WO2016143608A1 - Motor control apparatus, heat pump system, and air conditioner - Google Patents

Abstract

With a motor control apparatus according an embodiment of the present invention, a current detection control unit: sets a first detection scheme wherein a two-phase PWM signal is outputted if a current detection rate is high when the motor is in a low rotation range and wherein a current detection unit detects a current with one phase at fixed timing and the other one phase at variable timing; and that sets a second detection scheme wherein a three-phase PWM signal is outputted when the current detection rate is low and wherein the current detection unit detects the current of two phases at a fixed timing. The current detection control unit sets a third detection scheme wherein, when the current detection rate is in an intermediary state, the two-phase PWM signal is outputted, and wherein, in a state where current detection of one phase is set at a variable timing, two phases with a duty pulse outputted in a carrier wave period are a second phase and a third phase, and when the duty of one of these two phases decreases, making detection of the current of the two phases impossible, a duty pulse of a first phase is generated by a prescribed value, a duty pulse of the second phase and the third phase is increased by the prescribed value, and current detection of the other one phase is also set at a variable timing.

Description

Motor control device, heat pump system and air conditioner

Embodiments of the present invention provide a control device that controls a motor via an inverter circuit by PWM-controlling a plurality of switching elements connected in a three-phase bridge, a heat pump system including the control device, and an air conditioner About.

When detecting the current of each phase of U, V, W in order to control the motor, there is a technique for detecting the current using one shunt resistor inserted in the DC part of the inverter circuit. To detect all three-phase currents using this method, a three-phase PWM signal can be detected so that two or more phases of current can be detected within one cycle of a PWM (pulse width modulation) carrier (carrier wave). It is necessary to generate a pattern. Therefore, there has been proposed a motor control device that can always detect two or more currents without increasing noise by shifting the phase of the PWM signal within one cycle.

Japanese Patent No. 5178799

Also, there are three-phase modulation method and two-phase modulation method for PWM control of a three-phase motor. In the three-phase modulation method, the switching loss in the inverter circuit increases. Therefore, it is desirable to adopt a two-phase modulation method from the viewpoint of suppressing an increase in loss. However, when the current detection method disclosed in Patent Document 1 is adopted, there is a problem that it becomes difficult to detect current in the low-speed rotation region of the motor.

Therefore, the present invention provides a motor control device that can employ a current detection method using one current detection element while avoiding an increase in switching loss, and a heat pump system and an air conditioner including the control device.

According to the motor control apparatus of the embodiment, the current detection unit calculates the phase current of the motor based on the signal generated by the current detection element connected to the DC side of the inverter circuit corresponding to the current value and the PWM signal pattern. Then, the rotor position determination unit determines the rotor position based on the phase current, and the PWM signal generation unit generates a two-phase or three-phase PWM signal pattern so as to follow the rotor position.

The current detection rate calculation unit obtains a current detection rate according to the two-phase or three-phase PWM signal pattern, and the timing adjustment unit fixes the two-phase current within the carrier wave period of the PWM signal. Or at a variable timing according to the magnitude of the output voltage to the inverter circuit.

At this time, the PWM signal generation unit increases / decreases the duty in both directions of the delay side and the advance side with respect to the arbitrary phase of the carrier wave period for the first phase of the three-phase PWM signal patterns, and for the second phase. Increases or decreases the duty in one direction of the delay side and the advance side with respect to an arbitrary phase of the carrier wave cycle, and for the third phase, increases or decreases the duty in the opposite direction to the above direction with reference to the arbitrary phase of the carrier wave cycle A three-phase PWM signal pattern is generated so that

The current detection control unit outputs a two-phase PWM signal pattern in a state where the current detection rate is high when the motor is in a low-speed rotation region, and the current detection unit outputs one phase at a fixed timing. One phase is a first detection method in which current is detected at variable timing. When the current detection rate is low, a three-phase PWM signal pattern is output and the current detection unit detects two-phase current at a fixed timing. The second detection method is used.

Further, in the state where the current detection rate is intermediate, the two-phase PWM signal pattern is output, and the two-phase in which the duty pulse is output within the carrier wave period is the second phase in the state where the one-phase current detection is set as the variable timing. When the current of the two phases is decreased due to a decrease in the duty of one of the two phases, the first phase duty pulse is generated by a predetermined value, and the second phase and the third phase are generated. The PWM signal generation unit and the timing adjustment unit are controlled to increase the third-phase duty pulse by the predetermined value and use the third detection method in which the other one-phase current detection is also variable.

Functional block diagram showing the configuration of the motor control device according to the first embodiment Diagram showing the configuration of the heat pump system The figure which shows the change of the number of rotations of the motor built in the compressor, and the change of which method to perform current detection when the operation of the air conditioner is started Flowchart schematically showing switching between the drive control method and the current detection method corresponding to FIG. The figure which shows the electric current detection method selected corresponding to the rotation speed field of a motor The figure which shows the current detection rate of each detection method according to the modulation rate Flow chart illustrating the fourth detection method, showing interrupt processing executed every half cycle of the carrier The figure which shows the execution time image of the process shown in FIG. 7 with a PWM carrier waveform The figure which shows the output phase of a three-phase PWM duty pulse Flowchart showing processing contents of step S13 The figure which shows the waveform example of the two-phase PWM pulse corresponding to the pattern (1-11) classified by the process of FIG. Flow chart showing processing contents of step S14 (A) is a diagram showing a three-phase PWM signal when the maximum duty is 95%, and (b) when the maximum duty is 105%, and sectors and patterns corresponding to them. Flow chart showing processing contents of step S15 The figure which shows the definition of U0, V0, W0 and V0_bai, W0_bai Flowchart showing the processing content of step S16 (part 1) Flowchart showing the processing content of step S16 (part 2) Flowchart showing processing contents of step S17 The figure which shows the example of a change of the two-phase PWM signal corresponding to the process of FIG. Flow chart showing processing contents of step S3 (part 1) Flow chart showing processing contents of step S3 (part 2) Flow chart showing processing contents of step S3 (part 3) (A) is a figure which shows the PWM signal waveform and the 1st and 2nd electric current detection timing of a two-phase modulation corresponding to the combination of a pattern and a sector, (b) is the PWM signal waveform in an actual control state, a corresponding pattern, Diagram showing combinations with sectors (part 1) Fig. 23 equivalent (2) FIG. 23 equivalent (part 3) FIG. 23 equivalent (part 4) FIG. 23A is a diagram corresponding to FIG. 23A and is a diagram illustrating patterns (4 to 11). The figure which shows the example of a change of a detection timing in the case of pattern (2) or (3) The figure which shows the example of a change of a detection timing in the case of a pattern (1) The figure which shows the motor current waveform detected by patent document 1 by (a) 4th detection system in the case of the modulation factor 1.0, (b). FIG. 2 is a diagram illustrating a third detection method (part 1) and illustrating a characteristic PWM signal pattern; 25 equivalent diagram 26 equivalent diagram 16 equivalent view (part 1) 17 equivalent diagram FIG. 16 equivalent diagram (2) 22 equivalent diagram The figure which illustrates a 3rd detection system (the 2), and shows the area where an electric current cannot be detected with the motor current waveform detected by the 3rd detection system (the 1) The figure which illustrates a characteristic PWM signal pattern The flowchart which shows the process performed following the process shown in FIG. The flowchart which shows the process performed following the process shown in FIG. 20 is a flowchart showing processing executed following the processing shown in FIG. The flowchart which shows the processing content of a part of step S11 The figure which illustrates a characteristic PWM signal pattern (the 1) The flowchart which shows the processing content of a part of step S10 FIG. 2 is a diagram illustrating a characteristic PWM signal pattern (part 2) The flowchart which shows the processing content of a part of step S9 The figure which illustrates a characteristic PWM signal pattern Diagram showing detected motor current waveform Flow chart illustrating the first and second detection methods, and showing interrupt processing executed for each carrier cycle when performing two-phase modulation. (A) is a figure which shows the phase in which a PWM duty pulse is output in the case of two-phase modulation, and the timing at which A / D conversion is performed on the terminal voltage of the resistance element, and (b) is based on orthogonal voltages Vα and Vβ. The figure which shows the table for calculating 2 phase PWM duty, (c) is a figure which shows a sector on an alpha beta coordinate Flowchart showing interrupt processing executed every half of the carrier cycle when performing three-phase modulation Fig. 51 (b) equivalent diagram Flowchart showing motor speed region determination processing Flow chart showing current detection rate calculation processing Vector diagram showing areas where current detection is not possible Flow chart showing selection process of current detection method in low speed region Flow chart showing the current detection method selection process in the medium speed region Flow chart showing selection process of current detection method in high speed region The figure which shows the PWM signal waveform of the rectangular wave drive system by 120 degrees energization The figure which shows the output voltage waveform of each phase corresponding to FIG. The figure which shows the PWM signal waveform of the rectangular wave drive system by 150 degrees electricity supply The figure which shows the output voltage waveform of each phase corresponding to FIG. Flow chart showing interrupt cycle setting process corresponding to each current detection method The flowchart which is 2nd Embodiment and shows the selection process of the electric current detection system in a high-speed area | region. Flowchart showing an interrupt process executed every half cycle of a carrier cycle in the case of performing three-phase modulation in the third embodiment. The figure which shows the execution time image of the process shown in FIG. 66 with a PWM carrier waveform The flowchart which is 4th Embodiment and shows the outline process during a driving | operation corresponding to 2 phase modulation | alteration and 3 phase modulation | alteration FIG. 3 is a flowchart showing an interrupt process that is executed every half of the carrier period when phase modulation is performed. The figure explaining the processing content of step S326b of FIG.

(First embodiment)
Hereinafter, as an example of a heat pump system, a first embodiment for driving a compressor motor of an air conditioner will be described with reference to FIGS. 1 to 64. In FIG. 2, the compressor (load) 2 constituting the heat pump system 1 is configured by accommodating the compression unit 3 and the motor 4 in the same iron hermetic container 5, and the rotor shaft of the motor 4 is connected to the compression unit 3. Has been. The compressor 2, the four-way valve 6, the indoor heat exchanger 7, the pressure reducing device 8, and the outdoor heat exchanger 9 are connected by a pipe serving as a heat transfer medium flow path so as to form a closed loop. The compressor 2 is, for example, a rotary compressor, and the motor 4 is, for example, a three-phase IPM (Interior Permanent Magnet) motor (brushless DC motor). The air conditioner E includes the heat pump system 1 described above.

The four-way valve 6 is in a state indicated by a solid line during heating, and the high-temperature refrigerant compressed by the compression unit 3 of the compressor 2 is supplied from the four-way valve 6 to the indoor heat exchanger 7 and condensed. Thereafter, the refrigerant is depressurized by the decompression device 8, becomes a low temperature and flows into the outdoor heat exchanger 9, where it evaporates and returns to the compressor 2. On the other hand, at the time of cooling, the four-way valve 6 is switched to a state indicated by a broken line. For this reason, the high-temperature refrigerant | coolant compressed by the compression part 3 of the compressor 2 is supplied to the outdoor side heat exchanger 9 from the four-way valve 6, and is condensed. Thereafter, the refrigerant is depressurized by the decompression device 8, becomes a low temperature and flows into the indoor heat exchanger 7, where it evaporates and returns to the compressor 2. The indoor and outdoor heat exchangers 7 and 9 are blown by the fans 10 and 11, respectively, so that the heat exchange between the heat exchangers 7 and 9 and the indoor air and the outdoor air is efficient. It is structured to be performed well.

FIG. 1 is a functional block diagram showing the configuration of the motor control device. The DC power supply unit 21 is indicated by a DC power supply symbol, but includes a rectifier circuit, a smoothing capacitor, and the like when a DC power supply is generated from a commercial AC power supply. An inverter circuit (DC AC converter) 23 is connected to the DC power supply unit 21 via a positive bus 22a and a negative bus 22b. A shunt resistor 24, which is a current detection element, is inserted on the negative bus 22b side. The inverter circuit 23 is configured by connecting, for example, N-channel power MOSFETs 25 (U +, V +, W +, U−, V−, W−) as a switching element in a three-phase bridge connection. Each phase output terminal of the inverter circuit 23 is connected to each phase winding of the motor 4.

The terminal voltage (signal corresponding to the current value) of the shunt resistor (current detection element) 24 is detected by a current detection unit (current detection unit, timing adjustment unit) 27. When the current detection unit 27 performs A / D conversion and reads the terminal voltage, the current Iu, Iv of each phase of U, V, W is output based on the two-phase or three-phase PWM signal pattern output to the inverter circuit 3. , Iw is detected. Each phase current detected by the current detection unit 27 is input to a vector calculation unit (rotor position determination unit, PWM signal generation unit) 30.

In the vector calculation unit 30, when the rotational speed command ωref of the motor 4 is given from a functional part such as a microcomputer that sets the control conditions, the torque current command Iqref is calculated based on the difference from the estimated actual rotational speed of the motor 4. Generated. The rotor position θ of the motor 4 is determined from the phase currents Iu, Iv, and Iw of the motor 4, and the torque current Iq and the excitation current Id are calculated by vector control calculation using the rotor position θ.

For the difference between the torque current command Iqref and the torque current Iq, for example, a PI control calculation is performed to generate a voltage command Vq. The excitation current Id side is similarly processed to generate a voltage command Vd. The voltage commands Vq, Vd are converted into three-phase voltages Vu, Vv, Vw using the rotor position θ. The three-phase voltages Vu, Vv, and Vw are input to a DUTY generation unit (PWM signal generation unit) 31, and duties U_DUTY, V_DUTY, and W_DUTY for generating PWM signals for each phase are determined.

Each phase duty U, V, W_DUTY is given to the PWM signal generation unit (PWM signal generation unit) 32, and the level with the carrier is compared to generate a two-phase or three-phase PWM signal. In addition, a signal on the lower arm side is also generated by inverting the two-phase or three-phase PWM signal, and after a dead time is added as necessary, they are output to the drive circuit 33. The drive circuit 33 outputs a gate signal to each gate of the six power MOSFETs 25 (U +, V +, W +, U−, V−, W−) constituting the inverter circuit 23 according to the given PWM signal. At this time, the gate signal on the upper arm side is output at a potential boosted by a necessary level. As a method in which the PWM signal generation unit 31 generates a three-phase PWM signal, for example, the method of the fourth embodiment disclosed in Patent Document 1 is used.

In addition, the vector calculation unit 30 outputs the torque current Iq and the excitation current Id to the power consumption calculation unit 34, calculates the estimated speed ωe based on the torque current Iq, the excitation current Id, and the excitation voltage Vd, and the power consumption calculation unit. 34 and the detection method selection unit 35. The power consumption calculation unit 34 outputs the power consumption W to the detection method selection unit (current detection control unit) 35 when the power consumption W is calculated by the following equation based on each input current.

W = ωe × T = ωe × P / 2 × {φ × Iq + (Ld−Lq)} × Id × Iq (1)
However, T is a motor output torque, P is the number of poles of the motor 4, φ is an electric winding interlinkage magnetic flux, Ld is a d-axis inductance, and Lq is a q-axis inductance. The power consumption calculation unit 34 will be described in the third embodiment.

The current detection rate calculation unit (current detection rate calculation unit) 36 calculates a current detection rate for each carrier cycle in the current detection unit 27 based on the three-phase voltages Vu, Vv, and Vw input from the vector calculation unit 30. . The calculation result is output to the detection method selection unit 35. The speed fluctuation detection unit 37 detects the rotational speed of the motor 4 and the degree of speed fluctuation based on the phase current change period output by the current detection unit 27, and outputs the detection result to the detection method selection unit 35. The detection method selection unit 35 selects the detection method of the two-phase current in the current detection unit 27 based on the input information. Therefore, the detection method selection unit 35 also outputs a signal for switching between 2-phase modulation and 3-phase modulation to the PWM signal generation unit 32. Further, the PWM signal generation unit 32 outputs a current detection timing signal to the current detection unit 27.

Further, separately from the DUTY generation unit 31, a rectangular wave drive calculation unit 38 is provided. When the rotational speed of the motor 4 is stabilized in a specific speed region to be described later, the PWM signal generation unit 32 outputs a 120 ° or 150 ° rectangular wave drive signal input from the rectangular wave drive calculation unit 38 to the drive circuit 33. . In the above description, the functions of the configurations 27 to 38 (excluding the drive circuit 33) are functions realized by hardware and software of a microcomputer including a CPU.

Next, the operation of this embodiment will be described with reference to FIGS. FIG. 3 shows first to fourth detection methods to be described later for changes in the number of revolutions of the motor 4 built in the compressor 2 and two-phase current detection within the PWM carrier cycle when the cooling operation by the air conditioner is started. The switching state of which one is performed is shown. FIG. 4 is a flowchart schematically showing switching of the drive control method corresponding to FIG.

As shown in FIG. 4, PWM control is performed with three-phase modulation when the compressor 2 is started to operate the air conditioner (S301). Since the sensorless driving method cannot be executed in the region where the rotational speed of the motor 4 is low, the motor 4 is driven by forced commutation (S302). When the rotational speed increases to some extent, the position sensorless drive method is switched (S303). Thereafter, the detection method of the two-phase current in the current detection unit 27 is selected according to the rotation region (low speed, medium speed, high speed) of the motor 4 and the current detection rate as described later (S304 to S307).

As shown in FIG. 3, immediately after the start of the operation of the air conditioner, the rotation speed of the motor 4 is rapidly increased to reach the high speed region in order to rapidly decrease the temperature in the room where the air conditioner is installed. In this case, the second detection method is executed immediately after startup and while the rotation speed is increased until sensorless driving is possible (S301 to S303), and then the first or third detection method is executed (S307). When the room temperature decreases due to a sudden increase in output immediately after the start of operation, the number of rotations of the motor 4 is decreased to reach the middle speed region. In this case, the first or fourth detection method or the rectangular wave driving method is executed (S306). When the room temperature stabilizes and the low speed region is reached, one of the first to third detection methods is executed (S305).

Hereinafter, the above-described current detection switching control will be described in more detail. As shown in FIG. 5, the current detection method is determined according to the level of the rotation speed region of the motor 4 and the level of the current detection rate in each region. In the high-speed region, the threshold value X1 is set at a current detection rate of 90%, and the first detection method is switched to a threshold value X1 or higher, and the third detection method is switched below the threshold value X1. In the medium speed region, the threshold value X2 is set at a current detection rate of 85%, and the threshold is switched to the first detection method when the threshold value is X2 or more and to the fourth detection method when the threshold value is less than the threshold value X2. Further, in the medium speed region, when the rotational speed of the motor 4 is stabilized as described above, the rectangular wave driving method is switched. In the low-speed region, threshold values X3 and X4 are set to current detection rates of 90% and 80%, respectively, the first detection method is greater than or equal to threshold value X3, and the threshold value X4 is less than the third detection method and threshold value X4. If it is less, the second detection method is switched.

Here, the first to fourth detection methods will be described.
<First detection method>
This is a general current detection method in two-phase modulation. One-phase current is detected at a fixed timing in the center phase of the carrier cycle, and the other one-phase current is detected at a variable timing according to the change in duty. (Conventional two-phase modulation, see Japanese Patent Application Laid-Open No. 2014-171321).

<Second detection method>
This is a current detection method disclosed in Patent Document 1, and two-phase currents are detected at fixed timing in three-phase modulation (new three-phase modulation).

<Third detection method>
This is a mixture of two-phase modulation and three-phase modulation. In two-phase modulation, one phase of current detection is a fixed timing and the other one phase of current detection is a variable timing. Duty pulses are output within the carrier cycle. The two phases are based on the center phase of the carrier cycle. Are the second phase and the third phase in which the duty is increased or decreased in the respective directions of the delay side and the advance side. When one of the two phases decreases and the two-phase current can no longer be detected, a first-phase duty pulse for increasing or decreasing the duty in two directions with respect to the center phase is generated as well as a second value. The phase and third phase duty pulses are increased by the predetermined value to switch to three-phase modulation. In addition, other one-phase current detection that is detected at a fixed timing is also set to a variable timing. Details of this method will be described later.

<Fourth detection method>
Although this will also be described in detail later, this is a “new two-phase modulation” method in contrast to the “conventional two-phase modulation”.

As shown in FIG. 5, the current detection rate of the first detection method that has been conventionally performed for two-phase modulation increases and decreases as the motor speed changes. Therefore, an optimum detection method is selected and switched in consideration of power consumption, drive noise, and current detection rate for each rotation speed region. FIG. 6 shows the current detection rate by each detection method according to the level of the modulation rate. From the viewpoint of power consumption, it is desirable to employ two-phase modulation as much as possible.

The current detection rate at the modulation rate corresponding to the medium speed region is higher in the second detection method than in the first detection method. However, the second detection method has a demerit that driving noise becomes larger. Therefore, in the medium speed region, the first detection method is preferentially selected, and the second detection method is selected when the current detection rate decreases.

At the modulation rate corresponding to the low speed region, the current detection rates of the first and fourth detection methods are both low, and the current detection rates of the second and third detection methods are both 100%. If switching from 2-phase modulation to 3-phase modulation in this region, current detection may become impossible at the switching timing. Therefore, the detection method is selected in the order of first → third → second as the current detection rate decreases.

In the region where the modulation rate is near 100%, the current detection rate is higher in the order of 3> 1> 4th. Further, in the high speed region shown in FIG. 5 where the modulation rate exceeds 100%, the current detection rate of the first detection method is lowered. Therefore, the first detection method is preferentially selected from the viewpoint of power consumption, and the third detection method is selected when the current detection rate decreases.

Hereinafter, although the third and fourth detection methods will be described, the fourth detection method will be described first.
<Fourth detection method>
FIG. 7 is a flowchart showing interrupt processing executed every half cycle of the carrier. That is, a PWM interrupt occurs at the peak and bottom of the triangular wave amplitude that is the carrier. First, it is determined whether or not the flag M_INT_flg = 0 (reset) (S1). If “0”, the A / D converted data is extracted by the current detection unit 27 (S2). A phase current is detected (S3). In step S3, a “Start F” process described later is executed.

Here, the A / D conversion processing of the terminal voltage of the shunt resistor 24 in the current detection unit 27 is executed twice within one carrier cycle separately from the processing shown in FIG. 3 (execution timing will be described later). The A / D converted data is stored in, for example, a register. Therefore, the process of step S2 reads the data stored in the register.

Next, the rotor position (θ) of the motor 4 is estimated from the three-phase current by vector control calculation (S4), and frequency control (speed control, S5) and current control (PI control, etc.) are executed (S6). Then, the flag M_INT_flg is set to “1” (S7). The subsequent steps S8 to S10 are performed in the DUTY generation unit 31. With reference to the value of the carrier counter supplied from the PWM signal generation unit 32, it is determined whether the up-counting or down-counting is in progress (S8). If up-counting is in progress, D_Pwm_set_2 () is set (S9), and if down-counting is in progress, D_Pwm_set1_ () is set (S10). These will be described with reference to FIGS.

If the flag M_INT_flg is “1 (set)” in step S1, a two-phase PWM signal is output (S11), and the flag M_INT_flg is set to “0” (S12). Then, when the processing of “Start A to E” is executed (S13 to S17), the process proceeds to step S8. That is, in the PWM interrupt process, steps S2 to S8 and S10 are executed in the first half of the cycle, and steps S11 to S17, S8, and S9 are executed in the second half of the cycle.

FIG. 8 shows an execution time image of interrupt processing at the time of two-phase modulation together with a PWM carrier waveform. In the air conditioner, a motor for driving the fan 11 of the heat exchanger 9 corresponding to the outdoor unit is controlled in parallel with the compressor 2 by a single control circuit (microcomputer). The motor that drives the fan 10 of the heat exchanger 7 corresponding to the indoor unit is controlled by another control circuit, a driver IC, or the like.

Therefore, in FIG. 8, (a) shows processing times (1) to (4) related to motor control of the compressor 2 shown in FIG. 3, and (b) shows processing time related to motor (fan motor) control of the fan 11 ( 5). That is, when a PWM interrupt occurs at the bottom of the triangular wave amplitude, after executing the processing shown in FIG. 3, the motor current is also detected for the fan motor to perform vector control. In the processes (1) to (4) indicated by circled numbers in the figure, the processes (1) and (3) correspond to steps S2 to S8, and the processes (2) and (4) correspond to steps S9 and S10, respectively. It corresponds. In this case, the fan motor control (5) is performed after the processing (4) is executed.

FIG. 9 shows the output phase of each phase PWM duty pulse. As described above, the method disclosed in Patent Document 1 is used. That is, in the first phase among the three phases, the duty is increased / decreased in both directions of the delay side and the advance side with reference to the bottom of the triangular wave amplitude. For the second phase, for example, the duty is increased or decreased on the leading phase side with respect to the bottom, and for the third phase, the duty is increased or decreased on the delayed phase side with respect to the bottom. In this example, the first, second, and third phases are the U, V, and W phases, respectively, but these correspondences are of course arbitrary. When an interrupt occurs at the peak of the triangular wave amplitude, the carrier counter is counting down, so the duty pulse of the first half of the current carrier cycle is output by D_Pwm_set_2 (). Note that the duty values of the U, V, and W phases are twice the duty values (U0, V0, and W0 described later) calculated in step S11.

For the U phase, a pulse with half the duty is output from the timing after the interrupt at the peak to the bottom. For the V phase, if the duty is less than 50%, the pulse is output in the period from the timing after the interruption at the peak to the bottom as in the U phase. For the W phase, when the duty exceeds 50%, the excess pulses are output during the period from when the interrupt at the peak occurs until the bottom is reached. Therefore, it is these pulses that are output by D_Pwm_set_2 ().

On the other hand, when an interrupt occurs at the bottom of the triangular wave amplitude, the carrier counter is counting up, so the D_Pwm_set_1 () outputs a duty pulse for the latter half of the current carrier cycle. As for the U phase, as in the first half, a pulse having a duty of 1/2 is output in the period from the timing to the peak after the interruption at the bottom occurs. For the V phase, when the duty exceeds 50%, the excess pulses are output during the period from the timing when the interruption at the bottom occurs until the peak is reached. For the W phase, if the duty is less than 50%, the pulse is output in the period from the timing to the peak after the bottom interruption occurs, as in the U phase. Therefore, it is these pulses that are output by D_Pwm_set_1 ().

Although FIG. 9 shows three-phase duty pulses, since the actual drive format is two-phase modulation, only two-phase duty pulses are output.
Next, with reference to FIGS. 10 and 11, the process (Start A) in step S13 will be described. In this process, the patterns are classified into patterns (0) to (11) according to the magnitude relationship of the respective phase duty pulses in the two-phase modulation PWM signal. These patterns are indicated by a variable ptn in the processing described later. The pattern division here is based on the following conditions.

The current detection unit 27 sets a minimum duty that can be detected as a minimum width, and a maximum width (100%) obtained by subtracting the minimum width as a maximum width. For example, if the minimum time during which current can be detected is 10 μs and the carrier frequency is 4 kHz, the minimum width is 4% and the maximum width is 96%. If the duty that is less than the maximum width and exceeds the minimum width is an intermediate width, the output pattern of the two-phase PWM signal is divided into patterns according to the following combinations of U, V, and W phase duties.

(1) When U phase is intermediate width and V or W phase is greater than maximum width (2, 3) When either V or W phase is intermediate width and the other is greater than maximum width (4, 6) When the U phase and the V or W phase are both greater than or equal to the maximum width (5) When both the V phase and the W phase are greater than or equal to the maximum width (7) The U phase is greater than or equal to 0 and the V or W phase When either is less than the minimum width (8, 9) When either V or W phase is 0 or more and the other is less than the minimum width (10, 11) The U phase is less than the minimum width and the V or W phase When either is 0 or more (0): When other than (1) to (11)

In steps S21 to S33 shown in FIG. 10, patterns (variable ptn) (0) to (11) are sorted according to the above conditions. FIG. 11 shows two-phase PWM signal patterns corresponding to patterns (1) to (11). Among these, patterns (4) to (11) correspond to an overmodulation state in which the output voltage is extremely large. The pattern (7) is shown when the W-phase duty is less than the minimum width.

Next, with reference to FIG. 12, the process (Start B) in step S14 will be described. In this process, the sectors (0) to (5) are classified according to the relative magnitude relationship of the duty pulses of each phase in the PWM signal of two-phase modulation. These sectors are indicated by a variable sector in the processing described later. The sector division here is based on the following conditions.
(0) U phase is maximum and V phase> W phase (1) U phase is maximum and V phase <W phase (2) V phase is maximum and U phase> W phase (3) V phase is maximum And U phase <W phase (4) W phase is maximum and U phase> V phase (5) W phase is maximum and U phase <V phase

In steps S41 to S45 shown in FIG. 12, sectors (0) to (5) are determined according to the above conditions. FIG. 13 shows sectors and patterns that change according to the actual output of a PWM signal. (A) is the case where the maximum duty is 95%, which is near the maximum width, the sector changes from (0) to (5), and the pattern changes from (0) to (3), (8) to (10). is doing. (B) is the case where the maximum duty exceeds 105% (overmodulation state), the sector changes from (0) to (5), but the pattern changes from (0) to (9). ing. That is, as the output voltage increases, the time span occupied by the patterns (0) to (3) is expanded, and the section where the patterns (4) to (11) are generated at the boundary where the patterns (0) to (3) are switched. It can be seen that is increasing.

Next, with reference to FIG. 14, the process (Start C) of step S15 will be described. In this process, the current detection unit 27 determines the timing for A / D conversion of the terminal voltage of the shunt resistor 24 within the carrier period in accordance with the combination of the pattern and the sector. Note that α in the figure is set in consideration of the above-described current detectable time, current detection accuracy, and the like (for example, duty 5 to 10%). PWM_MAX is the maximum value of duty: 100%.

Further, U0, V0, and W0 in the figure correspond to 1/2 of the U, V, and W-phase duties that are initially determined with the intermediate point (bottom) of the carrier cycle as the base point, as shown in FIG. 15 (a). It is time to do. As shown in FIG. 15B, V0_bai and W0_bai are intermediate points of the carrier cycle when the V and W phase duty pulses are shifted in order to output the three-phase PWM signal in the pattern shown in FIG. This corresponds to the length of the pulse extending from the base point. Time is a variable indicating the A / D conversion timing of each phase of U, V, and W.

Step S53 is the case of pattern (1) and sector (2), and the A / D conversion timing is set to (PWM_MAX-α).
Step S54 is the case of pattern (1) and sector (4), and the A / D conversion timing is set to (PWM_MAX-α).

Step S58 is the case of pattern (3) and sector (3) and overmodulation exceeding V0_bai (PWM_MAX × 2) (S57: YES), and the A / D conversion timing is set to α. Yes. Step S59 is a case of “NO” in Step S57, and the A / D conversion timing is set to (PWM_MAX × 2−V0_bai + α).

Step S62 is a case of pattern (2) and sector (5), and a case of overmodulation in which W0_bai exceeds (PWM_MAX × 2) (S61: YES), and the A / D conversion timing is set to α. Yes. Step S63 is the case of “NO” in Step S61, and the A / D conversion timing is set to (PWM_MAX × 2−W0_bai + α).

Next, with reference to FIGS. 16 and 17, the process (Start D) in step S16 will be described. In this processing, the timing at which the current detection unit 27 performs A / D conversion within the carrier period is reduced from the beginning (peak) to the half period (bottom) of the carrier period according to the combination of the pattern and the sector. In each of the count period and the up-count period from the 1/2 period to the end of the carrier cycle, it is determined at which timing. The former is the first detection timing, and the latter is the second detection timing.

In the Start C flow and the Start D flow, the case classification by the combination of patterns and sectors is the same. Therefore, the variable time for setting each timing is the one corresponding to the same combination in StartC.

In the case of the pattern (0) (S71: YES), it is a case other than the patterns (1) to (11) shown in FIG. 11, and the two-phase currents can be detected at fixed timings. Therefore, the down timing / up count AD timing is set to α (S72). That is, A / D conversion is performed at the timing when the remaining count value reaches α from the beginning of the carrier cycle and at the timing when time α passes from ½ of the carrier cycle.

In the case of pattern (1) and sector (2) (S74: YES), the U-phase A / D conversion timing is set to time in the up-count period, that is, (PWM_MAX-α) determined in step S53. Further, the down-count period is set to α (S75).

In the case of the pattern (1) and the sector (4) (S76: YES), the up-count period α is set, and the down-count period is set to time, that is, (PWM_MAX−α) determined in step S54 ( S77). If the pattern is other than the sector (2-4) (S76: NO), the up-count period and the down-count period are set to α (S78).

In the case of pattern (3) and sector (3) (S80: YES), the up-count period is set to time, that is, α determined in step S58, or (PWM_MAX × 2-V0_bai + α) determined in step S59. To do. On the other hand, the down-count period is set to α (S81).

In the case of pattern (3) and sector (5) (S82: YES), the timing of the up-count period is set to α. Further, the timing of the downcount period is set to time, that is, (PWM_MAX-α) determined in step S60 (S83). If the pattern is (3) and other than sectors (3, 5) (S82: NO), the up-count period and the down-count period are set to α (S84).

In FIG. 17, in the case of pattern (2) and sector (5) (S86: YES), the timing of the up-count period is set to α, and the timing of the down-count period is determined to time, that is, determined in step S62. α or (PWM_MAX × 2-W0_bai + α) determined in step S63 is set (S87).

If it is not the pattern (2) (S85: NO), it is further determined whether the pattern is (10), (11) (S85a, 85c). If it is pattern (10) (S85a: YES), the timing of the up-count period is set to α, and the timing of the down-count period is set to α × 2 (S85b). If it is the pattern (11) (S85c: YES), the timing of the up count period is set to α × 2, and the timing of the down count period is set to α (S85d). If it is not the pattern (2) and the sector (5) (S86: NO), or if it is not the pattern (11) (S85c: NO), the timing of the up-count period and the down-count period is set to α, respectively. (S88).

Next, with reference to FIG. 18 and FIG. 19, the process of Step S17 (StartE) will be described. In this process, the variable shift used to change the increasing / decreasing direction of the duty pulse is set to any one of “0 to 2” for either the second phase (V) or the third phase (W). . First, if the V-phase duty is greater than or equal to the maximum width and less than 100% (S91: YES), W0_bai is obtained by adding the minimum width to the difference obtained by subtracting V0_bai from PWM_MAX (MAX in the figure) × 2. And W0_bai is less than 100% (= W-phase duty <50%) is determined (S92). If this condition is satisfied (YES), the variable shift is set to “1” (S93), and if not satisfied (NO), the variable shift is set to “0” (S94).

On the other hand, if “NO” is determined in step S91 and the W-phase duty is greater than or equal to the maximum width and less than 100% (S95: YES), V0_bai is the maximum difference obtained by subtracting W0_bai from PWM_MAX × 2. It is determined whether or not V0_bai is less than 100% (= V-phase duty <50%), which is smaller than the value obtained by adding the small width (S96). If this condition is satisfied (YES), the variable shift is set to “2” (S97). If not satisfied (NO), the variable shift is set to “0” (S98).

FIGS. 19A and 19B illustrate the case of pattern (3). Pattern (3) is a case where the V-phase duty is greater than or equal to the maximum width and the W-phase duty is greater than or equal to the minimum width. As shown in FIG. 19A, a V-phase current is detected at a fixed first detection timing, and a negative U-phase current is detected at a variable second detection timing. However, when at least one of the V and W phase duty decreases from this state, and when there is no period in which the V and W phase duty pulses overlap at the second detection timing, a negative U phase current is detected. Therefore, the same V-phase current or W-phase current as the first detection timing is detected.

Therefore, as shown in FIG. 19B, the direction in which the W-phase duty is increased is changed to the same direction as the V-phase duty. As a result, the negative U-phase current is detected at the fixed first detection timing, and the V-phase current is detected at the variable second detection timing. Therefore, if the V-phase duty is reduced, the second detection timing may be shifted in the right direction in the drawing to cope with it. Further, even if the W-phase duty is reduced, if the width is equal to or greater than the minimum width, detection can be performed at the fixed first detection timing.

FIG. 19C shows a case where the variable shift is set to “1” in the case of the pattern (3). The arrow with the circled number “1” in the figure indicates the value obtained by adding the minimum width to “the difference obtained by subtracting V0_bai from MAX × 2 (PWM_MAX × 2)” in the condition determination in step S92. The arrow with “2” indicates W0_bai. Here, the variable shift is set to “1” in the case where the left end (variable end) side of the V-phase duty and the right end (variable end) side of the W-phase duty overlap in the up-count section.

FIG. 19D shows a case where the variable shift is set to “2” in the case of the pattern (2). The arrow with the circled number “3” in the figure indicates the value obtained by adding the minimum width to “the difference obtained by subtracting W0_bai from MAX × 2” in the condition determination in step S96, and the circled number “4” is added. The indicated arrow indicates V0_bai. Here, the variable shift is set to “2” because, like FIG. 19C, the left end (variable end) side of the V-phase duty and the right end (variable end) side of the W-phase duty in the down-count section are set. This is an overlapping case.

Next, with reference to FIG. 20 to FIG. 22, the process of Step S3 (Start F) will be described. In this process, the two-phase current is detected within the carrier period based on the combination of the pattern and sector determined in the above processes and the first and second detection timings of the phase current determined by the combination (A / D conversion). Then, a three-phase current is obtained from the detected two-phase current.

As shown in FIG. 11, patterns (4) to (11) shown in FIG. 20 are cases of an overmodulation state in which the output voltage of one or more phases is extremely large, and two-phase output is performed within the carrier period. Since it is difficult to detect the current, only the current of one phase is detected. The patterns (4), (7), (8), and (10) are down-count timing, and the patterns (5), (6), (9), and (11) are up-count timing, respectively. Phase (S102), U phase (S104), V phase (S106), U phase (S108), V phase (S110), W phase (S112), V phase (S114), and W phase (S116) currents are acquired. . In the case of patterns (10) and (11) in which the U-phase duty is less than the minimum width, the current detection timing is α × 2.

In FIG. 21, in the case of sector (0), W and U phase currents are detected at the first detection timing (down count) and second detection timing (up count), and the V phase current is the detected two phase current. Is obtained by calculation (S118). In FIG. 21 and FIG. 22, the reason that the A / D conversion value (right side) stored in the variable R_Iu is attached with a sign − is because inverting amplification is performed on the input side of the A / D converter. is there. Since the sign of the detected W-phase current is negative, the sign-is not added when storing in R_Iw. Hereinafter, in the description, the presence or absence of the sign-is not referred to.

If it is sector (1), the U and V phase currents are detected at the first and second detection timings, and the W phase current is obtained by calculation (S120). In the case of sector (2), it is determined whether or not it is pattern (1) (step S122). If it is pattern (1) (YES), W and V phase currents are detected at the first and second detection timings ( S123). On the other hand, if it is not the pattern (1) (NO), the W and U phase currents are detected at the first and second detection timings, and the V phase current is obtained by calculation (S124).

If it is the sector (3) (S125: YES), it is determined whether or not the variable shift is “1” (S126). If it is “1” (YES), the U and V phases are detected at the first and second detection timings. The current is detected (S127). On the other hand, if it is not “1” (NO), it is determined whether or not the pattern is (1) (S128). If it is pattern (1) (YES), the V and U phase currents are detected at the first and second detection timings. (S129). On the other hand, if the pattern is not (1) (NO), the V and W phase currents are detected at the first and second detection timings (S130).

On the other hand, if it is not the sector (3) in step S125 (NO), as shown in FIG. 22, it is further determined whether it is the sector (4) (S131) or the pattern (1) (S132). In the case of sector (4) and pattern (1) (S132: YES), W and V phase currents are detected at the first and second detection timings (S133). If the pattern is not the pattern (1) (S132: NO), the U and V phase currents are detected at the first and second detection timings (S134).

Also, if it is not sector (4) in step S131 (NO), it is a case of sector (5), and it is determined whether variable shift is “2” (S135). When the variable shift is “2” (YES), the W and U phase currents are detected at the first and second detection timings (S136). If “NO” is determined in the step S135, it is determined whether or not the pattern is the pattern (2) (S137). If the pattern is the pattern (2) (YES), the U and W phase currents are determined at the first and second detection timings. Is detected (S138). If it is not the pattern (2) (S137: NO), the V and W phase currents are detected at the first and second detection timings (S141).

How the first and second current detection timings are finally determined according to the combination of the pattern and the sector described above will be described with reference to FIGS. FIG. 23 shows the case of pattern (0), and the sector can take all of (0 to 5). (B) shows a combination of an actual two-phase modulation PWM signal waveform and a corresponding pattern and sector. Although the phases to be detected are different depending on the sector, the first and second current detection timings are both fixed timings (both down count and up count are α).

FIG. 24 shows the case of pattern (1), and the sector is (2, 4). In these cases, the first and second current detection timings are both fixed timings. However, one is α and the other is (PMW_MAX−α).

FIG. 25 shows the case of pattern (2), and the sector is only (5). However, there are three cases depending on whether W0_bai exceeds PWM_MAX × 2 or shift (2). When W0_bai exceeds PWM_MAX × 2, the first and second current detection timings are both fixed. When W0_bai does not exceed PWM_MAX × 2, the first current detection timing is variable, and in the case of shift (2), the V phase duty increase / decrease direction is made the same as the W phase. As a result, the phase to be detected is changed from (U, W) to (W, U).

FIG. 26 shows the case of pattern (3), and the sector is only (3), but it is further divided into three cases depending on whether V0_bai exceeds PWM_MAX × 2 or shift (1). When V0_bai exceeds PWM_MAX × 2, the first and second current detection timings are both fixed. When V0_bai does not exceed PWM_MAX × 2, the second current detection timing is variable, and in the case of shift (1), the W phase duty increase / decrease direction is made the same as the V phase. As a result, the phase to be detected is changed from (V, U) to (U, V). FIG. 27 shows patterns (4) to (11) and corresponds to FIG.

FIG. 28 shows an example of a characteristic change in detection timing in the case of pattern (2) or (3). As shown in (a), the V and W phase duty pulses are output without a period in which they overlap each other, and the V and W phase currents are detected at the first and second detection timings, respectively. When the W-phase duty exceeds 96%, a period in which the V and W-phase duty pulses overlap each other occurs in the first half of the carrier cycle. In this case, the phase of the current detected at the first detection timing is changed to the U phase (−).

If the V or W phase duty is reduced from this state, there is a possibility that the U phase current cannot be detected because the V and W phase duty pulses deviate from each other when the first detection timing remains fixed. Therefore, the first detection timing is made variable, and the U-phase current is detected continuously within the overlapping period of the V and W-phase duty pulses.

FIG. 28 (b) shows a case where a period in which the V and W phase duty pulses overlap each other in the latter half of the carrier cycle due to the V phase duty exceeding 96%. In this case, the phase of the current detected at the second detection timing is changed to the U phase (−). If the V or W phase duty is reduced from this state, there is a possibility that the U phase current cannot be detected because the V and W phase duty pulses deviate from each other when the second detection timing remains fixed. Therefore, the second detection timing is made variable, and the U-phase current is detected continuously within the overlapping period of the V and W-phase duty pulses.

FIG. 29 shows an example of a characteristic change in detection timing in the case of pattern (1). As shown in (a), the period in which the U and V phase duty pulses overlap each other occurs only in the first half of the carrier cycle, and the W (−) and U phase currents are detected at the first and second detection timings, respectively. ing. From this state, when the V-phase duty exceeds 96%, an overlapping period occurs even in the second half of the carrier cycle. In this case, the current detected at the second detection timing is also the W phase (−). Therefore, the second detection timing is changed, and the V-phase current is detected in a period in which only the V-phase duty pulse is generated. In order to maintain this state, the second detection timing is fixed at the changed timing (however, it may be variable depending on the change in the V-phase duty).

FIG. 29 (b) is a case where a period in which the U and W phase duty pulses overlap each other in the first half of the carrier cycle occurs because the W phase duty exceeds 96%. In this case, the first detection timing is changed, and the W-phase current is detected during a period in which only the W-phase duty pulse is generated. In order to maintain this state, the first detection timing is fixed at the changed timing (however, it may be made variable depending on the change in the W-phase duty).

FIG. 30 shows (a) a motor current waveform detected by the method of the present embodiment and (b) a motor current waveform detected by the method of Patent Document 1 when the modulation factor is approximately 1.0. Is shown. As is apparent from this figure, as a result of the current detection rate being improved in this embodiment, the current waveform is less distorted and closer to a sine wave.

As described above, according to the fourth detection method, the current detection unit 27 is configured to operate the motor based on the signal generated by the shunt resistor 24 connected to the DC side of the inverter circuit 23 corresponding to the current value and the PWM signal pattern. 4 phase currents Iu, Iv, and Iw are detected, and the vector control unit 30 determines the rotor position θ based on the phase current, and together with the PWM signal generation unit 32, any one of the three phases follows the rotor position θ. A two-phase PWM signal pattern is generated. At this time, the PWM signal generation unit 32 increases or decreases the duty in both directions of the delay side and the advance side with respect to the bottom of the carrier cycle for the U phase of the three-phase PWM signal pattern, and the V phase is based on the bottom. In one direction of the delay side and the advance side, the W phase increases or decreases the duty in the direction opposite to the above direction.

Then, the current detection timing adjustment unit 34 detects the current at a fixed timing for one phase in the two-phase modulation within the carrier cycle, and detects the current at a fixed timing for the other phase. Alternatively, the detection timing is adjusted so that the current can be detected at a variable timing corresponding to the magnitude of the output voltage to the inverter circuit 23. Therefore, the current detection rate can be improved even in a region where the output voltage is high and the overmodulation state occurs, and the control accuracy can be improved while suppressing the switching loss.

The current detection timing adjustment unit 34 determines whether the current detection for the other phase is a predetermined fixed timing or a timing changed from the fixed timing according to the two-phase PWM signal pattern. decide. Specifically, the current detection unit 27 sets the minimum duty that can be detected as the minimum width, determines the maximum width and the intermediate width based on the minimum width, and sets the output pattern of the two-phase PWM signal to any one of the widths. The pattern is divided into patterns (0 to 11) according to the combination of the three-phase duty, and the sector (0 to 5) is classified according to the magnitude relationship of the three-phase duty. Then, depending on the combination of the pattern (0 to 11) and the sector (0 to 5), it is determined whether the current detection for the other phase is set to a predetermined fixed timing or a changed timing. To do.

This makes it possible to appropriately determine whether or not to make the other one of the current detection timings variable according to each combination of PWM signals in two-phase modulation. In addition, in an overmodulation state where the output voltage is extremely high, it is possible to reliably detect a state in which only one-phase current can be detected, to detect the current and use it for motor control as much as possible.

The current detection timing adjustment unit 34 sets current detection for the other phase to a predetermined fixed timing, and the two phases in which the duty pulse is output within the carrier cycle are the V and W phases, and both fixed timings. When a period overlapping the output timing of the two-phase duty pulse occurs from the state in which the two-phase current detected in step V is the V and W phases, one of the phases to be detected is changed to the U phase. Therefore, a two-phase current can be reliably detected.

In addition, the current detection timing adjustment unit 34 may change the period in which the V or W phase duty pulses overlap each other after changing one of the detection target phases to the U phase within a range in which the U phase can be detected. Change the current detection timing. Thereby, it is possible to prevent the repeated change as much as possible while maintaining the changed detection target phase.

Further, the current detection timing adjustment unit 34 has two phases for which a duty pulse is output within the carrier cycle, the U phase and the V or W phase, and the two-phase current detected at both fixed timings. When the U phase current cannot be detected from the U phase and the W or V phase, the current detection for the other phase is set as a variable timing, and one of the phases to be detected is set to V or W from the U phase. Change to phase. Therefore, also in this case, the two-phase current can be reliably detected. Then, the current detection timing adjustment unit 34 changes the current detection timing for the other phase once, and then fixes the changed timing to detect the V or W phase current. Also in this case, it is possible to prevent the repeated change while maintaining the detection target phase after the change as much as possible.

Furthermore, the current detection timing adjustment unit 34 is configured such that the two phases for which the duty pulse is output within the carrier cycle are the V and W phases, and when one of these duties decreases, the two-phase current cannot be detected. The duty increase / decrease direction of the phase with the smaller duty is changed to the same direction as the other phases. As a result, a period in which the two-phase duty pulses overlap each other is generated, and the two-phase current can be detected.

Furthermore, the motor 4 which comprises the compressor 2 is controlled about the air conditioner E provided with the heat pump system 1 provided with the compressor 2, the outdoor side heat exchanger 9, the decompression device 8, and the indoor side heat exchanger 7. Since it makes it object, the operating efficiency of the heat pump system 1 and the air conditioner E can be improved.

<Third detection method (part 1)>
In the fourth detection method, for example, as shown in FIG. 26, when the variable shift is “1” in the combination of the pattern (3) and the sector (3), the W phase duty increase / decrease direction is set to the same direction as the V phase. changed. In the third detection method (part 1), different actions are taken for the same case.

That is, as shown in FIG. 31A, a U-phase duty pulse is also output. Then, the V-phase and W-phase duty pulses are increased by the amount of the duty pulse to temporarily enter a three-phase modulation state. In this case, since the interphase voltage between U, V, and W does not change, the output voltage itself does not change. At this time, the first current detection timing is also variable. As a result, the current detection rate is improved without changing the phase to be detected at the second detection timing.

Further, FIG. 31B corresponds to the case where the variable shift is “2” by the combination of the pattern (2) and the sector (5) shown in FIG. 25 in the description of the fourth detection method. In this case as well, a U-phase duty pulse is also output, and the V and W-phase duty pulses are increased by the amount corresponding to the duty pulse to temporarily enter a three-phase modulation state. A list including these processing patterns is shown in FIGS. 32 and 33 (corresponding to FIGS. 25 and 26).

34 to 36 are flowcharts of StartD corresponding to FIGS. 16 and 17. However, FIG. 34 shows only steps S71 to S79 in FIG. 16. If “YES” is determined in the step S79, the process proceeds to the process shown in FIG. 35, in the case of the pattern (2) and the sector (5) (S86: YES), it is determined whether or not the variable shift is “0” (S151). If the variable shift is “0” (YES). Step S87 is executed. On the other hand, if the variable shift is not “0” (NO), the first and second detection timings are set to a value obtained by adding α to the U-phase duty pulse (S152).

In FIG. 36, in the case of pattern (3) and sector (3) (S80: YES), it is determined whether or not the variable shift is “0” (S153), and if the variable shift is “0” (YES). Step S81 is executed. On the other hand, if the variable shift is not “0” (NO), the process is the same as S152 (S154). Also in the case of pattern (3) and sector (5) (S82: YES), it is determined whether or not the variable shift is “0” (S157). If the variable shift is “0” (YES), step S83. Execute. On the other hand, if the variable shift is not “0” (NO), the process is the same as S152 (S156). FIG. 37 is a diagram corresponding to FIG. 22 and is a part of the StartF process.

As described above, in the third detection method (part 1), the current detection timing adjustment unit 34 uses the current detection for the other phase as a variable timing, and the two phases for which the duty pulse is output within the carrier cycle are V When the current of two phases cannot be detected because the duty of one of these two phases decreases, the U-phase duty pulse is generated by a predetermined value, and the V- and W-phase duty pulses are generated. Is increased by the predetermined value. The current detection for one phase is also made variable timing. Thereby, a current detection rate can be improved.

<Third detection method (part 2)>
Next, the third detection method (No. 2) will be described with reference to FIGS. In the first and second embodiments, as indicated by a broken line in FIG. 38, a section in which the phase current can be detected only for one phase regardless of the rotation speed of the motor 4 occurs. Therefore, as shown in FIG. 39, two-phase modulation is performed in the same manner as in the second embodiment by adding a pulse having a minimum width that can detect a two-phase current to a U, V, W phase PWM pulse. Temporarily three-phase modulation.

In the example shown in FIG. 39, (a) since the V-phase duty is small in the two-phase modulation state, the U-phase current is detected twice. (B) On the other hand, when a three-phase modulation is performed by adding a W-phase pulse having a predetermined duty value and also adding the duty value to the U and V-phase pulses, the W and V-phase currents (both negative) ) Can be detected. In this case, since there is no change in the voltage between U, V, and W (phase voltage), the output voltage itself to the motor 4 does not change, and the current detection rate can be improved.

FIG. 40 shows a process (StartA +) executed after the flowchart of StartA shown in FIG. 10 is executed. In this process, the patterns are classified into patterns (0) to (5) indicated by the variable Ptn_3phs_ch according to the magnitude relationship of the duty pulses of the phases in the PWM signal of the two-phase modulation. The pattern division here is based on the following conditions.

The minimum duty at which the current detection unit 27 can detect current is set as the minimum width, and the minimum width obtained by subtracting the minimum width from the maximum duty (100%) is set as the maximum width. For example, if the minimum time during which current can be detected is 10 μs and the carrier frequency is 4 kHz, the minimum width is 4% and the maximum width is 96%. The output pattern of the two-phase PWM signal is divided into patterns according to the following combinations of U, V, and W phase duties. U0bai_2, V0bai_2, and W0bai_2 are twice the duty values of the U, V, and W phases during the two-phase modulation calculated in step S11.

(1) W0bai_2 is less than maximum width or V0bai_2 is less than maximum width and U0bai_2 / 2 or V0bai_2 or W0bai_2 is less than minimum width and 0 or more (2) W0bai_2 is more than maximum width or V0bai_2 is more than maximum width and U0bai_2 1/2 is less than the minimum width and V0bai_2 is less than the minimum width and 0 or more. (3) W0bai_2 is more than the maximum width or V0bai_2 is more than the maximum width and 1/2 of U0bai_2 is more than the minimum width and W0bai_2 Is less than the minimum width and greater than or equal to 0. (4) W0bai_2 is greater than or equal to the maximum width or V0bai_2 is greater than or equal to the maximum width and U0bai_2 is less than the minimum width and greater than or equal to 0 and V0bai_2 is greater than W0bai_2. Is greater than the maximum width or V0bai_2 is greater than the maximum width, 1/2 of U0bai_2 is less than the minimum width and greater than 0, and V0bai_2 is less than W0bai_2 (0) Other than the above Pattern (0) to (5); Variable Ptn We have separated the 3phs_ch.

FIG. 41 is a process (StartD +) that is shifted to after the execution of step S88 in the flowchart of StartD shown in FIGS. 16 and 17, and the AD timing at the time of up-counting and down-counting is determined according to the variable Ptn_3phs_ch. . When Ptn_3phs_ch is (2) to (5), the current detection timing is set to α × 3 during up-counting and down-counting (S172, S174) at the timing when the PWM pulse for one phase is ON. This is for detecting the current, and the magnification may be another value, for example, twice. In the case of patterns (0) and (1), the fixed timing α is set twice (S175).

FIG. 42 is a process (StartF +) that is shifted to after the execution of step S141 in the flowchart of StartF shown in FIGS. 20 to 22, and two phases for detecting a current are determined according to Ptn_3phs_ch.

FIG. 43 is a flowchart of PWM output corresponding to step S11. In this process, the duties U02, V02, and W02 for two-phase modulation are determined. When Ptn_3phs_ch = 0, the minimum of U, V, and W phases is calculated from the respective duty values U0, V0, and W0 calculated by three-phase modulation. The duty value Min_Duty is subtracted (S192). On the other hand, when Ptn_3phs_ch ≠ 0, three-phase modulation is performed by setting DutyChang = Min_Duty−α as the correction duty value (S195).

44 shows a PWM pulse waveform obtained by three-phase modulation of the PWM output during two-phase modulation. In this example, the U phase, which has no pulse output in the two-phase modulation, is output with the pulse width α × 2, and the three-phase modulation is performed by adding the pulse width α × 2 to the V and W phase pulses. .

FIG. 45 is a flowchart of a part for determining the U-phase duty value of D_Pwm_set_1 () corresponding to step S10. In the third embodiment, the PWM output at the time of the two-phase modulation is three-phase modulated, but as shown in FIG. 46, for example, when Ptn_3phs_ch = 4, there is a case where a sufficient current detection time cannot be secured. In this example, the duty of the V-phase pulse is a large value approaching 100%. (A) V-phase current is detected twice during two-phase modulation, but (b) W-phase pulse is added. (C) Further, the U-phase pulse is further shifted leftward in the figure (output so as to extend the pulse in the advance direction from the center of the carrier period), and the current detection time is increased. This makes it possible to detect the W-phase current (negative).

In the case of Ptn_3phs_ch = 5, the same problem occurs when the duty of the W-phase pulse approaches 100%, but it can be dealt with by shifting the U-phase pulse to the right in the figure while performing three-phase modulation. To do.

45, in D_Pwm_set_1 (), when Ptn_3phs_ch = 2 or 5, the duty value is set to U0bai (S202), and when Ptn_3phs_ch = 3 or 4 is set, the duty value is set to 0 (S204). When Ptn_3phs_ch = 0 or 1, the duty value is set to U0bai / 2 (S205).

FIG. 47 is a flowchart of a portion for determining the U-phase duty value of D_Pwm_set_2 () corresponding to step S9. In D_Pwm_set_2 (), when Ptn_3phs_ch = 2or5, the duty value is 0 (S212), and when Ptn_3phs_ch = 3or4, the duty value is U0bai (S214). When Ptn_3phs_ch = 0 or 1, the duty value is set to U0bai / 2 (S215).

FIG. 48 shows a list including these processing patterns. FIG. 49 shows the waveform of the motor current detected by the third detection method (part 2). As is apparent from this figure, as a result of the current detection rate being improved by the three-phase modulation, the current waveform is less distorted and close to a sine wave.

As described above, according to the third detection method (part 2), when one of the two-phase pulses in the two-phase modulation cannot be detected due to a decrease in one duty, the remaining one-phase is detected. A duty pulse is additionally generated by a predetermined value for three-phase modulation, and the two-phase duty pulse is increased by the predetermined value. Furthermore, when the current of two phases cannot be detected because one of the two-phase pulses approaches the maximum, the three-phase modulation is similarly performed to increase the maximum phase duty, and the PWM pulse The generation base point of the U-phase PWM pulse is shifted according to the magnitude. Thereby, a current detection rate can be improved.
The foregoing is the description of the third and fourth detection methods.

Next, the first and second detection methods will be described.
<First detection method (conventional two-phase modulation processing)>
First, the first detection method will be described with reference to FIGS. FIG. 50 is a flowchart showing interrupt processing executed for each carrier cycle when performing two-phase modulation. First, when A / D converted data is extracted in the current detector 27 (S311), a three-phase current is detected based on the data (S312). Here, the A / D conversion processing of the terminal voltage of the shunt resistor 24 in the current detection unit 27 is executed twice within one carrier cycle separately from the processing shown in FIG. 50 (execution timing will be described later). The A / D converted data is stored in, for example, a register. Therefore, the processing in step S211 reads the data stored in the register.

Next, the rotor position (θ) of the motor 4 is estimated from the three-phase current by vector control calculation (S313), and frequency control (speed control, S314) and current control (PI control, etc.) are executed (S315). Then, when the two-phase PWM duty determined in the current computation process is output in the next cycle, it is stored in a register, memory or the like (S316). (The two-phase PWM duty obtained here is set in the output register in step S317 of the interrupt processing in the next carrier cycle.) Then, the two-phase PWM duty determined in the previous carrier cycle is used for output. It is set in the register (S317).

FIG. 51A shows the phase at which a PWM duty pulse is output in the case of two-phase modulation, and the timing at which the current detector 27 A / D converts the terminal voltage of the shunt resistor 24. In this example, U and V phase duty pulses are output so that the bottom of the triangular wave is the center phase. The first A / D conversion is executed at the bottom timing. The current detected at this time is a W-phase negative current. Then, the second A / D conversion is executed when a minute time α that further considers the switching delay has passed after the passage of the time D2 from the bottom. The current detected at this time is a U-phase positive current. The V-phase current is obtained by calculation based on the above two A / D conversion results.

FIG. 51B is a table for calculating the two-phase PWM duty based on the orthogonal voltages Vα and Vβ obtained in the vector control process. As shown in the left side of FIG. 51B and FIG. 8C, sectors 0 to 5 are determined according to the magnitude relationship between the voltages Vα and Vβ, and pulse width values D1 and D2 are determined for each sector. Is determined based on the voltages Vα and Vβ and the correction value H. The correction value H is a term for correcting the duty pulse width in accordance with the DC voltage that is the voltage of the DC power supply unit 21 and is expressed by the following equation.
H = √3 × (PWM register maximum value) × 32768 / (DC voltage) (2)
The “PWM register maximum value” is 65535 if the register is 16 bits, for example.

The PWMa, PWMb and PWMc shown on the right side of FIG. 51 (b) correspond to the three-phase voltages Vu, Vv and Vw output from the vector calculation unit 30 in FIG. It becomes the sum of D1 and D2, or only the pulse width value D2, or “0”.

<Second detection method (new three-phase modulation processing)>
Hereinafter, the three-phase modulation processing will be described with reference to FIGS. FIG. 52 is a flowchart showing interrupt processing executed every half cycle of the carrier cycle when three-phase modulation is performed. Steps S321 to S325 are executed in the same manner as steps S311 to S315 shown in FIG. 50, but in the subsequent step S326, a three-phase PWM duty is output. The subsequent steps S327 to S329 are performed in the DUTY generation unit 31. With reference to the value of the carrier counter provided from the PWM signal generation unit 32, it is determined whether the up-counting or down-counting is in progress (S327). If up-counting is in progress, D_Pwm_set2 () is set (S328), and if down-counting is in progress, D_Pwm_set1 () is set (S329). These will be described with reference to FIGS.

In FIG. 8, in the case of three-phase modulation, a PWM interrupt occurs at the peak and bottom of the triangular wave. In the processes (1) to (4) indicated by circles in the figure, the processes (1) and (3) correspond to steps S321 to S327, and the processes (2) and (4) correspond to steps S328 and S329, respectively. It corresponds. In this case, the fan motor control (5) is performed after the processing (4) is executed.

In FIG. 9, the two A / D conversion timings in the three-phase modulation are immediately before and after the triangular wave reaches the bottom. A W-phase current is obtained at the former timing, and a V-phase current is obtained at the latter timing. As for the former, even if A / D conversion is performed at the timing that coincides with the bottom, it is possible to obtain the W-phase current due to the timing of each control, signal delay, and the like.

FIG. 53 is a diagram corresponding to FIG. 51 (b), but conditions 1 to 3, sectors, D1 and D2 are exactly the same as in the case of two-phase modulation, and only the determined portions of PWMa, PWMb and PWMc are different. . These determinations include not only the pulse width values D1 and D2 but also the maximum value PD of the PWM register described in the explanation of the correction value H.

Next, details of the control for switching the first to fourth detection methods will be described with reference to FIGS. FIG. 54 is a flowchart showing mainly the control contents executed by the detection method selection unit 36. First, the current detection rate is calculated (S331), and the calculation process is shown in FIG. When the output duty is calculated for the PWM signal pattern of the first detection method (conventional two-phase modulation) (S334), it is determined whether or not two-phase current can be detected with the obtained duty (S335).

FIG. 56 is a vector diagram in which current detection impossible periods are indicated by hatching. If the above PWM output duty vector is within the shaded range (for example, when the duty of one phase is around 100% and the duty of the other one phase is around 0%), it is determined that the current cannot be detected. (S335: YES), it counts as a carrier cycle in which current detection is impossible (current detection impossible cycle) (S336). Next, it is determined whether or not one electrical angle cycle has elapsed using the current estimated angle θEst (S337). When one cycle has elapsed (YES), the current detection rate in that cycle is calculated ( S338).

The current detection rate is obtained by the following equation.
(Current detection rate) = {(Counter value corresponding to one electrical angle period) − (Counter value not detectable)}
/ (1 electrical angle cycle equivalent counter value) (3)
For example, if the electrical angular frequency is 20 Hz and the PWM carrier frequency is 4 kHz, the counter value corresponding to one electrical angular cycle is “200”. If there are 20 current non-detectable periods within the electrical angle period,
(Current detection rate) = (200−20) /200=0.9=90 (%)
It becomes. Thereafter, the detection impossible count is cleared (S339), and the calculation process is terminated. If one electrical angle cycle has not elapsed in step S337 (NO), the process ends at that point.

Reference is again made to FIG. In subsequent steps S332 and S333, the current rotational speed of the motor 4 and the rotational speed threshold value, or the motor output voltage and the output voltage threshold value are compared, and the currently driven motor 4 rotational speed region (high speed / medium speed / low speed) is determined. judge. The output voltage Vm of the motor 4 is calculated as follows using the α-axis output voltage Vα and the β-axis output voltage Vβ calculated by the vector calculation unit 30.
Vm = √ (Vα2 + Vβ2) (4)
The low speed region is, for example, a rotational speed region near the minimum rotational speed, and the high speed region is, for example, a rotational speed region where overmodulation control is effective. The medium speed area is a speed area between the high speed area and the low speed area.

FIG. 57 is a flowchart of processing for selecting a detection method in the low speed region. First, the current detection rate of the first detection method is compared with the threshold value X3 (S340). If the current detection rate is high (greater than the threshold value), the first detection method is selected (S344), and if the current detection rate is low ( The current detection rate of the first detection method is compared with the threshold value X4 (S341). If the current detection rate is high (greater than the threshold), the third detection method (2-phase + 3-phase modulation) is selected (S343), and if the current detection rate is low (below the threshold), the second detection method (new 3-phase modulation) is selected. Select (S342).

In the low speed region, the current detection rate of the first detection method tends to decrease, but it is preferable to adopt the first detection method in order to reduce power consumption. Therefore, when the current detection rate of the first detection method becomes equal to or less than the threshold value X3, the third detection method is selected to improve the current detection rate. Further, when the current detection rate of the third detection method becomes equal to or less than the threshold value X4, the second detection method is selected to improve the current detection rate again.

FIG. 58 is a flowchart of processing for selecting a detection method in the medium speed region. First, the speed fluctuation detecting unit 37 detects the maximum value and the minimum value of the current estimated speed ωEst during one mechanical angle rotation of the motor 4, and obtains the difference between them as a speed fluctuation width (S345). Next, it is determined whether or not the speed command of the motor 4 has changed using the target speed ωRef input from the host controller (S346). If the speed command is constant, the process proceeds to step S347, and if the speed command has changed, the process proceeds to step S349.

In step S347, the above-described speed fluctuation width is compared with the fluctuation width threshold value. If the speed fluctuation width is small (below the threshold value), switching to rectangular wave driving (S348), and if the speed fluctuation width is large (greater than the threshold value), the process proceeds to step S349. In step S349, the current detection rate of the first detection method is compared with the threshold value X2, and if the current detection rate is high (greater than the threshold value), the first detection method is selected (S351). On the other hand, if the current detection rate is low (below the threshold), the fourth detection method (new two-phase modulation) is selected (S350).

In the medium speed region, the modulation rate is higher and the current detection rate is higher than in the low speed region. Therefore, the first detection method is adopted with an emphasis on reducing power consumption. However, the current detection rate is reduced when the motor load is reduced. Is equal to or lower than the threshold value X2, the fourth detection method is selected to improve the current detection rate. If the speed command is constant and the speed fluctuation range is equal to or less than the threshold value, switching to rectangular wave driving is performed to further reduce power consumption.

FIG. 59 is a flowchart of a process for selecting a high-speed area detection method. In step S353, the current detection rate of the first detection method is compared with the threshold value X1, and if the current detection rate is high (greater than the threshold value), the first detection method is selected (S355), and if the current detection rate is low (below the threshold value). ) The third detection method is selected (S354). In a high-speed region where overmodulation control is effective, the current detection rate of the first detection method is reduced and controllability is deteriorated. Therefore, when the current detection rate of the first detection method becomes equal to or less than the threshold value X1, the third detection method is selected to improve the current detection rate.

Here, FIGS. 60 to 63 show the PWM signal waveform and the output voltage waveform in the rectangular wave driving method selected in step S348. FIGS. 60 and 61 show the case of the 120 ° energization method in FIG. FIG. 63 shows the case of the 150 ° energization method. 60 and 62, the waveform on the upper side of each phase indicates the ON section of the upper arm, and the waveform on the lower side indicates the ON section of the lower arm. Since the induced voltage of the motor 4 appears in the non-energized section of each phase, the rotor position can be detected by detecting the zero cross point of the induced voltage there. By selecting the rectangular wave driving method in this way, the switching loss is further reduced.

FIG. 64 is a flowchart schematically showing a modulation method switching process during operation of the air conditioner. In step S361, if the detection method currently being executed is the first detection method, the process proceeds to step S362, and the cycle for generating the PWM interrupt is set to the same cycle as the carrier cycle. Then, current data is acquired by the first detection method, vector control processing is performed, and a two-phase PWM signal pattern is generated and output (S363).

If the currently executed detection method is the second to fourth detection methods, the process proceeds from step S361 to S364, and the cycle for generating the PWM interrupt is set every half cycle of the carrier cycle. Then, current data is acquired by the second to fourth detection methods, vector control processing is performed, and a three-phase PWM signal pattern is generated and output (S365).

If the detection method currently being executed is rectangular wave drive control, the process proceeds from step S361 to S366, and the cycle for generating the PWM interrupt is set to the same cycle as the carrier cycle. Then, rectangular wave drive control processing is performed by a position detection method according to rectangular wave drive, and a two-phase PWM signal pattern is generated and output (S367). In the case of rectangular wave driving, it is not necessary to detect a two-phase current for position detection, but only a one-phase current is detected for overcurrent protection.

As described above, according to the present embodiment, the current detection unit 27 is configured so that the motor 4 is based on the signal generated by the shunt resistor 24 connected to the DC side of the inverter circuit 23 corresponding to the current value and the PWM signal pattern. The phase calculation unit 30 determines the rotor position θ based on the phase current, and together with the PWM signal generation unit 32, the two-phase or three-phase currents Iu, Iv, Iw are detected. A PWM signal pattern is generated. At this time, the PWM signal generation unit 32 increases or decreases the duty in either of the delay side and the advance side with respect to the bottom of the carrier cycle with respect to the three-phase PWM signal pattern, Is to increase or decrease the duty in one direction on the delay side and the advance side with respect to the bottom, and in the remaining one phase in the direction opposite to the direction.

The PWM signal generation unit 32 generates a three-phase PWM signal pattern so that the current detection unit 27 can detect a two-phase current at two fixed or variable timings within the PWM signal carrier cycle. Alternatively, all three phases are output symmetrically from the center of the carrier wave, and a two-phase PWM signal pattern for detecting current at a variable timing is generated. Then, when the motor 4 is in the high speed region, the detection method selection unit 35 selects the first and third detection methods according to the current detection rate in the DUTY generation unit 31 and the PWM signal generation unit 32. Is in the low speed region, one of the first to third detection methods is selected. When the motor 4 is in the medium speed region, the first and fourth detection methods are selected. Thereby, it is possible to improve the control accuracy while suppressing the switching loss while maintaining the necessary current detection rate according to the rotation speed region of the motor 4.

The detection method selection unit 35 selects a current detection method based on the result of referring to the duty ratio of the PWM signal and the length of the current detectable period within the carrier cycle. Therefore, switching of the PWM signal pattern can be performed appropriately based on the interrupt processing time and the length of the current detectable period.

In addition, when performing two-phase modulation, an interrupt is generated every carrier cycle, and when generating three-phase modulation, an interrupt is generated every half of the carrier cycle. The second detection method presented in Patent Document 1 can be easily introduced with respect to the detection method.

Furthermore, about the air conditioner provided with the heat pump system 1 provided with the compressor 2, the outdoor side heat exchanger 9, the decompression device 8, and the indoor side heat exchanger 7, the motor 4 which comprises the compressor 2 is controlled object. Therefore, the operation efficiency of the heat pump system 1 and the air conditioner can be improved.

(Second Embodiment)
FIG. 65 is a view corresponding to FIG. 59 showing the second embodiment. The same parts as those of the first embodiment are denoted by the same reference numerals, description thereof is omitted, and different parts will be described. In the detection method selection processing in the high-speed region in the second embodiment, steps S356 and S357 are inserted between steps S353 and S354. If it is determined in step S353 that it is “below the threshold value”, the current detection rate is compared with a threshold value X1 ′ (<X1) (S356). Then, when the current detection rate becomes equal to or less than the threshold value X1 ′, the PWM frequency in the PWM signal generation unit 32 is changed to be higher (for example, from 4.5 kHz to 5 kHz) (S357), and the third detection method is executed. (S354).

As described above, according to the second embodiment, when the motor 4 is in the high-speed rotation region, if it is determined that the current detection rate is equal to or less than the threshold value X1 ′, the carrier period is adjusted to be shorter. Can be improved.

(Third embodiment)
66 and 67 show the third embodiment, and FIG. 66 corresponds to FIG. As shown in FIG. 66, in the third embodiment, steps S320, S325a, and S326a are added to the flowchart shown in FIG. 52, and the place where step S326 is executed is changed. That is, when step S325 is executed, the flag M_Int_flg is set to “1” (S325a). The above flag indicates that the processing of steps S321 to S325 has already been executed in the half cycle of the carrier.

In step S320, it is determined whether or not the flag M_Int_flg = 1 (set). If “0 (reset)” (NO), step S326 is executed, and the flag M_Int_flg is set to “0” (S326a). ). If step S325a, 226a is performed, it will transfer to step S327. That is, in the third embodiment, in the PWM interrupt processing when performing three-phase modulation, steps S320 to S325a and S327 to S329 are executed in the first half of the cycle, and steps S320, S326, S326a, and S327 to are executed in the second half of the cycle. S329 is executed.

Accordingly, the interrupt processing times (1) and (3) shown in FIG. 66 are slightly shorter than those in the case of processing according to FIG. 52 (corresponding to the case shown in FIG. 8). Since the fan motor control process (5) of the outdoor unit is also executed in the second half of the carrier cycle, the processing time in the second half of the cycle can be provided by dividing the interrupt processing as described above. The process of dividing the first half and the second half is not limited to the above example, and may be set as appropriate.

(Fourth embodiment)
68 to 70 show the fourth embodiment. In step S371 of FIG. 68, it is determined whether the modulation method being executed is two-phase modulation or three-phase modulation. In either case, an interrupt is generated every half of the carrier cycle (S372, S374). . In the two-phase modulation, current data is acquired by the corresponding first or fourth detection method, vector control processing is performed, and a two-phase PWM signal pattern is generated and output (S373). In the three-phase modulation, current data is acquired by the corresponding second or third detection method, vector control processing is performed, and a three-phase PWM signal pattern is generated and output (S375).

FIG. 69 is a diagram corresponding to FIG. 52, but adding steps S326b and S326c between steps S326 and S327 makes the processing common to the two-phase modulation and the three-phase modulation. That is, when step S326 is executed, it is determined whether the modulation method being executed is two-phase or three-phase (S326b), and if it is three-phase modulation (NO), the process proceeds to step S327. On the other hand, in the case of two-phase modulation (YES), the three-phase PWM duty obtained in step S326 is converted into a two-phase PWM duty (S326c), and the process proceeds to step S327.

FIG. 70 illustrates the processing content of step S326c. Assume that the three-phase PWM duty is obtained as shown in FIG. Among these, the minimum duty is set to MINduty (U phase in this example). Then, the two-phase PWM duty is obtained by subtracting (MINduty + τ) from the duty of the other phases (V, W). Here, τ is the dead time equivalent time, but the duty is of course zero for the U phase. Therefore, in this case, the two-phase modulation is performed by the V and W phases. By converting the PWM pattern of the three-phase modulation method into the pattern of the two-phase modulation method in this manner, the two-phase modulation method can be set at 2 fixed timings as in the three-phase modulation method. The phase current can be detected.

As described above, according to the fourth embodiment, in both cases of two-phase modulation and three-phase modulation, processing is performed by generating a PWM interrupt every half cycle of the carrier cycle. In other words, with conventional two-phase modulation, it is common to perform interrupt processing every carrier cycle, so a new three-phase that performs interrupt processing every half cycle in the two-phase modulation control already performed If modulation is combined, the first embodiment and the like are easier to introduce.

On the other hand, if it is assumed that a program corresponding to the control of the above combination is created on a zero basis, the PWM interrupt generation pattern is changed in both two-phase modulation and three-phase modulation. It can be said that it is more efficient to create programs. In addition, when generating the two-phase PWM signal pattern, the DUTY generating unit 31 generates a three-phase PWM signal pattern, and sets the duty of the phase having the smallest duty among these three phases to zero, The two-phase PWM signal pattern is obtained by subtracting the minimum phase duty from the other two-phase duty. As a result, as shown in FIG. 69, it is possible to make the interrupt processing performed by the two-phase modulation and the three-phase modulation as common as possible, and at the two fixed timings in any modulation system, the two-phase modulation is performed. Current can be detected.

(Other embodiments)
The correspondence between the first to third phases and the U, V, and W phases is arbitrary.
The carrier period and the minimum width of the PWM duty may be appropriately changed according to individual design.
Regarding the method of the fourth embodiment, the second to third embodiments may be similarly implemented.
Further, the fourth embodiment is not limited to the one that generates a three-phase PWM pattern and then converts it to a two-phase PWM pattern, but may generate a two-phase PWM pattern as shown in FIG. 51 from the beginning.
As a method for determining the arrangement of the duty pulses of each phase, the first to third embodiments of Patent Document 1 may be applied.
The power consumption W is not limited to the value calculated by the equation (1), but may be determined by directly measuring the voltage and current.

The peak of the triangular wave carrier may be the center of the cycle.
The threshold values X1 to X4 related to the current detection rate may be changed according to individual products.
The current detection method at the time of motor start-up, forced commutation, and sensorless drive shown in FIGS. 3 and 4 may be the first detection method.

Not limited to air conditioners, other heat pump systems and heat pump systems are applicable as long as the motor is driven and controlled by switching between a two-phase modulation method and a three-phase modulation method.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

Industrial application fields

Embodiments of the present invention provide a control device that controls a motor by PWM controlling an inverter circuit composed of a plurality of switching elements connected in a three-phase bridge, and an air conditioner configured using the motor control device And heat pump systems, and those that control driving of a motor by switching between a two-phase modulation method and a three-phase modulation method.

Claims (19)

1. In a motor control device that drives a motor via an inverter circuit that converts direct current into three-phase alternating current by performing on / off control of a plurality of switching elements connected in a three-phase bridge according to a predetermined PWM signal pattern,
   A current detection element connected to the DC side of the inverter circuit and generating a signal corresponding to a current value;
   A rotor position determination unit for determining a rotor position based on the phase current of the motor;
   A PWM signal generator that generates a two-phase or three-phase PWM signal pattern to follow the rotor position;
   A current detection unit that detects a phase current of the motor based on a signal generated in the current detection element and the PWM signal pattern;
   A current detection rate calculation unit for obtaining a current detection rate according to the two-phase or three-phase PWM signal pattern;
   The current detector detects a two-phase current at a fixed timing within a carrier wave period of the PWM signal, or detects at a variable timing according to the magnitude of the output voltage to the inverter circuit. A timing adjustment unit to adjust,
   The PWM signal generation unit increases or decreases the duty in either of the delay side and the advance side for any one phase (first phase) of the three-phase PWM signal patterns based on an arbitrary phase of the carrier wave period. Let
   For the other one phase (second phase), the duty is increased or decreased in one direction on the lag side and the advance side based on an arbitrary phase of the carrier wave period,
   For the remaining one phase (third phase), a three-phase PWM signal pattern is generated so as to increase or decrease the duty in a direction opposite to the direction with reference to an arbitrary phase of the carrier wave period,
   When the motor is in a low-speed rotation region, a two-phase PWM signal pattern is output in a state where the current detection rate is high, and one phase is fixed to the current detection unit, and the other one phase is variable. First detection method that detects current at timing,
   In a state where the current detection rate is low, a second phase detection method is used in which a three-phase PWM signal pattern is output and the current detection unit detects a two-phase current at a fixed timing.
   In a state where the current detection rate is intermediate, a two-phase PWM signal pattern is output, and in a state where a single-phase current detection is set to a variable timing, a two-phase in which a duty pulse is output within the carrier wave period is the first phase. The two-phase and the third phase, and when the duty of one of the two phases decreases and the two-phase current cannot be detected, the first-phase duty pulse is generated by a predetermined value, and The PWM signal generation unit and the timing adjustment so as to adopt a third detection method in which the second-phase and third-phase duty pulses are increased by the predetermined value and the current detection of the other one-phase is also variable. The motor control apparatus which has a current detection control part which controls a part.
2. The current detection control unit is the first detection method when the motor is in a high-speed rotation region and the current detection rate is high.
   The motor control device according to claim 1, wherein the third detection method is used when the current detection rate is low.
3. The current detection control unit is the first detection method in a state where the current detection rate is high when the motor is in a medium speed rotation region,
   When the current detection rate is low, the PWM signal generation unit outputs a two-phase PWM signal pattern, the current detection unit detects a current at a fixed timing for one phase, and the other phase Is a fourth detection method that detects the current at a fixed timing or adjusts the detection timing so that the current can be detected at a variable timing according to the magnitude of the output voltage to the inverter circuit. Item 3. The motor control device according to Item 1 or 2.
4. In the fourth detection method, the timing adjustment unit determines whether the current detection for the other phase is a predetermined fixed timing or a timing changed from the fixed timing. 4. The motor control device according to claim 3, wherein the motor control device is determined according to the signal pattern.
5. In the fourth detection method, the timing adjustment unit is configured such that the current detection unit sets the minimum duty that can be detected as the minimum width, the maximum duty (100%) minus the minimum width as the maximum width, When the duty that is less than the maximum width and exceeds the minimum width is the intermediate width, the output pattern of the two-phase PWM signal is classified into patterns (0 to 11) by the following combinations of the first to third phase duties,
   (1) When the first phase is an intermediate width and the second or third phase is greater than or equal to the maximum width (2, 3) When one of the second or third phases is an intermediate width and the other is greater than or equal to the maximum width (4, 6) When the first phase and the second or third phase are both larger than the maximum width (5) When both the second phase and the third phase are larger than the maximum width (7) First When the phase is 0 or more and either the second or third phase is less than the minimum width (8, 9) When either the second or third phase is 0 or more and the other is less than the minimum width (10, 11) When the first phase is less than the minimum width and either the second or third phase is 0 or more (0): In cases other than (1) to (11) Also, in the duty of the first to third phases When classified into sectors (0 to 5) according to the following magnitude relationship:
   (0) First phase is maximum and second phase> third phase (1) First phase is maximum and second phase <third phase (2) Second phase is maximum and first phase> third Phase (3) Second phase is maximum and first phase <third phase (4) Third phase is maximum and first phase> second phase (5) Third phase is maximum and first phase <first Two phases Depending on the combination of the pattern (0 to 11) and the sector (0 to 5), the current detection for the other phase is set to a predetermined fixed timing or changed from the fixed timing. The motor control device according to claim 4, wherein it is determined whether to set the timing.
6. In the fourth detection method, the timing adjustment unit sets the current detection for the other phase to a fixed timing that is determined in advance.
   Two phases in which a duty pulse is output within the carrier wave period are the second phase and the third phase, and two-phase currents detected at both fixed timings are the second phase and the third phase. 6. When a period overlapping with the output timing of these two-phase duty pulses occurs from the state of the above, one of the phases to be detected is changed to the first phase. 6. Motor control device.
7. The timing adjustment unit, in the fourth detection method, after changing one of the detection target phases to the first phase, when the period in which the duty pulses of the second phase and the third phase overlap each other, The motor control device according to claim 6, wherein the current detection timing is changed within a range in which the first phase can be detected.
8. In the fourth detection method, the timing adjustment unit sets the current detection for the other phase to a fixed timing that is determined in advance.
   The two phases in which the duty pulse is output within the carrier wave period are the first phase and the second phase or the third phase, and the two-phase current detected at both fixed timings is the first phase. From the state of one phase and the third phase or the second phase,
   When the current of the first phase cannot be detected, current detection for the other phase is set as a variable timing, and one of the phases to be detected is changed to the second phase or the third phase. The motor control device according to claim 7.
9. In the fourth detection method, the timing adjustment unit changes the current detection timing for the other phase once and then fixes the changed timing to detect the current of the second phase or the third phase. The motor control device according to claim 8.
10. In the fourth detection method, the timing adjustment unit sets current detection for the other phase to a predetermined fixed timing, and two phases in which a duty pulse is output within the carrier wave period are the second phase and In the third phase, when the duty of one of the two phases decreases and the current of two phases cannot be detected, the duty increasing / decreasing direction of the phase with the smaller duty is set to the same direction as the other phase. The motor control device according to any one of claims 3 to 9, which is changed.
11. In the fourth detection method, the timing adjustment unit sets the current detection for the other phase to a fixed timing that is determined in advance. When the phase current cannot be detected, the remaining one-phase duty pulse is generated by a predetermined value, and the two-phase duty pulse is increased by the predetermined value.
    When the maximum phase duty of the three phases increases and the two-phase current cannot be detected, the first-phase duty pulse is set to the lag side and the advance side based on an arbitrary phase of the carrier wave period. The motor control device according to claim 3, wherein the duty is increased or decreased in one direction.
12. A rotation fluctuation detecting unit for detecting a fluctuation degree of the rotation speed of the motor;
    The current detection control unit generates the PWM signal when the motor speed command inputted from the outside is constant and the fluctuation of the rotation speed falls below a threshold value when the motor is in a medium speed rotation region. The motor control device according to claim 1, wherein a pulse signal corresponding to rectangular wave driving is output to the unit.
13. The PWM signal generation unit adjusts the period of the carrier wave to be shorter when it is determined that the current detection rate is below a threshold when the motor is in a high-speed rotation region. The motor control device according to any one of
14. At least a part of each of the parts is a function realized by a microcomputer,
    The current detection control unit refers to any one or more of a power value consumed by the motor, a duty ratio of the PWM signal, a rotation speed of the motor, and a length of a current detectable period within the carrier wave cycle. The motor control device according to any one of claims 1 to 13, wherein a rotation region of the motor is determined based on a result.
15. At least a part of each of the parts is a function realized by a microcomputer,
    When generating a two-phase PWM signal pattern in the PWM signal generation unit, generating an interrupt for causing the microcomputer to execute processing for each carrier cycle to generate a three-phase PWM signal pattern The motor control device according to any one of claims 1 to 14, wherein the interrupt is generated every half of the carrier wave period.
16. At least a part of each of the parts is a function realized by a microcomputer,
    The interrupt is generated every ½ of the carrier wave period in both cases where the PWM signal generation unit generates the two-phase PWM signal pattern and the three-phase PWM signal pattern. The motor control device according to any one of claims 1 to 15.
17. The PWM signal generation unit generates the three-phase PWM signal pattern when generating the two-phase PWM signal pattern, and sets the duty of the phase having the smallest duty among the three phases to zero. The motor control device according to claim 16, wherein the two-phase PWM signal pattern is obtained by subtracting the minimum phase duty from the other two-phase duty.
18. A compressor, a heat exchanger, and a decompressor;
    The motor which comprises the said compressor is controlled by the motor control apparatus as described in any one of Claim 1 to 17, The heat pump system characterized by the above-mentioned.
19. An air conditioner comprising the heat pump system according to claim 18.

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