltage waveform obtained from the brushless motor which concerns on one Embodiment of this invention. It is a figure which shows the structure of the brushless motor apparatus which concerns on one Embodiment of this invention. It is a figure which shows the various signal waveforms in the brushless motor apparatus which concerns on one Embodiment of this invention. It is explanatory drawing which shows the relationship between the phase delay by the low-pass filter which concerns on one Embodiment of this invention, and a motor rotation speed. It is explanatory drawing which shows the flow of the electric current in the brushless motor apparatus which concerns on one Embodiment of this invention. It is a figure which shows the induced voltage waveform which arises in the brushless motor which concerns on one Embodiment of this invention. It is explanatory drawing which shows the flow of the electric current in the brushless motor apparatus which concerns on one Embodiment of this invention. It is a figure which shows the induced voltage waveform which arises in the brushless motor which concerns on one Embodiment of this invention. It is a figure which shows the induced voltage waveform which arises in the brushless motor which concerns on the modification of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Brushless motor apparatus, 10 ... Brushless motor, 11 ... Stator, 11u, 11v, 11w ... Stator winding, 12 ... Rotor, 20 ... Controller (control device), 30 ... Inverter circuit part, 31a, 31b, 31c, 31d, 31e, 31f: switching element, 32a, 32b, 32c, 32d, 32e, 32f ... diode, 33 ... anode power line, 34 ... cathode power line, 35u, 35v, 35w ... intermediate connection, 40 ... rotation Position signal detection unit, 50... Control unit, 51... Phase confirmation circuit, 51 a... Conversion start timing generation unit, 51 b... A / D conversion unit (terminal voltage detection unit), 51 c. ... rotational speed detection circuit, 53 ... phase correction circuit (phase correction means), 53a ... base phase correction amount determination unit (base phase correction amount determination means), 53b Phase correction adjustment amount determination unit (phase correction adjustment amount determination unit), 53c ... Phase range setting storage unit (phase range setting storage unit), 53d ... Step adjustment amount setting storage unit, 53d ... Step adjustment amount setting unit, 53e ... Phase Correction amount determination unit (phase correction amount determination means), 54 ... delay circuit (delay means), 55 ... energization signal generation circuit (energization signal generation means), 60 ... DC power supply, α ... base phase correction amount, β ... phase Correction adjustment amount, γ ... Phase correction final value, θ ... Phase angle

Claims (13)

A rotational position signal detection unit that detects a terminal voltage waveform generated in each of a plurality of stator windings provided in the brushless motor and outputs a rotational position signal;
A controller that generates and outputs an energization signal based on the rotational position signal output from the rotational position signal detector;
An inverter circuit section for sequentially switching energization to the stator winding based on the energization signal output from the control section;
In a control device for a brushless motor configured with
The control unit includes the first non-energized section in a first non-energized section until the energization of at least one of the stator windings and the positive power supply ends and the energization of the negative power supply is started. The terminal voltage Vf1 generated in at least one of the stator windings is detected at a first timing when a predetermined electrical angle has elapsed since the start of the operation, and energization between at least one of the stator windings and a negative power source is performed. The second timing when the same electrical angle as the predetermined electrical angle has elapsed since the start of the second non-energized section in the second non-energized section until the energization with the positive-side power source is started. A terminal voltage detecting means for detecting a terminal voltage Vf2 generated in at least one of the stator windings;
The value of the phase angle θ or sin θ of the induced voltage generated in at least one of the stator windings at the first timing or the second timing is expressed by any of the following formulas (1), (2), and (3) Phase check means for calculating by
A control apparatus for a brushless motor, comprising:
Vf2−Vf1 = 3 Asin θ (1)
Vc / 2−Vf1 = 1.5 Asin θ (2)
Vf2-Vc / 2 = 1.5 Asin θ (3)
However, A is a product of a predetermined motor constant and a motor rotational speed determined from the rotational position signal, and Vc is a power supply voltage. The control unit delays the rotational position signal output from the rotational position signal detection unit and outputs a delay output signal;
Energization signal generating means for generating and outputting the energization signal based on the delayed output signal output from the delay means;
Phase correction means for determining a phase correction determination amount for correcting the delay phase angle of the delayed output signal output from the delay means,
The phase correction means detects a rotational speed of the brushless motor based on the rotational position signal output from the rotational position signal detector, and determines a base phase correction amount corresponding to the rotational speed of the brushless motor. Correction amount determining means;
Phase range setting storage means for setting and storing a prescribed range in advance for the value of the phase angle θ or sin θ of the induced voltage calculated by the phase confirmation means;
In order to increase or decrease the phase correction determination amount stepwise so that the value of the phase angle θ or sin θ of the induced voltage calculated by the phase confirmation unit falls within the specified range stored in the phase range setting storage unit. Phase correction adjustment amount determining means for determining the phase correction adjustment amount of
Phase correction amount determination means using a value obtained by adding the phase correction adjustment amount determined by the phase correction adjustment amount determination means to the base phase correction amount determined by the base phase correction amount determination means. When,
The brushless motor control device according to claim 1, wherein the brushless motor control device is provided. The control unit delays the rotational position signal output from the rotational position signal detection unit and outputs a delay output signal;
Energization signal generating means for generating and outputting the energization signal based on the delayed output signal output from the delay means;
Phase correction means for determining a phase correction determination amount for correcting the delay phase angle of the delayed output signal output from the delay means,
The phase correction means detects a rotational speed of the brushless motor based on the rotational position signal output from the rotational position signal detector, and determines a base phase correction amount corresponding to the rotational speed of the brushless motor. Correction amount determining means;
Phase prescribed value storage means for setting and storing a prescribed value in advance for the value of the phase angle θ or sin θ of the induced voltage calculated by the phase confirmation means;
Phase correction for adjusting the phase correction determination amount so as to eliminate the difference between the phase angle θ or sin θ value of the induced voltage calculated by the phase confirmation unit and the specified value stored in the phase specified value storage unit Phase correction adjustment amount determining means for determining the adjustment amount;
Phase correction amount determination means using a value obtained by adding the phase correction adjustment amount determined by the phase correction adjustment amount determination means to the base phase correction amount determined by the base phase correction amount determination means. When,
The brushless motor control device according to claim 1, wherein the brushless motor control device is provided.   4. The control unit according to claim 1, wherein the control unit detects the terminal voltage Vf <b> 2 at a timing having a phase difference that is an odd multiple of 180 degrees in phase angle with respect to the terminal voltage Vf <b> 1. The brushless motor control device according to claim 1.   The said control part uses the terminal voltage which arose in the stator winding of a phase different from the stator winding which detected the said terminal voltage Vf1 among the said stator winding as said terminal voltage Vf2. The brushless motor control device according to any one of claims 1 to 4.   When the PWM component is present in the terminal voltage waveform in the first non-energized section or the second non-energized section, the control unit is configured to select the PWM among the switching elements provided in the inverter circuit unit. 6. The brushless motor according to claim 1, wherein the terminal voltage Vf <b> 1 or the terminal voltage Vf <b> 2 is detected at a timing at which a switching element that generates a component is switched on. Control device. A brushless motor comprising a multi-phase stator winding and a permanent magnet rotor rotating by a magnetic field generated in the stator winding;
In a brushless motor device configured to have a controller for controlling the rotation of the brushless motor,
A brushless motor device using the brushless motor control device according to any one of claims 1 to 6 as the controller. A rotational position signal is generated based on a terminal voltage waveform generated in each of a plurality of stator windings provided in a brushless motor, and a predetermined delay correction phase is determined with respect to the rotational position signal by a predetermined amount of phase correction. A control method for a brushless motor that generates a delayed output signal by correcting the rotation of the brushless motor by sequentially switching the energization to the stator winding by the energization signal generated based on the delayed output signal. There,
From the start of the first non-energized section in the first non-energized section until the energization of at least one of the stator windings and the positive power supply ends and the energization of the negative power supply is started. A first step of detecting a terminal voltage Vf1 generated in at least one of the stator windings at a first timing when a predetermined electrical angle has passed;
From the start of the second non-energized section in the second non-energized section until the energization of at least one of the stator windings and the negative power supply ends and the energization of the positive power supply is started. A second step of detecting a terminal voltage Vf2 generated in at least one of the stator windings at a second timing when the same electrical angle as the predetermined electrical angle has elapsed;
The value of the phase angle θ or sin θ of the induced voltage generated in at least one of the stator windings at the first timing or the second timing is expressed by any of the following formulas (1), (2), and (3) A third step to calculate by
A method for controlling a brushless motor, comprising:
Vf2−Vf1 = 3 Asin θ (1)
Vc / 2−Vf1 = 1.5 Asin θ (2)
Vf2-Vc / 2 = 1.5 Asin θ (3)
However, A is a product of a predetermined motor constant and a motor rotational speed determined from the rotational position signal, and Vc is a power supply voltage. The control method of the brushless motor determines a base phase correction amount according to the rotation speed of the brushless motor, and defines a predetermined value of the phase angle θ or sin θ of the induced voltage calculated in the third step. A fourth step of determining a phase correction adjustment amount for gradually increasing or decreasing the phase correction determination amount so as to fall within a range;
A fifth step in which a value obtained by adding the phase correction adjustment amount to the base phase correction amount determined in the fourth step is set as the phase correction determination amount;
The brushless motor control method according to claim 8, further comprising: The control method of the brushless motor determines a base phase correction amount according to the number of rotations of the brushless motor, and the value of the phase angle θ or sin θ of the induced voltage calculated in the third step and a predetermined rule A fourth step of determining a phase correction adjustment amount for adjusting the phase correction determination amount so that there is no difference from the value;
A fifth step in which a value obtained by adding the phase correction adjustment amount to the base phase correction amount determined in the fourth step is set as the phase correction determination amount;
The brushless motor control method according to claim 8, further comprising:   The control method of the brushless motor detects the terminal voltage Vf2 at a timing having a phase difference of an odd multiple of 180 degrees in phase angle with respect to the terminal voltage Vf1. The brushless motor control method according to claim 10.   The control method of the brushless motor is characterized in that a terminal voltage generated in a stator winding of a phase different from that of the stator winding in which the terminal voltage Vf1 is detected is used as the terminal voltage Vf2. The method of controlling a brushless motor according to any one of claims 8 to 11.   When the PWM component is present in the terminal voltage waveform in the first non-energized section or the second non-energized section, the control method of the brushless motor is the switching element provided in the inverter circuit unit. 13. The terminal voltage Vf <b> 1 or the terminal voltage Vf <b> 2 is detected at a timing when a switching element that generates the PWM component is switched on. 13. Brushless motor control method.

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