JP2009254045A - Magnetic pole position detection device of synchronous motor, and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic pole position detection device and method which operates a magnetic pole position without performing complicated operation, and is improved in safety. <P>SOLUTION: A memory 11 stores a rotor initial position θ1 in a rotor initial state, a PI amplifier 14 operates a correction value by performing PI operation so that a rotor present position θ2 agrees with the rotor initial position θ1, and an adder 15 adds a magnetic pole position initial setting value to the correction amount, and calculates the magnetic pole position setting value. The magnetic pole position detection device 10 outputs position information θ3 corresponding to the magnetic pole position setting value. A motor control device 1 determines a DC current vector fed to a synchronous motor 2 by using the position information θ3, and the magnetic pole position is varied by the current vector. Since the rotor present position θ2 is controlled so as to agree with the rotor initial position θ1, the rotor is not rotated so much, and a feedback control system is stabilized in a state where safety is secured. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an apparatus and method for detecting a magnetic pole position of a synchronous motor, and more particularly, detects a magnetic pole position without suppressing rotation of a rotor (rotor) and performing complicated processing, and synchronizes based on the detected magnetic pole position. The present invention relates to a technique for driving and controlling an electric motor.

  An electric motor control device that drives and controls a synchronous motor needs to supply current at a phase corresponding to the magnetic pole position of the rotor in order to generate a desired torque. For this reason, detecting the magnetic pole position of the rotor is an indispensable technique for driving and controlling the synchronous motor.

  Conventionally, various techniques are known as techniques for detecting the magnetic pole position of a rotor. For example, there is a method in which a magnetic pole position sensor and a pulse generator are provided in a synchronous motor, and the magnetic pole position is detected based on these measured values. In some cases, a predetermined direct current (current vector) is supplied to the stator (stator) of the synchronous motor, and the position where the rotor is stopped by the current vector is set as the magnetic pole position.

  FIG. 5 is a diagram showing a configuration of a conventional magnetic pole position detection device. The magnetic pole position detection device 110 is an example of a device that realizes magnetic pole position detection. The magnetic pole position detection device 110 includes a coordinate converter 111, an absolute value calculator 112, a low-pass filter 113, and a magnetic pole position calculator 114, and is synchronized with a motor control device (not shown). A three-phase high-frequency current supplied to the electric motor 102 is input through the band-pass filter 120, and the magnetic pole position θ is detected and output based on the value of the three-phase high-frequency current.

  Specifically, a motor control device (not shown), when set to a mode for detecting the magnetic pole position of the rotor in the synchronous motor 102 by an operator's operation, controls a power converter (inverter / not shown) that controls the synchronous motor 102. ), An arbitrary three-phase high-frequency current is supplied to the synchronous motor 102 at a frequency outside the output frequency range.

  The band pass filter 120 extracts and outputs only a preset frequency from the three-phase high-frequency current. The coordinate converter 111 of the magnetic pole position detection device 110 receives the three-phase high-frequency current output from the bandpass filter 120, and performs coordinate conversion to the α axis, β axis, α ′ axis, and β ′ axis. The axis current value is output. Here, the U phase of the synchronous motor 102 is the α axis, the axis orthogonal to the α axis is 90 °, and the axis moved 45 ° from the α axis in the two-phase stationary coordinate system of the α axis and the β axis is α The axis is 90 ′ and the axis that is orthogonal to the α ′ axis is the β ′ axis.

  The absolute value calculator 112 receives the 4-axis current values converted by the coordinate converter 111, averages the respective peak values, and outputs the averaged 4-axis current values. The low-pass filter 113 receives the 4-axis current value from the absolute value calculator 112, removes the high-frequency component, and outputs it. The magnetic pole position calculator 114 receives the 4-axis current values from the low-pass filter 113, performs a predetermined calculation based on these 4-axis current values, and outputs the magnetic pole position θ. For detailed calculations in the magnetic pole position detection device 110, refer to Patent Document 1.

  Thus, the magnetic pole position θ detected by the magnetic pole position detection device 110 is used to generate a current to be supplied to the synchronous motor 102, and the motor control device (not shown) has an appropriate phase corresponding to the magnetic pole position of the rotor. Current can be supplied to the synchronous motor 102.

JP 2003-52193 A

  However, when the magnetic pole position detection device 110 of Patent Document 1 is used as a method for detecting the magnetic pole position, it is necessary to perform a complicated calculation in order to detect the magnetic pole position θ. was there.

  As another method for detecting the magnetic pole position, when a method is used in which a predetermined current vector is supplied to the stator of the synchronous motor and the position where the rotor stops is the magnetic pole position, the current vector and the magnetic pole position are Because of the orthogonal relationship, the rotor rotates to a position orthogonal to the current vector. In other words, if the mode of detecting the magnetic pole position of the rotor is set by the operation of the operator, the rotor of the synchronous motor 102 suddenly rotates, and thus it is necessary to give sufficient consideration to safety.

  Therefore, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a magnetic pole position detection apparatus and method that calculates the magnetic pole position without performing complicated calculations and is excellent in safety. There is.

  In order to achieve the above object, a magnetic pole position detection device according to the present invention inputs a rotor current position indicating a rotational position of a rotor in a synchronous motor, and uses the position information of the magnetic pole position based on the rotor current position to obtain the synchronization. In the motor control device for driving and controlling the motor, in the device for detecting the magnetic pole position, a storage unit that stores a rotor current position in an initial state for detecting the magnetic pole position as a rotor initial position, the rotor current position, A calculation unit that performs feedback control so as to match the rotor initial position stored in the storage unit and calculates a correction amount, and the synchronization information is obtained based on the position information based on the correction amount calculated by the calculation unit. A current vector of a direct current supplied to the electric motor is determined.

  The magnetic pole position detection device according to the present invention includes a subtractor that calculates a deviation between the current rotor position and the initial rotor position stored in the storage unit, and a second magnetic pole position initial setting value that is stored in advance. A storage unit; and an addition unit that adds the correction amount calculated by the calculation unit and the magnetic pole position initial setting value stored by the second storage unit. The calculated deviation is input, the correction amount is calculated by P (proportional) control and I (integral) control so that the deviation becomes zero, and the synchronization is calculated based on the position information based on the addition result by the adding unit. A current vector of a direct current supplied to the electric motor is determined.

  The magnetic pole position detection method according to the present invention inputs a rotor current position indicating a rotational position of a rotor in the synchronous motor, and uses the position information of the magnetic pole position based on the rotor current position to drive and control the synchronous motor. In the method of detecting the magnetic pole position by the control device, a first step of storing the rotor current position in the initial state of detecting the magnetic pole position as the rotor initial position, the input rotor current position, and the stored rotor initial position A second step of performing feedback control so as to match the position and calculating a correction amount; and a third step of determining a current vector of a direct current to be supplied to the synchronous motor based on position information based on the correction amount And a step.

  The magnetic pole position detection method according to the present invention includes a step of storing a magnetic pole position initial setting value in advance, and a step of adding the correction amount calculated in the second step and the stored magnetic pole position initial setting value. Then, the second step calculates a deviation between the input rotor current position and the stored rotor initial position, and P (proportional) control and I (integration) control so that the deviation becomes zero. The third step determines a current vector of a direct current to be supplied to the synchronous motor based on position information based on the addition result of the correction amount and the magnetic pole position initial setting value. It is characterized by.

  As described above, according to the present invention, by performing feedback control so that the rotor initial position and the rotor current position coincide with each other, the rotor magnetic pole position is not rotated so much from the initial state position. The current vector orthogonal to the magnetic pole position in the state is determined. Thereby, it is possible to realize a magnetic pole position detection apparatus and method that calculates the magnetic pole position without performing complicated calculations and is excellent in safety.

The best mode for carrying out the present invention will be described below with reference to the drawings.
[Configuration of motor control device]
FIG. 1 is a diagram showing a basic configuration of an electric motor control device in which a magnetic pole position detection device according to an embodiment of the present invention is used. The motor control device 1 includes a magnetic pole position detection device 10, a coordinate converter 20, a two-phase three-phase converter 30, a PWM controller 40, a power converter 50, subtracters 60-1 and 60-2, and a current controller 70. -1 and 70-2. The motor control device 1 inputs the rotor current position θ2 from an absolute position detector (absolute encoder) 3 connected to the synchronous motor 2, and position information (mechanical angle) θ3 corresponding to the magnetic pole position indicated by the rotor current position θ2. In this phase, the drive current is supplied to the synchronous motor 2. Hereinafter, in order to simplify the description, the number of magnetic poles of the rotor is two. The position information θ3 at this time coincides with the electrical angle. Further, the rotating part and the fixed part of the absolute position detector 3 are respectively attached to the rotor and the chassis part of the motor control device 1.

  The magnetic pole position detection device 10 of the motor control device 1 receives the rotor current position θ2 from the absolute position detector 3 and detects a normal mode signal which is a normal operation mode or a magnetic pole position as a mode signal. Input the signal. The mode signal is set by an operator's selection in a setting device (not shown). In the normal mode, the magnetic pole offset θ3 ′ is added to the input rotor current position θ2 and the position information θ3 is output to the coordinate converter 20. On the other hand, in the magnetic pole position detection mode, PI (P: proportionality, I: integration) is calculated so that the input rotor current position θ2 matches the rotor initial position θ1, and the position information θ3, which is the calculation result, is coordinate-converted. To the device 20.

  In the magnetic pole position detection mode, if the position information when the position information θ3 as a calculation result is stabilized after a predetermined time has elapsed is the magnetic pole offset θ3 ′, the magnetic pole position detection device 10 has a current corresponding to the magnetic pole offset θ3 ′. The vector is supplied to the synchronous motor 2, and the rotor maintains the same position as the initial rotor initial position θ1 in the initial state, which is the start time of the magnetic pole position detection mode. That is, in the magnetic pole position detection mode, the magnetic pole position detection device 10 calculates the magnetic pole offset θ3 ′ in which the rotor current position θ2 matches the rotor initial position θ1 while suppressing the rotation of the rotor, and corresponds to the magnetic pole offset θ3 ′. Determine the current vector.

  The subtractor 60-1 of the motor control device 1 subtracts the torque current feedback signal iq from the torque current command i * q, and outputs the subtraction result. The current controller 70-1 receives the subtraction result from the subtractor 60-1, and outputs a torque divided voltage command V * q by current control. The subtractor 60-2 subtracts the excitation current feedback signal id from the excitation current command i * d and outputs the subtraction result. The current controller 70-2 receives the subtraction result from the subtractor 60-2 and outputs the excitation voltage command V * d by current control. Here, the torque component current feedback signal iq and the excitation component current feedback signal id are current signals obtained by three-phase / two-phase conversion of the current signal of each UWV phase. Specifically, a current sensor (not shown) arranged on a winding between the power converter 50 and the synchronous motor 2 detects a current signal of each phase of UVW, and a three-phase / 2-phase coordinate converter ( (Not shown) performs a coordinate conversion operation on the current signal of each phase of the UVW, and obtains a torque component current feedback signal iq and an excitation component current feedback signal id. The current vector supplied from the power converter 50 to the synchronous motor 2 corresponds to a combined vector of the torque component current command i * q and the excitation component current command i * d.

  The coordinate converter 20 receives the torque voltage command V * q and the excitation voltage command V * d from the current controllers 70-1 and 70-2, and receives the position information θ3 from the magnetic pole position detector 10. It is converted into two-phase AC voltage commands Va and Vb. The two-phase three-phase converter 30 receives the two-phase AC voltage commands Va and Vb from the coordinate converter 20 and converts them into a three-phase sine wave voltage command. The PWM controller 40 receives a three-phase sine wave voltage command from the two-phase three-phase converter 30, performs pulse width control using a carrier wave signal (triangular wave signal) (not shown), and converts it into a three-phase PWM signal. The power converter 50 receives a PWM signal from the PWM controller 40, operates the gate on and off using this PWM signal as a drive signal, generates a three-phase pulsed sine wave voltage signal, and supplies the signal to the synchronous motor 2. In the magnetic pole position detection mode, the motor control device 1 supplies a DC current vector corresponding to the position information θ3 to the synchronous motor 2.

[Configuration of magnetic pole position detection device]
Next, the magnetic pole position detection apparatus 10 shown in FIG. 1 will be described in detail. FIG. 2 is a block diagram showing a configuration of the magnetic pole position detection apparatus 10 according to the embodiment of the present invention. The magnetic pole position detection device 10 includes a memory 11 for storing the rotor initial position, a memory 12 for storing the initial magnetic pole position setting value, a subtractor 13, a PI amplifier 14, an adder 15, a selector 16, a memory 17 and an adder 18. I have.

  The memory 11 stores the rotor current position θ2 when the load is not connected to the rotor as the rotor initial position θ1. That is, the magnetic pole position detection device 10 inputs the rotor current position θ2 in the free state (initial state) and stores it in the memory 11 as the rotor initial position θ1. The rotor current position θ2 input from the absolute position detector 3 shown in FIG. 1 is position information corresponding to the magnetic pole position of the rotor.

  FIG. 3 (1) is an explanatory view showing an initial state of the rotor. FIG. 3A shows the magnetic pole position a1 when the rotor is in a free state and no DC current is supplied to the stator winding of the synchronous motor 2. At this time, the rotor current position θ2 with respect to the reference axis becomes the rotor initial position θ1. Here, the reference axis indicates a phase position of a current vector that is a reference in an initial state among DC current vectors supplied from the motor control device 1 to the synchronous motor 2. That is, the motor control device 1 synchronizes the DC current vector corresponding to the position information θ3 with reference to a current vector b1 (current vector on the reference axis) in FIG. Supply to the electric motor 2. As described above, the memory 11 stores the rotor initial position θ1 in the initial state of FIG.

  FIG. 3B is an explanatory diagram showing the state of the rotor when the current vector b1 is supplied along the reference axis. When the motor control device 1 supplies a reference current vector (current vector on the reference axis) b1 in the initial state of FIG. 3 (1), the magnetic pole position a1 of the rotor is as shown in FIG. 3 (2). Then, it rotates to the magnetic pole position a2 orthogonal to the current vector b1. Therefore, in the embodiment of the present invention, as shown in FIG. 3 (3) described later, a current vector (position information θ3) orthogonal to the magnetic pole position a1 is set so that the rotor does not rotate as much as possible from the magnetic pole position a1 in the initial state. = Current vector) b2 corresponding to θ3 ′ is determined.

  FIG. 3 (3) is an explanatory diagram showing a state when the current vector b2 at a position orthogonal to the magnetic pole position a1 in the initial state is supplied. The magnetic pole position detection device 10 outputs the magnetic pole offset θ3 ′ for supplying the current vector b2 orthogonal to the magnetic pole position a1 in the initial state by the motor control device 1, thereby maintaining the magnetic pole position a1 of the rotor in the initial state. be able to. That is, the information on the magnetic pole position for preventing the rotor from rotating as much as possible from the initial state is the correction amount (magnetic pole offset θ3 ′) calculated by the PI amplifier 14 described later in the information on the rotor initial position θ1 of the magnetic pole position a1 in the initial state. It is detected that the amount of information) is added.

  Returning to FIG. 2, the magnetic pole position initial setting value is stored in the memory 12 in advance. This magnetic pole position initial setting value corresponds to the position information of the reference axis shown in FIGS. 3 (1) to 3 (3). In this example, 0 is set.

  The subtracter 13 inputs the rotor current position θ2 from the absolute position detector 3 and the rotor initial position θ1 from the memory 11, subtracts the rotor current position θ2 from the rotor initial position θ1, and obtains a deviation Δθ as a result of the subtraction. Output.

  The PI amplifier 14 receives the deviation Δθ from the subtractor 13, performs a proportional calculation and an integration calculation based on the deviation Δθ, and outputs a correction amount as a calculation result. This correction amount is output to the coordinate converter 20 as position information θ3 through the adder 15 and the selector 16. Then, the motor control device 1 supplies a DC current vector corresponding to the position information θ3 to the synchronous motor 2, and the rotor of the synchronous motor 2 rotates according to the position of the current vector. Then, the magnetic pole position detection device 10 inputs a new rotor current position θ2 from the absolute position detector 3. Here, the PI amplifier 14 performs feedback control by feedback control so that the rotor current position θ2 coincides with the rotor initial position θ1, that is, the deviation Δθ becomes 0, and the correction amount is calculated by PI amplification calculation. Output. When the feedback control system is stabilized, a correction amount when the rotor current position θ2 coincides with the rotor initial position θ1 is output, and position information θ3 = θ3 ′ corresponding to the correction amount is output. It is assumed that PI parameters are set in advance in the PI amplifier 14.

  The adder 15 inputs the correction amount from the PI amplifier 14 and the magnetic pole position initial setting value from the memory 12, adds the magnetic pole position initial setting value to the correction amount, and outputs the addition result as the magnetic pole position setting value.

  The memory 17 stores the magnetic pole position setting value output by the adder 15 when the feedback control system is stable as the magnetic pole offset θ3 ′. Here, the timing of storing the magnetic pole offset θ3 ′ is, for example, when the subtraction result Δθ by the subtractor 13 falls within a predetermined allowable range with reference to 0 for a predetermined time.

  The adder 18 inputs the rotor current position θ2 from the absolute position detector 3 and the magnetic pole offset θ3 'from the memory 17, adds the magnetic pole offset θ3' to the rotor current position θ2, and outputs the addition result.

  The selector 16 inputs the magnetic pole position setting value from the adder 15, the addition result from the adder 18, and the mode signal set by the operator in the setting device (not shown), and adds when the mode signal is a normal mode signal. The addition result from the device 18 is output as position information θ3, and when the mode signal is a magnetic pole position detection mode signal, the magnetic pole position setting value is output as position information θ3.

  Thus, in the magnetic pole position detection mode, the magnetic pole position detection device 10 inputs the rotor current position θ2 that reflects the position information θ3 that is the output signal, and the rotor current position θ2 matches the rotor initial position θ1. In addition, feedback control by PI calculation is performed. As a result, a correction amount is output so that the rotor current position θ2 matches the rotor initial position θ1, position information θ3 corresponding to this correction amount is output, and the control system gradually becomes stable. The position information θ3 = θ3 ′ at this time is the phase position of the current vector corresponding to the magnetic pole position to be detected.

[Processing of magnetic pole position detection device]
Next, the process of the magnetic pole position detection apparatus 10 shown in FIG. 2 will be described. FIG. 4 is an explanatory diagram showing processing of the magnetic pole position detection mode by the magnetic pole position detection device 10. First, when a magnetic pole position detection mode signal is input as a mode signal, the magnetic pole position detection apparatus 10 stores the initial rotor current position θ2 shown in FIG. 3A in the memory 11 as the initial rotor position θ1 (step S401). ).

  The magnetic pole position detection device 10 determines whether or not the input mode signal is a magnetic pole position detection mode signal (step S402), and as long as the mode signal is a magnetic pole position detection mode signal (step S402: Y), step S403 is performed. To step S406. On the other hand, when the mode signal is not the magnetic pole position detection mode signal (step S402: N), the processing of the magnetic pole position detection mode is terminated.

  The magnetic pole position detection device 10 inputs the rotor current position θ2 from the absolute position detector 3 (step S403). Then, the subtractor 13 of the magnetic pole position detection device 10 subtracts the rotor current position θ2 input in step S403 from the rotor initial position θ1 stored in the memory 11, and calculates a deviation Δθ as a subtraction result (step). S404).

  The PI amplifier 14 receives the deviation Δθ from the subtractor 13 and calculates the correction amount by performing PI calculation so that the deviation Δθ becomes zero (step S405). The adder 15 adds the magnetic pole position initial setting value stored in advance in the memory 12 and the correction amount from the PI amplifier 14 to calculate the magnetic pole position setting value as the addition result, thereby stabilizing the feedback control system. At this timing, the magnetic pole offset θ3 ′ is stored in the memory 17 (step S406). Further, the magnetic pole position set value is output to the coordinate converter 20 via the selector 16 as position information θ3.

  In this way, the magnetic pole position detection device 10 outputs the position information θ3 = θ3 ′ when the feedback control system is stabilized by performing feedback control from step S403 to step S406, and the motor control device 1 A DC current vector b2 corresponding to the offset θ3 ′ is determined.

  Next, normal mode processing will be described. When the magnetic pole position detection device 10 inputs a normal mode signal as a mode signal, the adder 18 adds the magnetic pole offset θ3 ′ stored in the memory 11 and the rotor current position θ2 in the magnetic pole position detection mode, and is obtained as a result of the addition. The value is output to the coordinate converter 20 via the selector 16 as position information θ3.

  As described above, according to the magnetic pole position detection device 10 according to the embodiment of the present invention, the memory 11 stores the rotor current position θ2 in the free state (initial state) where the load is not connected to the rotor as the rotor initial position θ1. Then, the PI amplifier 14 calculates the correction amount by performing PI calculation so that the rotor current position θ2 and the rotor initial position θ1 coincide with each other, and the position information θ3 of the current vector is output as the output of the magnetic pole position detection device 10. I tried to get it. When such a feedback control system is stabilized, the current vector b2 corresponding to the position information θ3 = θ3 ′ becomes a position orthogonal to the magnetic pole position a1 of the rotor initial position θ1. As a result, information obtained by adding the correction amount calculated by the PI amplifier 14 to the rotor initial position θ1 becomes information on the magnetic pole position, so that the magnetic pole position can be detected without performing complicated calculation. Further, since the rotor maintains the rotor initial position θ1, it does not rotate so much. Therefore, it is possible to detect the magnetic pole position while ensuring safety.

  The present invention has been described with reference to the embodiment. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the technical idea thereof. For example, in the above-described embodiment, the PI amplifier 14 performs the PI calculation based on proportionality and integration. However, the PID calculation may be performed by adding differentiation to the PI calculation, or the correction amount may be obtained by a method other than the PI calculation. May be output.

It is a block diagram which shows the basic composition of the electric motor control apparatus with which the magnetic pole position detection apparatus by embodiment of this invention is used. It is a block diagram which shows the structure of the magnetic pole position detection apparatus by embodiment of this invention. (1) is explanatory drawing which shows the initial state of a rotor. (2) is an explanatory view showing the state of the rotor when a current vector is supplied along the reference axis. (3) is explanatory drawing which shows a state when the electric current vector of the position orthogonal to the magnetic pole position of an initial state is supplied. It is explanatory drawing which shows the process of magnetic pole position detection mode. It is a block diagram which shows the structure of the conventional magnetic pole position detection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor control apparatus 2,102 Synchronous motor 3 Absolute position detector 10,110 Magnetic pole position detection apparatus 11,12,17 Memory 13,60-1,60-2 Subtractor 14 PI amplifier 15,18 Adder 16 Selector 20 Coordinate Converter 30 Two-phase three-phase converter 40 PWM controller 50 Power converters 70-1 and 70-2 Current controller 111 Coordinate converter 112 Absolute value calculator 113 Low-pass filter 114 Magnetic pole position calculator 120 Band-pass filter θ1 Rotor Initial position θ2 Current rotor position θ3 Position information θ3 ′ Magnetic pole offset i * q Torque component current command i * d Excitation current command iq Torque component current feedback signal id Excitation current feedback signal V * q Torque component voltage command V * d Excitation Voltage divider command

Claims (4)

An apparatus for detecting the magnetic pole position in an electric motor control apparatus that inputs the rotor current position indicating the rotational position of the rotor in the synchronous motor and drives and controls the synchronous motor by using position information of the magnetic pole position based on the rotor current position. In
A storage unit that stores a rotor current position in an initial state for detecting the magnetic pole position as a rotor initial position;
A calculation unit that performs feedback control so that the rotor current position and the rotor initial position stored in the storage unit match, and calculates a correction amount;
A magnetic pole position detection device, wherein a current vector of a direct current supplied to the synchronous motor is determined based on position information based on a correction amount calculated by the calculation unit. In the magnetic pole position detection apparatus according to claim 1,
A subtraction unit that calculates a deviation between the rotor current position and the rotor initial position stored in the storage unit;
A second storage unit that stores in advance magnetic pole position initial setting values;
An addition unit that adds the correction amount calculated by the calculation unit and the magnetic pole position initial setting value stored by the second storage unit;
The calculation unit inputs a deviation calculated by the subtraction unit, calculates a correction amount by P (proportional) control and I (integration) control so that the deviation becomes zero,
A magnetic pole position detecting device, wherein a current vector of a direct current supplied to the synchronous motor is determined based on position information based on an addition result by the adding unit. A method of detecting the magnetic pole position by an electric motor control device that inputs a rotor current position indicating a rotational position of the rotor in the synchronous motor and drives and controls the synchronous motor by using position information of the magnetic pole position based on the rotor current position. In
A first step of storing a rotor current position in an initial state for detecting the magnetic pole position as a rotor initial position;
A second step of performing feedback control so that the inputted rotor current position and the stored rotor initial position coincide with each other, and calculating a correction amount;
And a third step of determining a current vector of a direct current to be supplied to the synchronous motor based on position information based on the correction amount. In the magnetic pole position detection method according to claim 3,
Storing in advance magnetic pole position initial setting values;
Adding the correction amount calculated in the second step and the stored magnetic pole position initial setting value,
In the second step, a deviation between the input rotor current position and the stored rotor initial position is calculated, and corrected by P (proportional) control and I (integral) control so that the deviation becomes zero. Calculate the quantity,
In the third step, a current vector of a direct current to be supplied to the synchronous motor is determined based on position information based on the addition result of the correction amount and a magnetic pole position initial setting value. Method.

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