JP2006033976A - Control device of synchronous motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device 1 that can largely reduce an operation load and can obtain accuracy and responsiveness equal to current control without the need for performing axial conversion that uses a trigonometric function of a rotation position θ. <P>SOLUTION: In the control device 1, a current sensor 3 detects a U-phase current and a W-phase current, and outputs current detection signals Iu, Iw that correspond to the phase currents. Then, an ECU 5 calculates the magnitude Iαβ of a current vector as a current amount by using the current detection signals Iu, Iw, and also calculates a voltage amplification VA and a voltage phase Vθ as voltage properties by using the magnitude Iαβ ot the current vector. Since the magnitude Iαβ of the current vector is a function whose parameter is only the current vector, there is no need for performing the axial conversion that uses the trigonometric function of the rotation position θ. The operation load of the control device 1 can largely be reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control device for a synchronous motor.

[Conventional technology]
A synchronous motor energizes a plurality of phases (for example, U-phase, V-phase, and W-phase) armature coils provided in a stator, and rotates a rotor having a field pole such as a permanent magnet to obtain torque. It is. For this reason, in order to optimally drive and control the synchronous motor, information on the rotational position of the rotor (hereinafter simply referred to as the rotational position) is indispensable. Thus, a conventional synchronous motor is equipped with a dedicated position sensor for detecting the rotational position.

  By the way, when the position sensor is mounted, the size of the synchronous motor increases and the cost also increases. Furthermore, since the use environment of the position sensor itself is limited, the application of the synchronous motor is limited. Therefore, a technique is known in which a rotational position is calculated from information related to a phase current and a phase voltage supplied to an armature coil without using a position sensor, and a synchronous motor is driven and controlled using the calculated rotational position. It has become.

  A synchronous motor control device that is driven and controlled without using a position sensor (hereinafter simply referred to as a control device) detects, for example, a phase current energized in an armature coil and responds to this phase current. A current detector that outputs a current detection signal, a current amount calculator that calculates a current amount indicating the magnitude of the phase current using the current detection signal, and a position estimator that calculates a rotational position using the current detection signal And a voltage characteristic calculator that calculates a voltage characteristic indicating a characteristic of the voltage applied to the armature coil using the current amount calculated by the current amount calculator and the rotational position calculated by the position estimator. .

  The voltage characteristic calculator uses the rotor rotational speed (hereinafter simply referred to as rotational speed) calculated in response to a request from a host device (not shown), the rotational position calculated by the position estimator, and the like. Thus, the amplitude, phase, and the like of the applied voltage are calculated so that the current amount (measured value of the current amount) calculated by the current amount calculator substantially matches the target value. That is, the voltage characteristic calculator performs “current control” for manipulating the voltage characteristic so that the measured value of the current amount substantially matches the target value of the current amount.

  Then, a command signal corresponding to the amplitude and phase of the applied voltage is synthesized by the pulse synthesizer and output to the inverter, and each transistor of the inverter changes the operating state according to this command signal. As a result, the phase current is adjusted, and the synchronous motor is controlled to a rotational speed according to a request from the host device.

  By the way, in the case of using a control device that drives and controls a synchronous motor by current control, the driving of the synchronous motor may become unstable unless the gain adjustment of current control is reliably performed. For this reason, in a control device that performs current control, gain adjustment work becomes extremely complicated. In addition, since the calculation load of current control is extremely large, a microcomputer with high processing capability is required, and a highly accurate current detector is required.

  In view of this, there is a known control device that calculates the q-axis current magnitude as the current amount without performing the current control, and calculates the voltage characteristics using the q-axis current magnitude and the rotation speed (for example, Patent Documents). 1). This control device has a simpler configuration than that of a control device that performs current control, and a portion for performing gain adjustment is reduced.

[Problems with conventional technology]
However, if the magnitude of the q-axis current is used as the current amount, it is necessary to perform axis conversion using a trigonometric function of the rotational position, and the calculation load is insufficiently reduced.
JP 2002-272194 A

  The present invention has been made in order to solve the above-described problems, and it is not necessary to perform axis conversion using a trigonometric function of the rotational position, so that the calculation load can be greatly reduced and the current control is equivalent. It is an object of the present invention to provide a control device capable of obtaining the accuracy and responsiveness.

[Means of Claim 1]
The control device according to claim 1 detects a phase current supplied to the armature coil and outputs a current detection signal corresponding to the phase current, and the phase currents on two stationary axes orthogonal to each other. A current amount obtained by converting the current vector to a current amount, a current amount calculating means for calculating the current vector magnitude using the current detection signal, and using the current vector magnitude as a current amount indicating the magnitude of the phase current; Voltage characteristic calculation means for calculating a voltage characteristic indicating the characteristic of the voltage applied to the armature coil by using the magnitude.
The magnitude of the current vector is a function with only the phase current as a variable. According to this means, the phase current is directly detected by the current detection means. For this reason, when obtaining the magnitude of the current vector, which is the amount of current, it is not necessary to perform axis conversion using a trigonometric function of the rotational position. As a result, the calculation load of the control device can be significantly reduced.

[Means of claim 2]
According to a second aspect of the present invention, there is provided a control device that detects a phase current energized in an armature coil, outputs a current detection signal corresponding to the phase current, and an absolute value among the phase currents of a plurality of phases. The maximum amount of the maximum phase current is calculated using the current detection signal, and the amount of maximum phase current is calculated by using the amount of the maximum phase current as the amount of current indicating the size of the phase current. And a voltage characteristic calculation means for calculating a voltage characteristic indicating the characteristic of the voltage applied to the armature coil.
According to this means, the phase current is directly detected by the current detection means. For this reason, when obtaining the magnitude of the maximum phase current, which is the amount of current, it is not necessary to perform axis conversion using a trigonometric function of the rotational position. As a result, the calculation load of the control device can be significantly reduced.

[Means of claim 3]
According to a third aspect of the present invention, there is provided a control device that detects a phase current energized in an armature coil, outputs a current detection signal corresponding to the phase current, and an absolute value of a plurality of phase currents in a predetermined cycle. And calculating a maximum value of the current using a current detection signal, and a current amount calculation means that uses a maximum value of the predetermined cycle as a current amount indicating the magnitude of the phase current in the next cycle of the predetermined cycle, and a maximum in the predetermined cycle Voltage characteristic calculation means for calculating a voltage characteristic indicating the characteristic of the voltage applied to the armature coil using the value.
According to this means, the phase current is directly detected by the current detection means. For this reason, when obtaining the maximum absolute value of the phase currents of a plurality of phases in a predetermined cycle as the current amount, it is not necessary to perform axis conversion using a trigonometric function of the rotational position. As a result, the calculation load of the control device can be significantly reduced.

[Means of claim 4]
According to a fourth aspect of the present invention, there is provided an inverter that converts electric power supplied from a power source into a phase current that is passed through an armature coil, and detects a bus current that flows through the bus of the inverter, and a current corresponding to the bus current. Current detection means that outputs a detection signal, current amount calculation means that uses the magnitude of the bus current measured using the current detection signal as a current quantity indicating the magnitude of the phase current, and the magnitude of the bus current And a voltage characteristic calculation means for calculating a voltage characteristic indicating the characteristic of the voltage applied to the armature coil.
According to this means, the magnitude of the bus current of the inverter is directly detected by the current detection means. For this reason, it is not necessary to perform axis conversion using a trigonometric function of the rotational position when determining the magnitude of the bus current that is the amount of current. As a result, the calculation load of the control device can be significantly reduced.

[Means of claim 5]
The voltage characteristic calculation means of the control device according to claim 5 has voltage characteristic information storage means for storing voltage characteristic information indicating a correlation between the voltage characteristic and the current amount, and uses the current amount and the voltage characteristic information. Calculate the voltage characteristics.

[Means of claim 6]
The voltage characteristic of the control device according to claim 6 is the amplitude of the applied voltage and the phase of the applied voltage.

[Means of Claim 7]
The voltage characteristic of the control device according to claim 7 is an α-axis voltage and a β-axis voltage obtained by converting the applied voltage applied to the multi-phase armature coil onto two stationary axes orthogonal to each other. .

[Means of Claim 8]
The voltage characteristic calculation means of the control device according to claim 8 is a phase difference calculation means for calculating a phase difference between the applied voltage and the phase current using the current detection signal, and a level indicating a correlation between the phase difference and the current amount. A phase difference information storage means for storing phase difference information, so that a difference between the phase difference calculated by the phase difference calculation means and the phase difference calculated using the current amount and the phase difference information becomes a predetermined value. Adjust the voltage characteristics.
The phase difference can be manipulated by adjusting the voltage characteristics. Further, the motor efficiency becomes maximum when the phase difference is a predetermined value. Therefore, by adjusting the voltage characteristics so that the difference between the phase difference calculated by the phase difference calculation means and the phase difference calculated using the current amount and the phase difference information becomes a predetermined value, the motor efficiency can be increased. The synchronous motor can be driven and controlled.

[Means of Claim 9]
The phase difference calculation means of the control device according to claim 9 definitely integrates a predetermined sine function in a period corresponding to a predetermined range of the phase current, and calculates a phase difference according to an integral value obtained by the definite integration. To do.
If a value that is not affected by the magnitude of the phase current, etc., is selected as the boundary value of the predetermined range of the phase current, the above integrated value can be accurately obtained regardless of the influence of noise contamination, gain error, etc. on the detection of the phase current. Can be calculated. Therefore, the phase difference can be calculated using the current detection signal without being affected by noise mixing, gain error, or the like with respect to the detection of the phase current.

[Means of Claim 10]
The control device according to claim 10 includes temperature detection means for detecting a temperature of the synchronous motor or an ambient temperature of the synchronous motor, and outputting a temperature detection signal corresponding to the temperature of the synchronous motor or the ambient temperature of the synchronous motor, The amount calculation means corrects the amount of current using the temperature detection signal.
The magnetic flux generated by the field pole varies depending on the temperature of the synchronous motor. For this reason, the magnitude of the phase current varies according to the temperature of the synchronous motor even if the rotational speed, voltage characteristics, and the like are the same. Thus, by correcting the amount of current using the temperature of the synchronous motor, the influence of the temperature of the synchronous motor on the amount of current can be reduced.

  The best mode 1 is to detect a phase current to be supplied to an armature coil in a control device for a synchronous motor in which a plurality of phases of an armature coil provided in a stator is energized to rotate a rotor having a field pole. The current detection means for outputting a current detection signal according to the current, and the magnitude of the current vector obtained by converting the phase current onto two stationary axes orthogonal to each other are calculated using the current detection signal, A voltage characteristic for calculating a voltage characteristic indicating a characteristic of an applied voltage to the armature coil by using a current amount calculation means that uses a current vector magnitude as a current quantity indicating the magnitude of the phase current, and a current vector magnitude. And an arithmetic means.

  The voltage characteristic calculation means has voltage characteristic information storage means for storing voltage characteristic information indicating a correlation between the voltage characteristic and the current amount, and calculates the voltage characteristic using the current amount and the voltage characteristic information. The voltage characteristics are the amplitude of the applied voltage and the phase of the applied voltage.

  The voltage characteristic of the best mode 2 is an α-axis voltage and a β-axis voltage obtained by converting applied voltages applied to the armature coils of a plurality of phases onto two stationary axes orthogonal to each other.

  The voltage characteristic calculation means of the best mode 3 stores phase difference calculation means for calculating the phase difference between the applied voltage and the phase current using the current detection signal, and phase difference information indicating the correlation between the phase difference and the current amount. Voltage difference is adjusted so that the difference between the phase difference calculated by the phase difference calculation means and the phase difference calculated by using the current amount and phase difference information becomes a predetermined value. To do.

  The phase difference calculation means of the best mode 4 performs a constant integration of a predetermined sine function in a period corresponding to a predetermined range of the phase current, and calculates a phase difference according to an integration value obtained by this constant integration.

  The best mode 5 is a synchronous motor control device for energizing a plurality of armature coils provided in a stator and rotating a rotor having field poles, detecting a phase current energized in the armature coils, The current detection means that outputs a current detection signal according to the current and the magnitude of the maximum phase current having the maximum absolute value among the multiple phase currents are calculated using the current detection signal, and the maximum phase current Voltage characteristic calculation that calculates the voltage characteristic that indicates the characteristic of the voltage applied to the armature coil by using the current amount calculation means that sets the magnitude of the current as the current quantity that indicates the magnitude of the phase current, and the magnitude of the maximum phase current Means.

  The best mode 6 is a synchronous motor control device for energizing a plurality of armature coils provided in a stator and rotating a rotor having field poles, detecting a phase current energized in the armature coil, The current detection means for outputting a current detection signal corresponding to the current, and the maximum value of the absolute values of the phase currents of the plurality of phases in a predetermined cycle are calculated using the current detection signal, and predetermined in the next cycle of the predetermined cycle A voltage characteristic for calculating a voltage characteristic indicating a characteristic of an applied voltage to the armature coil by using a current amount calculation means that sets the maximum value in the cycle as a current amount indicating the magnitude of the phase current, and a maximum value in the predetermined cycle. And an arithmetic means.

  The best mode 7 is a control apparatus for a synchronous motor in which a plurality of armature coils provided in a stator are energized to rotate a rotor having field poles. An inverter that converts the phase current that is energized into the inverter, a current detection means that detects a bus current flowing through the bus of the inverter and outputs a current detection signal corresponding to the bus current, and a bus current measured using the current detection signal Voltage characteristic calculation that calculates the voltage characteristic indicating the characteristic of the voltage applied to the armature coil by using the current amount calculation means that sets the magnitude of the current as the current quantity indicating the magnitude of the phase current and the magnitude of the bus current Means.

  The control device according to the best mode 8 includes temperature detection means for detecting the temperature of the synchronous motor or the ambient temperature of the synchronous motor, and outputting a temperature detection signal corresponding to the temperature of the synchronous motor or the ambient temperature of the synchronous motor. The computing means corrects the amount of current using the temperature detection signal.

[Configuration of Example 1]
A configuration of the control device 1 according to the first embodiment will be described with reference to FIGS. 1 to 3.
The control device 1 is a device that drives and controls the synchronous motor 2. The synchronous motor 2 energizes an alternating current to a three-phase armature coil (not shown) of a U phase, a V phase, and a W phase provided in a stator (not shown), and field poles such as a permanent magnet (see FIG. A torque (not shown) is obtained by rotating a rotor (not shown).

  As shown in FIG. 1, the control device 1 includes a known current sensor 3 that detects an alternating current (hereinafter referred to as a phase current) that is passed through the armature coil, and converts electric power supplied from a power source into a phase current. And an electronic control unit (ECU) 5 that outputs a command signal for operating the inverter 4.

  The current sensor 3 is a current detection unit that detects phase currents of the U phase and the W phase and outputs current detection signals Iu and Iw corresponding to the phase currents.

  The inverter 4 has at least six switching elements. Each switching element changes an operation state according to a command signal output from the ECU 5. As a result, three-phase currents having different phases are supplied to the armature coil.

  The ECU 5 is a microcomputer having a well-known structure having a CPU, a storage device, an output device, and an input device. The ECU 5 calculates voltage characteristics indicating the characteristics of the voltage applied to the armature coil using the current detection signals Iu and Iw output from the current sensor 3, and based on the voltage characteristics, the inverter 5 The command signal output to 4 is synthesized.

  Further, the ECU 5 uses the current detection signals Iu and Iw to calculate a current amount indicating the magnitude of the phase current, a current amount calculator 7 as a current amount calculator, and the current amount to the armature coil. A voltage characteristic calculator 8 as voltage characteristic calculation means for calculating a voltage characteristic indicating the characteristics of the applied voltage, a pulse synthesizer 9 for synthesizing a pulsed command signal output to the inverter 4 based on the voltage characteristic, In response to a request from (not shown), a function of the speed calculator 10 for calculating the rotational speed ω of the rotor is provided.

As shown in FIG. 2, the current amount calculator 7 is a magnitude of a current vector obtained by converting three phase currents of U phase, V phase, and W phase onto two stationary axes orthogonal to each other. Iαβ is calculated as the amount of current. That is, assuming that two stationary axes orthogonal to each other are the α axis and the β axis, the magnitude of the α axis current is Iα, and the magnitude of the β axis current is Iβ, the magnitude of the current vector Iαβ is calculated by Equation 1. .

  The voltage characteristic calculator 8 is a position estimator 12 that calculates the rotational position θ using the current detection signals Iu and Iw, and voltage characteristic information storage means that stores voltage characteristic information indicating a correlation between the voltage characteristic and the current amount. Voltage characteristic information storage 13, voltage amplitude calculator for calculating amplitude (hereinafter referred to as voltage amplitude) VA of voltage applied to the armature coil using voltage characteristic information, current amount, rotational position θ and rotational speed ω 14. The function of the voltage phase calculator 15 for calculating the phase (hereinafter referred to as voltage phase) Vθ of the voltage applied to the armature coil using the voltage characteristic information, the current amount, the rotational position θ and the rotational speed ω. . As described above, the voltage characteristics of the first embodiment are the voltage amplitude VA and the voltage phase Vθ.

  The voltage characteristic information storage 13 includes, as voltage characteristic information, a voltage amplitude map (see FIG. 3A) showing a correlation between the voltage amplitude VA, the rotational speed ω, and the current vector magnitude Iαβ, the voltage phase Vθ and the rotational speed. A voltage phase map (see FIG. 3B) showing a correlation between ω and the current vector magnitude Iαβ is stored. The correlation shown in the voltage amplitude map and the voltage phase map is a correlation when the phase of the phase current (hereinafter referred to as current phase) is a predetermined value.

  The voltage amplitude calculator 14 calculates the voltage amplitude VA when the current phase is a predetermined value by applying the magnitude Iαβ and the rotation speed ω of the current vector to the voltage amplitude map. Then, the voltage amplitude calculator 14 corrects the voltage amplitude VA when the current phase is a predetermined value by the rotational position θ. As a result, the voltage amplitude VA corresponding to the actual current phase is calculated, and this voltage amplitude VA is used as the output value from the voltage amplitude calculator 14.

  The voltage phase calculator 15 calculates the voltage phase Vθ when the current phase is a predetermined value by applying the magnitude Iαβ and the rotation speed ω of the current vector to the voltage phase map. Then, the voltage phase calculator 15 corrects the voltage phase Vθ when the current phase is a predetermined value with the rotational position θ. Thus, the voltage phase Vθ corresponding to the actual current phase is calculated, and this voltage phase Vθ is used as the output value from the voltage phase calculator 15.

[Operation of Example 1]
The operation of the control device 1 according to the first embodiment will be described with reference to FIG.
First, the current sensor 3 detects U-phase and W-phase phase currents and outputs current detection signals Iu and Iw. The current detection signals Iu and Iw are input to the ECU 5 and used to calculate the current vector magnitude Iαβ in the current amount calculator 7 and the rotational position θ in the position estimator 12. Further, the speed calculator 10 calculates the rotational speed ω in response to a request from the host device.

  The magnitude Iαβ of the current vector is used for calculating the voltage amplitude VA in the voltage amplitude calculator 14 and the voltage phase Vθ in the voltage phase calculator 15 together with the rotational position θ and the rotational speed ω. That is, the voltage amplitude calculator 14 calculates the voltage amplitude VA by applying the magnitude Iαβ and the rotational speed ω of the current vector to the voltage amplitude map, and corrects the voltage amplitude VA at the rotational position θ. In addition, the voltage phase calculator 15 applies the magnitude Iαβ and the rotational speed ω of the current vector to the voltage phase map to calculate the voltage phase Vθ, and the voltage phase Vθ is corrected at the rotational position θ.

  Then, a command signal is synthesized by the pulse synthesizer 9 according to the corrected voltage amplitude VA and the corrected voltage phase Vθ, and is output to the inverter 4. And according to this command signal, each transistor of the inverter 4 changes an operating condition. As a result, each phase current is adjusted, and the synchronous motor 2 is optimally driven and controlled in accordance with a request from the host device.

[Effect of Example 1]
According to the control device 1 of the first embodiment, the current sensor 3 detects U-phase and W-phase phase currents and outputs current detection signals Iu and Iw corresponding to these phase currents. Then, the ECU 5 calculates the current vector magnitude Iαβ as the amount of current using the current detection signals Iu and Iw, and calculates the voltage amplitude VA and the voltage phase Vθ as voltage characteristics using the current vector magnitude Iαβ. calculate.
The magnitude Iαβ of the current vector is a function having only the phase current as a variable. According to the control device 1, U-phase and W-phase phase currents are directly detected by the current sensor 3. For this reason, when obtaining the magnitude Iαβ of the current vector that is the amount of current, it is not necessary to perform axis conversion using a trigonometric function of the rotational position θ. As a result, the calculation load of the control device 1 can be greatly reduced.

[Configuration of Example 2]
The configuration of the control device 1 according to the second embodiment will be described with reference to FIG. In addition, the same code | symbol is used for the part which is common in Example 1, and description is abbreviate | omitted.
The voltage characteristics of Example 2 are α-axis voltage Vα and β-axis voltage obtained by converting applied voltages applied to U-phase, V-phase, and W-phase armature coils onto two stationary axes that are orthogonal to each other. Vβ.

  That is, the voltage characteristic calculator 8 has functions as an α-axis voltage calculator 17 and a β-axis voltage calculator 18 instead of the voltage amplitude calculator 14 and the voltage phase calculator 15, and the voltage characteristic information storage 13 includes: As voltage characteristic information, an α-axis voltage map (not shown) showing a correlation between the α-axis voltage Vα and the rotational speed ω and the current vector magnitude Iαβ, the β-axis voltage Vβ, the rotational speed ω and the magnitude of the current vector Iαβ A β-axis voltage map (not shown) indicating the correlation with is stored.

[Operation of Example 2]
The operation of the control device 1 according to the second embodiment will be described with reference to FIG.
In the control device 1 of the second embodiment, the α-axis voltage calculator 17 applies the current vector magnitude Iαβ and the rotational speed ω to the α-axis voltage map to calculate the α-axis voltage Vα, and the α-axis voltage Vα. Is corrected at the rotational position θ. The β-axis voltage calculator 18 calculates the β-axis voltage Vβ by applying the current vector magnitude Iαβ and the rotational speed ω to the β-axis voltage map, and corrects the β-axis voltage Vβ with the rotational position θ. Is done. Then, a command signal is synthesized by the pulse synthesizer 9 according to the corrected α-axis voltage Vα and the corrected β-axis voltage Vβ, and is output to the inverter 4.

[Configuration of Example 3]
The configuration of the control device 1 according to the third embodiment will be described with reference to FIG. In addition, the same code | symbol is used for the part which is common in Example 1, and description is abbreviate | omitted.

  The position estimator 12 according to the third embodiment includes a phase difference calculator 20 that calculates a phase difference between the voltage phase Vθ and the current phase, and a phase difference information storage that stores phase difference information indicating a correlation between the phase difference and the current amount. 21. The target phase difference calculator 22 has a function of calculating a target phase difference using the current amount and the phase difference information. Then, the position estimator 12 calculates a difference ε between the phase difference calculated by the phase difference calculator 20 and the phase difference calculated by the target phase difference calculator 22.

  The phase difference calculator 20 is a phase difference calculator that calculates the phase difference between the voltage phase Vθ and the current phase using the current detection signals Iu and Iw. That is, the phase difference calculator 20 calculates the phase difference using the current detection signals Iu and Iw.

  The phase difference information storage 21 is phase difference information storage means for storing phase difference information. The phase difference information is a phase difference map indicating the correlation between the phase difference and the magnitude Iαβ of the current vector as the amount of current and the rotational speed ω, as shown in FIG.

  The target phase difference calculator 22 calculates the target phase difference by fitting the magnitude Iαβ and the rotation speed ω of the current vector to the phase difference map.

  The voltage amplitude calculator 14 calculates the voltage amplitude VA using the voltage characteristic information, the current vector magnitude Iαβ and the rotation speed ω, and further adjusts the voltage amplitude VA so that the difference ε becomes a predetermined value. The voltage phase calculator 15 calculates the voltage phase Vθ using the voltage characteristic information, the current vector magnitude Iαβ and the rotation speed ω, and further adjusts the voltage phase Vθ so that the difference ε becomes a predetermined value. Then, a command signal is synthesized and output based on the adjusted voltage amplitude VA and the adjusted voltage phase Vθ.

[Operation of Example 3]
The operation of the control device 1 according to the third embodiment will be described with reference to FIG.
In the position estimator 12 of the third embodiment, the phase difference calculator 20 calculates the phase difference using the current detection signals Iu and Iw. Further, the target phase difference calculator 22 calculates the target phase difference by applying the magnitude Iαβ and the rotational speed ω of the current vector to the phase difference map. The difference ε is calculated using the phase difference calculated by the phase difference calculator 20 and the phase difference calculated by the target phase difference calculator 22.

  Then, the voltage amplitude calculator 14 calculates the voltage amplitude VA using the voltage characteristic information, the current vector magnitude Iαβ and the rotation speed ω, and further adjusts the voltage amplitude VA so that the difference ε becomes a predetermined value. . The voltage phase calculator 15 calculates the voltage phase Vθ using the voltage characteristic information, the current vector magnitude Iαβ, and the rotation speed ω, and further adjusts the voltage phase Vθ so that the difference ε becomes a predetermined value. .

[Effect of Example 3]
In the control device 1 of the third embodiment, the position estimator 12 calculates the difference ε between the phase difference and the target phase difference, and adjusts the voltage amplitude VA and the voltage phase Vθ so that the difference ε becomes a predetermined value.
The phase difference and the voltage amplitude VA have a correlation as shown in FIG. 7A, and the phase difference and the voltage phase Vθ have a correlation as shown in FIG. 7B. Further, as shown in FIG. 7C, the motor efficiency becomes a maximum value when the phase difference is a value c. Therefore, by adjusting the voltage amplitude VA and the voltage phase Vθ so that the difference ε becomes a predetermined value, the synchronous motor 2 can be driven and controlled with high motor efficiency.

[Configuration of Example 4]
A configuration of the control device 1 according to the fourth embodiment will be described with reference to FIGS. 5 and 8. In addition, the part which is common in Example 3 uses the same code | symbol, and abbreviate | omits description.

  As shown in FIG. 8, the phase difference calculator 20 of the control device 1 according to the fourth embodiment uses, for example, a sine function (hereinafter referred to as a basic function) obtained by normalizing an applied voltage with its amplitude value or peak value as a phase current. The phase difference is calculated according to the integral value obtained by this definite integration. Here, the predetermined range of the phase current is, for example, a period from the zero crossing time ta when the phase current is inverted from a negative value to a positive value to the zero crossing time tb when the phase current is inverted from a positive value to a negative value. It is.

  According to this, as shown in FIG. 8A, when the range in which the basic function is a positive value and the range in which the phase current is a positive value match, the integral value of the basic function (basic function integral value) ) Is the maximum value S. If the phase difference when the basic function integration value reaches the maximum value S is 0 °, the basic function integration value is 0 when the phase difference is 90 ° (see FIG. 8C). When the phase difference is between 0 ° and 90 °, the basic function integral value is a positive value smaller than the maximum value S (see FIG. 8B).

[Operation of Example 4]
The operation of the control device 1 according to the fourth embodiment will be described with reference to FIGS. 5 and 8.
The phase difference calculator 20 according to the fourth embodiment determines, for example, whether the time t has passed the zero-crossing time ta and the zero-crossing time tb of the U-phase current using the current detection signal Iu. Then, the calculation of the basic function integral value is started when the zero crossing time ta elapses, and the calculation of the basic function integral value is terminated when the zero crossing time tb elapses. Then, the position estimator 12 calculates the difference ε using the phase difference corresponding to the calculated basic function integral value.

[Effect of Example 4]
The phase difference calculator 20 of the control device 1 according to the fourth embodiment performs constant integration of the basic function from the zero crossing time ta to the zero crossing time tb, and calculates a phase difference according to the basic function integration value obtained by the definite integration.
The magnitude of the phase current at zero and ta at zero crossing is zero. As a result, the detection of the phase current at the time of zero crossing ta and tb is not affected by noise mixing, gain error, or the like. For this reason, the basic function integral value is accurately calculated without being affected by noise mixing, gain error, and the like with respect to the detection of the phase current. As a result, the phase difference can be accurately calculated using the current detection signal.

  In the control device 1 of the fifth embodiment, the current amount calculator 7 shown in FIG. 1 has a maximum phase current magnitude (hereinafter simply referred to as the absolute value) among the U-phase, V-phase, and W-phase phase currents. Imax) (referred to as the maximum phase current) is calculated using the current detection signals Iu and Iw. Then, instead of the magnitude Iαβ of the current vector, the maximum phase current Imax is set as the current amount. That is, as shown in FIG. 9, the magnitude of the phase current having the maximum absolute value among the U-phase, V-phase, and W-phase phase currents at the same time is defined as the maximum phase current Imax. The voltage amplitude calculator 14 calculates the voltage amplitude VA using the maximum phase current Imax, and the voltage phase calculator 15 calculates the voltage phase Vθ using the maximum phase current Imax.

  According to the control device 1 of the fifth embodiment, the maximum phase current Imax can be calculated using only the phase current as a variable. For this reason, when obtaining the maximum phase current Imax as a current amount, it is not necessary to perform axis conversion using a trigonometric function of the rotational position θ. As a result, the calculation load of the control device 1 can be greatly reduced.

  In the control device 1 of the sixth embodiment, the current amount calculator 7 shown in FIG. 1 determines the maximum value ipeak of the absolute values of the U-phase, V-phase, and W-phase phase currents in the period of 60 electrical angles as the current detection signal Iu. , Iw is used for calculation. Then, instead of the magnitude Iαβ of the current vector, the maximum value ipeak is used as the amount of current. Specifically, as shown in FIG. 10, the maximum value peak in a predetermined 60 ° cycle is set as a current amount in the next 60 ° cycle. That is, the voltage amplitude calculator 14 calculates the voltage amplitude VA using the maximum value peak in the 60 ° period before the current 60 ° period, and the voltage phase calculator 15 calculates the 60 ° period before the current 60 ° period. The voltage phase Vθ is calculated using the maximum value ipeak at.

  According to the control device 1 of the sixth embodiment, the maximum value ipeak in the 60 ° cycle can be calculated using only the phase current as a variable. For this reason, it is not necessary to perform axis conversion using a trigonometric function of the rotational position θ when obtaining the maximum value peak as a current amount in a 60 ° cycle. As a result, the calculation load of the control device 1 can be greatly reduced.

  As shown in FIG. 11, the control device 1 according to the seventh embodiment includes a shunt resistor 24 that detects a bus current flowing through the bus of the inverter 4 and outputs a current detection signal Im corresponding to the bus current as current detection means. . Note that the inverter 4 includes six switching elements 23. Then, the current amount calculator 7 measures the bus current using the current detection signal Im, and sets the magnitude of the bus current as the current amount. The voltage characteristic calculator 8 calculates the voltage amplitude VA and the voltage phase Vθ using the magnitude of the bus current.

  According to the control device 1 of the seventh embodiment, the magnitude of the bus current can be directly calculated using only the current detection signal Im. For this reason, it is not necessary to perform axis conversion using a trigonometric function of the rotational position θ when determining the magnitude of the bus current as the amount of current. As a result, the calculation load of the control device 1 can be greatly reduced.

  As shown in FIG. 12, the control device 1 according to the eighth embodiment includes a temperature sensor 26 as a temperature detection unit that detects the temperature of the synchronous motor 2 and outputs a temperature detection signal corresponding to the temperature of the synchronous motor 2. The current amount calculator 7 corrects the current amount using the temperature detection signal.

  The magnetic flux generated by the field pole decreases as the temperature of the synchronous motor 2 increases as shown in FIG. For this reason, the magnitude of the phase current varies according to the temperature of the synchronous motor 2 even if the rotational speed ω, voltage characteristics, and the like are the same. For example, as shown in FIG. 13B, the amplitude of the phase current increases in accordance with the increase in the temperature of the synchronous motor 2 even if the rotational speed ω, voltage characteristics, and the like are the same.

  Therefore, by correcting the amount of current using the temperature detection signal, the influence of the temperature of the synchronous motor 2 on the amount of current can be reduced. For example, the influence of the temperature of the synchronous motor 2 on the amount of current can be reduced by multiplying the amount of current by a correction coefficient (see FIG. 13C) that decreases as the temperature of the synchronous motor 2 increases. As a result, as shown in FIG. 13D, if the rotational speed ω and voltage characteristics are the same, the amplitude of the phase current can be kept constant even if the temperature of the synchronous motor 2 rises.

[Modification]
The voltage characteristic information of the embodiment is stored as a map such as a voltage amplitude map, but may be stored as table data or a mathematical expression.
The control device 1 of Example 5 and Example 6 obtains the maximum phase current Imax or the maximum value ipeak by detecting the U-phase and W-phase two-phase currents, but detects only the single-phase phase current. By doing so, the maximum phase current Imax or the maximum value ipeak can be obtained.
The control device 1 according to the eighth embodiment is configured such that the temperature sensor 26 detects the temperature of the synchronous motor 2, but may be configured to detect the ambient temperature of the synchronous motor 2.

1 is a configuration diagram of a control device (Example 1). FIG. (Example 1) which is the explanatory view which shows conversion to the alpha beta axis of U phase, V phase and W phase. (A) is a voltage amplitude map, (b) is a voltage phase map (Example 1). (Example 2) which is a block diagram of a control apparatus. It is a block diagram of a control apparatus (Example 3, Example 4). (Example 3) which is a phase difference map which shows the correlation with a phase difference, the magnitude | size of a current vector, and a rotational speed. (A) is a correlation diagram between voltage amplitude and phase difference, (b) is a correlation diagram between voltage phase and phase difference, and (c) is a correlation diagram between phase difference and motor efficiency. (Example 3). (A) is explanatory drawing which shows the relationship between a phase current when a phase difference is 0 degree, and a basic function, (b) is a phase when a phase difference is between 0 degree and 90 degrees. (C) is explanatory drawing which shows the relationship between a phase current when a phase difference is 90 degrees, and a basic function (Example 4). (Example 5) which is a trend figure which shows transition of a phase current and electric current amount. (Example 6) which is a trend figure which shows transition of a phase current and electric current amount. (Example 7) which is a principal part block diagram of a control apparatus. (Example 8) which is a principal part block diagram of a control apparatus. (A) is a correlation diagram between the temperature and magnetic flux of the synchronous motor, (b) is a correlation diagram between the temperature of the synchronous motor and the amplitude of the phase current when the amount of current is not corrected, and (c) FIG. 10 is a correlation diagram between the temperature of the synchronous motor and the correction coefficient, and FIG. 8D is a correlation diagram between the temperature of the synchronous motor and the correction coefficient when correcting the current amount (Embodiment 8).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control apparatus 2 Synchronous motor 3 Current sensor (current detection means)
4 Inverter 5 ECU (current amount calculation means, voltage characteristic calculation means, voltage characteristic information storage means, phase difference calculation means, phase difference information storage means)
7 Current amount calculator (Current amount calculation means)
8 Voltage characteristics calculator (Voltage characteristics calculator)
13 Voltage characteristic information storage (voltage characteristic information storage means)
20 Phase difference calculator (phase difference calculation means)
21 Phase difference information storage (phase difference information storage means)
24 Shunt resistance (current detection means)
26 Temperature sensor (temperature detection means)
Iu, Iw, Im Current detection signal Iαβ Size of current vector (current amount)
VA Voltage amplitude (applied voltage amplitude, voltage characteristics)
Vθ voltage phase (phase of applied voltage, voltage characteristics)
Vα α-axis voltage (voltage characteristics)
Vβ β-axis voltage (voltage characteristics)
ε Difference Imax Maximum phase current (maximum phase current magnitude, current amount)
ipeak maximum value (current amount)

Claims (10)

In a control device for a synchronous motor that energizes a plurality of armature coils provided in a stator and rotates a rotor having a field pole,
Current detection means for detecting a phase current energized in the armature coil and outputting a current detection signal corresponding to the phase current;
The magnitude of the current vector obtained by converting the phase current onto two stationary axes orthogonal to each other is calculated using the current detection signal, and the magnitude of the current vector is calculated as the magnitude of the phase current. A current amount calculation means for setting the current amount to indicate
A control apparatus for a synchronous motor, comprising: voltage characteristic calculation means for calculating a voltage characteristic indicating a characteristic of a voltage applied to the armature coil using the magnitude of the current vector. In a control device for a synchronous motor that energizes a plurality of armature coils provided in a stator and rotates a rotor having a field pole,
Current detection means for detecting a phase current energized in the armature coil and outputting a current detection signal corresponding to the phase current;
The magnitude of the maximum phase current having the maximum absolute value among the phase currents of a plurality of phases is calculated using the current detection signal, and the magnitude of the maximum phase current is a current indicating the magnitude of the phase current. Current amount calculation means to be a quantity,
A control apparatus for a synchronous motor, comprising: voltage characteristic calculation means for calculating a voltage characteristic indicating a characteristic of a voltage applied to the armature coil using the magnitude of the maximum phase current. In a control device for a synchronous motor that energizes a plurality of armature coils provided in a stator and rotates a rotor having a field pole,
Current detection means for detecting a phase current energized in the armature coil and outputting a current detection signal corresponding to the phase current;
The maximum value of the absolute values of the phase currents of a plurality of phases in a predetermined cycle is calculated using the current detection signal, and the maximum value in the predetermined cycle is calculated as the magnitude of the phase current in the next cycle of the predetermined cycle. A current amount calculation means for setting the current amount to indicate
A control apparatus for a synchronous motor, comprising: voltage characteristic calculation means for calculating a voltage characteristic indicating a characteristic of a voltage applied to the armature coil using a maximum value in the predetermined period. In a control device for a synchronous motor that energizes a plurality of armature coils provided in a stator and rotates a rotor having a field pole,
An inverter that converts electric power supplied from a power source into a phase current that is passed through the armature coil;
Current detection means for detecting a bus current flowing in the bus of the inverter and outputting a current detection signal corresponding to the bus current;
A current amount calculation means for setting the magnitude of the bus current measured using the current detection signal as a current quantity indicating the magnitude of the phase current;
A control apparatus for a synchronous motor, comprising: voltage characteristic calculation means for calculating a voltage characteristic indicating a characteristic of a voltage applied to the armature coil using the magnitude of the bus current. In the synchronous motor control device according to any one of claims 1 to 4,
The voltage characteristic calculation means includes voltage characteristic information storage means for storing voltage characteristic information indicating a correlation between the voltage characteristic and the current amount, and the voltage characteristic is calculated using the current amount and the voltage characteristic information. A control apparatus for a synchronous motor, characterized in that the calculation is performed. In the synchronous motor control device according to claim 5,
The synchronous motor control device, wherein the voltage characteristics are an amplitude of the applied voltage and a phase of the applied voltage. In the synchronous motor control device according to claim 5,
The synchronous motor characterized in that the voltage characteristics are an α-axis voltage and a β-axis voltage obtained by converting applied voltages applied to the armature coils of the plurality of phases onto two stationary axes orthogonal to each other. Control device. In the synchronous motor control device according to any one of claims 1 to 4,
The voltage characteristic calculation means includes phase difference calculation means for calculating a phase difference between the applied voltage and the phase current using the current detection signal, and phase difference information indicating a correlation between the phase difference and the current amount. A phase difference information storage means for storing, so that a difference between the phase difference calculated by the phase difference calculation means and the phase difference calculated using the current amount and the phase difference information becomes a predetermined value. A control apparatus for a synchronous motor, characterized by adjusting a voltage characteristic. In the synchronous motor control device according to claim 8,
The phase difference calculation means performs a constant integration of a predetermined sine function in a period corresponding to a predetermined range of the phase current, and calculates the phase difference according to an integral value obtained by the constant integration. Control device for synchronous motor. In the synchronous motor control device according to any one of claims 1 to 4,
Temperature detecting means for detecting the temperature of the synchronous motor or the ambient temperature of the synchronous motor and outputting a temperature detection signal corresponding to the temperature of the synchronous motor or the ambient temperature of the synchronous motor;
The control device for a synchronous motor, wherein the current amount calculation means corrects the current amount using the temperature detection signal.

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