Inverter device

Abstract

To provide an inverter device that suppresses cost increases while also enabling the acquisition of motor parameters. [Solution] The inverter control device according to the embodiment includes: a current control unit 3 that controls the d-axis current and q-axis current supplied to the synchronous machine M so that they match the d-axis current command value and the q-axis current command value; a zero-torque current command value generation unit 1 that generates a zero-torque d-axis current command value and a zero-torque q-axis current command value so that the magnet torque and reluctance torque of the synchronous machine M are balanced; an estimation signal generation unit 2 that generates a corrected d-axis current command value and a q-axis current command value so that at least an AC component is generated in the q-axis current; an estimation voltage acquisition unit 10 that acquires the value of an estimation voltage generated by the AC component of the q-axis current; and a magnet flux calculation unit 11 that calculates the magnet flux, which is the magnetic flux linked from the permanent magnet to the stator coil of the synchronous machine M, using the value of the estimation voltage.

Description

[Technical Field]

[0001] Embodiments of the present invention relate to an inverter device. [Background technology]

[0002] When driving a synchronous machine using an inverter, motor parameters are required. Conventionally, in addition to obtaining data such as motor winding resistance and inductance through pre-testing to acquire the motor parameters of the synchronous machine, a method of automatic acquisition (auto-tuning) has been proposed. According to auto-tuning, by calculating estimated values ​​of motor parameters while the machine is stopped, it is possible to quickly construct the control system after connecting the permanent magnet synchronous machine and the inverter, thereby shortening the time until the synchronous machine can be put into operation.

[0003] For example, methods have been proposed to estimate the magnetic flux by observing the maximum value of the current flowing when a pulse voltage is applied to a synchronous machine and utilizing the correlation between the maximum value and the magnitude of the magnetic flux; to estimate the magnetic flux by utilizing the correlation between the high-frequency impedance calculated by the high-frequency current generated when a high-frequency voltage is applied to a synchronous machine and the magnetic flux; and to estimate the magnetic flux by utilizing the correlation between the amount of tooth strain obtained by strain gauges and the magnetic flux. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2006-262643 [Patent Document 2] Special Publication No. 2019-537412 [Patent Document 3] Japanese Patent Publication No. 2020-010477 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, adopting a method that requires testing in a dedicated environment to acquire the characteristics of the target synchronous machine in advance leads to increased costs, and the method cannot be applied if the target synchronous machine is unknown. Furthermore, adopting a method that requires the addition of sensors increases material costs.

[0006] Embodiments of the present invention have been made in view of the above circumstances, and aim to provide an inverter device that can acquire motor parameters while suppressing cost increases. [Means for solving the problem]

[0007] The inverter control device according to this embodiment includes: a current control unit that controls the d-axis current and q-axis current supplied to a synchronous machine having permanent magnets and magnetic salient polarity so that they match the d-axis current command value and the q-axis current command value, respectively; a zero-torque current command value generation unit that generates a zero-torque d-axis current command value and a zero-torque q-axis current command value so that the magnet torque and reluctance torque of the synchronous machine are balanced; an estimation signal generation unit that generates the d-axis current command value and the q-axis current command value obtained by correcting the zero-torque d-axis current command value and the zero-torque q-axis current command value so that at least an AC component is generated in the q-axis current; an estimation voltage acquisition unit that acquires the value of an estimation voltage generated by the AC component of the q-axis current; and a magnet flux calculation unit that calculates the magnet flux, which is the magnetic flux linked from the permanent magnets to the stator coils of the synchronous machine, using the value of the estimation voltage. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing one example configuration of the inverter device according to the first embodiment. [Figure 2] Figure 2 is a schematic block diagram showing one example configuration of the zero torque current command value generation unit shown in Figure 1. [Figure 3] Figure 3 is a schematic block diagram showing one example configuration of the estimation signal generation unit shown in Figure 1. [Figure 4]Figure 4 is a schematic block diagram showing one example configuration of the voltage acquisition unit for estimation shown in Figure 1. [Figure 5] Figure 5 is a schematic diagram showing one example configuration of the magnetic flux calculation unit shown in Figure 1. [Figure 6] Figure 6 is a flowchart illustrating an example of the operation of the inverter device according to the first embodiment. [Figure 7] Figure 7 is a timing chart illustrating an example of the operation of the inverter device according to the first embodiment. [Figure 8] Figure 8 shows an example of the output torque characteristics when the current supplied to a permanent magnet synchronous machine is varied under the condition of constant current amplitude. [Figure 9] Figure 9 illustrates an example of how the zero-torque current command value generation unit searches for the current phase when the output torque of the synchronous machine becomes zero. [Figure 10] Figure 10 schematically shows the relationship between the dq axis coordinate system and the d0q0 axis coordinate system, which is obtained by rotating the dq axis coordinate system by the output torque zero phase. [Figure 11] Figure 11 is a schematic block diagram showing another example configuration of the zero torque current command value generation unit shown in Figure 1. [Figure 12] Figure 12 is a timing chart illustrating an example of the operation of an inverter device of a modified version of the first embodiment. [Figure 13] Figure 13 is a schematic block diagram showing one example of the configuration of the zero torque current command value generation unit of the inverter device according to the second embodiment. [Figure 14] Figure 14 is a diagram illustrating the principle of minimum amplitude search control. [Figure 15] Figure 15 is a timing chart illustrating an example of the operation of the inverter device according to the second embodiment. [Figure 16] Figure 16 is a schematic diagram showing one example configuration of the inverter device according to the third embodiment. [Figure 17] Figure 17 is a schematic block diagram showing one example configuration of the estimation signal generation unit shown in Figure 16. [Figure 18] Figure 18 is a schematic diagram showing one example configuration of the inverter device according to the fourth embodiment. [Modes for carrying out the invention]

[0009] The inverter device of this embodiment will be described below with reference to the drawings.

[0010] In the inverter device of this embodiment, while the current is controlled so that the magnet torque and reluctance torque of the synchronous machine are balanced, an estimated voltage is obtained by applying an estimated current, and the magnet flux, which is a motor parameter, is calculated to perform parameter tuning.

[0011] Figure 1 is a schematic diagram showing one example configuration of the inverter device according to the first embodiment. The inverter device of this embodiment comprises an inverter main circuit (INV) 6 and an inverter control device, and controls a synchronous machine M.

[0012] The synchronous machine M is, for example, a motor with magnetic salient polarity, such as a permanent magnet synchronous motor (PMSM). In this embodiment, an example in which a PMSM is used as the synchronous machine M will be described.

[0013] The inverter main circuit 6 converts DC power into three-phase AC power and outputs it to the synchronous machine M. The inverter main circuit 6 is equipped with an upper arm switching element and a lower arm switching element for each phase. The inverter control device supplies the inverter main circuit 6 with control signals (gate commands) for the switching elements of the upper arm and lower arm. The inverter main circuit 6 can convert between AC power and DC power by switching the switching elements on and off. In response to the input gate command, the inverter main circuit 6 converts the DC power into AC power of any voltage and frequency and supplies it to the synchronous machine M to drive the synchronous machine M.

[0014] The current detection units 110U, 110V, and 110W detect the three-phase alternating current (I u , I v , I w ) flowing from the inverter main circuit 6 to the synchronous machine M. Note that it is sufficient to detect the current values of at least two phases of the three-phase alternating current flowing to the synchronous machine M. When detecting the current values of two phases, the current value of the remaining one phase can be calculated using the detected current values of the two phases.

[0015] The inverter control device includes a zero torque current command value generation unit 1, an estimation signal generation unit 2, a current control unit 3, a dq / 3Φ conversion unit 4, a gate generation unit 5, a 3Φ / dq conversion unit 7, a magnetic pole position / rotation frequency estimation unit 8, a stop determination unit 9, an estimation voltage acquisition unit 10, and a magnet magnetic flux calculation unit 11.

[0016] The inverter control device may include, for example, an arithmetic device including a processor and a memory storing a program executed by the processor, and can realize various functions described below by software or a combination of software and hardware.

[0017] The gate generation unit 5 converts the three-phase voltage command values V uRef , V vRef , V wRef into gate commands. In this embodiment, the gate generation unit 5 generates a gate command by PWM modulation that compares, for example, a triangular wave carrier with the voltage command values V uRef , V vRef , V wRef and outputs the gate command to the inverter main circuit INV.

[0018] The dq / 3Φ conversion unit 4 uses the estimated magnetic pole position θ to convert the voltage command values V dRef , V qRef supplied from the current control unit 3 into vector values V uRef , V vRef , V wRefThe voltage is converted and output to the modulation unit 104. In other words, the dq / 3Φ conversion unit 4 converts the voltage command value of the dq rotational coordinate system, which is synchronized with the rotational speed of the rotor of the synchronous machine M, to the voltage command value of the fixed coordinate system, which corresponds to the three-phase AC waveform of the synchronous machine M.

[0019] The 3Φ / dq conversion unit 7 uses the estimated magnetic pole position θ to determine the detected values ​​I from the current detection units 110U, 110V, and 110W. u , I v , I w The d-axis current I in the rotating coordinate system is estimated from the values ​​in the three-phase fixed coordinate system. d and q-axis current I q The 3Φ / dq conversion unit 7 converts the current value in a fixed coordinate system corresponding to the three-phase AC waveform of the synchronous machine M to the current value in a dq rotating coordinate system synchronized with the rotational speed of the rotor of the synchronous machine M.

[0020] In the αβ fixed coordinate system, the d-axis is a vector axis rotated by the estimated magnetic pole position θ from the α-axis (U-phase), and the q-axis is a vector axis orthogonal to the d-axis in terms of electrical angle. In contrast, the estimated rotating coordinate system corresponds to the d-axis and q-axis at the estimated position of the rotor of the synchronous machine M. That is, in the estimated rotating coordinate system, the d-axis is a vector axis rotated by the estimated magnetic pole position θ from the α-axis, and the q-axis is a vector axis orthogonal to the d-axis (estimated rotating coordinate system) in terms of electrical angle.

[0021] The current control unit 3 controls the d-axis current and q-axis current supplied to a synchronous machine M having permanent magnets and magnetic salient polarity so that they match the d-axis current command value and the q-axis current command value, respectively. The current control unit 3 performs PI control, for example, to control the three-phase AC current I u , I v , I w The d-axis current I generated by transforming the dq coordinate axis. d and d-axis current command value I dRef The d-axis voltage command V is calculated by summing the component obtained by multiplying the deviation by the gain and the component obtained by multiplying the integral of the deviation by the gain. dRef This generates the q-axis current I q and q-axis current command value I qRefThe q-axis voltage command value V is calculated by summing the component obtained by multiplying the deviation by the gain and the component obtained by multiplying the integral of the deviation by the gain. qRef The current control unit 3 generates the d-axis voltage command value V. dRef and q-axis voltage command value V qRef This is supplied to the dq / 3Φ conversion unit 4.

[0022] The magnetic pole position / rotation frequency estimation unit 8 receives the d-axis current I output from the 3Φ / dq conversion unit 7. d and q-axis current I q Using these values, the estimated values ​​of the magnetic pole position θreal and rotation frequency (angular velocity) ω are calculated and output using a known method. The magnetic pole position / rotation frequency estimation unit 8 can, if necessary, acquire motor parameters such as motor winding resistance and inductance, as well as information such as voltage command values ​​and high-frequency voltages superimposed on the voltage command values, and calculate the rotation frequency (angular velocity) ω. The magnetic pole position / rotation frequency estimation unit 8 can calculate the estimated magnetic pole position θ by integrating the calculated value of rotation frequency (angular velocity) ω.

[0023] Furthermore, since the rotor of the synchronous machine M is stopped when parameter tuning is being performed, the magnetic pole position / rotation frequency estimation unit 8 may be configured to output the angular velocity ω as 0 (zero).

[0024] The magnetic pole position / rotation frequency estimation unit 8 supplies the calculated angular velocity ω to the zero torque current command value generation unit 1 and the stop determination unit 9, and supplies the calculated estimated magnetic pole position θ to the dq / 3Φ conversion unit 4 and the 3Φ / dq conversion unit 7.

[0025] The stop determination unit 9 sets the estimation start flag to 0 if the angular velocity ω is not 0 rad / s, and to 1 if the angular velocity ω is 0 rad / s. The stop determination unit 9 supplies the generated value of the estimation start flag to the estimation signal generation unit 2 and the magnet flux calculation unit 11. The stop determination unit 9 operates during the period when output torque zero control is performed, and the value of the estimation start flag may be set to 0 (initial value) at the start and end of the output torque zero control. The stop determination unit 9 may also obtain the value of the estimation completion flag, which will be described later, and terminate the stop determination by setting the estimation start flag to 0 (initial value) when the estimation completion flag changes from 0 to 1, indicating that the estimation is complete.

[0026] The zero torque current command value generation unit 1 performs output torque zero control and generates a zero torque d-axis current command value I dRef0 and zero torque q-axis current command value I qRef0 This generates the output torque zero control, which generates current command values ​​(zero torque d-axis current command value and zero torque q-axis current command value) such that the magnet torque and reluctance torque of the synchronous machine M are balanced, thereby setting the output torque of the synchronous machine M to 0 (zero).

[0027] Figure 2 is a schematic block diagram showing one example configuration of the zero torque current command value generation unit shown in Figure 1. The zero torque current command value generation unit 1 comprises a subtraction unit 1A, a PI control unit 1B, a current command value generation unit 1C, and output switching units 1P and 1Q. The subtraction unit 1A calculates and outputs the difference (-ω) obtained by subtracting the angular velocity ω from 0 (angular velocity command value 0 rad / s).

[0028] The PI control unit 1B calculates and outputs the current phase β0 of the zero current command value so that the output value (-ω) of the subtraction unit 1A follows zero. The output value of the PI control unit 1B is input to the output switching unit 1P. The output switching unit 1P switches the output value according to the value of the estimation completion flag, which will be described later. When the value of the estimation completion flag is 0, the output switching unit 1P outputs the output value of the PI control unit 1B (current phase β0), and when the value of the estimation completion flag is 1, it outputs 0. The output switching unit 1Q switches the output value according to the value of the estimation completion flag, which will be described later. When the value of the estimation completion flag is 0, the output switching unit 1Q outputs the current amplitude command value I a0 It outputs [the specified value], and outputs 0 when the value of the estimation completion flag is 1.

[0029] The current command value generation unit 1C uses the output value (current phase β0) of the PI control unit 1B and the current amplitude command value I a0 Using the above, the zero torque d-axis current command value I is calculated based on equations (1) and (2) below. dRef0 and zero torque q-axis current command value I qRef0 The current amplitude command value I is calculated. a0 This can be set, for example, to the rated current value of the controlled synchronous machine M. That is, in this embodiment, the zero torque d-axis current command value I dRef0 and zero torque q-axis current command value I qRef0 The magnitude of the vector sum between these two values ​​is set to the rated current value of the synchronous machine M.

[0030]

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[0031] The zero torque current command value generation unit 1 acquires the value of the estimation completion flag (described later), and at the timing when the estimation completion flag changes from 0 to 1, it generates the zero torque d-axis current command value I dRef0 and zero torque q-axis current command value I qRef0 The calculation may be configured to stop.

[0032] The estimation signal generation unit 2 uses the value of the estimation start flag and the zero torque d-axis current command value I. dRef0 And, zero torque q-axis current command value I qRef0 The command value I of the zero torque d-axis current is obtained so that at least an AC component is generated in the q-axis current Iq. dRef0 and zero torque q-axis current command value I qRef0 The corrected d-axis current command value I dRef and q-axis current command value I qRef To generate. In this embodiment, after starting output torque zero control, the estimation signal generation unit 2, if in a stopped state (ω=0), starts supplying the estimation current and sets the zero torque q-axis current command value I qRef0 The q-axis estimation signal I, which is an AC component, is used in this calculation. qh Add to the q-axis current command value I qRef Generates.

[0033] Figure 3 is a schematic block diagram showing one example configuration of the estimation signal generation unit shown in Figure 1. The estimation signal generation unit 2 comprises output switching units 2A and 2F, and an addition unit 2B. The output switching unit 2A outputs the q-axis estimation signal I according to the value of the estimation start flag. qh The value of is switched. Output switching unit 2A switches the q-axis estimation signal I when the estimation start flag is 0 (rotation state). qh Output as 0, and when the estimation start flag is 1 (stopped state), the q-axis estimation signal I is calculated using equation (3) below. qh to A q sinω h Output as t.

[0034]

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[0035] Furthermore, in equation (3) above, ωh This is set to a value that is sufficiently slower than the cutoff frequency of the current control unit 3. In this embodiment, for example, ω is set to be 1 / 10 of the cutoff frequency of the current control unit 3. h This will be set.

[0036] The output switching unit 2F switches the output value according to the value of the estimation completion flag, which will be described later. When the value of the estimation completion flag is 0, the output value of the output switching unit 2A (q-axis estimation signal I qh It outputs ( ) and outputs 0 when the value of the estimation completion flag is 1. The summing unit 2B controls the zero torque q-axis current command value I qRef0 The output value of the output switching unit 2A (when the value of the estimation completion flag is 0, the q-axis estimation signal I qh The q-axis current command value I is the sum of the two values ​​obtained by adding the two values. qRef Outputs. The estimation signal generation unit 2 generates the d-axis current command value I dRef and q-axis current command value I qRef The and are supplied to the current control unit 3. The estimation signal generation unit 2 receives the zero torque d-axis current command value I obtained from the zero torque current command value generation unit 1. dRef0 The d-axis current command value I dRef This is output to the current control unit 3.

[0037] The estimation signal generation unit 2 acquires the value of the estimation completion flag, which will be described later, and when the estimation completion flag changes from 0 to 1, it generates the estimation d-axis current command value I dRef and q-axis current command value I qRef The output may be stopped and the current supply for estimation may be terminated.

[0038] The voltage acquisition unit 10 for estimation acquires the d-axis current I d and q-axis current I q The value of the d-axis voltage command value V dRef and q-axis current command value V qRef Furthermore, from the value of the current phase β0 during zero output torque control, the q-axis current I q Estimated voltage e generated by the AC component qEST Get the value.

[0039] FIG. 4 is a block diagram schematically showing a configuration example of the estimated voltage acquisition unit shown in FIG. 1. The estimated voltage acquisition unit 10 includes ab / dq conversion units 10A and 10B, and a minimum-order observer 10C.

[0040] The ab / dq conversion unit 10A acquires a d-axis voltage command value V dRef and a q-axis current command value V qRef and a current phase β0, and respectively coordinate-converts the d-axis voltage command value V dRef and the q-axis current command value V qRef by the current phase β0, and calculates and outputs a d-axis voltage command value V d0 and a q-axis voltage command value V q0 for output torque zero control.

[0041] The ab / dq conversion unit 10B acquires a value of a d-axis current I d and a value of a q-axis current I q and a current phase β0, and respectively coordinate-converts the d-axis current I d and the qq-axis current I q by the current phase β0, and calculates and outputs a d-axis current command value I d0 and a q-axis current command value I q0 for output torque zero control.

[0042] The minimum-order observer 10C uses a d-axis voltage command value V d0 for output torque zero control, a q-axis voltage command value V q0 , a d-axis current command value I d0 and a q-axis current command value I q0 to calculate and output an estimated voltage e qh (q-axis estimated signal I qEST ) flowing through the AC component of the q-axis current in the synchronous machine M. That is, the minimum-order observer 10C has a model equation simulating the operation from the inverter control circuit to the inverter main circuit INV and the synchronous machine M, and can calculate the voltage generated when the synchronous machine M is driven by the input voltage command value and current command value. <​​The magnetic flux calculation unit 11 calculates the estimated voltage e according to the value of the estimation start flag. qEST , q-axis current Iq and current amplitude command value I a0 Therefore, the estimated magnetic flux ψ of the synchronous machine M is the magnetic flux linked from the permanent magnet to the stator coil. fEST Calculate.

[0044] Figure 5 is a schematic diagram showing one example configuration of the magnetic flux calculation unit shown in Figure 1. The magnetic flux calculation unit 11 includes a delay circuit 11A, an estimated value calculation unit 11B, an output switching unit 11C, and a unit time delay unit 11D.

[0045] The delay circuit 11A obtains the value of the estimation start flag and outputs an estimation completion flag that is delayed by a predetermined time from the timing when the estimation start flag rises. In other words, the estimated magnetic flux value ψ is obtained within a predetermined time after the generation of the estimation signal begins (after the estimation start flag changes from 0 to 1). fEST The calculation is complete, and the estimated magnetic flux value ψ fEST After the calculation is complete, the estimation completion flag changes from 0 to 1. In this embodiment, the predetermined time for delaying the input value in the delay circuit 11A is, for example, the AC component of the estimation current (q-axis estimation signal I qh Set the time for 10 cycles. Note that the estimated completion flag can be initially set to 0 at the start of output torque zero control.

[0046] The estimated value calculation unit 11B calculates the estimated voltage e qEST And the q-axis current Iq and the current amplitude command value I a0 Therefore, the estimated magnetic flux value ψ is obtained using the estimation formula in equation (4) below. fEST Calculate.

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[0047] The unit time delay unit 11D inputs the output value of the output switching unit 11C, which has been delayed by a unit time (the previous value), to the output switching unit 11C. The output switching unit 11C acquires the output value of the estimated value calculation unit 11B and the output value of the unit time delay unit 11D, and outputs one of the input values. If the output value of the delay circuit 11A (estimation completion flag) is 0, the output switching unit 11C receives the estimated magnetic flux value ψ supplied from the estimated value calculation unit 11B. fEST The output value is updated accordingly. If the estimation completion flag is 1, the output switching unit 11C sets the previous value (output value of the unit time delay unit 11D) to the estimated magnetic flux value ψ. fEST It is held and output as such.

[0048] In this embodiment, after a predetermined time has elapsed from the timing when the estimation start flag changes from 0 to 1, the estimation completion flag changes from 0 to 1, the current supply for estimation by the estimation signal generation unit 2 is stopped, and the magnet flux calculation unit 11 calculates the estimated magnet flux value ψ fEST This is retained as the output value. The magnet flux calculation unit 11 supplies the value of the estimation completion flag to the zero torque current command value generation unit 1, the estimation signal generation unit 2, and the stop determination unit 9.

[0049] The stop determination unit 9, the estimation voltage acquisition unit 10, and the magnet flux calculation unit 11 use the estimated magnet flux value ψ, which is a motor parameter. fEST Once the parameters are updated and tuning is complete, the system may be configured to stop operating until output torque zero control is initiated again.

[0050] Next, we will describe an example of the operation of the inverter device mentioned above. Figure 6 is a flowchart illustrating an example of the operation of the inverter device according to the first embodiment. Figure 7 is a timing chart illustrating an example of the operation of the inverter device according to the first embodiment.

[0051] When parameter tuning begins, the zero-torque current command value generation unit 1 first generates the current command value I from the angular velocity ω. d , I q The values ​​obtained are such that the angular velocity ω is 0 rad / s and the current command value I d , I qDetermine whether it is 0A or not (Step S1).

[0052] The zero torque current command value generation unit 1 generates a current command value I when the angular velocity ω is 0 rad / s. d , I q Depending on whether it is 0A (Step S1, Yes), the zero torque d-axis current command value I dRef0 and zero torque q-axis current command value I qRef0 The generation of [the product] is initiated, and output torque zero control is started (step S2).

[0053] Next, the stop determination unit 9 determines whether the angular velocity ω is 0 rad / s or not (step S3). The stop determination unit 9 outputs the estimation start flag as 1 when the angular velocity ω is 0 rad / s (step S3, Yes), and as 0 when the angular velocity ω is not 0 rad / s (step S3, No).

[0054] When the estimation start flag changes from 0 to 1, the estimation signal generation unit 2 starts supplying the estimation current, and the magnet flux calculation unit 11 uses the estimated voltage calculated by the estimation voltage acquisition unit 10 to estimate the magnet flux ψ fEST This is calculated (Step S4).

[0055] The magnetic flux calculation unit 11 changes the estimation completion flag from 0 to 1 after a predetermined time has elapsed since the estimation start flag changed from 0 to 1 (step S5, Yes).

[0056] When the estimation completion flag changes from 0 to 1, the estimation signal generation unit 2 stops supplying the estimation current (step S6), and the estimated magnetic flux value ψ calculated by the magnetic flux calculation unit 11 is stopped. fEST This is held (step S7).

[0057] Next, the principle for calculating the estimated magnetic flux value of the magnet by zero output torque control performed in the inverter device of this embodiment will be explained. The output torque of a permanent magnet synchronous machine is given as the total torque, which is the sum of the magnet torque (first term) and the reluctance torque (second term), as shown in equation (5) below.

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[0058] Figure 8 shows an example of the output torque characteristics when the current supplied to a permanent magnet synchronous machine is varied under the condition of constant current amplitude. Referring to Figure 8, it can be seen that by controlling the permanent magnet synchronous machine M with a current phase in which the magnet torque is positive and the reluctance torque is negative, the values ​​of the magnet torque and reluctance torque cancel each other out, and there is an operating point where the total torque becomes 0 Nm (a state in which the magnet torque and reluctance torque are balanced). The condition for the current phase β (hereafter referred to as the zero output torque phase) when the total torque is 0 Nm is given by equation (6).

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[0059] In the zero torque current command value generation unit 1, the current amplitude command value I a0 By manipulating the current phase so that the angular velocity matches the angular velocity command value of 0 rad / s while a specific value is applied, the zero phase of the output torque is searched for.

[0060] Figure 9 illustrates an example of how the zero-torque current command value generation unit searches for the current phase when the output torque of the synchronous machine becomes zero. In equation (6) above, when the current phase β changes, the degree of magnetic saturation between the d-axis inductance Ld and the q-axis inductance Lq also changes. Therefore, the right-hand side of equation (6) is not a constant value and draws a curve as shown in Figure 9 (hereinafter referred to as the zero output torque curve). In other words, searching for the zero output torque phase under the condition of constant current amplitude means changing the operating point on the constant current circle and searching for the intersection point of the zero output torque curve and the constant current circle.

[0061] The voltage equation for a permanent magnet synchronous machine is given by equation (7) below, and by equation (8) below when the machine is stopped.

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[0062] By rearranging equation (8) above and performing a coordinate transformation at the zero phase of the output torque, we obtain equation (9) below.

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[0063] Figure 10 schematically shows the relationship between the dq axis coordinate system and the d0q0 axis coordinate system, which is obtained by rotating the dq axis coordinate system by the output torque zero phase. The relationship between the dq axis coordinate system and the d0q0 axis coordinate system is shown in Figure 10, and the current amplitude I a0 The d0 axis coincides with this.

[0064] (9) The q0 axis component v q0 The third term is the estimated voltage e qEST When extracted as shown, we obtain equation (10) below, and since equation (6) holds when output torque is under zero control, combining and rearranging the two equations allows us to derive the estimation equation (4).

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[0065] As described above, according to the inverter device of this embodiment, while controlling the current phase in which the magnet torque and reluctance torque are balanced, the AC component is supplied to the synchronous machine M as an estimation current, so that even when the synchronous machine M is stopped, the estimation voltage e, which is a state quantity correlated with the magnetic flux of the magnet, is maintained. qEST It is possible to observe the estimated voltage e qEST Using the estimated magnetic flux ψ fEST It is possible to calculate this.

[0066] In other words, in the inverter device of this embodiment, there is no need to conduct tests using a dedicated environment to acquire the characteristics of the target synchronous machine in advance in order to acquire the value of the magnetic flux, which is a motor parameter, nor is there any need to add new sensors, thus avoiding an increase in costs. Therefore, according to this embodiment, it is possible to provide an inverter device that can acquire motor parameters while suppressing an increase in costs.

[0067] Next, a modified example of the inverter device of the first embodiment will be described with reference to the drawings. In the following description, components similar to those in the inverter device of the first embodiment described above are denoted by the same reference numerals, and detailed explanations are omitted.

[0068] In the inverter device of the first embodiment described above, the zero torque current command value generation unit 1 generates the current amplitude command value I a0 An example was described in which the output torque zero phase β0 is searched by manipulating the current phase so that the angular velocity command value 0 rad / s and the angular velocity ω coincide while a certain condition is applied. In a modified example of the first embodiment, an example is described in which an initial value is given to the current phase operated by the zero torque current command value generation unit 1.

[0069] Figure 11 is a schematic block diagram showing another example configuration of the zero torque current command value generation unit shown in Figure 1. In this embodiment, the zero torque current command value generation unit 1 includes a subtraction unit 1A, a PI control unit 1B, an addition unit 1D, a current command value generation unit 1C, and output switching units 1R and 1S.

[0070] The subtraction unit 1A calculates and outputs the difference (-ω) obtained by subtracting the angular velocity ω from 0 (angular velocity command value 0 rad / s). The PI control unit 1B calculates and outputs the current phase β of the zero current command value so that the output value (-ω) of the subtraction unit 1A follows zero.

[0071] The summing unit 1D combines the output value β of the PI control unit 1B with the initial value β of the current phase. iniThe sum of these two values ​​is calculated and output as the current phase β0 during zero output torque control. The output switching unit 1S switches the output value according to the value of the estimation completion flag. When the value of the estimation completion flag is 0, the output switching unit 1S outputs the output value (current phase β0) of the adder 1D, and outputs 0 when the value of the estimation completion flag is 1. The output switching unit 1R switches the output value according to the value of the estimation completion flag, which will be described later. When the value of the estimation completion flag is 0, the output switching unit 1R outputs the current amplitude command value I a0 It outputs [the specified value], and outputs 0 when the value of the estimation completion flag is 1.

[0072] When the estimation completion flag is 0, the current command value generation unit 1C combines the output value β0 of the adder unit 1D with the current amplitude command value I a0 The current command value generation unit 1C obtains the output value β0 of the summing unit 1D and the current amplitude command value I. a0 Using and based on equations (1) and (2) above, the zero torque d-axis current command value I dRef0 and zero torque q-axis current command value I qRef0 The current amplitude command value I is calculated. a0 This can be set, for example, to the rated current value of the synchronous machine M being controlled.

[0073] The zero torque current command value generation unit 1 generates the calculated zero torque d-axis current command value I dRef0 and zero torque q-axis current command value I qRef0 The above is supplied to the estimation signal generation unit 2. This modified example is the same as the inverter device of the first embodiment described above, except for the configuration of the zero torque current command value generation unit 1.

[0074] In this modified example, the current amplitude command value I a0 With the given conditions, the current phase is manipulated so that the angular velocity matches the angular velocity command value of 0 rad / s, and the initial value of the current phase β is obtained. ini Adding this, the zero torque d-axis current command value I dRef0 and zero torque q-axis current command value I qRef0 The initial value of the current phase β is calculated. ini For example, this is set to the previous value of the current phase β0 during zero output torque control.

[0075] Figure 12 is a timing chart illustrating an example of the operation of an inverter device of a modified version of the first embodiment. As shown in Figure 12, when searching for an appropriate initial value β0 during output torque zero control, ini By setting this, the time until the synchronous machine M stops can be shortened, and the oscillation of angular velocity ω that occurs until the output torque converges to the zero phase can be suppressed.

[0076] Based on the above, this modified version provides an inverter device that can acquire motor parameters while suppressing cost increases, similar to the first embodiment described above. Furthermore, this modified version can shorten the time required for parameter tuning and suppress the rotation of the synchronous machine M during parameter tuning.

[0077] Next, the inverter device of the second embodiment will be described in detail with reference to the drawings. The inverter device of this embodiment differs from the first embodiment described above in that the zero-torque current command value generation unit 1 searches for the minimum current amplitude that balances the magnet torque and reluctance torque of the synchronous machine M (hereinafter referred to as minimum amplitude search control).

[0078] Figure 13 is a schematic block diagram showing one example of the configuration of the zero torque current command value generation unit of the inverter device according to the second embodiment. In this embodiment, the zero torque current command value generation unit 1 includes a subtraction unit 1A, a PI control unit 1B, a current command value generation unit 1C, an addition unit 1E, 1F, an output switching unit 1G, 1H, 1J, 1N, 1T, 1U, a unit time delay unit 1I, 1O, a current amplitude comparator 1K, an AC component amplitude calculation unit 1L, and an AC component comparator 1M.

[0079] The subtraction unit 1A calculates and outputs the difference (-ω) obtained by subtracting the angular velocity ω from 0 (angular velocity command value 0 rad / s). The PI control unit 1B calculates and outputs the current phase β0 of the zero current command value so that the output value (-ω) of the subtraction unit 1A follows zero.

[0080] The summer 1E calculates and outputs the sum of the initial current amplitude of 0A and the periodic increase of the AC signal ΔIa × n (where n is the number of periods of the AC signal). ΔIa is set, for example, to 10% of the rated current value of the synchronous machine M. The output value of the summer 1E is a current amplitude value whose magnitude is adjusted for each period of the AC component of the current amplitude, and is supplied to the summer 1F, the output switching unit 1J, and the current amplitude comparator 1K.

[0081] The summing unit 1F adds the AC signal I of the following formula (11) to the current amplitude value (ΔIa × n) output from the summing unit 1E. ah The sum I as The output value I of the summing unit 1F is calculated and output. as This is supplied to the output switching unit 1G.

[0082]

number

[0083] Phase ω h2 The phase ω is set to a value that is sufficiently slower than the cutoff frequency of the current control unit. h2 For example, this is set to 1 / 10 of the cutoff frequency of the current control unit 3.

[0084] The current amplitude comparator 1K combines the current amplitude (ΔIa × n) output from the summer 1E with the current condition threshold I amax By comparing the two, the current amplitude (ΔIa × n) is equal to the current condition threshold I. amax If the following conditions are met, the current condition flag is set to 0, and the current amplitude (ΔIa × n) is equal to the current condition threshold I amaxIf the value exceeds (is exceeded) the threshold, the current condition flag is set to 1. Current condition threshold I amax For example, this is set to the rated current of the controlled synchronous machine M. The current amplitude comparator 1K supplies current condition flags to the output switching units 1G and 1H.

[0085] In this embodiment, the zero torque current command value generation unit 1 performs minimum amplitude search control when the current condition flag is 0, and performs output torque zero control when the current condition flag is 1. The output switching unit 1G outputs the output value I of the adder unit 1F. as And the current amplitude I output from the unit time delay unit 1I a0 The current amplitude command value I is obtained from the previous value and the output value is switched according to the value of the current condition flag. The output switching unit 1G switches the output value when the current condition flag is 1. a0 Outputs the previous value, and if the current condition flag is 0, the output value of the summing unit 1F is I as current amplitude command value I a0 Output as follows. The output switching unit 1T switches the output value according to the value of the estimation completion flag. When the value of the estimation completion flag is 0, the output switching unit 1T outputs the output value of the output switching unit 1G, and when the value of the estimation completion flag is 1, it outputs 0.

[0086] The output switching unit 1H acquires 0 and the output value of the PI control unit 1B, and switches the output value according to the value of the current condition flag. When the current condition flag is 1, the output switching unit 1H outputs the output value of the PI control unit 1B as phase β0, and when the current condition flag is 0, it outputs 0 as phase β0. The output switching unit 1U switches the output value according to the value of the estimation completion flag. When the value of the estimation completion flag is 0, the output switching unit 1U outputs the output value of the output switching unit 1H, and when the value of the estimation completion flag is 1, it outputs 0.

[0087] The current command value generation unit 1C generates the current phase β0 and the current amplitude command value I when the value of the estimation completion flag is 0. a0 Using and based on equations (1) and (2) above, the zero torque d-axis current command value I dRef0 and zero torque q-axis current command value I qRef0Calculate the result.

[0088] The AC component amplitude calculation unit 1L calculates the AC signal I obtained by adding the angular velocity ω to the current amplitude. ah The AC component amplitude calculation unit 1L extracts the same component and calculates the amplitude Δω of the extracted AC component. The AC component amplitude calculation unit 1L supplies the calculated amplitude Δω to the AC component comparator 1M.

[0089] AC component comparator 1M measures the amplitude Δω and the minimum value of the amplitude component Δω. min By comparing the two, the amplitude Δω is the minimum value Δω min If it falls below (Δω<Δω min ) The minimum amplitude flag is set to 1, and the amplitude Δω is the minimum value Δω min If it is above (Δω≧Δω min The minimum amplitude flag is set to 0. The AC component comparator supplies the value of the minimum amplitude flag to the output switching units 1J and 1N.

[0090] The output switching unit 1J combines the output value of the summing unit 1E with the current amplitude command value I output from the unit time delay unit 1I. a0 The previous value is obtained, and the output value (current amplitude command value) I is determined according to the value of the minimum amplitude flag. a0 Switches the output. Output switching section 1J is set to (Δω≧Δω when the minimum amplitude flag is 0) min ), current amplitude command value I a0 The value is not updated and the previous value is output. The output switching unit 1J outputs the previous value when the minimum amplitude flag is 1 (Δω<Δω min ), the output value (current value) of the summing unit 1E is used to set the current amplitude I a0 Output as follows.

[0091] The output switching unit 1N receives the angular velocity ω and the minimum value Δω output from the unit time delay unit 1O. min The previous value is obtained, and the output value Δω is determined according to the value of the minimum amplitude flag. min Switches the output. When the minimum amplitude flag is 0, the output switching unit 1N sets the minimum value Δω min The previous value is output without updating the value. The output switching unit 1N, when the minimum amplitude flag is 1, sets the amplitude Δω (current value) to the minimum value Δω min Output as follows.

[0092] Figure 14 is a diagram illustrating the principle of minimum amplitude search control. Current amplitude command value I under the condition current phase = 0 degrees a0 As the value is increased, the current amplitude reaches the point where the zero output torque curve intersects with the d-axis. At this point, the current amplitude command value I a0 As the current amplitude increases, the AC component (AC signal I) added to the current amplitude increases. ah The AC component of angular velocity ω caused by ) decays, and the AC component of angular velocity ω reaches its minimum value when the current amplitude intersects the d-axis with the zero output torque curve. This is because the operating point changes to follow the vicinity of the zero output torque curve, making it less likely for torque pulsation to occur, and as a result, the AC component of angular velocity ω becomes smaller compared to other operating points.

[0093] Figure 15 is a timing chart illustrating an example of the operation of the inverter device according to the second embodiment. According to Figure 15, the current amplitude command value I a0 As the value increases, the amplitude of the AC component of the angular velocity ω decreases, but the current amplitude command value I a0 As we increase the value, we can see that the amplitude of the AC component of the angular velocity ω tends to increase.

[0094] In other words, in the inverter device of this embodiment, the current amplitude command value I is the value at which the AC component of the angular velocity ω is minimized by minimum amplitude search control. a0 The search is performed, and the search result is the current amplitude command value I for output torque zero control. a0 By being held in this state by the output switching unit 1J, output torque zero control can be performed with the minimum current amplitude.

[0095] Therefore, the inverter device of this embodiment provides the same effects as the first embodiment described above, and can balance the magnet torque and reluctance torque of the synchronous machine M with the smallest current amplitude, thereby minimizing the losses caused by supplying current to the synchronous machine M during parameter tuning.

[0096] Next, the inverter device of the third embodiment will be described in detail with reference to the drawings. In the inverter device of the first embodiment described above, the estimation current was supplied only to the q-axis of the synchronous machine M. However, the inverter device of this embodiment differs from the first embodiment in that the estimation current is supplied not only to the q-axis but also to the d-axis of the synchronous machine M.

[0097] Figure 16 is a schematic diagram showing one example configuration of the inverter device according to the third embodiment. This embodiment differs from the first embodiment described above in that the current phase β0 is input from the zero torque current command value generation unit 1 to the estimation signal generation unit 2.

[0098] Figure 17 is a schematic block diagram showing one example configuration of the estimation signal generation unit shown in Figure 16. In the inverter device of this embodiment, the estimation signal generation unit 2 includes output switching units 2A, 2G, and 2H, adder units 2B, 2C, and 2E, and an ab / dq conversion unit 2D.

[0099] The output switching unit 2A switches between 0A and the dq axis estimation signal I dqh The system acquires the and switches the output value according to the value of the estimation start flag. The output switching unit 2A outputs 0A if the estimation start flag is 0, and outputs the dq axis estimation signal I of equation (12) below if the estimation start flag is 1. dqh Outputs.

number

[0100] The adder 2C outputs the phase obtained by adding the current phase β0 during output torque zero control with 90deg to the ab / dq converter 2D. The ab / dq conversion unit 2D acquires 0 and the output value of the output switching unit 2A, performs a rotational coordinate transformation on the acquired value with the phase supplied from the adder unit 2C, and generates the d-axis estimation signal Idh and signal I for q-axis estimation qh Generates.

[0101] The output switching unit 2G outputs 0 and the d-axis estimation signal I. dh The system acquires the data and switches the output value according to the value of the estimation completion flag. The output switching unit 2G outputs the d-axis estimation signal I when the estimation completion flag is 0. dh It outputs the result, and if the estimation start flag is 1, it outputs 0. The output switching unit 2H switches between 0 and the q-axis estimation signal I qh The system acquires the and switches the output value according to the value of the estimation completion flag. The output switching unit 2H outputs the q-axis estimation signal I when the estimation completion flag is 0. qh It outputs the result, and if the estimation start flag is 1, it outputs 0.

[0102] The summing unit 2B uses the q-axis estimation signal I calculated by the ab / dq conversion unit 2D. qh And, zero torque q-axis current command value I qRef0 The sum of these two values ​​is the q-axis current command value I qRef Output as follows. The summing unit 2E calculates the d-axis estimation signal I calculated by the ab / dq conversion unit 2D. dh And, zero torque d-axis current command value I dRef0 The sum of these two values ​​is the d-axis current command value I dRef Output as follows.

[0103] According to the above embodiment, the same effects as the first embodiment described above can be obtained, and by energizing not only the q axis but also the d axis of the synchronous machine M with the estimation current, torque pulsation (ripple) caused by the energization of the estimation current can be reduced.

[0104] Next, the inverter device of the fourth embodiment will be described in detail with reference to the drawings. The inverter device of this embodiment further includes an AC voltage detection unit (voltage sensor) 12 and a 3Φ / dq conversion unit 13, and the voltage input to the estimation voltage acquisition unit 10 is the d-axis voltage command value V dRef q-axis voltage command value V qRef Instead, the d-axis voltage V was generated from the detected value (three-phase voltage) of the voltage sensor 12.d and q-axis voltage V q This differs from the first embodiment described above in that it uses [specific components / techniques].

[0105] Figure 18 is a schematic diagram showing one example configuration of the inverter device according to the fourth embodiment. The voltage sensor 12 detects the three-phase AC voltage supplied from the inverter main circuit 6 to the synchronous machine M, and supplies the detected values ​​Vu, Vv, and Vw to the 3Φ / dq conversion unit 13.

[0106] The 3Φ / dq conversion unit 13 uses the estimated magnetic pole position θ obtained from the magnetic pole position / rotation frequency estimation unit 8 to convert the detected values ​​Vu, Vv, and Vw supplied from the voltage sensor 12 to the d-axis voltage V of the dq rotation coordinate system. d and q-axis voltage V q Converts to V. The 3Φ / dq conversion unit 13 converts to the d-axis voltage V. d and q-axis voltage V q This is supplied to the estimation voltage acquisition unit 10.

[0107] The inverter device of this embodiment has the same configuration as the first embodiment described above, except for the above-mentioned features. According to this embodiment, the same effects as those of the first embodiment described above can be obtained, and the influence of errors occurring between the voltage command value and the output voltage can be eliminated, thereby improving the estimation accuracy of motor parameters.

[0108] The program according to this embodiment may be transferred while stored on an electronic device, or it may be transferred while not stored on an electronic device. In the latter case, the program may be transferred via a network, or it may be transferred while stored on a storage medium. The storage medium is a non-temporary tangible medium. The storage medium is a computer-readable medium. The storage medium can be any medium that is capable of storing a program and is readable by a computer, such as a CD-ROM or memory card, and its form is not limited.

[0109] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0110] 1...Zero Torque Current Command Value Generation Unit, 1A...Subtraction Unit, 1B...PI Control Unit, 1C...Current Command Value Generation Unit, 1D, 1E, 1F...Addition Unit, 1G, 1H, 1J...Output Switching Unit, 1I, 1O...Unit Time Delay Unit, 1K...Current Amplitude Comparator, 1L...AC Component Amplitude Calculation Unit, 1M...AC Component Comparator, 1N...Output Switching Unit, 2...Estimation Signal Generation Unit, 2A...Output Switching Unit, 2B, 2C, 2E...Addition Unit, 2D...ab / dq Conversion Unit, 3...Current Control Unit, 4...dq / 3Φ Conversion Unit, 5...Gate Generation unit, 6...Inverter main circuit, 7, 13...3Φ / dq conversion unit, 8...Magnetic pole position / rotation frequency estimation unit, 9...Stop determination unit, 10...Estimated voltage acquisition unit, 10A, 10B...ab / dq conversion unit, 10C...Minimum dimension observer, 11...Magnetic flux calculation unit, 11A...Delay circuit, 11B...Estimated value calculation unit, 11C...Output switching unit, 11D...Unit time delay unit, 12...AC voltage detection unit (voltage sensor), 110U...Current detection unit, 110V...Current detection unit, 110W...Current detection unit

Claims

1. A current control unit controls the d-axis current and q-axis current supplied to a synchronous machine having permanent magnets and magnetic salient polarity so that they match the d-axis current command value and the q-axis current command value, respectively. A zero-torque current command value generation unit generates a zero-torque d-axis current command value and a zero-torque q-axis current command value so that the magnet torque and reluctance torque of the synchronous machine are balanced. An estimation signal generation unit that generates the d-axis current command value and the q-axis current command value obtained by correcting the zero-torque d-axis current command value and the zero-torque q-axis current command value so that at least an AC component is generated in the q-axis current, An estimation voltage acquisition unit that acquires the value of the estimation voltage generated by the AC component of the q-axis current, An inverter device comprising: a magnetic flux calculation unit that calculates the magnetic flux, which is the magnetic flux linked from the permanent magnet to the stator coil of the synchronous machine, using the value of the estimated voltage.

2. The inverter device according to claim 1, wherein the zero torque current command value generation unit generates the zero torque d-axis current command value and the zero torque q-axis current command value such that the angular velocity command value of 0 rad / s matches the angular velocity of the synchronous machine.

3. The inverter device according to claim 1, wherein the zero-torque current command value generation unit generates a current command value by superimposing an AC component on the current amplitude, adjusts the magnitude of the current amplitude for each cycle of the AC component of the current amplitude to search for a current amplitude command value that minimizes the amplitude of the AC component of the angular velocity of the synchronous machine, and generates the zero-torque d-axis current command value and the zero-torque q-axis current command value using the current amplitude command value.

4. The inverter device according to claim 1, wherein the estimation signal generation unit generates the d-axis current command value and the q-axis current command value obtained by correcting the zero-torque d-axis current command value and the zero-torque q-axis current command value, such that an AC component is generated in a phase orthogonal to the current phase in which the magnet torque and reluctance torque of the synchronous machine are balanced.

5. The inverter device according to any one of claims 1 to 4, wherein the magnitude of the vector sum of the zero torque d-axis current command value and the zero torque q-axis current command value is the rated current value of the synchronous machine.

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