JP2010288331A - Inverter device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inverter device which can improve an input current waveform, makes a high power factor and enables highly precise phase control with a simple structure. <P>SOLUTION: A DC voltage detecting part 16 monitors a DC voltage signal given from a voltage detecting unit 30 and outputs a detection signal to a sampling judging part 17 when the signal becomes a prescribe voltage level or above. The sampling judging part 17 A/D-converts a motor current signal given from a motor current detection amplifier part 6 at prescribed timing in accordance with the detection signal so as to take it in. A phase difference detecting part 8 integrates respective current sampling data sampled in two locations at each motor drive voltage phase period concerning sampling data of the motor current signal which is A/D-converted by the sampling judging part 17, sets the result as a motor current signal area, and outputs an area ratio of both motor current signal areas as phase difference information. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an inverter device, for example, an inverter device that can drive a synchronous motor including a plurality of phase coils without using a sensor.

  Conventionally, when driving a synchronous motor having a multi-phase coil, optimization of so-called energization timing of flowing a motor current to the motor rotor at an appropriate timing and applying a voltage to the coil terminal has been important. It was. In order to detect the reference of the energization timing, there are various methods such as a method of detecting a counter electromotive voltage and a method of detecting a zero cross current phase.

  For example, in so-called sensorless driving in which a motor is controlled and driven without using a motor rotor position sensor, a back electromotive voltage generated in the motor coil due to rotation of the motor is detected from the motor coil terminal when the motor coil is energized. There is a method.

  In addition, the driving device disclosed in Japanese Patent Laid-Open No. 5-236789 detects a motor voltage phase at the time of motor current zero crossing, detects a motor current phase based on this voltage phase, and this motor current phase is a desired value. A method for calculating a voltage command or a frequency command so as to obtain a current phase is shown.

  Japanese Patent Application Laid-Open No. 2001-112287 by the applicant of the present application discloses that an alternating current signal area is integrated by accumulating each alternating current detection value for each phase period of two alternating voltages, and an area ratio of both alternating current signal areas. Is detected as AC voltage / current phase difference information, and a system capable of phase control with higher accuracy than the case of detecting the voltage phase at zero crossing is shown.

FIG. 7 shows a configuration of a conventional general inverter device.
Referring to FIG. 7, in order to drive synchronous motor 100 having a plurality of (three-phase) coils in the stator and a permanent magnet in the rotor, the inverter device includes inverter 150, converter circuit 130, AC power supply 160, A coil 170, a current sensor 180, and a controller 110 are included.

  Synchronous motor 100 is driven by inverter 150, and inverter 150 is supplied with AC power supply 160 converted from converter circuit 130 into a direct current.

  Specifically, converter circuit 130 includes a diode full-wave rectifier circuit 120 formed of diodes 122 to 128 and a smoothing capacitor 140 between buses, and the capacity of the smoothing capacitor can improve the ripple of the DC voltage waveform. Large enough.

  The converter circuit 130 converts the AC voltage of the AC power supply 160 into a DC voltage and supplies it to the inverter 150.

  The coil 170 is provided for the purpose of improving the power factor of the AC power supplied to the converter circuit 130.

FIG. 8 is a diagram for explaining the relationship between the waveform of the DC voltage and the U-phase motor current.
As shown in FIG. 8A, when the capacity of the smoothing capacitor 140 is sufficiently large, the ripple of the DC voltage waveform is improved and a constant DC voltage is supplied to the inverter 150.

  FIG. 8B is a diagram illustrating a U-phase current waveform detected by the current sensor 180.

  As shown in FIG. 8B, since the ripple of the DC voltage waveform is improved and a constant DC voltage is supplied to the inverter 150, the U-phase motor current that drives the synchronous motor 100 from the inverter 150 has a constant amplitude. It is detected as a stable waveform.

  On the other hand, in the conventional configuration as described above, there is a problem that it is difficult to obtain an improvement in the input current waveform and a high power factor. Therefore, in Japanese Patent Laid-Open No. 2002-51589, the coil 170 is not used. By using a capacitor with a small capacity of about 1/100 of the conventional smoothing capacitor between the buses of the inverter, a ripple of twice the frequency of the power supply is intentionally generated in the DC voltage, and the input current waveform can be generated in a simple manner. A method for improving the power factor is proposed.

JP-A-5-236789 JP 2001-112287 A JP 2002-51589 A

  However, when the above method is adopted, since the coil 170 for improving the ripple of the DC voltage waveform is not provided, a ripple having a frequency twice that of the power supply is generated in the DC voltage as shown in FIG. To do.

  Along with this, as shown in FIG. 9B, the fluctuation of the alternating current on the inverter output side is large, and the value of the motor current is small where the value of the direct current voltage is small. For this reason, it is difficult to ensure sufficient detection accuracy of AC voltage / current phase difference information even in the method disclosed in Japanese Patent Application Laid-Open No. 2001-112287, and it is difficult to acquire and control highly accurate phase difference information.

  The present invention has been made in order to solve the above-described problems, and provides an inverter device capable of improving the input current waveform and increasing the power factor and capable of highly accurate phase control with a simple configuration. The purpose is to provide.

  An inverter device according to an aspect of the present invention controls a rectifier circuit that receives a single-phase AC power source, an inverter that is connected to the rectifier circuit and converts DC power obtained by the rectifier circuit into three-phase AC power, and the inverter. And a control device. Preferably, the control device detects a value of a DC voltage applied to the inverter via the rectifier circuit, an output AC voltage detection unit detects the phase of the AC voltage of a specific output phase of the inverter, An output AC current detection unit that detects an AC current of a specific output phase, and a voltage / current phase difference detection unit that detects a phase difference between the output AC voltage and the output AC current. The area of the alternating current signal of the specific output phase during the two phase periods based on the phase of the alternating voltage of the specific output phase when the value of the direct current voltage detected by the voltage detector is equal to or greater than a predetermined value Is obtained in each phase period, the area ratio of the areas of the alternating current signals in the two phase periods is calculated, and this is used as phase difference information.

  Preferably, the phase difference detection unit outputs an alternating current signal of a specific output phase flowing per phase period n times (n is 1 or more) during two phase periods with reference to the alternating voltage of the specific output phase. (Integer) sampling, summing each sampled current sampling data, and outputting as an area of AC current signal.

Preferably, a very small capacitor is connected between the buses of the inverter.
Preferably, a motor is connected to the output side of the inverter, and the motor is sensorlessly driven by performing inverter control using phase difference information.

  Preferably, the motor includes a plurality of phase motor coils, the inverter includes a plurality of switching elements provided corresponding to each of the plurality of phase motor coils, and energizes the corresponding motor coils. In response to the command for setting the motor, the driving wave data generating means for generating the driving wave data for driving the motor for each of a plurality of phases, and the output from the phase difference detecting means. Phase difference control means for calculating a duty reference value for controlling the phase difference information to a target value, driving wave data for each phase output from the driving wave data creation means, and a duty reference value output from the phase difference control means According to the duty calculation means for calculating the output duty for each phase, and the output duty for each phase calculated by the duty calculation means Further comprising a PWM creation unit for generating a pulse width modulated signal for controlling the conduction of each switching element.

  The phase difference detection unit of the control device in the inverter device according to an aspect of the present invention uses the AC voltage phase of a specific output phase as a reference when the value of the DC voltage detected by the DC voltage detection unit is equal to or greater than a predetermined value. The area of the alternating current signal of the specific output phase in the two phase periods is calculated in each phase period, and the area ratio of the area of the alternating current signal in the two phase periods is calculated and Use phase difference information.

  With this configuration, the AC voltage / current phase difference information is detected by acquiring a sampling value in a period in which the amplitude of the motor current signal whose DC voltage is equal to or greater than a predetermined value is large under the condition that a large ripple is generated in the DC voltage. Therefore, it is possible to improve the input current waveform and increase the power factor.

  Further, by using a capacitor having a small capacity of about 1/100 of a conventional smoothing capacitor between the buses of the inverter, it is possible to realize a small, light and low cost inverter device.

  Further, by performing inverter control using the detected AC voltage / current phase difference information, the position of the rotor can be adjusted in motor drive by 180 ° energization including low noise, low vibration and high efficiency sinusoidal energization. It is possible to perform stable rotation without using a sensor to detect.

It is a block diagram of the inverter apparatus according to the embodiment of the present invention. It is a figure explaining the relationship between the waveform of the DC voltage of the inverter apparatus according to embodiment of this invention, and the motor electric current of U phase. It is a figure explaining the principle of phase difference information detection. It is a flowchart explaining the phase difference detection routine which detects the phase difference information in the controller. It is a flowchart explaining the sampling start routine which detects whether the sampling timing came by the value of the timer etc., and starts sampling. It is a wave form diagram of motor current signal b and motor drive voltage phase information c. It is the structure of the conventional general inverter apparatus. It is a figure explaining the relationship between the waveform of DC voltage, and a U-phase motor current. It is another figure explaining the relationship between the waveform of DC voltage, and a U-phase motor current.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  A block diagram of the inverter device according to the embodiment of the present invention will be described with reference to FIG.

  Referring to FIG. 1, in order to drive a synchronous motor 1 having a multi-phase (three-phase) coil in a stator and a permanent magnet in a rotor, an inverter device includes an inverter 2, a converter circuit 3, and an AC power source. 4, a current sensor 5, a motor current detection amplifier unit 6, and a controller 7 that is a microcomputer.

  The synchronous motor 1 is driven by an inverter 2, and the inverter 2 is supplied with an AC voltage from an AC power source 4 converted from a converter circuit 3 into a direct current.

  Specifically, converter circuit 3 includes a plurality of diodes 22 to 28, and full-wave rectifier circuit 20 is formed. A small-capacitance capacitor 40 is provided between the buses. In this example, the small capacitor 40 is 100 μF or less. Specifically, a capacitor of about 10 to 20 μF can be used in consideration of prevention of breakdown of the semiconductor element of the inverter 2 due to regenerative energy of the synchronous motor 1 on the load side.

  A voltage detection unit 30 is provided between the buses, and a DC voltage signal detected by the voltage detection unit 30 is given to the controller 7.

  The current sensor 5 detects a motor current a flowing in a specific phase (U phase in FIG. 1) among the motor coil terminals U, V, and W. The motor current detected by the current sensor 5 is given to the motor current detection amplifier unit 6. The motor current detection amplifier 6 amplifies the motor current signal b by a predetermined amount and adds the offset to the controller 7.

  The controller 7 includes a phase difference detection unit 8, a target phase difference information storage unit 9, an addition unit 10, a PI calculation unit 11, a rotation speed setting unit 12, a sine wave data table 13, and a sine wave data creation unit. 14, the PWM creation unit 15, the DC voltage detection unit 16, and the sampling determination unit 17 are performed in software. In the present embodiment, phase control is executed by a method similar to the phase control method described in Japanese Patent Application Laid-Open No. 2001-112287.

  The DC voltage detection unit 16 monitors the DC voltage signal provided from the voltage detection unit 30 and, when the voltage level becomes equal to or higher than a predetermined voltage level (Va in this example), is equal to or higher than the predetermined voltage level. When the detection signal indicating that the voltage is less than a predetermined voltage level (Va in this example) is output to the sampling determination unit 17, the detection signal indicating that the detection signal is less than the predetermined voltage level is output to the sampling determination unit 17. Output to.

  Sampling determination unit 17 takes in the motor current signal supplied from motor current detection amplifier unit 6 according to the detection signal from DC voltage detection unit 16 by A / D conversion at a predetermined timing.

  The phase difference detection unit 8 integrates each current sampling data sampled every two motor drive voltage phase periods with respect to the sampling data of the motor current signal A / D converted by the sampling determination unit 17 to obtain a motor current signal area. And the area ratio of both motor current signal areas is output as phase difference information.

  The target phase difference information is stored in the target phase difference information storage unit 9. Error data between the target phase difference information and the phase difference information is calculated by the adding unit 10. The PI calculation unit 11 calculates proportional error data and integral error data with respect to the calculated error data and outputs a duty reference value. The addition unit 10 and the PI calculation unit 11 constitute a phase difference control unit.

  The rotation speed setting unit 12 sets a rotation speed command of the synchronous motor 1, and the sine wave data table 13 includes a table of a predetermined number of data. The sine wave data creation unit 14 reads out sine wave data corresponding to each phase of the motor coils U, V, and W from the sine wave data table 13 according to the rotational speed command and the passage of time, and from the U phase sine wave data to the U phase. Motor drive voltage phase information c is output. The PWM generator 15 outputs a PWM waveform to the drive element of the inverter 2 for each phase from the sine wave data and the duty reference value.

  The current sensor 5 may be a so-called current sensor composed of a coil and a Hall element, or a current transformer.

  In this example, the case of detecting the U phase will be described. However, when the motor current of each phase as well as one phase is detected, higher accuracy can be achieved. Furthermore, the sine wave data may be created by calculation instead of being created based on the sine wave data table 13. Furthermore, although the constituent elements of the constituent elements 8 to 17 are processed by the controller 7 in a software manner, the present invention is not limited to this and may be configured as a hardware configuration as long as the same processing is performed.

  Although the motor drive waveform is a sine wave, the sine waveform makes it possible to supply a smooth motor current, thereby reducing vibration and noise. However, the present invention is not limited to this, and if a drive waveform that provides a motor current that matches the magnetic flux of the motor rotor is energized, a more efficient drive is possible.

  The area ratio of the two motor current signal areas detected in the two motor drive voltage phase periods is calculated by the phase difference detector 8, and this result is used as phase difference information. The PI calculation unit 11 performs a PI calculation on the error amount between the phase difference information and the target phase difference information, and the PWM generation unit 15 determines the output from the duty reference value and the sine wave data separately obtained from the rotation command. The synchronous motor 1 is driven by calculating the output duty ratio in each case, creating a PWM signal, and applying it to the motor coil via the inverter 2.

  That is, the magnitude of the drive voltage (duty width of the PWM duty) is determined by a phase difference control feedback loop for controlling the motor current phase difference with respect to the motor drive voltage (output duty) to be constant, and the synchronous motor 1 is rotated in a desired rotation. The number of rotations is determined by sine wave data output at a desired frequency in order to rotate the number. Thus, the motor can be driven and controlled with a desired phase difference and a desired rotation speed.

  It should be noted that when the motor is activated, each phase is forcibly energized, a rotating magnetic field is applied, forced excitation is performed, and control is performed by the above method during normal driving.

  Here, as described in JP-A-2001-112287, the synchronous motor can be driven and controlled by the phase difference control of the present invention.

  In the present embodiment, a system for executing the phase difference control will be described mainly under the condition that a large ripple is generated in the DC voltage when the phase difference control is executed.

  The relationship between the waveform of the DC voltage of the inverter device according to the embodiment of the present invention and the U-phase motor current will be described using FIG.

  As shown in FIG. 2A, as in FIG. 9A, since there is no coil 170 in this example, ripples having a sharp waveform are generated in the DC voltage waveform.

FIG. 2B shows a U-phase current waveform with respect to the DC voltage.
In the present embodiment, when the DC voltage supplied to inverter 2 is equal to or higher than a predetermined value level, motor current sampling data is acquired. In this example, sampling data of the U-phase motor current when the DC voltage is equal to or greater than the predetermined value Va is acquired.

  Here, the dotted line portion indicates a portion where sampling data is not used in the U-phase motor current waveform. On the other hand, the solid line portion indicates the portion using the sampling data in the U-phase motor current waveform.

Subsequently, processing for detecting phase difference information according to the present invention will be described.
The principle of phase difference information detection will be described with reference to FIG.

  Referring to FIG. 3A, the U-phase motor current a has a substantially sinusoidal waveform centered on the 0 level. The motor current a is amplified by the motor current detection amplifier unit 6 and is offset to create a motor current signal b. This is performed to adjust the motor current a to a convertible voltage range (for example, 0 to +5 V) of the A / D converter built in the controller 7.

  The U-phase motor drive voltage phase information c is created from the U-phase sine wave data by the sine wave data creation unit 14. The motor drive voltage phase information c does not actually need to be a sine wave waveform, and only the phase information needs to be known.

  A motor current signal b as shown in FIG. 3B and motor drive voltage phase information c shown in FIG. 3C are input to the phase difference detection unit 8. The phase difference detector 8 samples the motor current signal b in a predetermined phase period θ0, θ1 determined in advance from the motor drive voltage phase information c at a predetermined sampling phase (sampling timing) s0 to s3 and n per phase period. (2 times in the case of FIG. 4), the motor current signal areas in the respective phase periods θ0 and θ1 are set as IS0 and IS1, respectively, and current sampling data is integrated by sampling.

That is,
Is0 = I0 + I1
Is1 = I2 + I3
Then, the ratio of each motor current signal area Is0, Is1 is calculated and used as phase difference information.

  FIG. 4 is a flowchart for explaining a phase difference detection routine for detecting phase difference information in the controller 7.

  FIG. 5 is a flowchart for explaining a sampling start routine (timer interrupt routine) for starting sampling by detecting whether the sampling timing has come or not by using a timer value or the like. In addition, even if it is not especially such a process structure, the process should just be performed by the same view.

  Referring to FIG. 4, in step S2, the sampling timing of sampling phase s0 is set as an interrupt value for the sampling start routine from the motor rotation speed and timer count cycle, and each variable such as sampling count n is initialized. Turn into. This is performed only once immediately after the start of motor rotation, immediately after the phase period θ0 or before the phase period θ0, and subsequent sampling timing setting is performed in the sampling start routine.

  Step S4 and subsequent steps are loop processing. After step S2, the loop processing is repeated until the detection of the phase difference information is completed, and the loop processing is performed again in the next phase period θ0. In step S4, the sampling determination unit 17 detects whether the sampling commanded to start in the sampling start routine has ended. If completed, the process proceeds to step S6. If not completed, the following processing is performed. However, since loop processing is being performed, it is continuously detected whether sampling has ended.

  Next, it is determined whether or not the motor voltage is equal to or higher than a predetermined voltage (Va in this example) (step S6). Specifically, the sampling determination unit 17 determines whether there is an input of a detection signal indicating that the voltage level is equal to or higher than a predetermined voltage level from the DC voltage detection unit 16.

  If it is determined in step S6 that the motor voltage is equal to or higher than the predetermined voltage (YES in step S6), then a current sampling value is read (step S8). Specifically, when a detection signal indicating that the voltage level is equal to or higher than a predetermined voltage level is input from the DC voltage detection unit 16, the sampling determination unit 17 outputs a current sampling value to the phase difference detection unit 8.

  Next, in step S12, the sampling count is updated once. Specifically, the subsequent processing is executed in the phase difference detection unit 8.

  Next, in step S14, it is determined whether the current phase period is θ0 or θ1, and the process of step S16 or S22 is performed depending on the determination result. This determination may be made based on the number of samplings n.

  In step S16 or S22, it is determined whether the number of times of sampling has reached a predetermined number (2 or 4 times). If the number of samplings is a predetermined number (2 or 4 times), the process of step S18 or S24 is performed.

  In step S18 or S24, assuming that sampling in each phase period is completed, current sampling data is integrated (I0 + I1, I2 + I3), and the motor current signal area Is0 or Is1 is calculated. In step S20, it is determined whether the calculation of both the motor current signal areas Is0 and Is1 is completed. If not completed, the process returns to the loop processing.

  In step S26, assuming that the calculation of the motor current signal areas Is0 and Is1 has been completed, a ratio (Is0 / Is1) of both area data is calculated and used as phase difference information.

  Then, the detected phase difference information is stored (step S28). Then, a series of phase difference detection routines (loop processing) ends.

  On the other hand, if it is determined in step S6 that the motor voltage is less than the predetermined voltage (NO in step S6), then the current sampling value is invalidated (step S9). Then, the processing of the phase difference detection routine ends. When the motor voltage is less than a predetermined voltage, the amplitude of the motor current is small and the influence of the error is large. Therefore, since phase control with high accuracy is difficult with the phase difference information using the sampling value of the motor current having a large influence of error, the processing of the phase difference detection routine is terminated. In this case, phase control is executed based on the stored phase difference information. That is, the phase difference information is not updated, and phase control based on the updated phase difference information is executed when the motor voltage is equal to or higher than a predetermined voltage in the next phase difference detection routine.

  The sampling start routine (timer interrupt routine) shown in FIG. 4B is started at the sampling timing at which the timer interrupt is set. In step S40, the next sampling timing is determined in advance. Is set as the interrupt value for the sampling start routine.

In step S42, the A / D converter is instructed to start current sampling, and the process ends.
As described above, the next sampling timing is set in the sampling start routine processing because the current timer count value is known (≈the current timer interrupt value) and the current motor voltage phase is known. In this way, it is not necessary to refer to the timer count value and the motor voltage phase again, and efficient processing becomes possible.

  However, strictly speaking, the current timer interrupt value and the current sampling phase are values at the time of occurrence of the interrupt, and are slightly different from the timer count value and the motor voltage phase at the time of performing step S40. End up. Therefore, it is desirable to refer to the timer count value and the motor voltage phase each time a strict sampling timing needs to be set.

Here, the sampling timing of the motor current can be arbitrarily determined by setting a timer interrupt value to a predetermined value each time from the motor rotation speed and the timer cycle according to a predetermined sampling phase. Specifically, the setting method is as follows. For example, when the motor rotates once in two cycles of sine wave, and sampling is started when the motor rotation speed is 3000 rpm and the motor voltage phase is 30 °, the motor voltage phase is 0 °. If the current sampling timer count resolution is 1 μsec, the time until the motor voltage phase changes from 0 ° to 30 ° is 10 msec for one cycle of the sine wave.
0.01 [s] * 30 [°] / 360 [°] = 833 [μsec]
As the count of the current sampling timer,
833 [μsec] / 1 [μsec / count] = 833 [count]
It becomes. That is, if 833 is added to the count value of the timer when the motor voltage phase is 0 ° and this is used as the timer interrupt value, a timer interrupt is generated at the motor voltage phase of 30 ° and current sampling is started. . As described above, since the motor rotation speed is determined by the cycle of the sine wave data, that is, determined by the controller 7, it is possible to perform sampling at an accurate motor voltage phase.

  As for how to set the sampling timing in the two phase periods, each sampling timing is always sampled at the same phase of the motor voltage, and one rotor stator relative position or one phase difference information There is no problem as long as the driving voltage (output duty) can be obtained.

  However, as shown in FIG. 3, the phase is symmetrical about the motor voltage phase of 90 ° (the phase from the phase 90 ° to each sampling timing is the same at the sampling timing of each phase period). In other words, when the actual phase difference is 0, the phase of the motor current signal is detected as the same value), and current sampling in each phase period facilitates the phase difference control design.

  Further, the phase periods of the motor voltage phase need not be gathered. For example, in FIG. 3, the integrated value of I0 and I5 is the motor current signal area of the first phase period, and the integrated value of I2 and I7 is the second value. It may be divided from the motor current signal area of the phase period, which can be determined from the margin of the processing time of the control system.

  In addition, the phase difference detection after detecting the phase difference information (Is0 / Is1) in the phase periods θ0 and θ1 is faster by calculating the phase difference information (Is2 / Is1) using the phase periods θ1 and θ2. It is possible to detect the phase difference information.

  Here, a method for simplifying the setting of the sampling timing of the motor current, that is, the setting of the timer interrupt value will be described.

FIG. 6 is a waveform diagram of the motor current signal b and the motor drive voltage phase information c.
In FIG. 6, the number of times of sampling between predetermined phase periods θ0 and θ1 based on the motor drive voltage phase information c is set to three. What should be noted here is that the current sampling timing within each phase period is set to the sampling period θs = a having the same value, that is, sampling is performed at the same interval.

  In accordance with the sampling timing setting method described above, after calculating θs at the beginning of each phase period, it is only necessary to add the current timer count value θs for the subsequent timer interrupt values.

  By setting the timing in this way, it is possible to reduce the sampling timing setting in step S40 of FIG. 5, that is, the calculation of the timer interrupt value.

  As described above, in the present embodiment, even in a condition where a large ripple is generated in the DC voltage, a period during which the DC voltage is equal to or higher than a predetermined voltage, that is, a period in which a motor current waveform generated based on the DC voltage is sufficiently obtained is effective. The AC voltage / current phase difference information can be accurately detected with a simple configuration using the sampling data.

  Therefore, a coil is not used as in the conventional configuration, and a capacitor having a small capacity of about 1/100 of a conventional smoothing capacitor can be used between the buses of the inverter. Improvement and higher power factor can be realized.

  Further, by using a capacitor having a small capacity of about 1/100 of a conventional smoothing capacitor between the buses of the inverter, it is possible to realize a small, light and low cost inverter device.

  In addition, by performing inverter control using the detected AC voltage / current phase difference information, the rotor position is detected in motor drive by 180 degree energization including low noise, low vibration and high efficiency sinusoidal energization. Therefore, it is possible to perform stable rotation without using a sensor.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1 motor, 2 inverter, 3 converter circuit, 4 AC power supply, 5 current sensor, 6 motor current detection amplifier unit, 7 controller, 8 phase difference detection unit, 9 target phase difference information storage unit, 10 addition unit, 11 PI calculation unit , 12 rotation speed setting unit, 13 sine wave data table, 14 sine wave data creation unit, 15 PWM creation unit, 16 DC voltage detection unit, 17 sampling determination unit, 20 full-wave rectifier circuit, 30 voltage detection unit.

Claims (5)

A rectifier circuit with a single-phase AC power supply as input,
An inverter connected to the rectifier circuit and converting the DC power obtained by the rectifier circuit into three-phase AC power;
A control device for controlling the inverter,
The control device includes:
A DC voltage detector that detects a value of a DC voltage applied to the inverter via the rectifier circuit;
An output AC voltage detector that detects the phase of the AC voltage of the specific output phase of the inverter;
An output alternating current detector that detects an alternating current of the specific output phase;
A voltage / current phase difference detection unit that detects a phase difference between the output AC voltage and the output AC current;
When the value of the DC voltage detected by the DC voltage detection unit is greater than or equal to a predetermined value, the phase difference detection unit is in two phase periods based on the phase of the AC voltage of the specific output phase. An inverter device that obtains the area of the alternating current signal of the specific output phase in each phase period, calculates the area ratio of the areas of the alternating current signals in the two phase periods, and uses this as phase difference information.   The phase difference detection unit outputs the alternating current signal of the specific output phase that flows per phase period n times (n is 1 or more) during two phase periods with the alternating voltage of the specific output phase as a reference. 2. The inverter apparatus according to claim 1, wherein sampling is performed, and each sampled current sampling data is integrated and output as an area of the alternating current signal.   The inverter device according to claim 1, wherein an extremely small capacitor is connected between the buses of the inverter. Connect a motor to the output side of the inverter,
The inverter device according to claim 1, wherein the motor is sensorlessly driven by performing inverter control using the phase difference information. The motor includes a multi-phase motor coil,
The inverter includes a plurality of switching elements that are provided corresponding to the motor coils of the plurality of phases and energize the corresponding motor coils,
The control device includes:
Drive wave data creating means for creating drive wave data for driving the motor for each phase of the plurality of phases in response to a command for setting the rotational speed,
A phase difference control means for calculating a duty reference value for controlling the phase difference information output from the phase difference detection means to a target value;
Duty calculation means for calculating the output duty for each phase by multiplying the drive wave data of each phase output from the drive wave data creation means and the duty reference value output from the phase difference control means;
5. The inverter device according to claim 4, further comprising: a PWM generation unit that generates a pulse width modulation signal for controlling conduction of each switching element according to the output duty for each phase calculated by the duty calculation unit.

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