JP4432452B2 - Motor control device - Google Patents

Description

  The present invention relates to a motor control device that controls the frequency of a brushless DC motor.

  Conventionally, there are a 120 ° energization control method and a sine wave 180 ° energization control as motor control devices for controlling the rotational speed of a brushless DC motor. The 120 ° energization method is a method of directly detecting the zero-cross signal of the induced voltage, and is obtained by comparing the inverter phase voltage with the reference voltage in order to detect it. The commutation signal is changed based on this zero cross signal. This zero cross signal is generated 12 times during one rotation of the motor, and is generated every 30 ° mechanical angle, that is, every 60 ° electrical angle (see, for example, Patent Document 1).

The 180 ° energization method amplifies the differential voltage between the neutral point potential of the motor winding and the neutral point potential of the three-phase Y-connected resistor to the three-phase inverter output voltage, and inputs it to the integration circuit The position detection signal corresponding to the induced voltage is obtained by comparing the output signal of the integration circuit with the low-pass signal obtained by processing the output signal with a filter circuit and cutting the direct current. This position detection signal is generated 12 times during one rotation of the motor, and is generated every 30 ° mechanical angle, that is, every 60 ° electrical angle. In this method, phase correction control is required to pass through an integration circuit (see, for example, Patent Documents 2 and 3).
Japanese Patent No. 2642357 JP 7-245982 A Japanese Patent Laid-Open No. 7-337079

  Problems in the conventional configuration will be described.

  FIG. 5 is a control block diagram of a conventional motor control device. Since this 120 ° energization method compares the zero crossing of the induced voltage part, if the motor load sudden change or the power supply voltage sudden change occurs, the induced voltage zero crossing signal will be hidden in the inverter output voltage region and detected. It may not be possible. In such a state, first, a step-out phenomenon occurs and the inverter system stops. In addition, at 120 ° energization, the induced voltage per phase can be confirmed continuously for 60 ° electrical angle, but in order to reduce the noise and vibration during motor operation, the energization angle is set to about 150 ° for operation. As a result, the induced voltage per phase can only be confirmed continuously for an electrical angle of 30 °, the risk of stepping out during normal operation increases, and unstable phenomena such as turbulence tend to occur. It was. Further, this configuration has a problem that an operation close to 180 ° energization is impossible. FIG. 6A is a relationship diagram between the phase current waveform and the induced voltage waveform of 120 ° energization control. During normal operation, the position is set at the position of the phase current 20 with respect to the induced voltage 10, and the angle is advanced to the position of the phase current 21 when the maximum rotational speed is increased. However, since it is difficult to advance the position from the position of the phase current 21, the maximum number of revolutions is lowered, and there is a problem that only a limited speed range can be operated.

  FIG. 6B is a relationship diagram between the phase current waveform and the induced voltage waveform in the 180 ° energization control. Since the 180 ° energization method passes through the integration circuit, the zero cross position of the induced voltage cannot be accurately grasped with an absolute value, and the phase difference between the zero cross position and the position detection signal varies greatly depending on the operating state. Complicated control such as phase correction is required, and the phase correction adjustment is difficult, and the control calculation is complicated. In addition, the motor needs a neutral point output terminal, and uses the third harmonic component of the induced voltage waveform, and therefore has a problem that it cannot be used in a motor using a sine wave magnetized magnet.

In addition, in the sensorless sine wave 180 ° energization drive control by the current feedback method, the motor magnetic pole position is estimated and calculated by the motor current and the motor electrical constant, so the calculation error becomes large, and the limit point of the motor current advance control is There was a problem that the maximum number of rotations was not far from control with a position sensor. Also in the case of 180 ° energization control, the phase current 22 is set to the position of the induced voltage 10 during normal operation, and the phase current 23 is advanced to increase the maximum rotational speed.

  The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to provide a 180 ° sine wave with a position sensor by applying a new method of induced voltage feedback control that does not require a mechanical electromagnetic pickup sensor. An object of the present invention is to provide an inexpensive and highly reliable motor control device that achieves high speed performance at the same level.

The motor control device according to the present invention includes a plurality of switching elements, a DC / AC conversion means that converts a DC voltage into an AC voltage based on a PWM signal by opening and closing the switching elements and supplies the AC voltage to a three-phase brushless DC motor, and the brushless DC An induced voltage detecting means for detecting an induced voltage of the motor, a voltage control first means for outputting a voltage waveform 1 based on all the magnetic pole positions outputted from the induced voltage detecting means at every electrical angle of 60 ° , and the voltage In a motor control device having a PWM control means for converting a waveform 1 into the PWM signal, the magnetic pole positions operate within a predetermined frequency range and the magnetic pole positions are defined as 6-n (= defined as m ≧ 1 ) electrical angle. and the induced voltage selecting means for outputting a magnetic pole position selected by selecting the voltage controlled second hand and outputting the created voltage waveform 2 in the PWM controller based on the magnetic pole position selection Has the door, said voltage controlled second means, in the time domain each containing n points which are not selected a time domain is divided into every electrical angle of 60 °, and outputs the voltage waveform 2, wherein the predetermined Either the voltage control first means or the voltage control second means is operated by authenticity determination in the frequency domain, and the phase angle of the AC voltage is controlled based on the magnetic pole position and the magnetic pole position selection. Out of the current information from the current detection means when the phase angle setting means, the current detection means for detecting the armature current of the brushless DC motor for at least one phase, and the advance value of the phase angle is a predetermined value or more Current selection means for selecting and outputting the armature current value to the voltage control second means, and the voltage control second means includes a sinusoidal internal current command, and the internal current command and the armature current Based on value and above It is assumed that it has an operation characteristic that smoothly compensates for the rise of the armature current corresponding to all n time regions .

The motor control device according to the present invention includes a plurality of switching elements, a DC / AC conversion means that converts a DC voltage into an AC voltage based on a PWM signal by opening and closing the switching elements and supplies the AC voltage to a three-phase brushless DC motor, and the brushless DC An induced voltage detecting means for detecting an induced voltage of the motor, a voltage control first means for outputting a voltage waveform 1 based on all the magnetic pole positions outputted from the induced voltage detecting means at every electrical angle of 60 ° , and the voltage In a motor control device having a PWM control means for converting a waveform 1 into the PWM signal, the magnetic pole positions operate within a predetermined frequency range and the magnetic pole positions are defined as 6-n (= defined as m ≧ 1 ) electrical angle. and the induced voltage selecting means for outputting a magnetic pole position selected by selecting the voltage controlled second hand and outputting the created voltage waveform 2 in the PWM controller based on the magnetic pole position selection Has the door, said voltage controlled second means, in the time domain each containing n points which are not selected a time domain is divided into every electrical angle of 60 °, and outputs the voltage waveform 2, wherein the predetermined Either the voltage control first means or the voltage control second means is operated by authenticity determination in the frequency domain, and the phase angle of the AC voltage is controlled based on the magnetic pole position and the magnetic pole position selection. Out of the current information from the current detection means when the phase angle setting means, the current detection means for detecting the armature current of the brushless DC motor for at least one phase, and the advance value of the phase angle is a predetermined value or more Current selection means for selecting and outputting the armature current value to the voltage control second means, and the voltage control second means includes a sinusoidal internal current command, and the internal current command and the armature current Based on value and above It is assumed that it has an operation characteristic that smoothly compensates for the rise of the armature current corresponding to all n time regions . As a result, the phase angle of the armature current flowing through the brushless DC motor can be freely controlled, so that the driving performance and driving characteristics according to the driving application can be derived. Also motor current
The waveform becomes smooth, and the operation sound and resonance sound of the motor control device can be minimized.

(Embodiment 1)
Embodiments of a motor control device according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a control block diagram of the motor control device of the present embodiment. The motor control device of the present embodiment is a motor control device that controls the rotation speed of the three-phase brushless DC motor 7. In this figure, the motor control device converts DC voltage 8 into AC voltage and outputs it to a three-phase brushless DC motor (hereinafter abbreviated as BLM) 7 and induction for detecting the induced voltage of BLM 7. Voltage detection means 1, voltage control first means 3 for outputting voltage waveform 1 based on the magnetic pole position output from induced voltage detection means 1, PWM control means 5 for converting voltage waveform 1 into a PWM signal, and magnetic poles Inductive voltage selection means 2 that selects (6-n (defined as m)) positions in one cycle of electrical angle and outputs magnetic pole position selection, and voltage waveform 2 to PWM control means 5 based on magnetic pole position selection. Voltage control second means 4 for outputting, and the voltage control second means 4 advances the voltage phase of each of the n time domains not selected from the voltage phase in each of the m time domains of magnetic pole position selection by a predetermined value. Squared voltage waveform To output.

  The PWM control means 5 outputs a PWM signal for controlling the applied voltage, frequency, and phase for controlling the rotation speed of the BLM 7. The DC / AC converting means 6 comprises six switching elements that open and close at high speed.

  First, the role of the induced voltage detection means 1, voltage control first means 3, and PWM control means 5 in FIG. This part is the same as the operation of the control block diagram of the conventional motor control device of FIG.

  In FIG. 1, the induced voltage detecting means 1 drops the induced voltage of the BLM 7, detects the zero cross signal, and outputs the zero cross signal to the voltage control first means 3 as the magnetic pole position. The voltage control first means 3 calculates a voltage waveform for driving the BLM 7 based on the magnetic pole position, and outputs it to the PWM control means 5 as the voltage waveform 1. Based on the voltage waveform 1, the PWM control means 5 outputs a PWM signal to the DC / AC conversion means 6. In the motor control apparatus configured as described above, the rotation speed of the BLM 7 is controlled by changing the frequency and phase (hereinafter referred to as “inverter frequency”) of the AC voltage output from the DC / AC conversion means 6. .

  In the case of 120 ° energization control, the PWM control means 5 outputs six types of PWM signals for opening and closing the switching elements of the DC / AC conversion means 6, and the switching elements are opened and closed by the six kinds of PWM signals. The inverter frequency output from the AC conversion means 6 is controlled.

  Six kinds of PWM signals will be described. The six types of PWM signals are pulse signals for driving the switching elements of the DC / AC converter 6. The PWM signal has six basic patterns PTN1 to PTN6 in one cycle of the inverter electrical angle, and the reciprocal of one cycle of the PWM signal is the inverter frequency.

  Actually, the method for changing the rotation speed of the BLM 7 is that the PWM control means 5 controls the rotation speed of the BLM 7 while changing the inverter frequency of the DC / AC conversion means 6.

  The DC / AC converting means 6 has six switching elements, and includes one switching element on the upper arm and one switching element on the lower arm for the U phase, the V phase, and the W phase, respectively.

  In PTN1, the U-phase upper arm switching element and the V-phase lower arm switching element are energized.

  In PTN2, the U-phase upper arm switching element and the W-phase lower arm switching element are energized.

  In PTN3, the V-phase upper arm switching element and the W-phase lower arm switching element are energized.

  In PTN4, the V-phase upper arm switching element and the U-phase lower arm switching element are energized.

  In PTN5, the W-phase upper arm switching element and the U-phase lower arm switching element are energized.

  In PTN6, the W-phase upper arm switching element and the V-phase lower arm switching element are energized.

  The commutation switching of the PWM signal is performed based on the voltage waveform 1 output of the voltage control first means 3.

  The detailed operation of the induced voltage detection means 1 will be described with reference to the operation explanatory diagram of the induced voltage detection means of FIG. The induced voltage zero cross signal of the BLM 7 is generated six times during one electrical angle cycle. FIG. 3 describes the induced voltage zero cross signal per phase. FIG. 3A is a relationship diagram between the phase current waveform and the induced voltage waveform, and shows the induced voltage 10, the phase current 9, its positive zero cross signal 11, and the reverse zero cross signal 12. The positive zero cross signal 11 is generated at an electrical angle of 0 °, and the reverse zero cross signal 12 is generated at an electrical angle of 180 °. The induced voltage that can be actually observed by the induced voltage detecting means 1 is the induced voltages 10a and 10b in FIG. 3 if the negative side of the DC voltage 8 is set to the GND potential N. Although the voltage is observed, if the induced voltage near the zero cross signal is considered, a waveform in which the PWM voltage component is superimposed on the voltage waveform of the induced voltage 10 is obtained. Basically, the intersection of the induced voltage 10a (10b) which is half of the DC voltage 8VDC (= VDC / 2) and the conduction point of the upper arm element and the lower arm element of the DC / AC conversion means 6 one by one. The positive zero-cross signal 11 (reverse zero-cross signal 12) can be detected during the arcing period (TON portion in FIG. 3).

  The induced voltage detection means 1 detects the positive zero cross signal 11 and the reverse zero cross signal 12 in the figure, and outputs them to the voltage control first means 3 as magnetic pole positions. Based on the zero cross signal, the voltage control first means 3 calculates a voltage waveform 1 substantially similar to the phase current 9, and the PWM control means 5 performs PWM corresponding to each electrical angle based on the information of the voltage waveform 1. Create a base PTN for the signal. Electrical angles X1 to X2 and X3 to X4 are current cut sections. The voltage control first means 3 can create a voltage waveform 1 having a 120 ° to 180 ° conduction waveform. However, in order to observe the induced voltage, it is necessary to make the conduction angle less than 180 °.

  When the conduction angle> 120 °, in addition to the six PWM signals described in the 120 ° conduction control, a three-phase sine wave drive PWM signal is added. Basically, a PWM signal for 120 ° energization control is used in a section where the current is OFF in any one of the three phases. In the section where the phase current flows in all three phases, the PWM signal for three-phase sine wave drive is used. Since this PWM signal is already known as three-phase sine wave PWM control, detailed description thereof is omitted here.

  Although the voltage waveform 1 is almost similar to the phase current 9, the phase difference is actually slightly advanced with respect to the phase current 9. In the description of the text, for the sake of simplicity, the phase difference is assumed to be zero. That is, phase current 9 = voltage waveform 1 is defined.

  FIG. 7 is an equivalent circuit diagram of the BLM7. R1 is the primary resistance of the winding, Lu · Lv · Lw is the inductance of each phase, and Eu · Ev · Ew is the field induced voltage of each phase. Here, the field induced voltage means an induced voltage generated only by a magnet (field) when the BLM 7 rotates in a non-energized state. FIG. 4 is a field induced voltage waveform relationship diagram of a three-phase brushless DC motor. In the figure, U1 represents the positive zero cross position of Eu, and U2 represents the reverse zero cross position. Similarly, the other phases are also shown, and the interval between the zero cross positions is ideally generated 6 times every 60 ° and one cycle of the electrical angle. These zero-cross positions are named as the true magnetic pole positions of the BLM7.

The true magnetic pole position of the BLM 7 cannot be determined directly from the zero cross signal of the induced voltage 10 due to the influence of the armature reaction, and a phase difference occurs between the two. Further, since this phase difference depends on the operating load, it is difficult to specify the true magnetic pole position from the induced voltage zero cross signal. However, even if the true magnetic pole position cannot be specified, it is sufficiently possible to control the rotation speed of the BLM 7 only by the induced voltage zero cross signal, and it may be preferable to control by the induced voltage. In the present embodiment, description will be made assuming that the phase difference between the two is zero. That is,
True magnetic pole position = induced voltage zero cross position. That is, if the induced voltage 10 in FIG. 3A corresponds to the U phase, zero cross U1 = positive zero cross signal 11
Zero cross U2 = reverse zero cross signal 12
It is. In addition,
Eu ≠ induced voltage 10
It is. The above equation is generated because the voltage waveform amplitudes of both are different due to the influence of the armature reaction.

Next, operations of the induced voltage selection means 2 and the voltage control second means 4 will be described. This part is a new control mechanism according to the present invention. The induced voltage selection means 2 selects the magnetic pole position that is the output of the induced voltage detection means 1. As the selection operation,
Thinning out n pieces in one cycle of electrical angle (select (6-n) (= m) pieces)
It is. Where n and m are
n ≧ 0 and m ≧ 0; n + m = 6
It is a natural number that satisfies Note that the variable need not be a constant value, and may be changed every cycle or more. Alternatively, it may be changed even with a period of less than one period. The selected magnetic pole position is output to the voltage control second means 4 as a magnetic pole position selection.

  The voltage control second means 4 creates the voltage waveform 2 based on the magnetic pole position selection. Based on the voltage waveform 2, the PWM control means 5 calculates the PWM signal in the same manner as a method of creating a PWM signal from the voltage waveform 1. The PWM control means 5 selects the voltage waveform 1 or the voltage waveform 2 according to the operating state of the motor control device. The voltage waveform 2 will be described with reference to FIG. 2 showing the relationship between the phase current waveform and the induced voltage waveform of the present embodiment.

FIGS. 2A and 2B show the case where n = 4 (m = 2) is set and the zero cross U1 and the zero cross U2 are selected. A combination of zero cross V1 and zero cross V2, or zero cross W1 and zero cross W2 may be used. Since the positive zero cross signal 11 and the reverse zero cross signal 12 are inputted as magnetic pole position selections every 180 °, the voltage waveform 2 can be made like the phase current 9a based on this. In order to detect the positive zero-cross signal 11 and the reverse zero-cross signal 12, currents are set to zero in the sections X1 to X2 and X3 to X4. here,
It is a real number satisfying −30 ° ≦ X1 ≦ 0 ° 0 ° ≦ X2 ≦ 30 ° 150 ° ≦ X3 ≦ 180 ° 180 ° ≦ X4 ≦ 210 ° 330 ° ≦ X5 ≦ 360 °.

FIG. 2B shows current waveforms when X3 and X5 are set smaller (advance angle setting) than FIG. 2A. The phase current 9b apparently advances with respect to the induced voltage 10, and the rotational speed of the BLM 7 can be improved. Note that the above settings of n and m are an example, and over two cycles of electrical angle depending on the operating state of the motor control device,
n = 6 (m = 0)
But you can. In addition, even if the rotational speed of the BLM7 changes suddenly due to sudden accidental or inevitable disturbance, motor control is possible if n (or m) is controlled in real time (n changes several times within one electrical angle cycle). Since n can be made large while sufficiently ensuring the control stability and responsiveness of the apparatus, the degree of freedom in the waveform of the voltage waveform 2 that is the output of the voltage control second means 4 can be improved. Can be supplied to BLM7.

Next, the operation of the phase angle setting means 14 will be described with reference to FIG. The phase angle setting means 14 has an equal or different phase angle for each electrical angle 60 ° × integer multiple, and outputs the phase angle to the voltage control second means 4 for each electrical angle. The phase angle setting means 14 defines the maximum and minimum values of the phase angles, and can also set different maximum and minimum values for each electrical angle of 60 ° × integer multiple. The phase angle setting means 14 outputs the phase angle for each electricity corresponding to the induced voltage zero cross signal to the voltage control second means 4 based on the induced voltage zero cross signal of the induced voltage detection means 1. Further, based on the magnetic pole position selection output of the induced voltage selection means 2, in the case of the electrical angle region / time domain corresponding to the magnetic pole position selection, the phase angle setting means 14 sets the phase angle to 0 °, and the phase angle The value is output to the voltage control second means 4. These image diagrams are shown in FIG. FIG. 8 shows the operation of the phase angle setting unit 14. The phase angle set by the phase angle setting unit 14 is set for each electrical angle corresponding to the zero cross signal output from the induced voltage detection unit 1. To express. If the phase angle value is increased, the armature current of the brushless DC motor 7 advances to the induced voltage, and this state is defined as a current advance angle (also simply referred to as an advance angle). The phase angle 15 corresponding to each electrical angle is determined in the induced voltage selection means 2 by
n = 5, m = 1
If the phase angle setting number in the phase angle setting means 14 is n0,
n0 = 6
It is what. A section is divided for each electrical angle corresponding to each zero-cross signal, and a phase angle 15φi is defined for each rotation section i (natural number satisfying 0 ≦ i ≦ 5 in this figure). As shown in the figure, φi determines the phase angle of the U-phase current 16, the V-phase current 17, and the W-phase current 18. The phase angle here represents the phase angle with respect to the induced voltage zero-cross signal. In this figure, the setting of the induced voltage selection means 2 is a setting for selecting an induced voltage zero cross signal for each electrical angle of 360 ° * natural number. In this setting,
Electrical angle 360 ° * In the case of an electrical angle corresponding to a natural number, the phase angle is set to 0 °. That is,
φ0 = φ6 = 0 °.

Next, the operation of the current selection unit 32 will be described. The current selection means 32 has a function of independently selecting / deselecting current information of the current detection means 30 and the current detection means 31 and sending them to the voltage control second means 4. Note that the current detection means 30 and the current detection means 31 are for detecting the armature current of the BLM 7, and only have to detect at least one of the three phases. In this figure, it demonstrates as what is detecting the electric current for two phases. The current selection means 32 outputs current information to the voltage control second means 4 based on the phase angle output value of the phase angle setting means 14 if the advance value of the phase angle is greater than or equal to a predetermined value. Does not output at all.

The voltage control second means 4 has a sinusoidal internal current command and is made based on the magnetic pole position selection information from the induced voltage selection means 2. This is shown in FIGS. 2 (c) and 2 (d). In the figure, the internal current command 9 d advances the phase angle with respect to the induced voltage 10. That is, if the zero point electrical angles of the internal current command 9d are X1, X3, and X5, then X1 <0 °, X3 <180 °, and X5 <360 °. The voltage control second means 4 performs voltage control so that the phase current 9c follows the internal current command 9d. Since FIG. 2C corresponds to the U phase, the current selection unit 32 selects the current detection unit 30 and outputs current information to the voltage control second unit 4. This figure describes a case where the phase current 9c is cut at the electrical angle X1, and the phase current 9c is controlled to follow the internal current command 9d at the electrical angle of 0 °.

FIG. 2D is an example when the current frequency of the internal current command 9f is changed during one electrical angle cycle. Specifically, if the average frequency of the internal current command 9f is f9f and the frequency at the electrical angle X is f (X),
f (X) ≧ f9f; 0 ≦ X ≦ X5
f (X) ≦ f9f; X5 <X <360
It is. In this way, the phase current 9e in the vicinity of X> 0 becomes smoother while the phase angle advance effect similar to that in FIG. 2C is drawn out, so that the operation of the BLM 7 with low noise and low vibration is further improved. I think it is possible. However, the internal current command 9d in FIG. 2 (c) only advances the phase angle fixedly, whereas the internal current command 9f needs to change the frequency dynamically. FIG. 2C may be useful as a total, and an internal current command system that is optimal for the motor control system may be selected or newly created.

  In the above description, the magnetic pole position selection of the induced voltage selection means 2 is a description based on the zero-cross signal (U1) for one phase. Of course, any zero-cross signal over two to three phases may be selected. The zero cross signal can be selected / deselected as appropriate.

  If the PWM control means 5 selects the voltage waveform 1 when the BLM 7 rotates at a low speed to a medium speed, and selects the voltage waveform 2 at a high speed, the magnetic pole position is used at all times during the low and medium speeds, so the stability is improved. Also, 120 ° energization control to 150 ° energization control with good driving efficiency can be utilized. In the high-speed range, advance angle control using sinusoidal current, trapezoidal wave, or arc-shaped current can be used, so high-speed performance improves.

  The induced voltage selection unit 2 may output a magnetic pole position selection in which the magnetic pole position is selected once every electrical angle (number of magnet poles / 2) in terms of the electrical angle period of the BLM 7. As a result, the induced voltage zero cross signal is detected once per rotation of the motor. Therefore, even when a load (for example, a rotary compressor) with periodic and regular speed fluctuations is driven every rotation, a constant speed is detected. In the steady operation region, the motor rotation speed at the moment when the induced voltage zero cross signal is detected takes a substantially constant value. In this case, the motor control device is hardly affected by the speed fluctuation and can construct a very stable speed control system.

The present embodiment has been described by taking a three-phase brushless DC motor as an example. However, the concept of application to a single-phase brushless DC motor is the same, and does not depart from the spirit, concept, and claims of the present invention. Of course, it is possible to change, add, or delete the embodiment as appropriate within the scope.

  The motor control device according to the present invention can be applied to applications such as an inverter air conditioner and a general-purpose inverter device because a brushless DC motor can be operated at high speed with less noise and vibration.

Control block diagram of motor control apparatus according to an embodiment of the present invention Relationship diagram between phase current waveform and induced voltage waveform of the embodiment of the present invention Operation explanatory diagram of the induced voltage detection means Field induced voltage waveform diagram of three-phase brushless DC motor Control block diagram of a conventional motor control device Relationship diagram between conventional phase current waveform and induced voltage waveform Equivalent circuit diagram of three-phase brushless DC motor Operation explanatory diagram of phase angle setting means

DESCRIPTION OF SYMBOLS 1 Induced voltage detection means 2 Induced voltage selection means 3 Voltage control 1st means 4 Voltage control 2nd means 5 PWM control means 6 DC / AC conversion means 7 Brushless DC motor (BLM)
8 DC voltage 9 phase current 10 induced voltage 11 positive zero cross signal 12 reverse zero cross signal 14 phase angle setting means 15 phase angle 16 U phase current 17 V phase current 18 W phase current 20 phase current 21 phase current 22 phase current 23 phase current 30 Current detection means 31 Current detection means 32 Current selection means

Claims (1)

DC-AC conversion means that includes a plurality of switching elements, converts a DC voltage into an AC voltage based on a PWM signal by opening and closing the switching element, and supplies the AC voltage to a three-phase brushless DC motor, and an induced voltage for detecting the induced voltage of the brushless DC motor Detection means, voltage control first means for outputting voltage waveform 1 based on all the magnetic pole positions output from the induced voltage detection means at every electrical angle of 60 ° , and converting the voltage waveform 1 into the PWM signal In a motor control device having a PWM control means, operates within a predetermined frequency range, selects the magnetic pole positions (6-n (defined as m ≧ 1 )) for one electrical angle period, and outputs a magnetic pole position selection. has the induced voltage selecting means, and a voltage controlled second means for outputting and creating a voltage waveform 2 in the PWM controller based on the magnetic pole position selector, said voltage control second means In the time domain, each containing n points which are not selected a time domain is divided into every electrical angle of 60 °, and outputs the voltage waveform 2, wherein the voltage controlled first by the authenticity determination of the predetermined frequency range Phase angle setting means for operating either one of the means or the voltage control second means to control the phase angle of the AC voltage based on the magnetic pole position and the magnetic pole position selection; and the electric motor of the brushless DC motor Current detection means for detecting at least one phase of the child current, and when the advance value of the phase angle is equal to or greater than a predetermined value , the armature current value is selected from the current information from the current detection means to perform voltage control. Current selection means for outputting to two means, and the voltage control second means includes a sinusoidal internal current command, and all the n time regions are based on the internal current command and the armature current value. Before corresponding to A motor control device characterized by having an operating characteristic that smoothly compensates for the rise of the armature current .

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