GB2550719A

GB2550719A - Motor control device, compressing device, and air conditioner

Info

Publication number: GB2550719A
Application number: GB1711853.0A
Authority: GB
Inventors: Wada Yasuhiko; Yuasa Kenta; Uemura Keiji; Hatakeyama Kazunori; Kobayashi Takahiko
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2015-03-23
Filing date: 2016-01-14
Publication date: 2017-11-29
Anticipated expiration: 2036-01-14
Also published as: DE112016001391T5; GB201711853D0; WO2016152203A1; JP6320625B2; GB2550719B; JPWO2016152203A1

Abstract

This motor control device is provided with: an electrical power converter for converting a direct current voltage to a three-phase alternating current voltage using a PWM control to output the converted voltage to a motor; and a carrier synchronization processor for outputting, to the electrical power converter, a carrier wave and a three-phase alternating current voltage command value which are used to perform the PWM control by the electrical power converter, wherein an acceleration and deceleration adjusting processor is provided for outputting a frequency command value of the three-phase alternating current voltage to the carrier synchronization processor, and for determining the rate of change of the frequency command value on the basis of a carrier mode, which is a PWM control mode of the carrier wave, the carrier mode being determined by the carrier synchronization processor on the basis of the frequency command value.

Description

DESCRIPTION MOTOR CONTROL DEVICE, COMPRESSING DEVICE, and

AIR CONDITIONER

Technical field [0001] The present invention particularly relates to a technology for switching between PWM pulse modes in a motor controller provided with a power converter for driving a synchronous machine.

Background Art [0002] Conventionally, a system for controlling a motor using an inverter is employed to drive a vehicle. For electrically driven vehicles such as, for example, an electric car, a hybrid car, and a fuel-cell car, output torque of the drive motor is generally controlled by an inverter. Typically, a voltage switched by an inverter is applied to the motor according to a PWM control based on voltage comparison between a command voltage and a carrier wave. In the PWM control, the carrier frequency is desirably increased in order to approximate a voltage waveform for driving the motor to the command voltage; however, increase of the carrier frequency causes increase of switching loss. For that reason, a so-called synchronous PWM control method, which consistently keeps constant the relation between the drive frequency and the carrier frequency, is used as a technology of approximating the output voltage waveform to the command voltage with increase of the carrier frequency being suppressed as low as possible.

[0003] Patent Document 1 discloses a configuration in which the phases of both the fundamental wave and the carrier wave are simultaneously calculated, based on an instantaneous value of a commanded frequency, for the carrier frequency to be consistently kept at an integral multiple of the driving frequency even when the command frequency is changed at any timing. Patent Document 2 discloses, for a challenge to implementation of a smooth AC-motor control by a PWM control that selectively applies an asynchronous PWM control and a synchronous PWM control by setting an appropriate criteria for selecting both control, a controller that calculates the phase difference between a target phase and an actual phase of the command phase voltage at a time when the carrier wave becomes a maximum, to select the synchronous PWM control when the absolute value of the phase difference is smaller than a threshold and to select the asynchronous PWM control when the absolute value of the phase difference is larger than the threshold.

Prior Art Document Patent Document [0004] Patent Document 1- JP2014-027764 A; and

Patent Document 2- JP2011072103 A

Summary of the invention

Problem that the Invention is to Solve [0005] However, implementing the control disclosed in Patent Document 2 raises a problem of degrading the control performance since the control does not take into consideration that switching between the asynchronous PWM control and the synchronous PWM control intermittently occurs when revolution speed of the motor is changed. If this problem is resolved, it can be expected that the synchronous PWM control method is employed in various applications for widely accelerating/decelerating the motor revolution speed as well as in motor control for electric-driven vehicles.

[0006] The present invention is made to resolve the above problem and aimed at preventing the control performance from degradation due to a synchronous condition deviation occurring when switching from an asynchronous PWM control to a synchronous PWM control or from a synchronous PWM control to a different PWM control in a case, such as with air conditions for example, where responsiveness is not necessary for a target speed (a target revolution speed), in other words, a constant acceleration/deceleration operation is performed toward the target speed (the target revolution speed).

Means for Solving the Problem [0007] In a motor controller including a power converter configured to convert a DC voltage to a three-phase AC voltage by a pulse width modulation (PWM) control, to output the three-phase AC voltage to a motor and a carrier synchronization processing unit configured to output, to the power converter, a carrier wave and a command three-phase AC voltage for the power converter to perform the PWM control, the the motor controller according to the present invention further includes an acceleration/deceleration adjustment processing unit configured to output a command frequency for the three-phase AC voltage to the carrier synchronization processing unit and to determine a rate of change of the command frequency, based on a carrier mode of the carrier wave, which is a mode of the PWM control, determined based on the command frequency by the carrier synchronization processing unit.

Advantage of the Invention [0008] According to the present invention, the rate of change of the command frequency is determined based on a carrier mode, thus preventing a synchronous condition deviation occurring when switched from an asynchronous PWM control to a synchronous PWM control or from a synchronous PWM control to a different synchronous PWM control. As a result, the control performance is prevented from degrading.

Brief Description of the Drawings [0009] FIG. 1 is a block diagram showing a configuration of a motor system including a motor controller according to Embodiment 1 of the present invention; FIG. 2 is a block diagram showing an example of a hardware configuration of the motor controller according to the present invention; FIG. 3 is a diagram for explaining a method of generating a command carrier-mode value ptn* by a the carrier mode value generating unit of the motor controller according to Embodiment 1 of the present invention; FIG. 4 is a block diagram showing a configuration of a carrier synchronization processing unit of the motor controller according to Embodiment 1 of the present invention; FIG. 5 is a diagram showing a relation between a command voltage phase ^*and synchronous-mode carrier waves; FIG. 6 is a block diagram showing a configuration of a carrier-mode switching permission determiner of the motor controller according to Embodiment 1 of the present invention; FIG. 7 is a table for explaining an operation of the carrier-mode switching permission determiner of the motor controller according to Embodiment 1 of the present invention; FIG. 8 is a flowchart showing the operation of a carrier synchronization correction-amount calculator of the motor controller according to Embodiment 1 of the present invention; FIG. 9 is a flowchart showing the operation of a carrier wave generator of the motor controller according to Embodiment 1 of the present invention; FIG. 10 is a flowchart showing the operation of an acceleration/deceleration adjustment processing unit of the motor controller according to Embodiment 1 of the present invention; FIG. 11 is a time chart for explaining the operation of the acceleration/deceleration adjustment processing unit of the motor controller according to Embodiment 1 of the present invention; FIG. 12 is a block diagram showing a configuration of a motor system including a motor controller according to Embodiment 2 of the present invention; FIG. 13 is a block diagram showing a configuration of a carrier synchronization processing unit of the motor controller according to Embodiment 2 of the present invention; FIG. 14 is a flowchart showing the operation of an acceleration/deceleration adjustment processing unit of the motor controller according to Embodiment 2 of the present invention; FIG. 15 is a time chart for explaining the operation of the acceleration/deceleration adjustment processing unit of the motor controller according to Embodiment 2; FIG. 16 is a flowchart showing the operation of an acceleration/deceleration adjustment processing unit of a motor controller according to Embodiment 3 of the present invention; FIG. 17 is a time chart for explaining the operation of the acceleration/deceleration adjustment processing unit of the motor controller according to Embodiment 3 of the present invention; FIG. 18 is a block diagram showing a configuration of a motor system including a motor controller according to Embodiment 4 of the present invention; FIG. 19 is a flowchart showing the operation of an acceleration/deceleration adjustment processing unit of the motor controller according to Embodiment 4 of the present invention; FIG. 20 is a graph showing a relation between a phase difference ΔΡ and a current distortion factor Ithd, for explaining the motor controller according to Embodiment 4 of the present invention; FIG. 21 is a time chart for explaining the operation of the acceleration/deceleration adjustment processing unit of the motor controller according to Embodiment 4 of the present invention; FIG. 22 is a block diagram showing a schematic configuration of a compressor apparatus according to Embodiment 5 of the present invention; and FIG. 23 is a block diagram showing a schematic configuration of an air conditioner according to Embodiment 6 of the present invention.

Embodiments for Carrying Out the Invention Embodiment 1 [0010] Hereinafter, preferred embodiments of motor controllers according to the present invention are described with reference to the accompanying drawings. FIG. 1 is a block diagram showing a configuration of a motor controller according to Embodiment 1 of the present invention. The motor controller 10 according to Embodiment 1 includes a known power converter 2 (for example, an inverter), a revolution speed calculating unit 4, a carrier mode value generating unit 5, a carrier synchronization processing unit 6, and an acceleration/deceleration adjustment processing unit 7. The power converter 2 applies to a motor 1 three-phase AC voltages Vu, Vv, Vw controlled by a pulse width modulation (PWM) based on comparison between the DC voltage Vdc of a DC bus 3, a carrier wave carrier, and command three-phase AC voltages Vu *, Vv*, Vw* The revolution speed calculating unit 4 calculates command two-axis voltages Vd*, Vq* to be applied to the motor 1 and a reference voltage phase θν subjected to a control delay correction, based on a command three-phase AC-voltage frequency finv* from the acceleration/deceleration adjustment processing unit 7, which is described later. The carrier mode value generating unit 5 generates a carrier-mode value ptn* based on the command frequency finv*. The carrier synchronization processing unit 6 generates the carrier wave carrier and the command three-phase AC voltages Vu*, Vv* IV*based on the command voltages Vd*and Vq*, the command frequency finv*, and the command carrier-mode value ptn*. The acceleration/deceleration adjustment processing unit 7 determines the rate of change of the command frequency finv*, based on a carrier mode value ptn calculated by the carrier synchronization processing unit 6.

[0011] FIG. 2 is a block diagram showing an example of a hardware configuration of a motor system provided with a motor controller according to the present invention. In FIG. 2, the motor system is provided with the motor controller 10 and the motor 1. The hardware of the motor controller 10 includes a processor 100, a storage unit 101, and the power converter 2 for converting a DC voltage to the three-phase AC voltages using a PWM control. The storage unit 101 is equipped with, for example, a volatile storage device such as a random access memory and a non-volatile auxiliary storage device such as a flash memory. Otherwise, an auxiliary storage device such as a hard disc may be equipped in place of the non-volatile auxiliary storage device. Since the storage unit 101 is equipped with the auxiliary storage device and the volatile storage device, a program is input to the processor 100 from the auxiliary storage device via the volatile storage device. Note that the processor 100 may output data, such as of calculation results, to the volatile storage device of the storage unit 101 or may store the data in the auxiliary storage device via the volatile storage device. Input/output of data and the like between the constituents in the hardware configuration shown in FIG.2 will be described later.

[0012] The functions of the revolution speed calculating unit 4, the carrier mode value generating unit 5, the carrier synchronization processing unit 6, and the acceleration/deceleration adjustment processing unit 7 shown in FIG. 1 are implemented by the processor 100 executing the program stored in the storage unit 101 or by processing circuits such as in a system LSI having the functions to be implemented by the processor 100 and the storage unit 101. In addition, a plurality of processors 100 and a plurality of storage units 101 may cooperatively execute the above functions, or a plurality of processing circuits may cooperatively execute the above functions. Further, a combination of a plurality of processors 100, a plurality of storage units 101, and a plurality of processing circuits may cooperatively execute the above functions. For example, the function of the acceleration/deceleration adjustment processing unit 7 may be implemented by a host controller provided with a processor and a storage device, and the functions of the other units may be implemented by a subordinate controller provided with another processor and a storage device.

[0013] Next, a method of generating the command carrier-mode value ptn* by the carrier mode value generating unit 5 in Embodiment 1 is described with reference to FIG. 3. The carrier mode is a PWM control mode of the motor controller 10. The carrier mode is divided into an asynchronous PWM mode (hereinafter, referred to as an asynchronous mode) in which the frequency of the carrier wave is set independently of the frequency of the tree-phase AC voltages and a synchronous PWM mode (hereinafter, referred to as a synchronous mode) in which the carrier wave frequency is set to have an integer multiple of the tree-phase AC-voltage frequency. Further, the synchronous mode may be divided into multiple synchronous modes such as, for example, a nine-pulse synchronous mode, a six-pulse synchronous mode, and a three-pulse synchronous mode, or be a single synchronous mode only. The carrier mode value generating unit 5 generates the command carrier-mode value ptn* for the carrier synchronization processing unit 6 to determine the carrier mode of the carrier wave depending on the frequency for driving the motor, i.e., the command frequency finv*· Specifically, the command carrier-mode value ptn* is for the carrier synchronization processing unit 6 to switch the carrier mode of the carrier wave from the asynchronous mode to a synchronous mode, from a synchronous mode to the asynchronous mode, or from a synchronous mode to a different synchronous mode. In the carrier mode value generating unit 5, switch frequencies finv*l, finv*2, finv*3 are set in advance for the carrier synchronization processing unit 6 to switch the carrier mode. For example, the switch frequency finv*i is for switching from the asynchronous mode to the nine-pulse synchronous mode of the synchronous modes. These switch frequencies finv*l, finv*2, finv*3 are set in advance for switching loss in the power converter 2 to be reduced.

[0014] The carrier mode value generating unit 5 generates the command carrier-mode value ptn* in the following manner for the carrier synchronization processing unit 6 to determine the carrier mode of the carrier wave. If the command frequency iW’is equal to or more than 0 [Hz] and less than finv*i [Hz], a value of 0 that indicates the asynchronous mode is generated as the command carrier-mode value ptn*. If finv* is equal to or more than finv*l [Hz] and less than finv*2 [Hz], a value of 9 that indicates the nine-pulse synchronous mode of the synchronous modes is generated as the command carrier-mode value ptn*. If finv* is equal to or more than finv*2 [Hz] and less than finv*3 [Hz], a value of 6that indicates the six-pulse synchronous mode of the synchronous modes is generated as the command carrier-mode value ptn*. If finv*is equal to or more than finv*3 [Hz], a value of 3 that indicates the three-pulse synchronous mode of the synchronous modes is generated as the command carrier-mode value ptn*. Thus, the command carrier-mode value ptn* takes the value of 0 for the asynchronous mode and takes any one value of 3, 6, and 9 for the synchronous modes.

[0015] Next, a configuration of the carrier synchronization processing unit 6 according to Embodiment 1 is described with reference to FIGS. 4 and 5. FIG. 4 is a block diagram showing in detail an internal processing in the carrier synchronization processing unit 6 according to Embodiment 1, and FIG. 5 is a diagram showing a relation between a command voltage phase Θν2* and the carrier waves in the synchronous modes. The carrier waves of the synchronous modes need to be synchronized with the command voltage. For that reason, the carrier waves each containing Nx3 pulses (N is a natural number of one or more) in one cycle of the command voltage Vu* Vv* or Vw*are shown in FIG. 5. Note that FIG. 5 shows the command voltage Vu* only as a representative thereof. Specifically, the carrier wave in the nine-pulse synchronous mode is a triangular wave having nine peaks in one cycle (360 [deg]) of the command voltage. Likewise, the carrier wave in the six-pulse synchronous mode and that in the three-pulse synchronous mode are triangular waves having six peaks and three peaks in one cycle, respectively. As shown in FIG. 4, the carrier synchronization processing unit 6 is provided with a voltage phase calculator 61, a carrier-mode switching permission determiner 62, a carrier synchronization correction-amount calculator 63, and a carrier wave generator 64. The voltage phase calculator 61 calculates a voltage phase θν2 for one cycle (from 0 [deg] to 360 [deg]) of the command voltages Vu*, Vv* Vw* with respect to a zero-crossing point, defined as 0 [deg], in the upstroke of their sine waves. The carrier-mode switching permission determiner 62 generates the carrier mode value ptn, based on the command carrier-mode value ptn* generated by the carrier mode value generating unit 5 and the voltage phase θν2 calculated by the voltage phase calculator 61. The carrier synchronization correction-amount calculator 63 calculates a carrier period correction amount Ate based on the carrier mode value ptn and the voltage phase Θν2· The carrier wave generator 64 generates a carrier wave carrier based on the carrier mode value ptn, the command frequency finv*, and the carrier period correction amount Ate using, for example, a complementary PWM function of a microcomputer employed as the processor 100 or a compare-match output function provided in a timer counter.

[0016] The functions of respective constituents of the carrier synchronization processing unit 6 are described with reference to FIGS. 5 through 9. The voltage phase calculator 61 calculates the command voltages Vu*, Vv* Vw* by performing three-phase coordinate transformation on the command voltages Vd*, Vq* calculated by the revolution speed calculating unit 4 using the voltage phase θν2 obtained by phase-adjusting the voltage phase θν calculated by the revolution speed calculating unit 4, so that the carrier wave has the FIG. 5 shown phase relation to, for example, the command voltage Vn*. For example, the voltage phase Θν2 is a phase advanced by 90 [deg] with respect to the voltage phase θν. Then, the carrier phase is controlled as follows using the voltage phase Θν2. In a case of the carrier mode being the nine-pulse synchronous mode, the carrier phase is controlled so that the carrier wave has a value of the middle from its peak to its bottom when the voltage phase Θν2 is 0 [deg]. In a case of the carrier mode being the six-pulse synchronous mode, the carrier phase is controlled so that the carrier wave has its peak when the voltage phase Θν2 is 0 [deg]. In a case of the carrier mode being the three-pulse synchronous mode, the carrier phase is controlled so that the carrier wave has a value of the middle from its bottom to its peak when the voltage phase Θν2 is 0 [deg]. Control of the carrier period is described later.

[0017] Next, the processing in the carrier-mode switching permission determiner 62 is described with reference to FIG. 6. FIG. 6 is a block diagram showing a detail configuration of the carrier-mode switching permission determiner 62 shown in FIG. 4. The carrier-mode switching permission determiner 62 is made up of a phase switching conditioner 621 and an asynchronous/synchronous switching condition determiner 622. The phase switching conditioner 621 generates, based on the voltage phase Θν2, a phase switching permission signal ptn_theta necessary for performing a synchronous switching action from a synchronous mode to a different synchronous mode. The asynchronous/synchronous switching condition determiner 622 generates the carrier mode value ptn based on the command carrier-mode value ptn* and the phase switching permission signal ptn_theta.

[0018] The processing in the phase switching conditioner 621 is described with reference to FIG. 5. As shown in FIG. 5, switching between the carrier waves in the synchronous mode is performed at any phase of 90 [deg], 210 [deg], and 330 [deg] of the command voltage phase 0K2*with respect to the command voltage Vu* which degrees are timings when bottoms of the carrier waves are coincident with each other. This allows the carrier waves to be switched smoothly. Hence, the phase switching permission signal ptn_theta having a value of 1 is output at the timing when the phase of the voltage phase θν2 becomes any phase of 90, 210, and 330 [deg]. Meanwhile, a value of O is output except when the voltage phase θν2 is 90, 210, and 330 [deg]. Next, the processing in an asynchronous/synchronous switching condition determiner 622 is described with reference to FIG. 7. FIG. 7 shows timings of generating the carrier mode value ptn in accordance with the command carrier-mode value ptn* in response to the change timings of the value of the phase switching permission signal ptn_theta. The asynchronous/synchronous switching condition determiner 622 changes the carrier mode value ptn when the command frequency finv* crosses the switch frequency (see FIG. 3) set in advance, to switch the carrier mode from the asynchronous mode to a synchronous mode or from a synchronous mode to the asynchronous mode, as shown in FIG. 7. More specifically speaking, switching from a synchronous mode to a different synchronous mode is performed by changing the carrier mode value ptn at the timing when the value of the phase switching permission signal ptn_theta from the phase switching conditioner is changed to 1 after the command frequency finv* crosses one of the switch frequencies set in advance (see FIG. 3).

[0019] FIG. 8 is a flowchart for the carrier synchronization correction-amount calculator 63 shown in FIG. 4 to calculate the carrier period correction amount Ate- First, the command voltage phase 0V2* is generated for each synchronous pulse in the step ST631 during the synchronous mode, based on the relation between the command voltage Fiz*and the synchronous carrier waves shown in FIG. 5. In order to perform stably the control, the voltage phase Θν2 calculated by the voltage phase calculator 61 needs to be controlled so as to approximate the command voltage phase ΘΥ2* as close as possible. Hence, a phase difference ΔΡis calculated in the step ST632 using, for example, the following formula (l):

[0020] Then, the carrier period correction amount Ate is calculated in the step ST633 using, for example, the following formula^

(2) where GAIN is a carrier period gain. The carrier period gain GAIN may be set to a fixed value or a variable value as long as the bound of the value allows the phase difference AP to converge over the entire range of operation. For example, in the case of setting the carrier period gain GAIN to a variable value, the carrier period gain GAIN may be adjustably set depending on the command frequency finv*· [0021] FIG. 9 is a flowchart for the carrier wave generator 64 shown in FIG. 4 to generate the synchronous carrier wave carrier. First, the carrier period tc is calculated in the step ST641 using, for example, the following formula (3):

(3) where, ptn is the carrier mode value, and finv* is the command frequency.

[0022] During the asynchronous mode, the carrier mode value ptn is 0 and the carrier period tc is not calculated using the formula (3) but set to a fixed value given in advance. For example, in a case of the asynchronous mode being desired to operate with 4 [kHz], the carrier period tc is set to 250 [psec] that is the inverse of 4 [kHz], And then, the carrier wave is generated in the step ST642based on the carrier period tc calculated in the carrier frequency calculation step ST641 using, for example, a complementary PWM function of the microcomputer used as the processor 100 or a timer counter having a compare-match output function.

[0023] With the above configuration, the carrier synchronization processing unit 6 has the function of generating the constant-period asynchronous carrier wave independent of the period of the command voltages Vu*, Vv* or Vw* or generating the synchronous-mode carrier waves shown in FIG. 5, and outputs any one of the carrier waves based on the command carrier-mode value ptn*.

[0024] Next, the operation of the acceleration/deceleration adjustment processing unit 7, which is a distinctive part of the motor controller according to Embodiment 1, is described with reference to FIG. 10. FIG. 10 is a flowchart for setting the command frequency finv*. First, the command frequency finv* is generated in the step ST71 under the condition that acceleration/deceleration of the frequency, i.e., the rate of change of the frequency, which is input externally or stored internally, is kept constant, to vary the revolution speed of the motor 1. This generation processing is referred to as “constant acceleration/deceleration processing”. For example, when the motor at rest is accelerated to a certain revolution speed, the constant acceleration/ deceleration processing varies the frequency linearly at a rate of change set in advance in order to prevent abrupt change in the motor revolution speed. Consequently, the command frequency finv* is accelerated to the certain revolution speed with the acceleration being kept constant. In a case of decelerating the motor, the revolution speed is decelerated with the deceleration being kept constant as with acceleration of the motor. In step ST72, determination is made whether or not the carrier mode value ptn is changed. If the carrier mode value ptn is not changed (“NO” in the step ST72), the command frequency finv* set in the step ST71 is output. If “YES” determination is made in the step ST72, the routine process proceeds to the step ST73. In the step ST73, the absolute value of the acceleration/deceleration of the command frequency finv*, i.e., the rate of change of the command frequency finv* generated in the constant acceleration/deceleration processing step ST71 is decreased from a rate of change having been set before the carrier mode value ptn is changed. When the carrier mode value ptn is changed at a time during the command frequency finv* being output by the step ST71 to accelerate the motor 1 at an acceleration (rate of change) of 10 [rps/sec] for example, the step ST73is executed to decrease the acceleration, i.e., the rate of change of the command frequency finv*to 3 [rps/sec], for example. In this way, the acceleration/deceleration adjustment processing unit 7 determines the rate of change of the command frequency finv*, based on the carrier mode value ptn output by the carrier synchronization processing unit 6, to output a command frequency iinv* that varies at the determined rate of change.

[0025] The operation of the acceleration/deceleration adjustment processing unit 7 according to Embodiment 1 is described specifically with reference to FIG. 11. FIG. 11 is a time chart showing temporal variations around the time when the carrier mode is switched from the asynchronous mode to a synchronous mode, in which the top shows the command frequency finv* the middle, the phase difference ΔΡ, and the bottom, the carrier mode value ptn. In FIG. 11, the solid-lines indicate an operation in a case of providing the acceleration/deceleration adjustment processing unit 7 and executing the acceleration/deceleration adjustment processing, and the broken-lines indicate an operation in a case of not providing the acceleration/deceleration adjustment processing unit 7 and not executing the acceleration/deceleration adjustment processing.

[0026] First, the command frequency finv* is accelerated at a constant acceleration, based on the constant acceleration/deceleration processing in the step ST71, from a time of 0 [sec] until it reaches the switch frequency finv*l for switching to the nine-pulse PWM synchronous mode of the synchronous PWM modes. Then, when the carrier mode value ptn is changed from 0 indicating the asynchronous mode to 9 indicating the nine-pulse synchronous mode, a phase difference ΔΡι is produced associated with the switching of the carrier mode. Here, an operation in a case of not providing the acceleration/deceleration adjustment processing unit 7 is explained (the broken lines in FIG. 11). In this case, a phase difference ΔΡ2 produced correspondingly to the acceleration is further added to the phase difference ΔΡι, so that the phase difference APbecomes maximum at a time Ti [sec]. And then, the phase difference AP converges to 0 [deg] as time elapses. Next, the operation of the motor controller provided with the acceleration/deceleration adjustment processing unit 7 according to Embodiment 1 of the present invention is described (the solid lines in FIG. 11). When the carrier mode value ptn is changed from 0 indicating the asynchronous PWM mode to 9 indicating the nine-pulse PWM synchronous mode, the processing in the step ST73 works to decrease the rate of change of the command frequency finv* from the rate of change having been set immediately before the carrier mode value ptn is changed. Accordingly, increase of the phase difference ΔΡ can be more suppressed than the case of not providing the acceleration/deceleration adjustment processing unit 7. After that, the phase difference ΔΡ converges to zero as time elapses. Thus, in the case of providing the acceleration/deceleration adjustment processing unit 7, the phase difference ΔΡ2 corresponding to the acceleration can be prevented from being produced, compared to the case of not providing the acceleration/deceleration adjustment processing unit 7.

Consequently, the phase difference ΔΡ can be reduced by the suppression amount PD in the case of executing the acceleration/deceleration adjustment processing, compared to the case of executing no acceleration/deceleration adjustment processing. According to the motor controller of Embodiment 1 of the present invention, the phase difference ΔΡ can be reduced in this way, thus bringing about an effect of being able to prevent the control performance from degradation due to occurrence of a synchronous condition deviation caused by increase of the phase difference ΔΡ. Likewise, in a case of decelerating the motor 1, when the carrier mode value ptn is changed, the acceleration/deceleration adjustment processing unit 7 decreases the deceleration i.e., decreases the absolute value of the rate of change of the command frequency finv*from the absolute value of a rate of change having been set before the carrier mode is switched. This also brings about the effect of being able to prevent the control performance from degradation due to occurrence of a synchronous condition deviation.

[0027] As described above, the motor controller according to Embodiment 1 adjusts acceleration/deceleration based on the carrier mode value ptn when the carrier mode is switched from the asynchronous mode to a synchronous mode or from a synchronous mode to a different synchronous mode, thus bringing about the effect of being able to prevent the control performance from degrading.

Embodiment 2 [0028] FIG. 12 is a block diagram showing a configuration of a motor controller 10 according to Embodiment 2 of the present invention. The motor controller 10 of Embodiment 2 differs compared to that of Embodiment 1 in that a current sensor 8 is provided for acquiring motor currents of the motor l; any two signals of the motor currents Iu, Ir, Iw acquired from the current sensor 8 are sent to the revolution speed calculating unit 4; and the phase difference ΔΡ calculated by the carrier synchronization processing unit 6 is sent to the acceleration/deceleration adjustment processing unit 7. The revolution speed calculating unit 4 shown in FIG. 12 calculates dq-axis currents by coordinate-transforming any two of the motor currents Iu, Iv, Iw acquired from the current sensor 8, to perform a feedback control for calculating the command voltages Vd*, Vq* from a value subjected to high-pass filtering for removing noise from the q-axis current and from the command frequency finv* received from the acceleration/deceleration adjustment processing unit 7.

[0029] Further, a configuration of the carrier synchronization processing unit 6 of the motor controller 10 according to Embodiment 2 is described with reference to FIG. 13. The carrier synchronization processing unit 6 in Embodiment 2 is different in the output signal of the carrier synchronization correction-amount calculator 63, compared to that in Embodiment 1. Specifically, the carrier synchronization correction-amount calculator 63 outputs the phase difference ΔΡto the acceleration/deceleration adjustment processing unit 7. Note that the method of calculating the phase difference APis the same as with Embodiment 1.

[0030] Next, the operation of the acceleration/deceleration adjustment processing unit 7, which is a distinctive part in the motor controller according to Embodiment 2, is described with reference to FIG. 14. FIG. 14 is a flowchart for setting the command frequency finv*. Comparing to the flowchart for the acceleration/deceleration adjustment processing unit 7 according to Embodiment 1, a conditional step ST74 is appended anew to the flowchart for the acceleration/deceleration adjustment processing unit 7 according to Embodiment 2. The other process and conditional steps ST71 through ST73 are the same as with Embodiment 1. If the phase difference APis equal to or more than a high threshold X [deg] set in advance (“YES” in the step ST74), the routine process proceeds to the step ST73. If the phase difference APis smaller than a low threshold y[deg] set in advance (“NO” in the step ST74), the constant acceleration/deceleration processing step ST71 is executed, and then the command frequency finv* setting routine is ended.

[0031] The operation of the acceleration/deceleration adjustment processing unit 7 according to Embodiment 2 is described specifically with reference to FIG. 15. FIG. 15 is a time chart showing temporal variations, in which the top shows the command frequency finv* the middle, the phase difference ΔΡ, and the bottom, the carrier mode value ptn. The command frequency finv* is accelerated at a constant acceleration, based on the constant acceleration/deceleration processing in the step ST71, from a time of 0 [sec] until it reaches the switch frequency finv*i for switching to the nine-pulse asynchronous mode. Then, when the command frequency finv*crosses the switch frequency finv*i, the carrier mode value ptn is changed from Vindicating the asynchronous mode to 9 indicating the nine-pulse synchronous mode and the carrier mode is switched to the nine-pulse synchronous mode of the asynchronous modes. At this time, the phase difference ΔΡ is produced, and at the timing when the phase difference ΔΡexceeds a high threshold X [deg] set in advance (“YES” in the step ST74 in FIG. 14), the routine process proceeds to the acceleration/deceleration adjustment processing step ST73 to set the command frequency finv* to 0 [rps/sec]. Note that the high threshold X[deg] is set to such a level that the current of the motor 1 has not a distortion caused by too large phase difference ΔΡ. After that, the phase difference ΔΡis decreased gradually according to the processing in the carrier synchronization processing unit 6. And then, the constant acceleration/deceleration processing step ST71 is executed at the timing when the phase difference ΔΡ crosses a low threshold y[deg] set in advance (“NO” in the step ST71 shown in FIG. 14). Subsequently, the rate of change of the command frequency iiav*is increased by the acceleration/deceleration adjustment processing step ST73, i.e., the command frequency finv* is accelerated at a constant acceleration as with, for example, the acceleration in the asynchronous mode shown in FIG. 15. At this time, the phase difference AP momentarily increases correspondingly to the acceleration, but decreases gradually according to the processing in the carrier synchronization processing unit 6. In addition, the low threshold y[deg] is desirably set to 0 [deg] from the standpoint of preventing the phase difference ΔΡfrom increasing; however, since setting to 0 [deg] reduces resistance to load fluctuations, the low threshold is preferably set to a small value close to 0 [deg].

[0032] And then, the command frequency finv* is further accelerated by the constant acceleration/deceleration processing step ST71 also in a case of the synchronous mode being changed from the nine-pulse synchronous mode to the six-pulse synchronous mode, i.e., until the command frequency finv* reaches the switch frequency finv*2. When the carrier mode value ptn is changed from 9 indicating the nine-pulse synchronous mode to 6 indicating the six-pulse synchronous mode, the carrier mode is switched to the six- pulse synchronous mode and the phase difference ΔΡis thereby produced. At the timing when the phase difference ΔΡ exceeds the high threshold .5T[deg] set in advance, the routine process proceeds to the acceleration/deceleration adjustment processing step ST73 and the acceleration of the command frequency finv* is set to 0 [rps/sec]. Then, the constant acceleration/deceleration processing step ST71 is executed at the timing when the phase difference ΔP crosses the low threshold y[deg]. After that, the rate of change of the command frequency finv* is increased by the acceleration/deceleration adjustment processing step ST73 and the command frequency finv*is constantly accelerated. While FIG. 15 shows an example of setting the acceleration (the rate of change of the command frequency) to 0 [rps/sec] by the acceleration/deceleration adjustment processing, the acceleration is not necessarily set to 0 [rps/sec]. Setting the acceleration to a value smaller than that having been set before the carrier mode is switched, allows the control performance to be prevented from degrading. Likewise, in a case of decelerating the motor 1, the acceleration/deceleration adjustment processing decreases the absolute value of the rate of change of the command frequency when the carrier mode value ptn is changed. This also allows the control performance to be prevented from degrading. While FIG. 15 illustrates the operation of switching from the asynchronous mode to the nine-pulse mode and from the nine-pulse mode to the six-pulse mode, it goes without saying that the operation in a case of switching, for example, from the six-pulse mode to the three-pulse mode is similar to the above.

[0033] Thus, the acceleration/deceleration adjustment processing unit 7 adjusts and determines the acceleration/deceleration, i.e., the rate of change of the command frequency finv* based on the phase difference AP, thereby bringing about an effect of being able to prevent a synchronous condition from deviating even in a case of occurrence of an abrupt load fluctuation when the carrier mode is switched.

[0034] Moreover, the absolute value of the rate of change of the command frequency finv* is decreased in the acceleration/deceleration adjustment processing step ST73 immediately after the carrier mode value ptn is changed and when the phase difference ΔΡexceeds the high threshold -5T[deg], thereby preventing motor current distortion associated with control performance degradation when the carrier mode is switched.

[0035] Furthermore, the rate of change of the command frequency finv* is set to 0 [rpm/sec] in the acceleration/deceleration adjustment processing step ST73 after the carrier mode value ptn is changed. This eliminates concurrent operations of the carrier mode switching action and the accelerating/decelerating action, thereby bringing about the effect of being able to prevent the control performance from degrading.

[0036] Still furthermore, the absolute value of the rate of change of the command frequency finv* is increased again depending on the phase difference AP after the absolute value of the rate of change is decreased in the acceleration/deceleration adjustment processing step ST73. This prevent the phase difference APfrom too largely increasing, thus bringing about an effect of being able to accelerate the revolution speed to a target value without deviating from a synchronous condition.

[0037] As described above, the motor controller according to Embodiment 2 adjusts the acceleration/deceleration based on the phase difference ΔΡ, thus bringing about the effect of being able to prevent the control performance from degrading even in a case of occurrence of a load fluctuation when the carrier mode is switched from the asynchronous mode to a synchronous mode or from a synchronous mode to a different synchronous mode.

Embodiment 3 [0038] FIG. 16 is a flowchart showing the operation of an acceleration/deceleration adjustment processing unit 7 of a motor controller according to Embodiment 3 of the present invention. Comparing to the flowchart for the acceleration/deceleration adjustment processing unit 7 according to Embodiment 1, a process step ST75 and a conditional step ST76 are appended anew, as shown in FIG. 16, to the flowchart for the acceleration/deceleration adjustment processing unit 7 according to Embodiment 3. The other process and conditional steps ST71 through ST73 are the same as with Embodiment 1. When the carrier mode value ptn is changed, time counting is started in the step ST75. Then, if the time count value counted in the step ST75 is equal to or more than a value Tmax set in advance (“YES” in the step ST7(?), the constant acceleration/deceleration processing step ST71 is executed. If the time count value is less than the value Tmaxset in advance (“NO” in the step ST70), the acceleration/deceleration adjustment processing step ST73 is executed.

[0039] The operation of the acceleration/deceleration adjustment processing unit 7 according to Embodiment 3 is described specifically with reference to FIG. 17. FIG. 17 is a time chart showing temporal variations around the time when the carrier mode is switched from the asynchronous mode to a synchronous mode, in which the top shows the command frequency finv* the second top, the phase difference ΔΡ, the second bottom, the load torque Tm of the motor; and the bottom, the carrier mode value ptn. In FIG. 17, the solid-lines indicate the operation in a case with a load torque fluctuation, and the broken-lines indicate the operation in a case with no load torque fluctuation.

[0040] In the example shown in FIG. 17, the command frequency finv* is first accelerated at a constant acceleration, based on the constant acceleration/deceleration processing in the step ST71, from time of 0 [sec] until it reaches the switch frequency finv*l for switching to the nine-pulse asynchronous mode. Then, when the command frequency finv* crosses the switch frequency finv*i, the carrier mode value ptn is changed from O indicating the asynchronous mode to 9 indicating the nine-pulse synchronous mode. At this time, the time counting is started in step ST75. And then, the routine process proceeds to the acceleration/deceleration adjustment processing step ST73 to set the rate of change of the switch frequency finv* to 0 [rps/sec]. After that, in a case of no load torque fluctuation (the broken lines in FIG. 17), the phase difference ΔΡ decreases gradually based on the processing in the carrier synchronization processing unit 6. In a case of a load torque fluctuation (the solid lines in FIG. 17) , on the other hand, the time for the phase difference ΔΡ to converge to 0 [deg] is delayed compared to the case of no load torque fluctuation because a phase difference ΔPs is produced correspondingly to the load torque fluctuation. After that, when the time count value exceeds a value Tmax set in advance, the command frequency finv*is accelerated based on the constant acceleration/deceleration processing step ST71. While FIG. 17 shows the example of the rate of change of the command frequency being set to 0 [rps/sec] by the acceleration/deceleration adjustment processing, the rate of change may not necessarily be set to 0 [rps/sec]. Setting the rate of change to a value smaller than that having been set before the carrier mode is switched, allows the control performance to be prevented from degrading. Likewise, in a case of decelerating the motor, the acceleration/deceleration adjustment processing step ST73 is executed, when the carrier mode value ptn is changed, to decrease the absolute value of the rate of change of the acceleration/deceleration, i.e., the absolute value of the rate of change of the command frequency finv*. This also allows the control performance to be prevented from degrading.

[0041] As described above, the motor controller according to Embodiment 3 brings about an effect of being able to operate over the entire range of operation even in a case of the carrier mode not converging to a synchronous condition owing to occurrence of an abrupt load torque fluctuation while the acceleration/deceleration adjustment processing unit 7 adjusts and determines the acceleration/deceleration, i.e., the rate of change of the command frequency finv*.

Embodiment 4 [0042] FIG. 18 is a block diagram showing a configuration of a motor controller 10 according to Embodiment 4 of the present invention. Compared to the motor controller 10 according to Embodiment 2, the FIG. 18 shown motor controller 10 according to Embodiment 4 differs in that any two signals of the motor currents Iu, Iv, Iw acquired by the current sensor 8 of the motor 1 are sent to the acceleration/deceleration adjustment processing unit 7. It should be noted that acquiring information of any two signals of the motor currents Iu, Iv, Iw allows the other one of the motor currents Iu, Iv, Iw to be calculated as a matter of course.

[0043] Next, the operation of the acceleration/deceleration adjustment processing unit 7, which is a distinctive part in the motor controller according to Embodiment 4, is described with reference to FIG. 19. FIG. 19 is a flowchart for setting the command frequency finv* in the acceleration/deceleration adjustment processing unit 7. Comparing to the flowchart for the acceleration/deceleration adjustment processing unit 7 according to Embodiment 1, a process step ST77 and a conditional step ST78 are appended anew to the flowchart for the acceleration/deceleration adjustment processing unit 7 according to Embodiment 4. The other process and conditional steps ST71 through ST73 are the same as with Embodiment 1. If “YES” determination is made in the conditional step ST72, an effective current value Irms is calculated in the current distortion factor calculating step ST77 using the motor current acquired from the current sensor 8. A current distortion factor Ithd is calculated from the effective current value Irms according to the following formula (4):

(4) where a is a natural number of two or more; and Irms(l) is an effective current value of the fundamental component, Irms(2) is an effective current value of the second harmonic, and Irms(i) is an effective current value of the j’-th harmonic. In other words, setting n to an appropriate value depending on a possible distortion allows the degree of distortion with respect to the fundamental component of the effective current to be calculated from the formula (4).

[0044] Then, if the calculated current distortion factor Ithd is equal to or larger than a high threshold iT set in advance (“YES” in the step ST7&), the routine process proceeds to the step ST73. If the calculated current distortion factor Ithd is smaller than a low threshold Q set in advance (“NO” in the step ST78), the constant acceleration/deceleration processing step ST71 is executed. Here, a relation between the phase difference ΔΡ and the current distortion factor Ithd is as shown in FIG. 20. FIG. 20 shows the relation by taking the phase difference ΔP as the horizontal axis and the current distortion factor Ithd as the vertical axis. When the phase difference ΔΡis 0 [deg], the current distortion factor Ithd is also 0. And, as deviation from a synchronous condition increases, i.e., the phase difference ΔΡ increases, the current distortion factor Ithd is also increases, that is, there is a monotonically increasing relation between Ithd and ΛΡ [0045] The operation of the acceleration/deceleration adjustment processing unit 7 according to Embodiment 4 is described specifically with reference to FIG. 21. FIG. 21 is a time chart around the time when the carrier mode is switched from the asynchronous mode to a synchronous mode, in which the top shows the command frequency finv* the middle, the current distortion factor Ithd> and the bottom, the carrier mode value ptn.

[0046] In FIG. 21, the command frequency £av*is first accelerated at a constant acceleration, based on the constant acceleration/deceleration processing in the step ST71, from a time of 0 [sec] until it reaches the switch frequency finv*i for switching to the nine-pulse asynchronous mode. Then, when the command frequency i5nv*crosses the switch frequency finv*l, the carrier mode value ptn is changed from 0 indicating the asynchronous mode to 9 indicating the nine-pulse synchronous mode. At this time, the current distortion factor Ithd increases, and the rate of change of the command frequency i5av*is set to 0 [rps/sec] at the timing when the current distortion factor Ithd exceeds the high threshold Z set in advance (“YES” in the step ST7&), based on the acceleration/deceleration adjustment step ST73. Note that the high threshold if is set to such a level that the current of the motor 1 has not a distortion due to too large current distortion factor Ithd. After that, the current distortion factor Ithd decreases gradually by the processing in the carrier synchronization processing unit 6. And then, the command frequency finv* is increased at a constant acceleration by the constant acceleration/deceleration process step ST71 after the current distortion factor Ithd crosses the low threshold Q set in advance (“NO” in the step ST78). At this time, the current distortion factor Ithd momentarily increases, but decreases gradually by the processing in the carrier synchronization processing unit 6. In addition, the low threshold $is desirably set to 0 from the standpoint of suppressing increase of the phase difference ΔΡ, but is preferably set to a small value close to 0 because setting to 0 reduces resistance to a load fluctuations. While FIG. 21 shows the example of the acceleration (the rate of change of the command frequency) being set to 0 [rps/sec] by the acceleration/deceleration adjustment processing, the rate of change may not necessarily be set to 0 [rps/sec]. Setting the acceleration to a value smaller than that having been set before the carrier mode is switched, allows the control performance to be prevented from degrading. Likewise, in a case of decelerating the motor, the acceleration/deceleration adjustment processing step ST73 is executed, when the carrier mode value ptn is changed, to decrease the absolute value of the rate of change of the command frequency. This also allows the control performance to be prevented from degrading.

[0047] In this way, since the acceleration/deceleration adjustment processing unit 7 calculates the current distortion factor and adjusts the acceleration/deceleration based on the current distortion factor, the acceleration/deceleration can be corrected by utilizing condition of the current, thus bringing about an effect of suppressing harmonic currents with a synchronous condition being kept. Moreover, in the acceleration/deceleration operation, harmonic currents can be suppressed over the entire range of operation without deviating from a synchronous condition.

[0048] As described above, since the motor controller according to Embodiment 4 adjusts and determines the acceleration/deceleration, i.e., the rate of change of the command frequency finv* based on the current distortion factor Ithd, harmonic current can be suppressed, thus bringing about the effect of being able to prevent the control performance from degrading.

Embodiment 5 [0049] FIG. 22 is a block diagram showing a schematic configuration of a compressor apparatus 20 according to Embodiment 5 of the present invention. The compressor apparatus 20 includes a compressor 80 equipped with a motor 1 and a motor controller 10 for outputting a three-phase AC voltage to the motor 1. The motor controller 10 is any one of the motor controllers described in Embodiments 1 to 4. The compressor 80 shown in FIG. 22 is a twin-rotary compressor having compressing parts 83a, 83b. The compressing parts 83a, 83b each are provided with a piston rotated with a rotation of the shaft 84 coupled to the motor 1, a vane, on-off valve, and the like to compress a medium such as a refrigerant by rotation of the motor. The compression ratio and the flow rate of the refrigerant in the compressing parts are varied with the revolution speed of the motor. For example, the flow rate increases with increasing revolution speed of the motor. In Embodiment 5, when the flow rate is varied due to change in the compression ratio of the refrigerant, the rate of change of the flow rate in the compressing parts can be reduced in response to the revolution speed of the motor because the acceleration/deceleration adjustment processing unit 7 decreases the absolute value of the rate of change of the command frequency £nF*when the carrier mode is switched.

[0050] In this way, the compressor apparatus according to Embodiment 5 is capable of switching the carrier mode from the asynchronous mode to a synchronous mode or from a synchronous mode to a different synchronous mode during acceleration/deceleration of the motor, thus allowing the phase difference ΔΡ to be more reduced than a case of not implementing the present invention even when the compression ratio of the refrigerant varies. Thus, using the motor controller 10 according to Embodiments 1 through 4 as a motor controller for the compressor apparatus brings about an effect of being able to prevent the control performance from degrading.

[0051] While the description is made here using a twin rotary compressor as an example of the compressor, the compressor is not limited to a twin rotary compressor but may be a single rotary compressor, and may have one or more compressing parts. In addition, the compressor only needs to be driven by the motor; hence, the compressor may be, for example, a scroll compressor or a screw compressor other than a rotary compressor, as a matter of course.

Embodiment 6 [0052] FIG. 23 is a block diagram showing a schematic configuration of an air conditioner 200 according to Embodiment 6 of the present invention. The air conditioner 200 includes as main constituent components a heat exchanger 40, a heat exchanger 50, an air-conditioner controller 30, and the compressor apparatus 20 described in Embodiment 5. A motor controller 10 provided for the compressor apparatus 20 controls the motor 1 of the compressor 80 in accordance with a command from the air-conditioner controller 30. In the compressor 80, a refrigerant is compressed as a heat exchangeable medium, and the refrigerant is heat-exchanged with, for example, the outdoor air during passing through the heat exchangers 40 and 50. The heat exchanger 40 is, for example, a heat exchanger of the outdoor unit placed outdoors, for exchanging heat between the outdoor air and the refrigerant; and the heat exchanger 50 is, for example, a heat exchanger of the indoor unit placed indoors, for exchanging heat between the indoor air and the refrigerant.

[0053] Air conditioners need to vary heat exchange capability depending on, for example, the outdoor temperature and the indoor temperature. Accordingly, the revolution speed of the motor for the compressor needs to be controlled in accordance with a command from the air-conditioner controller 30. For that reason, the motor controller 10 controls the motor to accelerate/decelerate in accordance with the command from the air-conditioner controller 30. As described in Embodiments 1 through 4, the carrier mode may be in some cases switched from the asynchronous mode to a synchronous mode or from a synchronous mode to a different synchronous mode when the motor is accelerated/decelerated. In switching the carrier mode, the phase difference ΔΡ can be more reduced than a case of not implementing the present invention. Thus, using the motor controller 10 according to Embodiments 1 through 4 as a motor controller for the compressor apparatus brings about an effect of being able to prevent the control performance from degrading.

[0054] It should be noted that the configurations described in above Embodiments 1 through 6 are examples of configurations of the present invention, and may be combined with another prior art and modified or partly omitted without departing from the scope of the invention.

Numeral Reference [0055] 1: motor; 2- power converter; 3: DC power source; 4- revolution speed calculating unit; 5: carrier mode value generating unit; 6: carrier synchronization processing unit; 7- acceleration/deceleration adjustment processing unit; 10: motor controller; 20: compressor apparatus; 80: compressor; and 200: air conditioner.

Claims

1. A motor controller that includes a power converter configured to convert a DC voltage to a three-phase AC voltage by a PWM control, to output the three-phase AC voltage to a motor and a carrier synchronization processing unit configured to output, to the power converter, a carrier wave and a command three-phase AC voltage for the power converter to perform the PWM control, the motor controller comprising an acceleration/deceleration adjustment processing unit configured to output a command frequency for the three-phase AC voltage to the carrier synchronization processing unit and to determine a rate of change of the command frequency, based on a carrier mode of the carrier wave, which is a mode of the PWM control, determined based on the command frequency by the carrier synchronization processing unit.

2. The motor controller of Claim 1, further comprising: a carrier mode value generating unit configured to output a command carrier-mode value for the carrier synchronization processing unit to determine, based on the command frequency, the carrier mode of the carrier wave; and a revolution speed calculating unit configured to calculate, based on the command frequency, and outputs a reference voltage phase for the three-phase AC voltage and a command two-axis voltage, wherein the carrier synchronization processing unit determines a carrier mode of the carrier wave, based on the command frequency and the command carrier-mode value, and the reference voltage phase for the three-phase AC voltage and the two-axis command voltage calculated by the revolution speed calculating unit, and outputs the carrier wave based on the determined carrier mode and the command three-phase AC voltage to the power converter and outputs the carrier mode determined by the carrier synchronization processing unit to the acceleration/deceleration adjustment processing unit.

3. The motor controller of Claim 2, wherein the carrier mode consists of an asynchronous mode in which a frequency of the carrier wave is set independently of a frequency of the three-phase AC voltage and a synchronous mode that includes one synchronous mode or a plurality of synchronous modes in which the frequency of the carrier wave is set to an integral multiple of the frequency of the three-phase AC voltage; and wherein the acceleration/deceleration adjustment processing unit decreases, when the carrier mode received from the carrier synchronization processing unit is changed from the asynchronous mode to the synchronous mode or from a synchronous mode to a different synchronous mode in the case of the carrier mode including the plurality of synchronous modes, the absolute value of the rate of change of the command frequency to a value smaller than the absolute value of a rate of change of the command frequency, having been set before the carrier mode is switched.

4. The motor controller of Claim 3, wherein the acceleration/deceleration adjustment processing unit decreases the absolute value of the rate of change of the command frequency to a value smaller than the absolute value of a rate of change of the command frequency, having been set before the carrier mode is switched, and sets the rate of change of the command frequency to 0.

5. The motor controller of Claim 3 or Claim 4, wherein the carrier synchronization processing unit calculates a phase difference that is a difference between a command voltage phase generated based on a relation between the command three-phase AC voltage and the carrier wave, and a voltage phase calculated based on the reference voltage phase, to output the phase difference to the acceleration/deceleration adjustment processing unit, and calculates a carrier period correction amount for correcting a period of the carrier wave using the phase difference, to correct the carrier wave using the carrier period correction amount; and wherein the acceleration/deceleration adjustment processing unit decreases, after the carrier mode is switched, the absolute value of the rate of change of the command frequency, based on the phase difference received from the carrier synchronization processing unit.

6. The motor controller of Claim 5, wherein the acceleration/deceleration adjustment processing unit decreases, when the phase difference exceeds a high threshold set in advance, the absolute value of the rate of change of the command frequency to a value smaller than the absolute value of a rate of change of the command frequency, having been set before the carrier mode is switched.

7. The motor controller of Claim 6, wherein the acceleration/deceleration adjustment processing unit, after decreases the absolute value of the rate of change of the command frequency, increases the absolute value of the rate of change of the command frequency when the phase difference becomes equal to or smaller than a low threshold set in advance.

8. The motor controller of Claim 3 or Claim 4, wherein a time counting is started at a time when the carrier mode is switched, and the absolute value of the rate of change of the command frequency is increased when a value of the time counting exceeds a value set in advance.

9. The motor controller of Claim 3 or Claim 4, wherein the acceleration/deceleration adjustment processing unit calculates a current distortion factor of an output current of the power converter and decreases, when the current distortion factor exceeds a high threshold set in advance after the carrier mode is switched, the absolute value of the rate of change of the command frequency to a value smaller than the absolute value of a rate of change of the command frequency, having been set before the carrier mode is switched.

10. The motor controller of Claim 9, wherein the acceleration/deceleration adjustment processing unit, after decreasing the absolute value of the rate of change of the command frequency, increases the absolute value of the rate of change of the command frequency when the current distortion factor becomes equal to or smaller than a low threshold set in advance.

11. A compressor apparatus comprising: a compressor equipped with a motor, for compressing a medium by revolution of the motor; and a motor controller of any one of Claims 1 through 10, for outputting a three-phase AC voltage to the motor.

12. An air conditioner comprising a compressor apparatus of Claim 11.