JP4123598B2 - Inverter device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an inverter device used in an air conditioner, a refrigerator, a dishwasher, an electric washing machine, and the like.
[0002]
[Prior art]
14 includes an AC power source 1, a rectifying / smoothing circuit 2, an inverter circuit 3, a motor 4 having three-phase armature windings 8, 9, and 10, and a rotor 7 having permanent magnets 5 and 6. The position detecting means 43 is configured by Hall ICs 40, 41 and 42 and magnetically detects the positions of the permanent magnets 5 and 6.
[0003]
The speed setting unit 12 sets the rotation speed of the electric motor 4.
[0004]
The rectifying and smoothing circuit 2 includes a choke coil 18, a rectifier 19, and electrolytic capacitors 20 and 21, and the rectifier 19 includes diodes 22, 23, 24, and 25 connected in a bridge shape. The voltage doubler rectifies and outputs a DC voltage to the inverter circuit 3.
[0005]
The inverter circuit 3 has a three-phase specification having switching elements 26, 27, 28, 29, 30, and 31 configured by connecting IGBTs and reverse conducting diodes in parallel.
[0006]
The control circuit 44 performs on / off control on the switching elements 26, 27, 28, 29, 30, and 31 from the signal from the position detection means 43 and the output signal from the speed setting means 12.
[0007]
FIG. 15 shows ON / OFF waveforms of the input signals S1, S2, and S3 and the outputs V1, V2, V3, V4, V5, and V6 from the position detecting unit 43 of the control circuit 44.
[0008]
15, (a) is the output signal S1 of the Hall IC 40, (A) is the output signal S2 of the Hall IC 41, (A) is the output signal S3 of the Hall IC 42, (D) is the on / off signal V for the switching element 26, (E) is an on / off signal V2 for the switching element 27, (f) is an on / off signal V3 for the switching element 28, (g) is an on / off signal V4 for the switching element 29, and (k) is an on / off signal for the switching element 30. Signals V5 and (K) indicate the on / off signal V6 for the switching element 31.
[0009]
That is, since the inverter circuit 3 has a three-phase six-stone configuration, the number of Hall ICs 40, 41, and 42 is also set to three, so that switching elements are switched every 60 electrical angles.
[0010]
In the above configuration, the inverter device of the prior art operates as a so-called DC brushless motor, and the position detecting means 43 turns on and off the switching elements 26 to 31 while detecting the positions of the permanent magnets 5 and 6. The switching elements 29, 30 and 31 on the low potential side are repeatedly turned on and off at a frequency of about 15 kHz during the period of 120 electrical degrees. It has become a thing.
[0011]
By changing the ratio of the ON period, that is, the duty (conduction ratio), a value obtained by multiplying the output voltage of the rectifying / smoothing circuit 2 by the duty value is equivalently input to the inverter circuit 3 with respect to the electric motor 4. Thus, the speed of the electric motor 4 can be adjusted.
[0012]
The control circuit 44 detects the speed of the electric motor 4 from the frequency of the signal input from the position detection means 44 and adjusts the duty value so that it becomes equal to the value of the speed setting means 12.
[0013]
[Problems to be solved by the invention]
However, in the above prior art, in order to make the speed of the motor equal to the output value of the speed setting means, it is necessary to adjust the duty value by feedback control.
[0014]
Here, in order to ensure the responsiveness of the feedback control to the load change of the motor 4 and the stability of the speed and the supply current to the motor 4, the current to the motor 44 is detected in the control circuit 44. A configuration called a current detector or a current minor loop, which amplifies the difference between the actual current values for the torque command and adds or subtracts the duty value using PI control, etc., and the speed setting means 12 and the actual speed Similarly, there is a first problem that the difference is a complicated configuration in which a torque command value is output using feedback control such as PI control to obtain the set value of the current minor loop.
[0015]
Further, when the inverter circuit 3 and the electric motor 4 that are generally used have a three-phase configuration, the position detection unit 43 requires three Hall ICs, and at the same time the configuration of the position detection unit 43 becomes complicated. The second problem is that the number of wires connecting the position detecting means 43 and the control circuit 44 is increased and the apparatus is complicated.
[0016]
[Means for Solving the Problems]
The present invention provides the above first to second. Task The Resolution In order to do so, a synchronous motor, an inverter circuit that supplies an alternating current to the synchronous motor, speed setting means, and position detection means, the motor includes a first object having an armature winding, The position detection means detects the position of the permanent magnet of the second object, the output frequency of the inverter circuit is: By setting the value according to the output of the speed setting means, the output voltage value of the inverter circuit is a value that makes the output voltage phase and the phase angle of the output signal of the position detection means substantially constant, Even without using a current minor loop or speed feedback loop, the frequency response according to the output of the speed setting means is given to the synchronous motor to ensure speed response with a relatively simple configuration. Rukoto is possible, also for the constitution of the position detecting means, for example, even in the inverter circuit configuration of the 3-phase 6 stone, the Hall IC becomes shall operate in one, and it can be a simple structure.
[0017]
Also, first to first 2 of Task The Resolution To claim 1 By setting the output current of the inverter circuit of the mounted inverter device to a substantially sine wave, the frequency corresponding to the output of the speed setting means can be set to the synchronous motor without using a current minor loop or a speed feedback loop. This makes it possible to ensure speed response with a relatively simple configuration, and to improve the overall efficiency of the device by reducing the current value. In addition, the current waveform of the armature winding is a sine wave. It is also possible to reduce the noise by approaching.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
The invention according to claim 1 includes a synchronous motor, an inverter circuit that supplies an alternating current to the synchronous motor, speed setting means, and position detection means, and the electric motor has an armature winding. An object and a second object movable relative to the first object and having a permanent magnet; and the position detecting means detects a position of the permanent magnet of the second object; The output frequency is a value according to the output of the speed setting means, and the output voltage value of the inverter circuit is a value that makes the output voltage phase and the phase angle of the output signal of the position detection means almost constant. Therefore, even if a current minor loop, a speed feedback loop, etc. are not used, a frequency corresponding to the output of the speed setting means is given to the synchronous motor, so that the speed can be adjusted with a relatively simple configuration. As for the position detection means, for example, even in the case of a three-phase six-stone inverter circuit structure, even one Hall IC can be operated, and the structure can be simplified. It becomes.
[0019]
Claim 2 The described invention is claimed. 1 By setting the output current of the inverter circuit of the mounted inverter device to a substantially sine wave, the frequency corresponding to the output of the speed setting means can be set to the synchronous motor without using a current minor loop or a speed feedback loop. This makes it possible to ensure speed response with a relatively simple configuration, and to improve the overall efficiency of the device by reducing the current value. In addition, the current waveform of the armature winding is a sine wave. It is also possible to reduce the noise by approaching.
[0020]
【Example】
(Example 1)
Examples of the present invention will be described below. FIG. 1 shows an example of a circuit configuration of a fully automatic electric washing machine including an inverter device according to a first embodiment of the present invention.
[0021]
In FIG. 1, a 100 V 60 Hz AC power source 1, a rectifying and smoothing circuit 2 for rectifying the AC power source 1, an inverter circuit 3 connected to the output of the rectifying and smoothing circuit 2, and a synchronous motor 4 connected to the output of the inverter circuit 3 are provided. Yes.
[0022]
The synchronous motor 4 has armature windings 8, 9, and 10, which are realized by winding them around an iron core formed by laminating silicon steel plates, and a first object 45 generally called a stator, and an N pole on the outside. It is composed of a ferrite permanent magnet 5 magnetized to a polarity that exits and a ferrite permanent magnet 6 magnetized to a polarity that the S pole is exposed to the outside, and is composed of a second object 7 generally called a rotor.
[0023]
The position detecting means 11 is constituted by a Hall IC, and detects the magnetic poles of the opposing permanent magnets 5 and 6 of the second object 7, thereby detecting the second object 7 relative to the first object 45. The angle is detected.
[0024]
The speed setting means 12 outputs a voltage corresponding to the rotation speed setting value of the synchronous motor 4, and in this embodiment, the output of the speed setting means 12 is input to the oscillation circuit 13, and the oscillation circuit 13 operates as a voltage control type oscillation circuit that outputs a pulse train having a frequency corresponding to the input voltage value.
[0025]
The output of the oscillation circuit 13 is input to the distributor 14 and outputs a signal for turning on the six switching elements in the electrical angle only for a 120-degree period and turning off the 240-degree period for the three-phase inverter circuit 3. It has become a thing.
[0026]
The voltage control circuit 15 performs PWM of 15.6 kilohertz for the above-described 120-degree on-period for three of the six switching elements constituting the inverter circuit 3 on the low potential side. Thus, the output voltage of the inverter circuit 3 is almost equivalently supplied with a voltage obtained by multiplying the DC voltage supplied from the rectifying and smoothing circuit 2 by the PWM conduction ratio (duty).
[0027]
In the present embodiment, the voltage control circuit 15 performs PWM control on the switching element on the low potential side. However, the voltage control circuit 15 may perform PWM control on the switching element on the high potential side. In addition, the high-potential side switching element and the low-potential side switching element are alternately PWM-controlled every 60 degrees of electrical angle, thereby suppressing di / dt of the output current of the inverter circuit 3 and reducing electromagnetic noise. An inverter device with quiet sound may be realized.
[0028]
In this embodiment, the phase detection circuit 16 reads the Q6 signal of the distributor 14, that is, the 120-degree on / off signal of the W-phase low potential side switching element and the high / low signal output from the position detection means 11. When the rise timings of these two signals are the same, 0 volt is output. When there is a deviation between the timings of the two signals, the polarity changes depending on which is advanced, and the absolute value of the deviation is An analog signal whose absolute value changes in proportion to the magnitude is output.
[0029]
In the present embodiment, the phase detection circuit 16 outputs a positive voltage when the phase of the signal is delayed from the position detection unit 11 and is negative when the phase of the signal is advanced from the position detection unit 11. It is intended to output a voltage of.
[0030]
The error amplifier 17 amplifies and outputs the output of the phase detection circuit 16 and operates as a PI compensator having a first-order lag component in order to ensure the stability of feedback control. In order to make the deviation substantially zero, the voltage gain is as high as 80 dB at ω = 0.
[0031]
FIG. 2 shows detailed circuits of the rectifying / smoothing circuit 2 and the inverter circuit 3 of the inverter device according to the first embodiment.
[0032]
In FIG. 2, a choke coil 18 having an inductance of 5 mH, a rectifier 19, and electrolytic capacitors 20 and 21 having a capacitance of 560 microfarads are formed. The rectifier 19 includes four silicon diodes 22 and 23.・ 24 and 25 are connected by bridge connection.
[0033]
The capacitors 20 and 21 are connected in series and connected to one end of the AC power source 1 to operate as a so-called voltage doubler rectifier circuit. When the voltage of the AC power source 1 is 100 V AC, the capacitors 20 and 21 are connected. Each is charged with a DC voltage of about 140 V, and a DC voltage of about 280 V is input to the inverter circuit 3.
[0034]
The inverter circuit 3 has a three-phase, six-stone configuration with switching elements 26, 27, 28, 29, 30, and 31 formed of IGBTs and diodes for reverse conduction.
[0035]
FIG. 3 shows a detailed circuit of the voltage control circuit 15 of the inverter device according to the first embodiment.
[0036]
In FIG. 3, AND circuits 32, 33, and 34, a voltage comparator 35 having an open collector output generally called a comparator, a triangular wave oscillation circuit 36 that outputs a triangular wave at a frequency of 15.6 kHz, and an output of the voltage comparator 35 A pull-up resistor 37 for pulling up the terminal and a DC power supply 38 are included.
[0037]
FIG. 4 shows input / output operation waveforms of the distributor 14 of the inverter device according to the first embodiment.
[0038]
4, (a) is a pulse waveform input from the oscillation circuit 13 to the B terminal, (A) is a signal waveform at the output terminal Q1, (C) is a signal waveform at the output terminal Q2, and (D) is an output terminal Q3. (E) shows the signal waveform at the output terminal Q4, (f) shows the signal waveform at the output terminal Q5, and (g) shows the signal waveform at the output terminal Q6, and shows the pulse train input from the B terminal. For each shot, the output is switched between high and low at each rise timing, and the rise interval of the B terminal corresponds to an electrical angle of 60 degrees.
[0039]
FIG. 5 shows the input / output characteristics of the oscillation circuit 13. In the first embodiment, every time the input voltage from the A terminal increases by 1V, the pulse frequency of 60 Hz increases. .
[0040]
The operation of the above configuration will be described.
[0041]
When it is desired to drive the synchronous motor 4 at 600 rpm, a voltage of 1 V is output from the speed setting means 12 and input to the A terminal of the oscillation circuit 13.
[0042]
Since the oscillation circuit 13 has characteristics as shown in FIG. 5, a 60 Hz pulse train is input to the B terminal of the distributor 14.
[0043]
Since the distributor 14 operates as shown in FIG. 4, an on / off signal of 10 Hz is output to each of Q <b> 1 to Q <b> 6, and the inverter circuit 3 outputs an output of 10 Hz to the synchronous motor 4.
[0044]
Since the synchronous motor 4 has two poles in this embodiment, the synchronous motor 4 rotates at 600 rpm at a frequency of 10 Hz.
[0045]
Here, the phase detection circuit 16 detects the timing difference between the rising edge of the output signal of the position detection means 11 inputted from the Y terminal and the Q6 signal inputted from the X terminal, and the signal of the position detection means 11 is detected. A negative analog voltage is output when the direction is advanced.
[0046]
Then, the output is amplified by the error amplifier 17 and the voltage at the D terminal of the voltage control circuit 15 is decreased, so that the voltage input to the synchronous motor 4 is lowered and the output voltage of the inverter circuit with respect to the phase of the induced electromotive force. Since the phase of the terminal voltage (equivalent to the terminal voltage) gradually advances, feedback control that the signal from the position detecting means 11 is relatively delayed is applied, and finally in a predetermined direction on the dq plane. The vector of the terminal voltage Va is located, that is, the voltage phase difference angle δ is controlled to a predetermined value.
[0047]
In the first embodiment, the vector diagram when δ = 0 is the same as that described in the related art in FIG. 16, that is, the vector of the terminal voltage Va is on the q axis. Thus, even though the position detecting means 11 is constituted by one Hall IC, an operation equivalent to the conventional technique is performed.
[0048]
In FIG. 16, δ = 0, but the current phase β is a negative value, and the positive direct-axis current Id is slightly flowing.
[0049]
However, claim 1 is not particularly limited to δ = 0. For example, the Hall IC constituting the position detecting means 11 is shifted from the position of this embodiment in the direction opposite to the rotation direction. Alternatively, feedback control may be performed to a voltage phase angle δ corresponding to the shifted electrical angle.
[0050]
Therefore, for example, by adjusting the position of the position detection means 11 so that the voltage phase angle δ is such that the current phase β is substantially zero under rated operating conditions, or by providing a circuit that electrically shifts the phase. It is possible to increase the effect of realizing a high efficiency and a high power factor, just as in the case where the position detection means constituted by three Hall ICs in the prior art is provided with an advance angle.
[0051]
(Example 2)
The second embodiment of the present invention will be described below. FIG. 6 shows a block diagram of the inverter device in the present embodiment.
[0052]
In FIG. 6, the current detection circuit 46 detects the current of the W-phase output of the inverter circuit 3, and outputs a high value when the instantaneous value of the current IW is positive, and outputs a low value when it is negative. ing.
[0053]
In the second embodiment, the Y terminal of the phase detection circuit 17 receives a signal from the current detection circuit 46.
[0054]
The phase shift circuit 47 delays the phase of the output signal of the current detection circuit 46 to detect the phase in a state where the current vector is in phase with the output voltage of the inverter circuit 3, that is, the vector of the input voltage of the synchronous motor 4. The circuit 16 has an effect of making the rising timings of the signals input to both the X and Y terminals equal, and has a delayed phase of about 30 degrees in electrical angle.
[0055]
Also in the second embodiment, the phase detection circuit 16 detects the timing difference between the rising edge of the output signal of the phase shift circuit 47 input from the X terminal and the Q6 signal input from the Y terminal, and When the direction is advanced, a positive analog voltage is output.
[0056]
Other configurations are the same as those in FIG.
[0057]
In the above configuration, when a set speed signal of 600 rpm is output from the speed setting means 12 as in the first embodiment, each switching element of the inverter circuit 3 is turned on and off via the oscillation circuit 13 and the distribution circuit 14. The synchronous motor 4 rotates at 600 rpm in synchronization with the frequency of 10 hertz supplied from the inverter circuit 3.
[0058]
Here, the input voltage of the synchronous motor 4, that is, the output voltage of the inverter circuit 3, and the phase of the current detected by the current detection circuit 46 are compared by the phase detection circuit 16, and if the current phase is advanced, X Since the terminal is in phase with the Y terminal, a positive analog signal is output.
[0059]
Since the error amplifier 17 amplifies the output of the phase detection circuit 16 and raises the voltage at the D terminal of the voltage control circuit 15, the duty value of the PWM control increases and the output voltage of the inverter circuit 3 increases. It will be a thing.
[0060]
Then, the current phase of the synchronous motor 4 is gradually delayed, β becomes small, and the phase advance angle of the current with respect to the voltage is also reduced, so that the voltage and current vectors are constantly in phase.
[0061]
FIG. 7 shows a vector diagram in a state where the phase difference between the voltage and the current is zero. The power factor of the synchronous motor 4 is almost 1, and the current phase angle β (the voltage phase difference angle δ is also equal). Becomes a positive value and both are located in the second quadrant on the dq plane.
[0062]
In this state, the current Ia includes a slight negative direct-axis current Id component.
[0063]
In the present embodiment, in particular, the phase shift circuit 47 is provided, and as a result of causing a phase delay of about 30 degrees in electrical angle, the voltage phase and the current phase as described above are controlled to the same phase. Yes.
[0064]
However, in claim 2, it is not always an absolute condition that the voltage phase and the current phase are equal as shown in FIG. 7. For example, by adjusting the delay phase angle of the phase shift circuit 47, A phase angle such that the voltage phase is, for example, an electrical angle of 15 degrees with respect to the current phase may be set. In that case, the power factor of the synchronous motor 4 as viewed from the inverter circuit 3 is set. The delay power factor is smaller than 1, but for example, the phase on the dq plane of the current Ia in the rated load condition can be set to a condition of approximately β = 0, and the orthogonality between the magnetic flux and the current is obtained. It is possible to operate with high efficiency due to the characteristics.
[0065]
(Example 3)
The third embodiment of the present invention will be described below. FIG. 8 shows a block diagram of the inverter device of this embodiment.
[0066]
In FIG. 8, the position detection means 11 constituted by the Hall IC as described in the first embodiment and the current detection circuit 46 described in the second embodiment are provided, and the phase detection circuit 16 is provided with position detection. The signal from the means 11 is input from the Y terminal, and the signal from the current detection circuit 46 is input to the X terminal.
[0067]
Also in the third embodiment, the phase detection circuit 16 detects the timing difference between the edges of the signal at the X terminal and the signal at the Y terminal, and outputs a positive analog voltage when the X signal is advanced.
[0068]
Other components are the same as those in the first embodiment.
[0069]
In the above configuration, when a set speed signal of 600 rpm is output from the speed setting means 12 as in the first embodiment, each switching element of the inverter circuit 3 is turned on and off via the oscillation circuit 13 and the distribution circuit 14. The synchronous motor 4 rotates at 600 rpm in synchronization with the frequency of 10 hertz supplied from the inverter circuit 3.
[0070]
Here, the output voltage of the position detection means 11, that is, the magnetic poles of the permanent magnets 5 and 6, and the phase of the current detected by the current detection circuit 46 are compared by the phase detection circuit 16, and the current phase is advanced. Since the X terminal is in phase with the Y terminal, a positive analog signal is output.
[0071]
Since the error amplifier 17 amplifies the output of the phase detection circuit 16 and raises the voltage at the D terminal of the voltage control circuit 15, the duty value of the PWM control increases and the output voltage of the inverter circuit 3 increases. It will be a thing.
[0072]
Then, the current phase of the synchronous motor 4 gradually lags, β becomes small, and the magnetic flux φa generated by the permanent magnets 5 and 6 and the current vector are constantly in phase.
[0073]
FIG. 9 shows a vector diagram in a state where the current phase angle β is zero. The power factor of the synchronous motor 4 is slightly lower than 1 (lagging phase), but the current phase angle β is zero, both on the q axis Position Will be placed.
[0074]
In this state, the direct current Id component is zero, and the configuration of the second object 7 is the minimum for obtaining the same torque as what is called SPM, where the direct inductance Ld and the horizontal inductance Lq are equal. The current value can be obtained.
[0075]
In the first to third embodiments, the second object 7 is configured with a so-called SPM configuration. However, the second object 7 is not particularly limited to this configuration. For example, a permanent magnet is an iron core. By realizing the second object with a configuration that is embedded inside, the horizontal axis inductance Lq may be larger than the value of the direct axis inductance Ld.
[0076]
In this case, in the region where the current phase angle β is positive, the reluctance force (torque) is added to the BIL force (torque) generated by the so-called Fleming's left-hand rule, and as a result, the current supplied to the synchronous motor Therefore, the efficiency of the apparatus can be improved.
[0077]
In order to obtain the effect, the delay phase value of the phase shift circuit is set so as to further advance the current phase angle β in the steady state in the first to third embodiments, or the position of the Hall IC of the position detecting means is set. Or set it.
[0078]
In the first to third embodiments, the number of poles of the synchronous motor 4 is two. However, it is not particularly limited to two poles, and may be four poles, six poles, eight poles, or the like.
[0079]
Example 4
The fourth embodiment of the present invention will be described below. FIG. 10 shows a block diagram of the inverter device of this embodiment.
[0080]
In FIG. 10, the current detection circuit 48 detects not the phase of the W-phase output current IW of the inverter circuit 3 but the magnitude (amplitude).
[0081]
In the present embodiment, the current detection circuit 48 is connected to the output of the inverter circuit 3, but may be connected to the input side of the inverter circuit 3 to detect the peak value of the input current of the inverter circuit 3. The inventors have confirmed that the magnitude of the current output from the inverter circuit 3 to the synchronous motor 4 can be detected even during PWM control by providing a peak hold circuit or the like.
[0082]
The tracking circuit 49 outputs the duty value to the D terminal of the voltage control circuit 15 while increasing / decreasing the PWM duty value in a range of plus / minus 2/256 at a frequency of twice per second, and simultaneously outputs the duty value from the current detection circuit 48. An output signal is input from the Z terminal, and the duty value is output so that the voltage value input from the Z terminal is always minimized.
[0083]
That is, if the voltage input to the Z terminal also decreases when the duty value is decreased and the output voltage to the D terminal is decreased, the duty value is further decreased, and conversely the voltage input to the Z terminal. When the value increases, the duty value is further increased.
[0084]
Also, when the duty value is increased and the output voltage to the D terminal is increased, if the voltage input to the Z terminal also increases, the duty value is decreased, and conversely the voltage input to the Z terminal decreases. In such a case, the duty value is further reduced.
[0085]
Other components are the same as those in the first embodiment.
[0086]
The operation of the above configuration will be described.
[0087]
FIG. 11 shows the relationship between the operation speed, the output voltage of the inverter circuit 4 of Example 4 and the output current of the inverter circuit 4 under the condition that the load torque is fixed.
[0088]
In general, a synchronous motor using a permanent magnet has a characteristic that the magnitude of the input current, that is, the output current of the inverter circuit 4 is minimized under the condition that the terminal voltage, that is, the output voltage of the inverter circuit 4 is a certain value. .
[0089]
In FIG. 11, the current value is minimum at point A, and if the voltage value is increased further than that, a delayed phase current flows, the current value increases, and conversely, the voltage value is increased from point A. If it is decreased, a lead phase current flows, and the current value also increases.
[0090]
In the fourth embodiment, since the voltage output to the voltage control circuit 15 is always made by the action of the tracking circuit 49 so that the voltage value input to the Z terminal is minimized, the operation at the point A in FIG. As a result, the copper loss of the armature windings 8, 9, and 10 of the synchronous motor 4 can be minimized, and high-efficiency operation is possible.
[0091]
Here, when the second object 7 is configured to be called SPM in which the direct-axis inductance value Ld and the horizontal-axis inductance value Lq are substantially equal, β = 0 as shown in FIG. 9 is obtained. .
[0092]
(Example 5)
The fifth embodiment of the present invention will be described below. FIG. 12 shows a cross-sectional view of the second object of the inverter device of this embodiment.
[0093]
In FIG. 12, permanent magnets 51, 52, 53 and 54 are provided in an iron core 50 formed by laminating silicon steel sheets punched with a press machine. The permanent magnets 53 and 54 are magnetized on the outside to the S pole.
[0094]
Such a permanent magnet embedded configuration has a characteristic called a reverse salient pole in which the horizontal axis inductance Lq is larger than the direct axis inductance Ld. In particular, when the current phase β is positive, the reluctance force (torque ) Can be used in combination, and high-efficiency operation with a current value suppressed as compared to torque becomes possible.
[0095]
Other components are the same as those described in the fourth embodiment.
[0096]
However, since the second object shown in FIG. 12 has a four-pole configuration, all of the three-phase armature windings 8, 9, and 10 have a four-pole configuration.
[0097]
In the fifth embodiment, since the operation is performed so that the output value of the current detection circuit is minimized as described in the fourth embodiment, in the case of using the second object shown in FIG. The operation is performed under the condition that the current value becomes the smallest in accordance with the load condition and in the values of the horizontal axis inductance Lq and the direct axis inductance Ld.
[0098]
Therefore, for example, in a DC brushless motor, the current phase β that minimizes the current value for each load condition is stored in a microcomputer or the like, and compared with a configuration in which control is performed. However, the operating conditions are automatically shifted to the conditions that minimize the current under all load conditions, and even if there are variations in each component, etc., the minimum current conditions are met under those conditions. Operation will be realized.
[0099]
(Example 6)
The sixth embodiment of the present invention will be described below. FIG. 13 shows the output current waveform of the inverter circuit of the inverter device of this embodiment.
[0100]
In FIG. 13, (a), (b), and (c) show output current waveforms of the U phase, the V phase, and the W phase, respectively.
[0101]
In the sixth embodiment, the on / off PWM of each switching element of the inverter circuit having a three-phase six-stone structure is changed within one cycle, whereby the voltage of each phase of U, V, and W is substantially sinusoidally modulated. Since the current waveform is almost a sine wave, electromagnetic noise generated from the synchronous motor can be suppressed, and an inverter device with quiet operation sound can be realized. ing.
[0102]
Here, as an alternative to the position detection means using the Hall IC described in the prior art, from the induced electromotive force generated when the magnetic flux of the permanent magnet of the second object cuts the armature winding of the first object. In some cases, a configuration in which position detection is performed is also used.
[0103]
Especially in devices such as air conditioners and refrigerators that are built in compressors, called hermetic motors, the installation of Hall ICs etc. is extremely difficult due to the provision of an electric motor in the refrigerant. Therefore, position detection from the induced electromotive force as described above is often performed.
[0104]
However, such a position detection method is not suitable for an inverter circuit having a three-phase six-stone configuration.
As called 0 degree energization, the width of the ON period of each switching element is set to 120 degrees in electrical angle, and the ON period of the high potential side switching element and the low potential side of each phase of U, V, and W are Between the ON period of the switching element, both the high potential side switching element and the low potential side switching element are in the OFF state for a period of 60 degrees in electrical angle. During this period, the voltage at the output terminal of the inverter circuit is Since the induced electromotive force is reversely applied as it is, after passing through a low-pass filter or the like, the zero point is detected using a comparator or the like, and a position detection means equivalent to that using the Hall IC is provided. It was to be composed.
[0105]
Therefore, when a sine wave operation as shown in FIG. 13 is performed to achieve a quiet operation device, a period of 60 degrees in which both the high potential side switching element and the low potential side switching element are off. Therefore, the position cannot be detected from the induced electromotive force.
[0106]
In the sixth embodiment, since it is not necessary to detect the induced electromotive force, even when the inverter circuit is operated with the operation waveform shown in FIG. 13, for example, the configurations of the second and fourth embodiments. Since the configuration can be made without using the position detecting means as shown in Fig. 5, it can be used as a configuration for realizing an apparatus having quiet operation sound even for the compressor.
[0107]
In addition, for example, a configuration using Hall ICs can also be expected to reduce the operation sound by sine wave operation, and further, for example, the number of Hall ICs can be configured by one.
[0108]
Further, even when a configuration is used in which reluctance torque is obtained by using a reverse salient pole characteristic in which the horizontal axis inductance Lq is larger than the direct axis inductance Ld as shown in the fifth embodiment, the operation noise is reduced. In addition to the effect, high efficiency can also be realized.
[0109]
In the first to sixth embodiments, when the set speed of the speed setting unit 12 is high, even if the PWM duty is set to 100% and the output voltage of the inverter circuit is maximized, the current is in the state of the leading phase. Driving.
[0110]
Therefore, in this case, the efficiency and the power factor of the input of the synchronous motor are somewhat reduced. However, in an apparatus having an operation mode that requires a low torque and high-speed rotation, the electromotive force of the synchronous motor If the constant Ke is designed to be high and the torque constant Kt is large, the output current value of the inverter circuit can be reduced when high torque is required in the low speed range, and rational operation is possible. Become.
[0111]
【The invention's effect】
As described above, the invention according to claim 1 includes a synchronous motor, an inverter circuit that supplies an alternating current to the synchronous motor, a speed setting unit, and a position detection unit, and the motor includes an armature winding. And a second object that is movable relative to the first object and has a permanent magnet, and the position detecting means detects the position of the permanent magnet of the second object. The output frequency of the inverter circuit is a value corresponding to the output of the speed setting means, and the output voltage value of the inverter circuit is a value at which the output voltage phase and the phase angle of the output signal of the position detection means are substantially constant. With this configuration, it is relatively easy to provide the synchronous motor with a frequency corresponding to the output of the speed setting means without using a current minor loop or a speed feedback loop. As a result, it is possible to ensure speed responsiveness, and the position detection means, for example, in a three-phase six-stone inverter circuit structure, can operate even one Hall IC. Will be able to do.
[0112]
Claims 2 In particular, the invention according to the present invention makes it possible to set the frequency according to the output of the speed setting means without using a current minor loop or a speed feedback loop by making the output current of the inverter circuit of the inverter device substantially sinusoidal. By giving to the synchronous motor, it becomes possible to ensure speed responsiveness with a relatively simple configuration, and it is possible to improve the efficiency of the entire device by reducing the current value, and in addition, the current of the armature winding Noise can be reduced by making the waveform close to a sine wave.
[Brief description of the drawings]
FIG. 1 is a block circuit diagram of an inverter device according to a first embodiment.
FIG. 2 is a detailed circuit diagram of a rectifying / smoothing circuit and an inverter circuit of the inverter device.
FIG. 3 is a detailed circuit diagram of a voltage control circuit of the inverter device.
[Fig. 4] Input / output waveform diagram of the distributor of the inverter device
FIG. 5 is an input / output characteristic diagram of the oscillation circuit of the inverter device.
6 is a block circuit diagram of an inverter device according to Embodiment 2. FIG.
FIG. 7 is a vector diagram of the inverter device.
FIG. 8 is a block circuit diagram of an inverter device according to a third embodiment.
FIG. 9 is a vector diagram of the inverter device.
FIG. 10 is a block circuit diagram of an inverter device according to a fourth embodiment.
FIG. 11 is an operating characteristic diagram of the synchronous motor of the inverter device.
12 is a cross-sectional view of a second object in Embodiment 5. FIG.
FIG. 13 is an operation waveform diagram of the inverter circuit according to the sixth embodiment.
FIG. 14 is a block circuit diagram of a conventional inverter device.
FIG. 15 is an input / output waveform diagram of the control circuit of the inverter device.
FIG. 16 is a vector diagram of the inverter device.
[Explanation of symbols]
4 Synchronous motor
3 Inverter circuit
12 Speed setting means
11 Position detection means
8. 9, 10 Armature winding
45 First object
5.6 Permanent magnet
7 Second object

Claims (2)

  A synchronous motor; an inverter circuit that supplies an alternating current to the synchronous motor; a speed setting unit; and a position detection unit. The motor includes a first object having an armature winding, and the first object. And a second object having a permanent magnet, the position detecting means detects the position of the permanent magnet of the second object, and the output frequency of the inverter circuit is the speed An inverter device having a value corresponding to the output of the setting means, and an output voltage value of the inverter circuit having a value at which an output voltage phase and a phase angle of an output signal of the position detecting means are substantially constant. Output current of the inverter circuit, according to claim 1 Symbol placement of inverter device is substantially sinusoidal.

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