JP2020137286A - Motor drive system and inverter control method in motor drive system - Google Patents

Abstract

To provide a motor drive system capable of performing vibration suppression control on a permanent magnet synchronous motor using a fixed pulse pattern.SOLUTION: A motor drive system comprises: a speed control unit 10 for outputting a speed command ω2 by performing control so that a speed command ω3 to be input to a pulse pattern table reference unit 30 follows a speed command ω1 input to the system; and a vibration suppression control unit 20 that takes as input detection current idet of a PMSM 50 driven by an inverter 40, a phase θ output from the reference unit 30, and the speed command ω2, calculates a vibration component of the PMSM 50, performs suppression control on it, and outputs the speed command ω3 and a modulation rate d that corresponds to the ω3 and is defined by a ratio of a voltage to a frequency. The pulse pattern table reference unit 30 refers to a fixed pulse pattern corresponding to the input modulation rate d and ω3 and outputs a gate signal g generated on the basis of the pattern to the inverter 40.SELECTED DRAWING: Figure 1

Description

The present invention relates to a motor control system in a system in which a permanent magnet synchronous motor is driven by an inverter.

The input three-phase AC voltage is converted to a DC voltage by a rectifier (diode rectifier, PWM converter, 120 ° flow converter, etc.), and the DC voltage is output as an AC voltage with a desired frequency and amplitude by an inverter to output the motor. Consider the motor drive system to be controlled.

When the motor is a permanent magnet synchronous motor (hereinafter, also referred to as PMSM), it is known that load fluctuations tend to excite torque vibration, and vibration suppression control is performed for stable driving. It has been devised.

Further, as one of the PMSM control methods, there is a sensorless V / f control which can eliminate the consideration of the accuracy of the speed sensor at high speed, the risk of sensor failure, and the cost of parts, and is a simple implementation method. Patent Document 1 has been proposed as an example of such control, and in this sensorless V / f control, vibration is suppressed by feeding back the detected current to a frequency command or a voltage command.

Further, there is a PWM (Pulse Width Modulation) method as a pulse generation method often used for power converters such as rectifiers and inverters.

PWM is widely used because it can easily achieve an appropriate output of a voltage vector and the calculation load is not large. Patent Document 1, which is an example of the sensorless V / f control, also presupposes PWM.

However, since PWM is a method of outputting the command voltage on average based on the carrier frequency (own pulse generation frequency), it does not always generate the optimum pulse for expressing the command voltage. To solve this problem, a pulse generation method has been proposed in which a fixed pulse pattern capable of appropriately expressing a command voltage based on a fundamental wave frequency is calculated in advance, and Non-Patent Document 1 is an example.

Japanese Unexamined Patent Publication No. 2000-236694

Masahiko Tsukagoshi, Kouki Matsuse, "Derivation of Optimal Fixed Pulse Patterns Conforming to Harmonic Regulations for Large Capacity PWM Rectifiers", Institute of Electrical Engineers of Japan D, Vol. 131, No. 3, 2011

In the prior art, a specific control configuration for controlling PMSM by a fixed pulse pattern has not been proposed, and precautions for its implementation have not been discussed.

The present invention has been made in view of the above points, and an object of the present invention is to provide an electric motor drive system capable of controlling vibration suppression of a permanent magnet synchronous motor using a fixed pulse pattern and an inverter control method in the electric motor drive system. To provide.

The electric motor drive system according to claim 1 for solving the above problems is
A system in which a permanent magnet synchronous motor is driven by an inverter controlled by a gate signal output from a pulse pattern table reference unit having a fixed pulse pattern table.
A speed control unit that outputs a second speed command from a first speed command set and input to the system and a third speed command input to the pulse pattern table reference unit.
The vibration component of the permanent magnet synchronous motor is input from the second speed command output from the speed control unit, the detection current that detects the current flowing through the permanent magnet synchronous motor, and the phase output from the pulse pattern table reference unit. A vibration suppression control unit that obtains and controls the suppression of the vibration component and outputs a modulation factor defined by the ratio of the voltage and the frequency corresponding to the third speed command and the third speed command. With
The pulse pattern table reference unit receives the modulation factor output from the vibration suppression control unit and the third speed command as inputs, and inputs the gate signal of each semiconductor element of the inverter and the phase obtained by integrating the third speed command. It is characterized by outputting.

Further, the electric motor drive system according to claim 2 is claimed in claim 1.
The pulse pattern table reference unit is
It is a table in which the modulation factor and phase are associated with the voltage level expressed by the fixed pulse pattern in advance, and the modulation factor output from the vibration suppression control unit and the third speed command are integrated. A fixed pulse pattern table that takes the phase as an input and outputs the voltage level corresponding to the input modulation factor and phase.
It has a gate generator that generates a gate signal for each semiconductor element of the inverter based on the voltage level output from the fixed pulse pattern table.
It is characterized by outputting the phase obtained by integrating the generated gate signal and the third speed command.

Further, the electric motor drive system according to claim 3 is claimed in claim 1 or 2.
The modulation factor input to the pulse pattern table reference unit is a modulation factor corresponding to the first speed command instead of the modulation factor from the vibration suppression control unit.

Further, the electric motor drive system according to claim 4 is claimed in claim 1 or 2.
The modulation factor input to the pulse pattern table reference unit is a modulation factor corresponding to the second speed command instead of the modulation factor from the vibration suppression control unit.

In addition, the electric motor drive system according to claim 5 is the one according to any one of claims 1 to 4.
The vibration suppression control unit
A 3-phase / 2-phase conversion unit that converts the detected current into a dq-axis current according to the phase input from the pulse pattern table reference unit, and a vibration suppression unit that multiplies the converted d-axis current or q-axis current by a vibration suppression gain. Obtain the vibration component by the gain part and
It is characterized in that the vibration component is suppressed and controlled by taking a deviation between the obtained vibration component and the input second speed command.

Further, the inverter control method in the electric motor drive system according to claim 6 is described.
This is an inverter control method in a system in which a permanent magnet synchronous motor is driven by an inverter controlled by a gate signal output from a pulse pattern table reference unit having a fixed pulse pattern table.
The pulse pattern table reference unit is a table in which the modulation factor and phase are associated with the voltage level expressed by the fixed pulse pattern in advance, and the modulation factor output from the vibration suppression control unit is used as a third. It has a fixed pulse pattern table that takes the phase in which the speed command is integrated as an input and outputs the voltage level corresponding to the input modulation factor and phase.
A step in which the speed control unit controls the third speed command input to the pulse pattern table reference unit to follow the first speed command set and input to the system and outputs the second speed command. ,
The vibration suppression control unit receives the detection current that detects the current flowing through the permanent magnet synchronous motor, the phase output from the pulse pattern table reference unit, and the second speed command output from the speed control unit as inputs to the permanent magnet. A step of obtaining the vibration component of a synchronous motor, performing suppression control of the vibration component, and outputting a third speed command and a modulation factor defined by a ratio of voltage and frequency corresponding to the third speed command. When,
A step in which the gate generation unit of the pulse pattern table reference unit generates a gate signal of each semiconductor element of the inverter based on the voltage level output from the fixed pulse pattern table.
The step in which the pulse pattern table reference unit outputs the phase obtained by integrating the third speed command, and
The gate generation unit of the pulse pattern table reference unit includes a step of outputting the generated gate signal to the inverter.

(1) According to the inventions of claims 1 to 6, vibration suppression control of the permanent magnet synchronous motor is performed in an electric motor drive system on the premise that the permanent magnet synchronous motor is controlled by using a fixed pulse pattern. Can be done.
(2) According to the inventions of claims 3 and 4, it is possible to avoid a sudden change in the output voltage level of the fixed pulse pattern table.
(3) According to the invention of claim 5, the obtained vibration component can be fed back to the second speed command side to perform vibration suppression control.

The system block diagram of Example 1 of this invention. The block diagram of the vibration suppression control part of FIG. The block diagram of the pulse pattern table reference part of FIG. The simulation results of vibration suppression control according to the present invention are shown, (a) is a characteristic diagram of speed and speed command, (b) is a characteristic diagram of motor torque, and (c) is a waveform diagram of a three-phase voltage near 0.4 s. (D) is a waveform diagram of a three-phase voltage around 0.5 s.

The present invention is applied to an electric motor drive system in which a permanent magnet synchronous motor is driven by an inverter controlled based on a fixed pulse pattern.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following examples of embodiments. In the following, since the output frequency of the inverter is proportional to the motor rotation speed, the "electric angular frequency" may be referred to as "speed". In consideration of the fact that the control output is always electrically realized, in the present specification, the electric angular frequency obtained by multiplying the rotation speed of the motor by the pole logarithm is replaced with the speed.

FIG. 1 shows a system configuration diagram according to the first embodiment in which the permanent magnet synchronous motor 50 is driven by the inverter 40. In the system of FIG. 1, the first speed command ω1 based on the operation panel operation amount and the like is set and input.

Reference numeral 10 denotes a comparison between the input first speed command ω1 and the third speed command ω3 (speed command input to the pulse pattern table reference unit 30) output from the vibration suppression control unit 20 described later, and ω3. Is a speed control unit that calculates the second speed command ω2 by performing, for example, PI (proportional / integral) control so that is followed by ω1.

Reference numeral 20 denotes a three-phase (U, V, W) detection current idet in which the current flowing through the permanent magnet synchronous motor 50 is detected by a transformer or the like (not shown), and a phase θ and a speed output from the pulse pattern table reference unit 30. This is a vibration suppression control unit that receives the second speed command ω2 output from the control unit 10 as an input, obtains the vibration component of the permanent magnet synchronous motor 50 by the configuration shown in FIG. 2, for example, and controls the suppression of the vibration component.

In FIG. 2 showing an example of the vibration suppression control unit 20, 21 is obtained by converting the three-phase detection current idet into a dq-axis current by the phase θ input from the pulse pattern table reference unit 30, for example, the q-axis. It is a three-phase / two-phase conversion unit that outputs a current iq.

The q-axis current iq output from the three-phase / two-phase conversion unit 21 is passed through a low-pass filter 22 to remove noise, and then the vibration suppression gain unit 23 is multiplied by the vibration suppression gain Gv.

In the circuit of FIG. 2, the vibration component of the permanent magnet synchronous motor 50 is obtained by the three-phase / two-phase conversion unit 21, the low-pass filter 22, and the vibration suppression gain unit 23.

Reference numeral 24 denotes a subtractor that subtracts the output (vibration component) of the vibration suppression gain 23 from the second speed command ω2 input from the speed control unit 10.

The subtraction result of the subtractor 24 is output from the vibration suppression control unit 20 as the third speed command ω3.

Reference numeral 25 denotes a ratio multiplication unit in which the ratio of voltage and speed (electric angular frequency obtained by multiplying the rotation speed of the motor by the number of pole pairs), that is, the ratio Gd of voltage and frequency is set. The modulation factor d is output by multiplying the subtraction output ω3 of the subtractor 24 by the ratio Gd of the ratio multiplication unit 25.

30 in FIG. 1 takes the modulation factor d and the third speed command ω3 output from the vibration suppression control unit 20 as inputs, and fixes the voltage level corresponding to the modulation factor d and the speed command ω3 in FIG. 3, which will be described later. This is a pulse pattern table reference unit that is referred to by the pulse pattern table 32 to generate and output the gate signal g and the output phase θ.

In FIG. 3 showing the details of the pulse pattern table reference unit 30, reference numeral 31 denotes an integrator that integrates the third velocity command ω3 input from the vibration suppression control unit 20 and outputs the output phase θ.

Reference numeral 32 denotes a fixed pulse pattern table in which the modulation factor and the phase are associated with the voltage level expressed by the fixed pulse pattern in advance, and the modulation factor d from the vibration suppression control unit 20 and the integrator 31 are used. The output phase θ is used as an input, and the voltage level L corresponding to the modulation factor d and the output phase θ is output as a reference result.

Reference numeral 33 denotes a gate generation unit that generates a gate signal g of each semiconductor element (not shown) in the inverter 40 based on the voltage level L output from the fixed pulse pattern table 32.

This gate signal g is input to the inverter 40, a voltage is applied to the PMSM 50 by switching of each semiconductor element in the inverter, a current flows through the PMSM 50, and the current is detected as an idet.

The fixed pulse pattern tabulated in the fixed pulse pattern table 32 is desired by using, for example, the method of Non-Patent Document 1 "Drivation of the optimum fixed pulse putter conforming to the harmonic regulation for a large-capacity PWM rectifier". A fixed pulse pattern is obtained. Further, it is assumed that the fixed pulse pattern is tabulated in advance in the fixed pulse pattern table 32 so that the voltage level L to be output can be known from the output phase θ and the modulation factor d.

In the electric motor drive system configured as described above, first, the entire vibration suppression control will be described.

In the system configuration diagram of FIG. 1, the vibration suppression control unit 20 mainly suppresses vibration. In the vibration suppression control, since the vibration suppression effect is obtained by adding the compensation term to the speed command, there arises a problem that the speed of the plant (PMSM50) cannot converge to the speed command input to the system.

In order to solve this problem, a speed control unit 10 is provided that compares the speed command ω3 after the vibration suppression compensation by the vibration suppression control unit 20 with the speed command ω1 of the system input and performs PI control to follow the system input. .. Regarding the response of the speed control unit 10, the responsiveness is set lower than that of the vibration suppression control unit 20, and if the responsiveness is not so required, only the I control may be used.

As described above, the speed command is corrected twice in the entire vibration suppression control. In consideration of this, the speed command of the system input is the first speed command ω1, the speed command after the speed control is the second speed command ω2, and the speed command after the vibration suppression control is the third speed command ω3.

Next, the vibration suppression control and the period of the pulse pattern table reference unit 30 will be described.

The vibration suppression control cycle may be a control cycle that allows observation of current vibration. Further, the pulse pattern table reference unit 30 may have a control cycle sufficient to appropriately express the pre-generated pulse pattern. The pulse pattern is usually set in a phase that takes into account frequency components that are several to several tens of times the fundamental wave in order to suppress harmonics. That is, the control cycle capable of appropriately expressing the pulse pattern is a control cycle capable of expressing a frequency several to several tens of times the highest frequency in the speed command range. Although it depends on the speed command range and the demand for harmonic suppression accuracy, this time, the pulse pattern table reference unit 30 is treated as having to have a shorter control cycle than the vibration suppression control unit 20.

In order to obtain the output phase θ more accurately, the frequency integration calculation is performed by the pulse pattern table reference unit 30 having a short control cycle as shown in the integrator 31 of FIG. And θ is also used in the vibration suppression control unit 20 as an accurate phase. However, the delay until the output phase θ, the detected current idet, or both of them are used for vibration suppression control may affect the control performance. In such a case, the amount of phase rotation during the delay may be compensated for θ by adding the delay times ta and ω3.

That is, θ + ta / ω3 obtained by adding ta / ω3 to the output phase θ (output phase of the integrator 31) output from the pulse pattern table reference unit 30 is sent to the 3-phase / 2-phase conversion unit 21 of the vibration suppression control unit 20. It may be configured to be input.

Next, the vibration suppression control unit 20 of FIG. 2 will be described.

The current on the dq axis can be obtained by coordinate-converting the detected current idet in the three-phase / two-phase conversion unit 21. In FIG. 2, only iq is used for control among id and iq. In this regard, since the main purpose is to feed back the vibration component, another detection amount in which the vibration component appears, such as id or detection torque if there is a detection torque means, may be fed back.

Further, in FIG. 2, vibration is suppressed by feeding back iq to ω2, but here, the purpose is to feed back the vibration component to the input value of the fixed pulse pattern table 32 of FIG. Therefore, a form of feeding back to another target within a range reflected in the input value of the fixed pulse pattern table 32, such as feeding back to the modulation factor d or feeding back to the output phase θ, is also allowed.

That is, for example, when the vibration component detection amount is fed back to the modulation factor d, the subtractor 24 in FIG. 2 is removed and the second speed command ω2 is used as it is as the output of the vibration suppression control unit 20, and the vibration suppression gain unit 23 The output is multiplied by a ratio (Gd) in which the ratio of voltage and frequency similar to that of the gain multiplication unit 25 is set to obtain the modulation factor corresponding to the vibration component, and the modulation factor corresponding to the vibration component and the second The deviation from the modulation factor d (modulation rate corresponding to the second speed command) obtained by multiplying the speed command ω2 by the ratio Gd of the gain multiplication unit 25 is taken by a subtractor, and the deviation output is used as the modulation factor to suppress vibration. It is output from the control unit 20. In this case, ω3 in FIGS. 1 to 3 is treated as ω2.

Further, for example, when the vibration component detection amount is fed back to the output phase θ, the subtractor 24 in FIG. 2 is removed and the second speed command ω2 is used as it is as the output of the vibration suppression control unit 20, and the vibration suppression gain unit 23 The output is integrated by an integrator similar to the integrator 31 to obtain the phase corresponding to the vibration component, and the phase corresponding to the vibration component and the output phase θ (fixed pulse) output from the integrator 31 in FIG. 3 are obtained. The deviation from the phase θ) input to the pattern table 32 is taken by a subtractor, and the deviation output is input to the fixed pulse pattern table 32 as the output phase θ and output from the pulse pattern table reference unit 30. .. In this case, ω3 in FIGS. 1 to 3 is treated as ω2.

In FIG. 2, the q-axis current iq is passed through a low-pass filter (LPF) 22 to reduce noise. The low-pass filter 22 is not essential for vibration suppression control, and iq may be used without providing a filter. However, in the fixed pulse pattern, since switching is performed in synchronization with the output frequency, an appropriate constant sampling period does not exist, and switching noise may affect vibration suppression control. Therefore, stable control can be performed by providing a low-pass filter 22 having a time constant that can eliminate switching noise.

The strength of vibration suppression is adjusted by the vibration suppression gain Gv. The vibration suppression gain Gv is a value of 0 or more. If Gv is small, the responsiveness is high and the vibration suppression performance is low, and if Gv is large, the responsiveness is low and the vibration suppression performance is high.

Next, the modulation factor setting will be described.

In the configuration of FIG. 2, the modulation factor d is obtained by multiplying the third speed command ω3 by the ratio Gd, but since the output value of the fixed pulse pattern table 32 is changed by the modulation factor d, a sudden change is avoided. Therefore, ω1 and ω2 may be used instead of ω3.

That is, when the modulation factor is obtained by using the first speed command ω1, the ratio multiplication unit 25 in FIG. 2 is removed, and the voltage set in the first speed command ω1 in FIG. 1 in the same manner as the ratio multiplication unit 25. And the frequency ratio Gd are multiplied to generate a modulation factor d, and the generated modulation factor d is directly input to the fixed pulse pattern table 32 of the pulse pattern table reference unit 30.

When the modulation factor is obtained by using the second speed command ω2, the ratio multiplication unit 25 of FIG. 2 is arranged on the input side of the subtractor 24, and the ratio of the ratio multiplication unit 25 to the second speed command ω2. A modulation factor d is generated by multiplying Gd, and the generated modulation factor d is input to the fixed pulse pattern table 32 of the pulse pattern table reference unit 30.

However, when the modulation factor d is generated from the first speed command ω1 and the second speed command ω2, the speed command ω3 used for generating the output phase θ and the modulation factor d are not always in a constant ratio. That is, since the correspondence between the modulation factor d and the switching frequency becomes unclear, it is desirable to create the fixed pulse pattern table 32 with a sufficient margin for the number of switchings.

FIG. 4 shows the results of a simulation for confirming the effect of vibration suppression control in the first embodiment. In FIG. 4, (a) is a characteristic diagram of speed and speed commands ω1 to ω3, (b) is a characteristic diagram of motor torque, (c) is a waveform diagram of a three-phase voltage near 0.4 s, and (d) is 0. The waveform diagram of the three-phase voltage around 5s is shown.

In this simulation, a constant load of about 150 Nm is applied up to 0.4 s, and the load is changed to about 720 Nm in steps after 0.4 s. The first speed command ω1 which is a system input is set to 860 Hz. As for the time domain, only the region related to the vibration suppression control is extracted.

As can be seen from the speed graph of FIG. 4A, the third speed command ω3 is lowered to deal with the fluctuation of the load. The speed of the plant is the number of revolutions converted to the electrical frequency and is always almost the same as ω3. Since the third speed command ω3 has decreased, the second speed command ω2 has increased due to the operation of the speed control unit 10, ω3 has increased in accordance with the increase of ω2, and it can be seen that ω3 coincides with ω1.

In the graph of the motor torque in FIG. 4B, it can be seen that although some vibration components can be seen when rising, the load fluctuation can be followed without overshoot. There is a period in which the torque ripple increases intermittently when the torque is steady, but this is an impact due to pulse pattern switching.

The graphs of the three-phase voltage of FIGS. 4C and 4D show that this simulation is performed with a fixed pulse pattern. The reason why the dotted line of the level in FIGS. 4 (c) and 4 (d) and the output voltage value do not always match is due to the DC voltage fluctuation and the presence of the output filter. It can be seen that the pulse pattern changes before the load change of 0.4 s shown in FIG. 4 (c) and after the load change of 0.5 s shown in FIG. 4 (d).

That is, when the third speed command ω3 decreases from a constant load to a load fluctuation in 0.4 s, the modulation factor d is changed and the output voltage level L of the fixed pulse pattern table 32 is lowered, so that the three-phase voltage of the inverter output is lowered. Has changed from FIG. 4 (c) to FIG. 4 (d).

10 ... Speed control unit 20 ... Vibration suppression control unit 21 ... 3-phase / 2-phase conversion unit 22 ... Low-pass filter 23 ... Vibration suppression gain unit 24 ... Subtractor 25 ... Ratio multiplication unit 30 ... Pulse pattern table reference unit 31 ... Inverter 32 ... Fixed pulse pattern table 33 ... Gate generator 40 ... Inverter 50 ... Permanent magnet synchronous motor

Claims (6)

A system in which a permanent magnet synchronous motor is driven by an inverter controlled by a gate signal output from a pulse pattern table reference unit having a fixed pulse pattern table.
A speed control unit that outputs a second speed command from a first speed command set and input to the system and a third speed command input to the pulse pattern table reference unit.
The vibration component of the permanent magnet synchronous motor is input from the second speed command output from the speed control unit, the detection current that detects the current flowing through the permanent magnet synchronous motor, and the phase output from the pulse pattern table reference unit. A vibration suppression control unit that obtains and controls the suppression of the vibration component and outputs a modulation factor defined by the ratio of the voltage and the frequency corresponding to the third speed command and the third speed command. With
The pulse pattern table reference unit receives the modulation factor output from the vibration suppression control unit and the third speed command as inputs, and inputs the gate signal of each semiconductor element of the inverter and the phase obtained by integrating the third speed command. An electric motor drive system characterized by outputting. The pulse pattern table reference unit is
It is a table in which the modulation factor and phase are associated with the voltage level expressed by the fixed pulse pattern in advance, and the modulation factor output from the vibration suppression control unit and the third speed command are integrated. A fixed pulse pattern table that takes the phase as an input and outputs the voltage level corresponding to the input modulation factor and phase.
It has a gate generator that generates a gate signal for each semiconductor element of the inverter based on the voltage level output from the fixed pulse pattern table.
The electric motor drive system according to claim 1, wherein a phase obtained by integrating the generated gate signal and the third speed command is output. Claim 1 or 2 is characterized in that the modulation factor input to the pulse pattern table reference unit is a modulation factor corresponding to the first speed command instead of the modulation factor from the vibration suppression control unit. The electric motor drive system described in. Claim 1 or 2 is characterized in that the modulation factor input to the pulse pattern table reference unit is a modulation factor corresponding to the second speed command instead of the modulation factor from the vibration suppression control unit. The electric motor drive system described in. The vibration suppression control unit
A 3-phase / 2-phase conversion unit that converts the detected current into a dq-axis current according to the phase input from the pulse pattern table reference unit, and a vibration suppression unit that multiplies the converted d-axis current or q-axis current by a vibration suppression gain. Obtain the vibration component by the gain part and
The electric motor drive system according to any one of claims 1 to 4, wherein the vibration component is suppressed and controlled by taking a deviation between the obtained vibration component and the input second speed command. .. This is an inverter control method in a system in which a permanent magnet synchronous motor is driven by an inverter controlled by a gate signal output from a pulse pattern table reference unit having a fixed pulse pattern table.
The pulse pattern table reference unit is a table in which the modulation factor and phase are associated with the voltage level expressed by the fixed pulse pattern in advance, and the modulation factor output from the vibration suppression control unit is used as a third. It has a fixed pulse pattern table that takes the phase in which the speed command is integrated as an input and outputs the voltage level corresponding to the input modulation factor and phase.
A step in which the speed control unit controls the third speed command input to the pulse pattern table reference unit to follow the first speed command set and input to the system and outputs the second speed command. ,
The vibration suppression control unit receives the detection current that detects the current flowing through the permanent magnet synchronous motor, the phase output from the pulse pattern table reference unit, and the second speed command output from the speed control unit as inputs to the permanent magnet. A step of obtaining the vibration component of a synchronous motor, performing suppression control of the vibration component, and outputting a third speed command and a modulation factor defined by a ratio of voltage and frequency corresponding to the third speed command. When,
A step in which the gate generation unit of the pulse pattern table reference unit generates a gate signal of each semiconductor element of the inverter based on the voltage level output from the fixed pulse pattern table.
The step in which the pulse pattern table reference unit outputs the phase obtained by integrating the third speed command, and
An inverter control method in an electric motor drive system, wherein the gate generation unit of the pulse pattern table reference unit includes a step of outputting the generated gate signal to the inverter.

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