JP5999416B2 - Control device for synchronous motor - Google Patents

Description

  The present invention relates to a control apparatus for a synchronous motor that improves the efficiency by correcting a magnetic pole position error during operation of the synchronous motor.

  The synchronous motor detects a magnetic pole position of 0 ° by direct current excitation, and then controls torque based on the detected magnetic pole position of 0 °. However, according to such a magnetic pole position detection method, an error may occur between the magnetic pole position detection value and the true magnetic pole position due to static friction of the bearing portion or the like.

On the other hand, Patent Document 1 discloses a conventional technique for detecting a magnetic pole position error of a permanent magnet synchronous motor and correcting the error to improve torque control accuracy.
FIG. 5 is a configuration diagram of the magnetic pole position error correction circuit described in Patent Document 1. In FIG.
In FIG. 5, 1 is a DC power source, 2 is an inverter, 3 is a synchronous motor, 4 is a speed detector, 5 is a magnetic pole position detector, 6 is a voltage detector, and 7 is a current detector.
In the control circuit for correcting the magnetic pole position error, 8, multiplier for calculating a DC input power P _DC by multiplying the DC current detection value and the DC voltage detection value, 9, and the speed detection value N multiplier for obtaining the mechanical output P _m by multiplying the torque command value T ^*, 10 is the magnetic pole position error when the error power ΔP between the DC input power P _DC and mechanical output P _m is greater than or equal to the specified value It is a window comparator that outputs a notification signal indicating occurrence. Further, 11 is a correction amount calculation means for calculating and outputting a correction amount Δθ _f of a predetermined polarity according to the speed of the synchronous motor 3 and the magnitude of the error power ΔP, 12 is a switch that is turned on by the notification signal, 13 Is an adder for adding the magnetic pole position detection value θ _f and the correction amount Δθ _f to obtain the corrected magnetic pole position θ _f ′.

In this prior art, when the error power ΔP is positive to reduce the magnetic pole position detection value theta _f, when the error power ΔP is negative correction is performed so as to increase the magnetic pole position detection value theta _f, results The torque of the synchronous motor 3 is controlled so that the error power ΔP becomes smaller. Thereby, the torque control accuracy is improved while correcting the magnetic pole position error of the synchronous motor 3.

JP-A-8-308292 (paragraphs [0017] to [0021], FIG. 3, FIG. 4 etc.)

In Patent Document 1, as a method of setting the correction amount Δθ _f, a constant value is set regardless of the absolute value of the error power ΔP, or it is proportional to the absolute value of the error power ΔP, or time integration of the absolute value of the error power ΔP. A method of making it proportional to a value is disclosed. However, this prior art focuses on the error power ΔP, detects the occurrence of magnetic pole position deviation, corrects the magnetic pole position error, and improves the torque control accuracy. For example, pay attention to the efficiency of the synchronous motor. Thus, specific means for correcting the magnetic pole position in real time during the rated operation of the synchronous motor is not disclosed.
Accordingly, an object of the present invention is to provide a control device that can correct a magnetic pole position error during operation for the purpose of maximizing the efficiency of a synchronous motor.

In order to solve the above problem, the invention according to claim 1
Position detecting means for detecting the magnetic pole position of the synchronous motor driven by the power converter;
Calculation means for obtaining the rotational speed of the synchronous motor from the magnetic pole position detection value by the position detection means,
Torque command means for generating a torque command so that the rotation speed detection value by the calculation means matches the rotation speed command;
Control means for generating a drive signal for the semiconductor switching element of the power converter based on the magnetic pole position detection value, the rotation speed detection value, the torque command, and the output current of the power converter. In the motor control device,
Efficiency calculating means for obtaining efficiency from input power and output power of the synchronous motor;
An initial value correction calculating means for calculating a first correction value that is inputted with a correction start command and is added to a preset magnetic pole position initial value;
Correction means for obtaining the second correction value by adding to the initial value of the magnetic pole position while increasing or decreasing the first correction value, and correcting the detected magnetic pole position value by adding the second correction value to the detected magnetic pole position value And comprising
The torque command means detects that the synchronous motor is in an operating state at a rated rotational speed and a rated torque, outputs the correction start command, and uses the magnetic pole position detection value corrected by the correction means. The efficiency when the synchronous motor is operated is sequentially calculated by the efficiency calculation means, and the magnetic pole position detection value is corrected using the second correction value when the efficiency reaches the maximum value.

  According to the present invention, it is possible to improve efficiency while operating a synchronous motor by correcting the magnetic pole position detection value using a correction value that maximizes the efficiency calculated sequentially during the operation of the synchronous motor. .

It is a block diagram which shows embodiment of this invention. It is a characteristic view which shows operation | movement of embodiment of this invention. It is a characteristic view which shows operation | movement of embodiment of this invention. It is a characteristic view which shows operation | movement of embodiment of this invention. It is a block diagram of the prior art described in patent document 1. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a control device according to this embodiment together with a main circuit. In the main circuit shown in FIG. 1, as in FIG. 5, 1 is a DC power source, 2 is an inverter, 3 is a synchronous motor, 5 is a magnetic pole position detector such as a resolver, 6 is a voltage detector, 7 is a current detector, Reference numeral 20 denotes a load driven by the synchronous motor 3. In this embodiment, a current detector 8 for detecting the output current I of the inverter 2 is provided.

In the control device 100, first, the voltage detection value V _in and the current detection value I _in are multiplied by the multiplying means 101 to calculate the input power P _in .
The output of the magnetic pole position detector 5 are input to the position detection unit 102, the magnetic pole position theta ₀ is detected. This magnetic pole position detection value θ ₀ is added to a later-described second correction value θ ₁₂ in the adding means 103 and inputted to the differentiating means 104 as a corrected magnetic pole position detection value θ ₂ . In the differentiating means 104, the speed detection value ω is calculated by differentiating the magnetic pole position detection value theta _2.

Reference numeral 105 denotes torque command means to which an operation command is input. The torque command means 105 calculates a torque command T ^* so that the detected speed value ω matches the rotational speed command ω ^* .
The torque command T ^* , the output current detection value I of the inverter 2, the magnetic pole position detection value θ _2, and the speed detection value ω are input to the inverter control means 106, and based on these, a drive signal ( Gate signal) is generated.
The torque command T ^* and the speed detection value ω are multiplied by the multiplication means 107, and the output power P _out of the synchronous motor 3 is calculated. This output power P _out is input to the efficiency calculating means 108 together with the input power P _in , and the efficiency η of the synchronous motor 3 is calculated by calculating P _out / P _in .

When performing magnetic pole position correction, the torque command means 105 confirms that the synchronous motor 3 has entered a specific operation state based on the operation command, the rotation speed command ω ^* , the rotation speed detection value ω, and the torque command T ^*. Detect and output correction start command. Here, the specific operation state is, for example, a rated operation state of the synchronous motor 3.

Initial value correction operation section 109, when the correction start command is input, it calculates a first correction value theta ₁₁ for correcting the initial value theta ₁ of the magnetic pole position. The first correction value theta ₁₁ is added to the initial value theta ₁ specific small amount Δθ units, thereby changing the second correction value theta ₁₂ in the positive or negative direction.
That is, the first correction value θ ₁₁ is added to the initial value θ ₁ by the adding unit 110, and the second correction value θ _{12 as} the addition result is input to the adding unit 103. As described above, by being added to the magnetic pole position detection value theta ₀ in the second correction value theta ₁₂ is adding means 103, so that the magnetic pole position detection value theta ₀ is corrected to theta _2.

Next, the operation of this embodiment will be further described with reference to FIGS.
When the torque command unit 105 detects the rated operation state of the synchronous motor 3, a correction start command is input to the initial value correction calculation unit 109. In the initial value correction computing means 109, as shown in FIG. 2, the first correction value theta ₁₁ to zero, storing the efficiency eta at that time as eta _0. In this state, the output of the adding means 110 in FIG. 1, that is, the second correction value θ ₁₂ is equal to the initial value θ ₁ .

Then, the initial value correction operation section 109, sequentially increases the first correction value theta ₁₁ a small amount Δθ units, the second correction value theta ₁₂ in the positive direction which is the output of the summing means 110 (in FIG. 2 arrow (1 ) Direction). Then, the operation is continued using the magnetic pole position detection value θ ₂ corrected by adding the second correction value θ ₁₂ to the magnetic pole position detection value θ ₀ by the adding means 103, and the efficiency η is peak-held each time. In the process of increasing the first correction value θ ₁₁ (in other words, the second correction value θ ₁₂ ), the maximum value of the efficiency η is stored.
This operation is the (larger) improves efficiency eta than the previous Δθ addition continues as long as, in each case the second correction value theta ₁₂ and efficiency eta, and stored.

Further, when the first correction value theta ₁₁ efficiency η than the previous Δθ added in the allowed to continue the process increase is degraded (If smaller), sequentially reducing the first correction value theta ₁₁ and Δθ units, addition means 110 is an output of the second correction value theta ₁₂ in the negative direction is varied (arrow in FIG. 3 (2) direction).
In this state, the operation is continued using the magnetic pole position detection value θ ₂ obtained by adding the second correction value θ ₁₂ to the magnetic pole position detection value θ ₀ in the same manner as described above, and the efficiency η is peak-held each time. Accordingly, storing a second correction value theta ₁₂ and efficiency η in the process of decreasing the second correction value theta _12.

By repeating the above operation, the first correction value theta ₁₁ thus second correction value theta ₁₂ when efficiency eta _max is the maximum value is determined as shown in FIG. 4, the magnetic poles of the second correction value theta ₁₂ By continuing operation using the magnetic pole position detection value θ ₂ corrected by adding to the position detection value θ ₀ , the efficiency can be improved while correcting the magnetic pole position to an appropriate value during the operation of the synchronous motor 3. it can.

1: DC power supply 2: Inverter 3: Synchronous motor 5: Magnetic pole position detector 6: Voltage detector 7, 8: Current detector 20: Load 100: Control device 101, 107: Multiplication means 102: Position detection means 103, 110 : Addition means 104: differentiation means 105: torque command means 106: inverter control means 108: efficiency calculation means 109: initial value correction calculation means

Claims (1)

Position detecting means for detecting the magnetic pole position of the synchronous motor driven by the power converter;
Calculation means for obtaining the rotational speed of the synchronous motor from the magnetic pole position detection value by the position detection means,
Torque command means for generating a torque command so that the rotation speed detection value by the calculation means matches the rotation speed command;
Control means for generating a drive signal for the semiconductor switching element of the power converter based on the magnetic pole position detection value, the rotation speed detection value, the torque command, and the output current of the power converter. In the motor control device,
Efficiency calculating means for obtaining efficiency from input power and output power of the synchronous motor;
An initial value correction calculating means for calculating a first correction value that is inputted with a correction start command and is added to a preset magnetic pole position initial value;
Correction means for obtaining the second correction value by adding to the initial value of the magnetic pole position while increasing or decreasing the first correction value, and correcting the detected magnetic pole position value by adding the second correction value to the detected magnetic pole position value When,
With
The torque command means detects that the synchronous motor is in an operating state at a rated rotational speed and a rated torque, outputs the correction start command, and uses the magnetic pole position detection value corrected by the correction means. The efficiency when the synchronous motor is operated is sequentially calculated by the efficiency calculation means, and the magnetic pole position detection value is corrected using the second correction value when the efficiency reaches a maximum value. Electric motor control device.

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