JP3695889B2 - Inverter device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an inverter device that forms an energization signal based on a position sensor signal and drives a brushless DC motor.
[0002]
[Prior art]
  In recent years, brushless DC motors have been adopted as fan motors for air conditioners, motors for electric vehicles, or motors for washing machines in order to control a wide range of variable speeds and save electricity consumption. This is driven by an inverter device.
[0003]
  In a brushless DC motor having three-phase windings, normally, three Hall ICs that are simple and inexpensive as a position sensor are arranged for every 120 degrees of electrical angle, for example. The inverter device obtains a signal corresponding to the rotational position of the rotor by these Hall ICs, forms energization timing, applies voltage to the winding of the brushless DC motor, and drives it.
[0004]
  The voltage applied to the windings of a brushless DC motor is generally a 120-degree conduction type rectangular wave drive. However, for the purpose of improving the motor efficiency and reducing the vibration, a roughly sinusoidal voltage is supplied to the motor. As a possible inverter device, Japanese Patent Application No. 07-224299 has been filed.
[0005]
  As shown in FIG. 9, a three-phase rectangular wave signal is formed from three position sensor signals and started by a rectangular wave drive, and then switched to a substantially sine wave energization. A position sensor period measuring means for obtaining a position sensor signal from the sensor and measuring a period at which the position sensor signal changes, and a voltage having a resolution higher than the electrical angle corresponding to the change period based on the position sensor signal and the change period A voltage phase determining means for determining a phase; a voltage rate storage means for storing a voltage rate corresponding to the voltage phase; and an energization waveform forming means for forming an energization waveform of a three-phase approximate sine wave from the voltage phase and the voltage ratio. This is an inverter device having a driving means for energizing the three-phase windings based on the energization waveform, realizing low cost and low noise vibration.
[0006]
[Problems to be solved by the invention]
  However, further cost reduction is desired, and in order to realize this, it is desired to reduce the number of position sensors used. There has also been a demand for reduction of vibration noise at the time of starting generated by rectangular wave driving.
[0007]
  The present invention has been made in view of the above circumstances, and an object thereof is to provide an inverter device capable of forming a three-phase sine wave energization signal from a smaller number of position sensors and sine wave energizing a brushless DC motor. It is in.
[0008]
  Another object of the present invention is to provide an inverter device that does not involve rectangular wave driving at the time of starting. Another object of the present invention is to provide an inverter device capable of detecting the rotational state of a motor before starting.
[0009]
[Means for Solving the Problems]
[0010]
  In order to achieve the above object, the inverter device has a constant phase relationship with the induced voltage generated by the winding of the brushless DC motor having a three-phase winding.,DigitalN (n: 1 or 2) position sensors that output signals, position sensor period measuring means that measures a period in which position sensor signals obtained by the n position sensors change,Parameter storage means for storing the rotor phase difference corresponding to the change period of the position sensor signal measured by the position sensor period measurement means and the rotor phase corresponding to the change time of the position sensor signal;n position sensor signals,Change period, Rotor phase and rotor phase differenceVoltage phase determining means for determining a voltage phase having a resolution higher than the electrical angle corresponding to the change period, voltage rate storage means for storing a voltage rate corresponding to the voltage phase, and from the voltage phase and the voltage rate , Having an energization waveform forming means for forming a three-phase energization waveform, and a drive means for energizing the three-phase winding based on the energization waveform;At start-up, three-phase DC excitation energization is performed based on the rotor phase limited by n position sensor signals.
[0011]
  Furthermore, the voltage rate corresponding to the voltage phase stored in the voltage rate storage means is a voltage rate corresponding to a sine wave. When n = 1, the power supply voltage supply line and the sensor signal line for the position sensor are shared.
[0012]
  Further, when n = 1, a power supply voltage supply unit and a power supply current detection unit are provided for the position sensor, and a position sensor signal determination unit that determines a position sensor signal based on the power supply current detection result is provided.
[0013]
  In the case of n = 2, the position sensor signal obtained by the position sensor changes by π / 2 in the electrical angle of the rotor phase depending on the position sensor arrangement. Further, the voltage phase determination means includes a change period of the position sensor signal measured by the position sensor period measurement means, a rotor phase difference corresponding to the change period, a change time of the position sensor signal, and a rotor phase corresponding to the change time. And a parameter storage means for storing the voltage phase command as a calculation parameter, and a voltage phase at a certain time is determined by calculation based on the calculation parameter.
[0014]
  Further, when the change period is Ts, the change time is Tx, the rotor phase at the change time is Px, and the voltage phase command is Pr, the voltage phase Pn at the time Tc for determining the voltage phase is Pn = Px + Pr + (π / n) X (Tc-Tx) / Ts.
[0015]
  Furthermore, a predetermined value corresponding to the position signal is written at the change timing of the position sensor signal, and an electrical angle counter is provided in which the count cycle is determined based on the change cycle of the position sensor signal obtained by the position sensor cycle measuring means. The voltage phase determining means determines the voltage phase based on the sum of the count value of the electrical angle counter and the phase command value.
[0016]
  In addition, a predetermined value corresponding to the position signal is written at a change timing for each π / n of the position sensor signal, and counted for every π / n based on the change period of the position sensor signal obtained by the position sensor cycle measuring means. An electrical angle counter whose period is determined is provided, and the voltage phase determining means determines the voltage phase based on the sum of the count value of the electrical angle counter and the phase command value.
[0017]
  Furthermore, the initial value of the voltage phase is determined by n position sensor signals.StartIs the method. In addition, this is a starting method in which the initial value of the voltage phase is determined by the sum of the rotor phase at an intermediate point in a range that can be limited by n position sensor signals and the voltage phase command.
[0018]
  Further, this is a starting method in which DC excitation is performed to move the rotor to a predetermined rotor phase, and an initial value of the voltage phase is determined by the sum of the predetermined rotor phase and the voltage phase command.
[0019]
  Further, a three-phase DC excitation energization waveform is formed from the voltage phase delayed by π / 2 of the rotor phase, which is limited by n position sensor signals, and the voltage ratio stored in the voltage ratio storage means. In this starting method, after direct current excitation is performed on the three-phase winding, the initial value of the voltage phase is determined by the sum of the rotor phase limited by n position sensor signals and the voltage phase command.
[0020]
  Further, a motor winding current detecting means is provided, and when n = 1, means for starting energization at the timing specified by the position sensor signal and stopping energization according to the result of the current detecting means, and means for measuring the energization time And rotation direction detecting means for determining the rotation direction from the measured energization time.
[0021]
  Further, the position sensor cycle measuring means, the voltage phase determining means, the voltage ratio storing means, the energization signal forming means, and the starting means are constituted by a microcomputer. Further, the position sensor period measuring means, the voltage phase determining means, the voltage ratio storing means, the energization signal forming means, the starting means, and the rotation direction detecting means are constituted by a microcomputer.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, as a first embodiment of the present invention, the case of one position sensor (n = 1) will be described with reference to FIGS. 1 to 8 and FIG. FIG. 1 is an electrical configuration diagram showing a first embodiment of the present invention. In FIG. 1, both terminals of the AC power supply 1 are connected to the AC input terminal of the full-wave rectifier circuit 2b, and a reactor 2a is inserted in one of them. A smoothing capacitor 2c is connected between the DC output terminals of the full-wave rectifier circuit 2b, and the DC power supply circuit 2 is constituted by the reactor 2a, the full-wave rectifier circuit 2b, and the smoothing capacitor 2c. The three-phase bridge circuit 4 is connected to the output terminal of the DC power supply circuit 2, and the motor current detecting means 10 is installed on the negative DC bus. In the three-phase bridge circuit 4, transistors (IGBT) Tr1 to Tr6 each having a diode between an emitter and a collector are connected in a three-phase bridge. The output terminals 4u, 4v, 4w of the three-phase bridge circuit 4 are connected to the respective star windings 6u, 6v, 6w of the three-phase brushless DC motor 6 having the fan 13.
[0023]
  Therefore, in the three-phase bridge circuit 4, the transistors Tr1 to Tr3 correspond to positive side switching elements, and the transistors Tr4 to Tr6 correspond to negative side switching elements.
[0024]
  As shown in FIG. 14, the brushless DC motor (hereinafter simply referred to as the motor) 6 has a Hall IC 7a and one position sensor 7 comprising a resistor 7b connected between the open collector output and the positive power source. It is configured to be driven by sensor power supply means 12 comprising a DC power supply 12a and a capacitor 12b. A power supply current detection means 11 is connected between the position sensor 7 and the sensor power supply means 12, and its output terminal is connected to the input terminal I1 of the microcomputer 8 to output a signal Hs. The power supply current detecting means 11 includes a resistor 11a connected between the Hall IC 7a and the sensor power supply means 12, a separately provided reference voltage generating means 11c, a positive input terminal connected to the resistor 11a, and a negative input TerminalButThe comparator 11b is connected to the reference voltage generator 11c.
[0025]
  Further, the output signal Si of the motor current detecting means 10 is supplied to the input terminal I2 of the microcomputer 8, and the phase command signal Pr and the voltage command signal Da are respectively supplied to the input terminals I3 and I4 from the outside. ing. Further, the microcomputer 8 has a sine wave corresponding to 360 degrees (0 to 359 degrees) in electrical angle as shown in FIG. 2 in a ROM 8a (voltage ratio storage means, parameter storage means) provided therein. One period of voltage rate data Db is stored. In addition, the microcomputer 8 includes a RAM 8b as a work area and a time counter 8c that repeats counting in units of 1 μs, for example.
[0026]
  The PWM circuit 9 has a triangular wave generator (not shown) inside, and compares the energization signals Du, Dv, Dw of the respective phases obtained from the output terminals O1, O2, O3 of the microcomputer 8 with the triangular wave. Drive signals Dup, Dun, Dvp, Dvn, Dwp, and Dwn are output from the six output terminals of the PWM circuit 9, respectively. Further, the output terminal O4 of the microcomputer 8 outputs a signal So that instructs the drive circuit 5 to stop, output, brake, and test.
[0027]
  The drive circuit 5 is configured to supply drive signals Dup to Dwu obtained by the PWM circuit 9 to the gates of the corresponding transistors Tr1 to Tr6 of the three-phase bridge circuit 4.
[0028]
  Next, the effect | action of this Embodiment is demonstrated with reference to FIGS. 3-8 and FIG. In FIG. 14, in the Hall IC 7a, the open collector output terminal is either low or open depending on the direction of the magnetic field. When low, the current consumption of the Hall IC 7a and the current due to the resistor 7b flow through the power supply line, and when open, only the current consumption of the Hall IC 7a flows. That is, there is a difference in the current flowing through the power supply line (power supply current) depending on the direction of the magnetic field.
[0029]
  A voltage proportional to the power supply current is generated in the resistor 11a of the power supply current detecting means 11, which is connected to the positive input terminal of the comparator 11b and compared with the reference voltage from the reference voltage generating means 11c connected to the negative input terminal. Therefore, the output signal of the comparator 11b changes due to the difference in the power supply current according to the direction of the magnetic field.
[0030]
  FIG. 4 shows a main flowchart of the microcomputer 8. In step M1, a start condition given by an external signal or the like is determined, and in the case of stop, a stop signal is output as an output signal So in step M2. As a result, the drive circuit 5 outputs an off signal to the three-phase bridge circuit 4 to turn off the energization of the motor 6. Further, in step M3, an interrupt processing routine described later is prohibited.
[0031]
  In step M1, the starting conditionButIn the case of start, the sensor signal Hs is input in step M4, and the electrical angle Px is determined based on data stored in a ROM 8a (parameter storage means) shown in FIG. This determination is performed in relation to the arrangement of the position sensor 7. In FIGS. 3A and 3B, the arrangement of the position sensor 7 is defined. This shows the relationship between the windings 6u, 6v and 6w of each phase of the motor 6 and the permanent magnet as an induced voltage in FIG. 3A, and the timing of the position sensor signal Hs corresponding to this is shown in FIG. 3B. Indicated. FIG. 7 is a data table including the sensor signal Hs and the electrical angle Px, and the electrical angle Px is set using the data table. Each electrical angle Px indicates an intermediate point of the rotor position range obtained by the sensor signal Hs. In step M6, the voltage phase Pn is determined by subtracting 90 degrees from the electrical angle Px as shown in the following equation (1).
[0032]
  Pn = Px−90 ――― (1)
In step M7, on the basis of the voltage command value Da inputted from the outside, the energization signals Du, Dv, Dw of each phase are calculated and output in each step M8, M9, M10. Step M8 is a step of forming a U-phase energization signal Du, and voltage rate data Db based on the voltage phase Pn determined in step M6 based on the data table stored in ROM 8a (voltage rate storage means) in step M8a. Is read out. Next, in step M8b, the energization signal Du is calculated according to the following equation (2).
[0033]
  Du = Db × (Da / 255) +128 (2)
Here, the range of the voltage rate data Db is “−127 to 127” that can be represented by 2's complement representation of 8-bit data, and “128” is set as an offset value in order to shift to “0 to 255”. . The value range of the voltage command Da is also “0 to 255”, and by multiplying the voltage rate data Db, the amplitude of the sine wave corresponding to the voltage command can be obtained. In step M8c, the energization signal Du is output to the PWM circuit 9.
[0034]
  In the next step M9 and step M10, similarly to the calculation and output of the U-phase energization signal Du in step M8 described above, calculation and output of the V-phase and W-phase energization signals Dv and Dw are performed. At this time, the voltage phase Pn is determined in accordance with Equation (3) in Step M9 and Equation (4) in Step M10.
[0035]
  Pn = (Px−90) −120 (3)
  Pn = (Px−90) −240 (4)
By outputting the output signal So in step M11, the energization signals Dup to Dwn of each phase pulse-width modulated by the PWM circuit 9 are output to the three-phase bridge circuit 4, and each phase winding of the motor 6 from the driving means 3 is output. A current is applied to 6u, 6v, and 6w. Then, the rotor of the motor 6 moves and stops in the vicinity of the electrical angle Px set when the voltage phase Pn is determined in step M5.
[0036]
  Step M12 is a step of determining the elapse of a predetermined time determined from the time required for the movement of the rotor position, and is repeated until the predetermined time elapses. When a predetermined time has elapsed, the time counter Tc is read and stored as data Tx in step M13, and then a start flag is set in step M14. Further, in step M15, execution of the interrupt processing routine shown in FIGS. 5 and 6 is permitted.do itReturn to Step M1.
[0037]
  Next, the flowchart of the interrupt processing routine (Sa) shown in FIG. 5 will be described. This is, for example, a time interrupt processing routine executed every 100 μs. After reading the voltage phase command Pr input from the outside in step A1, the start flag is determined in step A2. Here, since the start flag is set in step M14 described above, it is determined as YES and the voltage phase Pn is determined in step A5. In step A5, the voltage phase Pn is determined as in the following equation (5) based on the electrical angle Px determined in step M5 described above.
[0038]
  Pn = Px + Pr + Km ――― (5)
Here, K is preset data, for example, an electrical angle of 1 degree. m is an initial value 1 and is 1 each time this process is executed.One by oneThe data is increasing.
[0039]
  The processing of steps A6 to A9 is the same as that of steps M7 to M10 described above, and the energization signals Du, Dv, Dw of each phase are calculated and output according to the voltage phase command Pr.
[0040]
  By repeatedly executing the interrupt processing routine (Sa) described above, the motor 6 is started by gradually increasing the voltage phase Pn determined in step A5. Then, when the motor 6 rotates, the sensor signal Hs reaches the changing point.
[0041]
  Next, the flowchart of the interrupt processing routine (Sb) shown in FIG. 6 will be described. This is an interrupt processing routine executed by a change in sensor signal every electrical angle of 180 degrees. First, in step B1, the time counter read data Tc is read. If the start flag is cleared, the difference between the data Tx obtained in the previous time counter reading process and the data Tc obtained in the current process is calculated and stored as operator data Ts in step B2 (formula (6a Further, the current read data Tc is stored as data Tx (see equation (6c)). When the start flag is set, the operator data Ts is determined to be twice the difference between the data Tx and the current read data Tc (see equation (6b)), and the current read data Tc is used as the data Ts. Store (see equation (6c)).
[0042]
  Ts = Tc-Tx When the start flag is cleared ――― (6a)
  Ts = 2 (Tc-Tx) When the start flag is set ――― (6b)
  Tx = Tc ――― (6c)
By the process of step B1 and step B2, the change period of the sensor signal Hs, that is, the time Ts during which the rotor rotates by an electrical angle of 180 degrees is measured, but at the start, the rotation starts from the intermediate position of the sensor signal Hs. Therefore, the rotation is an electrical angle of 90 degrees, so that the time Ts for rotating the electrical angle by 180 degrees is set to 2 times.
[0043]
  After the start flag is cleared in step B3, the position sensor signal Hs is input in step B4. In step B5, the electrical angle Px is obtained based on the data table based on the position sensor signal Hs and the electrical angle Px shown in FIG. The data in FIG. 8 shows the relationship between the change point of the sensor signal Hs and the rotor position electrical angle Px.
[0044]
  Even after the position sensor signal Hs changes, the motor 6 continues to rotate, but the interrupt processing routine (Sa) changes as follows when the start flag is cleared. First, the determination of the start flag in step A2 is no, and the processing of step A3 and step A4 is executed. In step A3, the current read data Tc of the time counter is read, and in step A4, the voltage phase Pn is determined by the calculation shown in the following equation (7). The processing from step A6 to step A9 is the same as the processing described above, and will be omitted.
[0045]
  Pn = Px + Pr + 180 × (Tc−Tx) / Ts (7)
With the above configuration and microcomputer operation, the motor 6 continues to rotate. Then, the voltage phase Pn is calculated every 100 μs as shown in FIG. 3C, and the waveform of the energization signal becomes a sine wave corresponding to the rotor position, the voltage command, and the phase command as shown in FIG. Furthermore, a sinusoidal winding current as shown in FIG.
[0046]
  Next, as a second embodiment of the present invention, the case of one position sensor (n = 1) will be described with reference to FIGS. About the same structure as 1st Embodiment, description is abbreviate | omitted by attaching | subjecting the same code | symbol. FIG. 10 is an electrical configuration diagram showing the present embodiment. The difference from the first embodiment (see FIG. 1) is that a timer 8b whose operation cycle can be set is added to the microcomputer 8. It is.
[0047]
  Hereinafter, the operation will be described with reference to the flowcharts of FIGS. FIG. 11 shows a main flowchart of the microcomputer 8, and after the rotor is positioned based on the position sensor signal Hs in steps M1 to M12 in the same manner as in the first embodiment, steps M13 and M14 are performed. In the present embodiment, before execution of permission of the interrupt process in step M15, the process includes step M16 for setting a predetermined value as the period data Td of the timer 8d. The interrupt processing routine (Sc) shown in FIG. 12 corresponding to the interrupt processing routine (Sa) of the first embodiment is an interrupt processing generated based on the set periodic data Td by the timer 8d. Execution is started by the process of step M15, and the electrical angle Px determined in step M5 is used as an initial value, and the electrical angle Px is counted up in step C1 (see equation (8)).
[0048]
  Pn = Px + N ――― (8)
Here, N is 1 (electrical angle 1 degree), for example, and when the calculation result exceeds 359, 360 is subtracted and adjusted to a range of 0 to 359.
[0049]
  After reading the voltage phase command Pr in step C2, the voltage phase Pn is determined based on the following equation (9) in step C3.
  Pn = Pr + Px ――― (9)
Here again, as in step C1, when “359” is exceeded, “360” is subtracted and adjusted to the range of “0 to 359”. The processing from step C4 to step C7 below is the same as the processing from step M7 to M10 in the first embodiment, and a description thereof will be omitted.
[0050]
  The interrupt processing routine (Sd) in FIG. 13 is generated by a change in the position sensor signal Hs every 180 degrees of electrical angle, as in the interrupt processing routine (Sb) in the first embodiment. This is the addition of a calculation setting process for the timer period Td in step D6. Step D6 is a step of calculating and setting the period data Td of the timer 8d based on the position sensor signal change period data obtained in Step D2 (see Expression (10)).
[0051]
  Td = Ts / (180 / N) ――― (10)
By the operation of the microcomputer described above, the electrical angle counter (electrical angle Px) indicating the rotor electrical angle changes in units of N degrees smaller than 180 degrees in synchronization with the position sensor signal Hs that changes every 180 degrees. The voltage phase is determined by the voltage phase command Pr. Furthermore, a sine wave can be energized by forming an energization signal from the voltage command and the stored waveform data.
[0052]
  Next, a case where the brushless DC fan is used for an application that is rotated by an external force such as an outdoor fan or a ventilation fan of an air conditioner will be described with reference to flowcharts of FIGS. 15 and 16. FIG. 15 is a flowchart showing a rotation state determination processing routine. In step E1, the number of rotations is detected. For example, the number of changes in the position sensor signal Hs per second is detected. In step E2, based on the detected number of rotations, it is determined as “stop” if it is less than the predetermined number of rotations, and “in rotation” if it is equal to or greater than the predetermined number of rotations. If it is determined that “rotating”, steps E3 to E17 are executed to determine the direction of rotation.
[0053]
  In step E3, the position sensor signal Hs is monitored to wait for a change from low to high. When the position sensor signal Hs becomes high, the time counter data Tc is read and stored in step E4, and a signal So as a test command is output in step E5. The test signal So is a signal for turning on the U-phase positive transistor Tr1 and the V-phase negative transistor Tr5, and a current flows from the winding 6u to 6v of the motor 6. This current continues to increase, and when it reaches a predetermined value, the current signal Si that is the output of the winding current detection means 10 is set to high. After confirming this in step E6, a signal So as a stop command is output in step E7 to cut off the current. In step E8, the time counter data Tc is read again, and the energization time is determined from the difference from the previously read data. Step E9 for obtaining TH is executed. Similarly, when the position sensor signal Hs becomes low, steps E10 to E16 are executed to determine the energization time TL.
[0054]
  From the relationship between the induced voltage and the position sensor signal Hs shown in FIGS. 3A and 3B, there are the following differences between forward rotation and reverse rotation. In the case of normal rotation, the induced voltage of the U phase with reference to the V phase (hereinafter referred to as UV induced voltage) is generated as positive when the position sensor signal Hs is high and negative when the position sensor signal Hs is low. In the case of reverse rotation, it is generated as negative when the position sensor signal Hs is high and positive when it is low.
[0055]
  Assuming now that the rotation is normal, in the energization when the position sensor signal Hs in steps E3 to E9 is high, the increase in current is slow due to the timing at which the induced voltage increases in the positive direction, and the time until the predetermined current value is reached. That is, the energization time TH becomes longer. On the other hand, in the energization when the position sensor signal Hs in Steps E10 to E16 is low, the induced voltage is negative and decreases at a timing, so that the current increases rapidly and the time until the predetermined current value is reached, that is, the energization time TL is Shorter. Therefore, in the case of normal rotation, the energization time TH> energization time TL, and in the case of reverse rotation, the energization time TH <energization time TL.
[0056]
  From the above relationship, in step E17, the rotational direction can be determined by comparing the energization times TH and TL. FIG. 16 shows a flowchart of the microcomputer 8 in the case of a brushless DC fan, which is a flowchart having another step between step M3 and step M4 of the main routine shown in FIG. When the start condition of step M1 is start, the rotational state determination step of step M0 is executed, and when it is “stop”, the process proceeds to step M4 and the positioning process is executed.
[0057]
  In the case of “reverse rotation”, a signal So as a brake command is output in step G1, the negative transistors Tr4, Tr5, Tr6 of the three-phase bridge circuit 4 are all turned on, and the motor windings 6u, 6v, 6w are short-circuited. And brake torque is generated. In step G2, the number of rotations is detected in the same manner as in step E1, and is continued until the stop of step G3 is confirmed. After the stop is confirmed, the process proceeds to step M4.
[0058]
  In the case of “forward rotation”, the positioning process is omitted, the execution of the interrupt process routine (Sb) is permitted in step F1, and the process when the position sensor signal Hs shown in FIG. 6 is changed is executed. Since the interrupt processing routine (Sb) is performed twice, the electrical angle Px and the position sensor cycle data are obtained and information necessary for the rotation of the motor 6 is determined. After confirming the execution twice in step F2, step F3 The execution of the interrupt processing routine (Sa) is permitted and the output of the signal So in step F4 is executed. Accordingly, the motor 6 starts rotating by driving the inverter.
[0059]
  Hereinafter, as a third embodiment of the present invention, the case of two position sensors (n = 2) will be described with reference to FIG. In FIG. 17, which is an electrical configuration showing this embodiment, the difference from the first embodiment is that two position sensors 17 are provided, and no motor current detection means is provided. The same parts are denoted by the same reference numerals, and description thereof is omitted.
[0060]
  A brushless DC motor (hereinafter simply referred to as a motor) 6 has two position sensors 17a and 17b arranged with a phase difference of 90 degrees in electrical angle, and their output terminals are connected to input terminals I1a and I1b of the microcomputer 8, respectively. They are connected to supply signals Ha and Hb, respectively.
[0061]
  Next, the operation of the present embodiment will be described with reference to the drawings used in the first embodiment. In FIG. 4 showing the main flowchart of the microcomputer 8, the start condition given by an external signal or the like is judged (step M1), and in the case of stop, a signal So as a stop command is outputted (step M2). As a result, the drive circuit 5 generates an off signal for the three-phase bridge circuit 4 to turn off the energization of the motor 6 and prohibit the execution of the interrupt processing routine (step M3).
[0062]
  In the case of starting at step M1, position sensor signals Ha and Hb from the two position sensors 17a and 17b are inputted (step M4), and a data table stored in the ROM 8a (parameter storage means) (see FIG. 19). To determine the electrical angle Px (step M5). This determination is made in relation to the arrangement of the position sensors 17a and 17b. In FIGS. 18A and 18B, the arrangement of the position sensors 17a and 17b is defined. FIG. 18A shows the relationship between the coil of each phase of the motor 6 and the permanent magnet as an induced voltage, and FIG. 18B shows the timing of the position sensor signals Ha and Hb corresponding thereto.
[0063]
  Each electrical angle Px indicates an intermediate point of the rotor position range defined by the sensor signals Ha and Hb. In step M6, a value obtained by subtracting 90 degrees from the electrical angle Px is determined as the voltage phase Pn (see formula (1)).
[0064]
  After the voltage phase Pn is determined, the voltage command value Da is input (step M7), and the energization signals Du, Dv, Dw of each phase are calculated and output (steps M8, M9, M10). Step M8 is a step of forming a U-phase energization signal Du. In step M8a, the voltage rate data Db is read from the ROM 8a (voltage rate storage means) based on the voltage phase Pn, and in step M8b, equation (2) is obtained. Based on this, the energization signal Du is calculated.
[0065]
  Also in this case, the value range of the voltage rate data Db is “−127 to 127” that can be represented by 2's complement representation of 8-bit data, and “128” is set as an offset value in order to shift to “0 to 255”. . The value range of the voltage command Da is also “0 to 255”, and by multiplying the voltage rate data Db, the amplitude of the sine wave corresponding to the voltage command can be obtained. In step M8c, the energization signal Du is output to the PWM circuit 9.
[0066]
  In Step M9 and Step M10, calculation and output of the V-phase energization signal Dv and the W-phase energization signal Dw are performed, respectively. At this time, the determination of the voltage phase Pn is based on the equation (3), W In phase, it is performed according to equation (4).
[0067]
  By outputting the signal So in step M11, the energization signals Dup to Dwn of each phase pulse-width modulated by the PWM circuit 9 are output to the three-phase bridge circuit 4, and each phase winding 6u of the motor 6 from the driving means 3 is output. , 6v, 6w are energized, the rotor of the motor 6 moves and stops near the electrical angle Px. For example, if it was initially stopped at an electrical angle of 80 degrees, it would move to an electrical angle of around 45 degrees. During this time, the sensor signal remains Ha = H and Hb = L.
[0068]
  In step M12, it is determined whether a predetermined time determined from the time required for the movement of the rotor position has elapsed. In step M13, the time counter data Tc is stored as read data Tx, and then in step M14. Set the start flag. In step M15, the execution of the interrupt processing routine shown in FIGS. 5 and 6 is permitted.do itReturn to step M1.
[0069]
  Since the processing in the interrupt processing routine (Sa) shown in FIG. 5 is the same as that in the first embodiment, description thereof is omitted. However, when the motor 6 starts rotating, assuming that the rotor has moved to a position where the electrical angle is 45 degrees, the rotor position changes from Ha = H and Hb = L to Ha = H and Hb = H.
[0070]
  Next, an interrupt processing routine (Sb) executed by a change in the position sensor signals Ha and Hb every 90 electrical degrees will be described using the flowchart shown in FIG. First, in step B1, the time counter read data Tc is read, and in step B2, the difference between the data Tx obtained in the previous time counter read process and the data Tc obtained in the current process is stored as operator data Ts ( When the start flag is cleared, the difference is kept as it is, and when the start flag is set, the difference is doubled), and the current time counter data Tc is stored as data Tx (see equations 6a, 6b, 6c).
[0071]
  The time Ts for rotating the electrical angle by 90 degrees is measured in Step B1 and Step B2, but since the rotation is started from the intermediate position of the position sensor signals Ha and Hb at the start, the electrical angle is rotated by 45 degrees. Therefore, the time Ts for rotating by an electrical angle of 90 degrees is obtained by doubling. Then, after clearing the start flag (step B3), position sensor signals Ha and Hb are input (step B4), and an electrical angle Px is obtained based on the L table shown in FIG. 20 (step B5). The data of FIG. 20 shows the relationship between the change points of the sensor signals Ha and Hb and the rotor position electrical angle Px.
[0072]
  Even after the position sensor signals Ha and Hb change to Ha = H and Hb = H, the motor 6 continues to rotate, but the interrupt processing routine (Sa) is changed as follows when the start flag is cleared. . In step A2, the determination of the start flag is no. In step A3, the time counter data Tc is read. In step A4, the voltage phase Pn is determined based on equation (7). The processing in steps A6 to A9 is the same.
[0073]
  With the above configuration and microcomputer operation, the motor 6 continues to rotate. Then, as shown in FIG. 18C, the voltage phase Pn is calculated every 100 μs,FigureAs shown in FIG. 18 (d), the waveform of the energization signal becomes a sine wave corresponding to the rotor position, voltage command, and voltage phase command, and a sinusoidal winding current as shown in FIG. 18 (e) is generated.
[0074]
  Next, as a fourth embodiment of the present invention, a case of two position sensors (n = 2) will be described with reference to FIG. The same parts as those of the third embodiment are denoted by the same reference numerals, and the description thereof is omitted. FIG. 21 is an electrical configuration diagram showing the present embodiment. The difference from the third embodiment is that a timer 8b whose operation cycle can be set is added to the microcomputer 8.
[0075]
  The operation will be described below with reference to the flowcharts of FIGS. 11 to 13 used in the second embodiment. In FIG. 11, as in the third embodiment, after the rotor is positioned based on the position sensor signals Ha and Hb in the processes of steps M1 to M12, the processes of steps M13 and M14 are executed. A predetermined value is set as the period data Td of the timer 8d before executing the permission of the interrupt process of M15 (step M16). The interrupt process routine (Sc) shown in FIG. 12 is an interrupt process that is generated by the timer 8d based on the set cycle data Td, and its execution is started by the processes of Step M16 and Step M15. Then, using the electrical angle Px as an initial value, the electrical angle Px is counted up in step C1 (see formula (8)). Here, N is, for example, 1 or an electrical angle of 1 degree, and when the calculation result exceeds “359”, “360” is subtracted and adjusted to a range of “0 to 359”.
[0076]
  After the voltage phase command Pr is read in step C2, the voltage phase Pn is determined in step C3 (see equation (9)). Similarly, the voltage phase Pn is adjusted to a range of “0 to 359”. The following processing from step C4 to step C7 is the same as that in the third embodiment, and a description thereof will be omitted.
[0077]
  The interrupt processing routine (Sd) shown in FIG. 13 is generated by a change in the position sensor signals Ha and Hb every 90 degrees of electrical angle, and an interrupt processing routine (Sb) is added in that timer period calculation and setting processing are added. And different. In step D6, the period data Td of the timer 8d is calculated and set based on the position sensor signal change period data (see equation (10)).
[0078]
  As a result of the above microcomputer operation, the electrical angle counter (electrical angle Px) indicating the rotor electrical angle changes in units of N degrees smaller than 90 degrees in synchronization with the position sensor signals Ha and Hb that change every 90 degrees. The voltage phase is determined by this and the voltage phase command Pr. Furthermore, a sine wave can be energized by forming an energization signal from the voltage command and the stored waveform data.
[0079]
  The present invention is not limited to the above-described embodiments, and the following modifications or expansions are possible. Although the voltage command Da and the voltage phase command Pr are given from the outside, the voltage command Da and the voltage phase command Pr may be changed with time, or may be determined by detecting the number of rotations in the microcomputer, for example.
[0080]
  Although the initial position is determined by the position sensor signal and the rotor position is moved by energization, when the number of poles of the motor is large, only the initial position may be determined and the movement of the rotor position by energization may be omitted.
[0081]
  Although the rotor position sensor is a Hall IC, a sensor such as an optical element may be used. In addition, when n = 2, the sine wave can be continued even during acceleration, and can be applied to a washing machine that repeats rapid acceleration of forward and reverse rotation, particularly between a driving source and a driven body. When used in a direct drive type washing machine that does not use a mechanical transmission mechanism, low vibration and low noise can be realized.
[0082]
【The invention's effect】
  According to the present invention, one or twoOutput digital signalsThe position sensor can drive a three-phase brushless DC motor.,The cost related to the sensor and its wiring can be reduced.Further, since the digital means is used until the energization waveform is formed, it is not affected by environmental factors such as temperature and is easily integrated at the same time as compared with the case including the analog means. Also,One or twoDigitalSince a three-phase sine wave energization signal can be formed from the position sensor signal, the brushless DC motor can be driven with low vibration and low noise.
[0083]
  Since the rotor position is initialized by energization for positioning at the time of starting, sinusoidal driving including starting is possible, and driving can be performed with low vibration and low noise compared to starting by rectangular wave driving.
[0084]
  Since the initialization of the rotor position at the start is performed based on the position sensor signal, the movement of the rotor due to positioning is minimized, and an increase in the start time is prevented..
[0085]
  Position sensor power and signal wiresShareTherefore, only two wires are required, and cost reduction is realized. Since the rotation direction before starting can be determined, it can also be used with a brushless DC fan such as an outdoor fan or a ventilation fan of an air conditioner that is rotated by an external force, or a washing machine drive source. Since a microcomputer is used and software is the main component, it is possible to reduce the size and cost of the inverter.
[Brief description of the drawings]
FIG. 1 is a diagram showing an electrical configuration of a main part in a first embodiment of the present invention.
FIG. 2 is a diagram showing voltage rate data for one cycle of a sine wave.
FIG. 3 is a timing chart when a motor is driven by a drive signal based on an induced voltage.
FIG. 4 is a flowchart showing control contents of a main routine of the microcomputer.
FIG. 5 is a flowchart showing the control contents of an interrupt processing routine Sa.
FIG. 6 is a flowchart showing the control content of an interrupt processing routine Sb.
FIG. 7 is a view showing the contents of an electrical angle data table.
FIG. 8 is a diagram showing the contents of an electrical angle data table.
FIG. 9 is a diagram showing an electrical configuration of a main part of the prior art.
FIG. 10 is a diagram showing an electrical configuration of a main part according to a second embodiment of the present invention.
FIG. 11 is a flowchart showing control contents of a main routine of the microcomputer.
FIG. 12 is a flowchart showing the control content of an interrupt processing routine Sc.
FIG. 13 is a flowchart showing the control content of an interrupt processing routine Sd.
FIG. 14 is an electrical configuration diagram of a position sensor.
FIG. 15 is a flowchart showing details of a rotation state determination process.
FIG. 16 is a flowchart showing the control content of a main routine.
FIG. 17 is a diagram showing an electrical configuration of a main part according to a third embodiment of the present invention.
FIG. 18 is a timing chart when a motor is driven by a drive signal based on an induced voltage.
FIG. 19 is a diagram showing the contents of an electrical angle data table.
FIG. 20 is a view showing the contents of an electrical angle data table.
FIG. 21 is a diagram showing an electrical configuration of a main part according to a fourth embodiment of the present invention.
[Explanation of symbols]
  2 is a DC power supply circuit, 3 is a drive means, 4 is a three-phase bridge circuit, 5 is a drive circuit, 6 is a motor, 7 is a position sensor, 8 is a microcomputer, 9 is a PWM circuit, 10 is a current detection circuit, and 11 is a power supply A current detection circuit 12 indicates a sensor power supply means.

Claims (16)

N (n: 1 or 2) position sensors each having a constant phase relationship with the induced voltage generated by the winding of the brushless DC motor having three-phase windings and outputting digital signals;
Position sensor cycle measuring means for measuring a cycle in which the position sensor signals obtained by the n position sensors change;
Parameter storage means for storing the rotor phase difference corresponding to the change period of the position sensor signal measured by the position sensor period measurement means and the rotor phase corresponding to the change time of the position sensor signal;
Voltage phase determining means for determining a voltage phase having a resolution higher than an electrical angle corresponding to the change period, based on the n position sensor signals , the change period , the rotor phase, and the rotor phase difference ;
Voltage rate storage means for storing a voltage rate corresponding to the voltage phase;
From the voltage phase and the voltage ratio, energization waveform forming means for forming a three-phase energization waveform,
Based on the energization waveform, comprising driving means for energizing the three-phase winding,
An inverter device characterized in that at the time of starting, three-phase DC excitation energization is performed based on a rotor phase limited by the n position sensor signals . 2. The inverter device according to claim 1 , wherein the voltage rate corresponding to the voltage phase stored in the voltage rate storage means is a voltage rate corresponding to a sine wave. 3. The inverter device according to claim 1, wherein when n = 1, the power supply voltage supply line and the sensor signal line for the position sensor are shared. In the case of n = 1, a power supply voltage supply means and a power supply current detection means for the position sensor are provided, and a position sensor signal determination means for determining a position sensor signal obtained by the position sensor based on a power supply current detection result is provided. The inverter device according to any one of claims 1 to 3 . 2. The inverter device according to claim 1 , wherein when n = 2, two position sensor signals obtained by the position sensor change by π / 2 in electrical angle of the rotor phase. The parameter storage means stores, in addition to the rotor phase and the rotor phase difference, a change period of the position sensor signal measured by the position sensor period measurement means, a change time of the position sensor signal, and a voltage phase command as calculation parameters. And
The voltage phase determining means, an inverter device according to voltage phase at a certain time, to any one of claims 1 to 5, characterized in that determined by calculation based on the calculated parameters. When the change period is Ts, the change time is Tx, the rotor phase at the change time is Px, and the voltage phase command is Pr, the voltage phase Pn at time Tc for determining the voltage phase is
Pn = Px + Pr + (π / n) × (Tc−Tx) / Ts
The inverter device according to claim 6 , wherein the inverter device is obtained by: A predetermined value corresponding to the position signal is written at the change timing of the position sensor signal, and an electrical angle counter is provided in which the count cycle is determined based on the change cycle of the position sensor signal obtained by the position sensor cycle measuring means,
Voltage phase determining means inverter apparatus according to any one of claims 1 to 5, wherein the determining the voltage phase by the sum of the count value and the phase command value of the electric angle counter. A predetermined value corresponding to the position signal is written at a change timing for each π / n of the position sensor signal, and the count cycle is set for every π / n based on the change cycle of the position sensor signal obtained by the position sensor cycle measuring means. With an electrical angle counter to be determined,
Voltage phase determining means inverter apparatus according to any one of claims 1 to 5, wherein the determining the voltage phase by the sum of the count value and the phase command value of the electric angle counter. The inverter device according to any one of claims 1 to 9 , wherein an initial value of a voltage phase at the start is determined by n position sensor signals. The initial value of the voltage phase at the start, the rotor phase of the intermediate point of the range that can be defined by n pieces of the position-sensor signal, any one of claims 1 to 9, characterized in that determined by the sum of the voltage phase command The inverter device described in 1. Performs DC excitation to move the rotor to a predetermined rotor phase, the initial value of the voltage phase at the start, said a predetermined rotor phase, 1 to claim, characterized in that determined by the sum of the voltage phase command The inverter device according to any one of 9 . A three-phase DC excitation energization waveform is formed from a voltage phase delayed by π / 2 of the rotor phase limited by n position sensor signals and the voltage ratio stored in the voltage ratio storage means, and the driving means After the three-phase winding is subjected to direct current excitation, the initial value of the voltage phase at start-up is determined by the sum of the rotor phase limited by n position sensor signals and the voltage phase command. The inverter device according to claim 1 , wherein the inverter device is a device. A motor winding current detecting means, and when n = 1, means for starting energization at a timing specified by the position sensor signal and stopping energization according to the result of the current detecting means;
Means for measuring the energization time;
The inverter device according to any one of claims 1 to 4 and 6 to 13 , further comprising a rotation direction detection unit that determines a rotation direction from the measured energization time. A position sensor period measurement means, and the voltage phase determining means, and the voltage ratio storage means, and energization signal forming means, according to any one of claims 1 to 14, characterized in that the starting means and a microcomputer Inverter device. A position sensor period measurement means, and the voltage phase determining means, and the voltage ratio storage means, and energization signal forming means, and starting means, according to claim 1 to 4, characterized in that the rotation direction detecting means is a microcomputer And the inverter apparatus in any one of 6 thru | or 14 .

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