Motor control device and motor control method

Abstract

To provide a motor controller capable of simply and highly accurately identifying a motor constant and a control gain required for vector control based on a motor current.SOLUTION: When a first motor driving signal VSP is inputted after a control power source VCC is inputted, the identifying operation of a motor constant and a control gain is executed. As the identification operation, a first step of identifying the armature winding resistance "Ra", the d-axis inductance "Ld", and the q-axis inductance "Lq", a second step of calculating the current PI control gain and the Ke estimation gain (counter electromotive force estimation gain) using the identification result of the first step, a third step of calculating the counter electromotive force constant "Ke" using the identification results of the first step and the second step, and a fourth step of identifying the speed PI control gain and the θ e estimation gain (rotor position estimation gain) using the identification result of the first step are sequentially executed.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] An embodiment of the present disclosure relates to a motor device and a motor control method for digitally controlling a brushless DC motor. [Background technology]

[0002] A method for automatically measuring motor constants while the motor is stationary has been disclosed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-164188 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional technology, it is necessary to construct a motor control device using expensive current sensors and microcomputers in order to identify the motor constants and control gains.

[0005] The present disclosure aims to provide a motor control device and a motor control method that can easily and accurately identify motor constants and control gains required for vector control based on motor current. [Means for solving the problem]

[0006] The motor control device disclosed herein controls a brushless DC motor using vector control based on detected motor current, and includes an identification unit that performs identification operations for motor constants and control gains when the first motor drive signal is input after control power is turned on.The identification operations of the identification unit sequentially include a first step of identifying the armature winding resistance, d-axis inductance, and q-axis inductance, a second step of calculating a current PI control gain and a back EMF constant estimation gain using the identification results of the first step, a third step of calculating a back EMF constant using the identification results of the first and second steps, and a fourth step of identifying the speed PI control gain and rotor position estimation gain using the identification results of the first step. [Effects of the Invention]

[0007] The motor control device and motor control method disclosed herein can easily and accurately identify the motor constants and control gains required for vector control based on the motor current. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a configuration of an embodiment of a motor control device. [Figure 2] FIG. 2 is a diagram illustrating a configuration of a control circuit shown in FIG. [Figure 3] FIG. 10 is a diagram illustrating the execution timing of the identification operation. [Figure 4] FIG. 10 is a diagram showing the steps of an identification operation. [Figure 5] FIG. 10 is a diagram showing a motor current during an identification operation. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings.

[0010] 1, a motor control device 10 of this embodiment is a device that controls the driving of a brushless DC motor 2. The motor control device 10 operates when a control power supply VCC is turned on, and drives the brushless DC motor 2 at a speed corresponding to a motor drive signal VSP.

[0011] Motor control device 10 includes inverter 11, gate drive circuit 12, current detection amplifier 13, control circuit regulator 14, and control circuit 20. Part or all of motor control device 10 can be configured as a control IC, which is a semiconductor device integrated on a substrate.

[0012] The inverter 11 is a three-phase inverter including a plurality of switching elements such as IGBTs. The inverter 11 includes three-phase (U-phase, V-phase, and W-phase) series circuits each including a high-side switching element and a low-side switching element. The inverter 11 is driven and controlled by a drive signal from a gate drive circuit 12, and converts the DC voltage VDD of the DC power supply 3 into a three-phase AC voltage of a predetermined frequency and voltage and outputs it to the brushless DC motor 2.

[0013] The gate drive circuit 12 outputs drive signals for driving the switching elements of the inverter 11 based on three-phase PWM (Pulse Width Modulation) signals supplied from the control circuit 20.

[0014] The current detection amplifier 13 includes shunt resistors R connected in series to the U, V, and W phases. U , R V , R W Together with this, they form a current detection circuit, and detect the motor current i u , i v , i w Detect.

[0015] The control circuit 20 generates three-phase PWM signals by calculating voltage command signals to be applied to the brushless DC motor 2 using dq vector control, and outputs the PWM signals to the gate drive circuit 12. The control circuit 20 is an information processing device such as a microcomputer that operates under program control.

[0016] Referring to the functional blocks shown in FIG. 2 , the control circuit 20 includes a three-phase two-axis conversion unit 21, a rotor position / speed estimation unit 22, a speed PI control unit 23, a current PI control unit 24, a decoupling control unit 25, a calculation unit 26, a two-axis three-phase conversion unit 27, a PWM conversion unit 28, and a motor constant / control gain identification unit 29.

[0017] The three-phase two-axis conversion unit 21 converts a three-phase AC coordinate system (U-phase, V-phase, W-phase) into an orthogonal two-axis DC coordinate system (d-axis, q-axis). By performing the coordinate conversion process, the three-phase two-axis conversion unit 21 converts the motor currents i of the U-phase, V-phase, and W-phase input from the current detection amplifier 13 into u , i v , i w The d-axis current i d and q-axis current i q The three-phase two-axis conversion unit 21 converts the calculated d-axis current i d and q-axis current i q to the rotor position / speed estimation unit 22, the speed PI control unit 23 and the decoupling control unit 25.

[0018] The rotor position / speed estimation unit 22 converts the d-axis current i calculated by the three-phase two-axis conversion unit 21 into d and q-axis current i q Based on the rotor position θ e and actual speed ω e The rotor position / speed estimation unit 22 estimates the estimated rotor position θ e is output to the three-phase two-axis conversion unit 21, and the estimated actual speed ω e is output to the speed PI control unit 23 and the decoupling control unit 25.

[0019] The speed PI control unit 23 calculates a speed command value ω e * and the actual speed ω eThe d-axis current command value i d * and q-axis current command value i q * and outputs it to the current PI control unit 24.

[0020] The current PI control unit 24 calculates the d-axis current command value i d * and q-axis current command value i q * and the d-axis current i d and q-axis current i q The d-axis voltage V d and q-axis voltage V q and outputs it to the calculation unit 26.

[0021] The non-interference control unit 25 controls the speed ω e , d-axis current i d , q-axis current i q is input, the decoupling voltage required to cancel out the interference voltage between the d-axis and q-axis is calculated, and output to the calculation unit 26.

[0022] The calculation unit 26 calculates the d-axis voltage V d and q-axis voltage V q The decoupling voltage calculated by the decoupling control unit 25 is added to (cancelled out) the output voltage, and the result is input to the two-axis three-phase conversion unit 27.

[0023] The two-axis three-phase conversion unit 27 converts the orthogonal two-axis DC coordinate system (d-axis, q-axis) into a three-phase AC coordinate system (U-phase, V-phase, W-phase). By performing the coordinate conversion process, the two-axis three-phase conversion unit 27 converts the d-axis voltage V d and q-axis voltage V q is the phase voltage V u , V v , V w Convert to.

[0024] The PWM converter 28 converts the phase voltage V u , V v , V wBy comparing this with a carrier wave (triangular wave, sawtooth wave, etc.), a PWM signal with a specified duty ratio is generated.

[0025] 3, when the control power supply VCC is turned on (step S101) and the first motor drive signal VSP is turned on (step S102), the motor constant and control gain identifying unit 29 executes an operation to identify the motor constant and control gain (step S103). The motor constant and control gain identifying unit 29 sets the motor constant and control gain identified in step S103 as control parameters for the rotor position / speed estimating unit 22, the speed PI control unit 23, the current PI control unit 24, and the decoupling control unit 25.

[0026] As a result, sensorless vector control of the brushless DC motor 2 is appropriately performed using the motor constants and control gains identified in step S103, and motor driving begins (step S104).

[0027] Even if the motor drive signal VSP is turned off (step S105), as long as the control power supply VCC remains on, the state in which the motor constants and control gains identified in step S103 are substituted is maintained. Therefore, when the motor drive signal VSP is turned on again (step S106), the process proceeds to step S104, and motor drive begins.

[0028] When the control power supply VCC is turned off (step S105), the control parameters of the rotor position / speed estimation unit 22, the speed PI control unit 23, the current PI control unit 24 and the non-interference control unit 25 are initialized (the motor constants and control gains identified in step S103 are erased), and the operation is restarted from step S101.

[0029] The digital control of the control circuit 20 performs sensorless vector control that combines rotor position estimation and vector control algorithms. The control parameters required to realize the rotor position estimation and vector control algorithms are determined based on the motor constants.

[0030] The motor constant / control gain identification unit 29 identifies the armature winding resistance "Ra", the d-axis inductance "Ld", the q-axis inductance "Lq", and the back electromotive force constant "Ke" as motor constants. In the rotor position estimation algorithm of the rotor position / speed estimation unit 22, the position estimation observer uses "Ra", "Ld", and "Lq", and the back electromotive force estimation observer uses "Ra", "Ld", "Lq", and "Ke". In addition, in the vector control algorithm, the current PI control unit 24 uses "Ld", "Lq", and "Ra", the speed PI control unit 23 uses "Ke" and "Lq", and the decoupling control unit 25 uses "Ra", "Ld", "Lq", and "Ke", respectively.

[0031] The motor constant and control gain identification unit 29 determines, as control gains, the current PI control gain in the current PI control unit 24, the speed PI control gain in the speed PI control unit 23, the Ke estimation gain and θ e The estimated gain is identified.

[0032] The motor constant and control gain identification unit 29 identifies the motor constant and control gain by sequentially executing the first to fourth steps as shown in Fig. 4 and Fig. 5. Fig. 5 shows the timing of execution of the identification of the motor constant and control gain and the motor current i u , i v , i w This shows the relationship between

[0033] In the first step, of the motor constants to be identified, "Ra", "Ld", and "Lq" are measured in sequence.

[0034] "Ra" is measured by turning on the high-side switching element of one of the three phases (for example, U phase) and the low-side switching elements of the other two phases (for example, V phase and W phase). u , i v , i w Detects the motor current i u If is I, the motor current i v , i wis -I / 2. "Ra" is calculated using the measured I and VDD by (2 / 3) × VDD / I.

[0035] To measure "Ld," the high-side switching element of one of the three phases (for example, the U phase) and the low-side switching elements of the other two phases (for example, the V phase and the W phase) are turned on, and the time constant t is measured. "Ld" is calculated by multiplying the measured t and "Ra" by t x "Ra."

[0036] To measure "Lq", apply an AC voltage of frequency f to two of the three phases (for example, V phase and W phase) and measure the applied voltage V v and the motor current i v The amplitude and phase difference θ of the detected V v , i v , θ and the known value of f, (V v ×sinθ) / (i v × 2πf).

[0037] In the second step, the current PI control gain and the Ke estimation gain are set. The current PI control gain and the Ke estimation gain are calculated based on the values ​​of "Ra," "Ld," and "Lq" identified in the first step.

[0038] The third step is to estimate "Ke" among the motor constants to be identified. The current and voltage values ​​are detected when the brushless DC motor 2 is rotated at a constant speed ω under open-loop control. "Ke" is calculated by using the detected current and voltage values, calculated values, and known values ​​to calculate the back electromotive force e q Estimate and e q Calculated by / ω.

[0039] In the fourth step, the speed PI control gain and the θe estimation gain are set. The speed PI control gain and the θe estimation gain are calculated based on the values ​​of "Ra," "Ld," and "Lq" identified in the first step.

[0040] As described above, in this embodiment, the detected motor current i u , iv , i w The motor control device 10 controls a brushless DC motor 2 by vector control based on the above, and includes a motor constant and control gain identification unit 29 (identification unit) that performs an identification operation of the motor constants and control gains when the first motor drive signal VSP is input after the control power supply VCC is turned on. The motor constant and control gain identification unit 29 sequentially performs the following identification operations as its identification operation: a first step of identifying an armature winding resistance "Ra", a d-axis inductance "Ld", and a q-axis inductance "Lq", a second step of calculating a current PI control gain and a Ke estimation gain (back electromotive force estimation gain) using the identification results of the first step, a third step of calculating a back electromotive force constant "Ke" using the identification results of the first and second steps, and a fourth step of identifying a speed PI control gain and a θe estimation gain (rotor position estimation gain) using the identification result of the first step. This configuration allows the motor current i u , i v , i w The motor constants and control gains required for vector control based on the eigenvalue can be easily and accurately identified.

[0041] Furthermore, according to this embodiment, the motor constant and control gain identified by motor constant / control gain identifying unit 29 are maintained even if motor drive signal VSP is turned off as long as control power supply VCC continues to be applied, and are erased when control power supply VCC is turned off. This configuration allows the motor constants and control gains to be identified at appropriate timing.

[0042] It is clear that the present invention is not limited to the above-described embodiments, and that each embodiment can be appropriately modified within the scope of the technical concept of the present invention. Furthermore, the number, position, shape, etc. of the above-described components are not limited to the above-described embodiments, and the number, position, shape, etc. can be set to be suitable for implementing the present invention. Note that the same components are denoted by the same reference numerals in each drawing. [Explanation of symbols]

[0043] 2 Brushless DC motor 3 DC power supply 10 Motor control device 11 Inverter 12 Gate drive circuit 13 Current Sense Amplifier 14 Control circuit regulator 20 Control circuit 21 Three-phase two-axis converter 22 Rotor position / speed estimation unit 23 Speed ​​PI control section 24 Current PI control unit 25 Interference control section 26 Arithmetic section 28 PWM conversion unit 27 2-axis 3-phase conversion unit 29 Motor constant and control gain identification section

Claims

1. A motor control device that controls a brushless DC motor by vector control based on a detected motor current, an identification unit that performs an identification operation of a motor constant and a control gain when a first motor drive signal is input after a control power supply is turned on; The identification unit performs the identification operation by: a first step of identifying an armature winding resistance, a d-axis inductance, and a q-axis inductance; a second step of calculating a current PI control gain and a back electromotive force constant estimation gain using the identification result of the first step; a third step of calculating a back electromotive force constant using the identification results of the first step and the second step; a fourth step of identifying a speed PI control gain and a rotor position estimation gain using the identification result of the first step; A motor control device characterized by:

2. 2. The motor control device according to claim 1, wherein the motor constants and the control gains identified by the identification unit are maintained even when the motor drive signal is turned off as long as the control power supply is kept turned on, and are erased when the control power supply is turned off.

3. A motor control method for controlling a brushless DC motor by vector control based on a detected motor current, comprising: When the first motor drive signal VSP is input after the control power is turned on, the motor constants and control gains are identified. The identification operation includes: a first step of identifying an armature winding resistance, a d-axis inductance, and a q-axis inductance as the motor constants; a second step of calculating a current PI control gain and a back electromotive force estimation gain using the identification result of the first step; a third step of calculating a back electromotive force constant using the identification results of the first step and the second step; a fourth step of identifying a speed PI control gain and a rotor position estimation gain using the identification result of the first step; A motor control method comprising:

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