JP2009240147A - Inverter apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce noise and vibration on positioning an inverter detecting a phase current by a current sensor disposed in between a DC power supply and the inverter. <P>SOLUTION: The inverter is equipped with an inverter circuit having an upper-arm switching element connected to the plus side of a DC supply, and a low-arm switching element connected to the minus side of the supply; a current sensor to detect the current between the DC supply and the inverter circuit; and a controlling circuit to make the inverter circuit output a driving current to the motor. The controlling circuit makes the inverter circuit output the DC current to the motor through a PWM energization; and at the same time corrects the energization only just after stabilization of the positioning current to detect the phase current by means of the current sensor, when positioning the magnetic rotor before operating the motor. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an inverter device that detects a phase current by a current sensor provided between a DC power source. In particular, it is intended to reduce noise in positioning of the magnet rotor before operation.

  There has been proposed an inverter device that detects a phase current using a current sensor provided between a DC power supply (see, for example, Patent Document 1). FIG. 8 shows an example of an electric circuit around the inverter device and its periphery. The control circuit 12 of the inverter device 21 detects the phase current for two phases based on the voltage from the shunt resistor 6. The phase current for the remaining one phase is calculated from the two current values (Kirchhoff's current law is applied at the neutral point of the stator winding 4).

  During operation of the motor, based on these current values, an induced voltage by the magnet rotor 5 constituting the sensorless DC brushless motor 11 (hereinafter referred to as a motor) is calculated, and its position is detected. Then, based on the position detection and communication speed command signal (not shown), the switching element 2 (IGBT, FET, transistor, etc.) constituting the inverter circuit 10 is controlled via the connection line 18. To do. As a result, the DC voltage from the battery 1 is switched by PWM modulation, and a sinusoidal AC current is output to the stator winding 4 constituting the motor 11. The diode 3 constituting the inverter circuit 10 serves as a circulation route for the current flowing through the stator winding 4. For the switching element 2, the upper arm switching element is defined as U, V, W, and the lower arm switching element is defined as X, Y, Z.

  Next, the positioning of the magnet rotor before the operation of the motor will be described below. In order to start the rotation of the magnet rotor 5, it is necessary to position the magnet rotor 5 before energization (see, for example, Patent Document 2). An example will be described below. FIG. 9A shows a case in which the magnet rotor 5 is positioned with the U phase and V phase of the stator winding 4 as the S pole and the W phase as the N pole in the case of 4 poles. The N pole of the magnet rotor 5 is positioned on the S pole of the stator winding 4 and the S pole of the magnet rotor 5 is positioned on the N pole of the stator winding 4 so as to be opposed to each other. . At this time, as shown in FIG. 9B, a current flows from the W phase to the U phase and the V phase of the stator winding 4.

  In FIG. 10A, the ON periods (Duty) of the upper arm switching elements U, V, and W within one carrier (carrier cycle) in the positioning example are displayed symmetrically from the center. The ON period of the U-phase upper arm switching element U is represented by a thin solid line, the ON period of the V-phase upper arm switching element V is represented by a solid solid line, and the ON period of the W-phase upper arm switching element W is represented by a thick solid line. ing. This is generally realized by the timer function of the microcomputer. If the upper arm switching element of the same phase is ON, the lower arm switching element is OFF, and if the upper arm switching element is OFF, the lower arm switching element is ON. However, a dead time period is provided to prevent a short circuit between the upper arm switching element and the lower arm switching element.

Although details of phase current detection by the shunt resistor 6 are omitted, it is possible to know the phase current flowing through the power supply line (shunt resistor 6) when the upper arm switching elements U, V, W are turned on and off. It does not flow when the upper arm switching element does not have an ON phase (de-energized, lower circulation). When only one phase is ON, the current of that phase flows (energized). When the two-phase is ON, the current of the remaining phase flows. (Energized) Does not flow when all three phases are ON (not energized, upper circulation). Therefore, the detectable phase current can be known by confirming that the upper arm switching elements U, V, and W are ON. However, in the current detection by the shunt resistor 6, the ON time is required to be longer than the minimum predetermined time necessary for current detection. This predetermined time is defined as δ.

  Here, energization refers to a state in which power is supplied from the battery 1 to the inverter circuit 10 (motor 11), and non-energization refers to a state in which power is not supplied from the battery 1 to the inverter circuit 10 (motor 11). It is defined as In the non-energized state, the lower circulation is a state in which all of the lower arm switching elements X, Y, and Z are turned on and current is circulated between the lower arm and the motor 11, and the upper circulation is the upper arm switching. It is defined as a state in which all of the elements U, V, W are turned on and current is circulating between the upper arm and the motor 11.

  FIG. 10A shows a case where the energization period is set so that a predetermined constant current flows. In this state, the predetermined time δ cannot be secured, and current detection by the shunt resistor 6 cannot be performed. Corresponding examples for this are shown in FIGS. 10B and 10C. In FIGS. 10B and 10C, the period in which the current can be detected by the shunt resistor 6 is set as the detection period, and is indicated by a solid line arrow, and the phase of the current detected near the solid line arrow is indicated. Show. In this case, the detection period of the V-phase current is indicated as V, and the detection period of the U-phase current is indicated as U.

  FIG. 10B increases the ON period of the upper arm switching element U and the ON period of the upper arm switching element W in FIG. 10A to the right so that the V-phase current can be detected. . FIG. 10C is a diagram in which the amount of increase in FIG. 10B is reduced from FIG. 10A so that the U-phase phase current can be detected. Thereby, the phase current for two phases can be detected. Then, the phase current for the remaining one phase (phase current of the W phase) can be calculated. By executing both FIG. 10B and FIG. 10C, addition and reduction to the ON period of the upper arm switching element U and the ON period of the upper arm switching element W are cancelled.

  By executing FIG. 10B and FIG. 10C instead of FIG. 10A, a constant current of the positioning intended in FIG. 10A is supplied while detecting phase currents for two phases. be able to. Then, approximately 100 ms is executed. When the carrier frequency is 10 kHz and the carrier cycle is 100 μS, the carrier cycle is 1000 times.

FIG. 11 shows the W-phase phase current from positioning to operation. Positioning includes an initial stage in which the current gradually increases and a stationary period in which the current is constant. A sine wave alternating current during operation flows following the steady-state current.
JP 2003-189670 (page 14, FIG. 1, page 16, FIG. 14) Japanese Patent Laid-Open No. 11-356088 (page 7, FIG. 6)

  As described above, the phase current detection method with only one current sensor can be downsized because there are fewer components compared to other methods in which two or three current sensors are used to directly detect the phase current. In addition, there is an advantage that reliability such as vibration resistance can be improved.

  However, when the phase current cannot be detected, energization correction is required to increase or decrease the ON period of the upper arm switching element in some phases. By this energization correction, a ripple current is generated as compared with the original PWM modulation current. This ripple current becomes an electromagnetic force and acts on the stator winding, the mechanism, the housing, etc. of the motor to generate noise and vibration. The additional reduction in the ON period is canceled and the PWM modulation result does not change, but a ripple current is generated within the carrier period.

  In particular, at the time of positioning before the operation, the influence by the energization correction is large. For one thing, the magnet rotor does not rotate, so there is no operating noise, and noise caused by ripple current is easily noticeable. Secondly, the energization period is short (because the magnet rotor is stopped and no induced voltage is generated in the stator winding, and the energization period may be short to allow the same current to flow), and the energization correction amount is This is because it becomes relatively large (the minimum predetermined time δ necessary for current detection becomes relatively large with respect to the original energization period of PWM modulation). Third, when energization correction is not performed, only one phase (W phase in the conventional example) is connected to the positive side of the DC power supply, whereas when energization correction is performed, the other phases (U phase and V in the conventional example) are connected. Phase) also has an energization moment connected to the positive side of the DC power supply, and the current ratio between the three phases changes instantaneously. As a result, the position of the magnet rotor is instantaneously changed to generate noise and vibration.

  The present invention solves such a conventional problem, and aims to reduce noise and vibration at the time of positioning in an inverter device that detects a phase current by a current sensor arranged between a DC power source. To do.

  In order to solve the above problems, an inverter device according to the present invention includes an inverter circuit including an upper arm switching element connected to the plus side of a DC power supply and a lower arm switching element connected to the minus side, a DC power supply, A current sensor for detecting a current between the inverter circuits; and a control circuit for causing the inverter circuit to output a drive current to the motor. The control circuit performs PWM modulation on the inverter circuit in positioning the magnet rotor before the motor is operated. A DC current is output to the motor by energization, and the phase current is detected by the current sensor by correcting the energization only immediately before the stabilization of the positioning current, just after the stabilization, or just before and after the stabilization. .

  Thereby, since the time for performing energization correction is short, it is possible to suppress noise and vibration during positioning that are greatly affected by the energization correction. The energization can be adjusted so that a predetermined positioning current flows by detecting the current by performing energization correction only immediately before the stabilization of the positioning current, just after the stabilization, or just before and after the stabilization. Therefore, appropriate positioning can be performed.

  The inverter device of the present invention can detect a phase current by a single current sensor while suppressing noise and vibration during positioning by energization correction, and can perform appropriate positioning.

  According to a first aspect of the present invention, there is provided an inverter circuit including an upper arm switching element connected to a positive side of a DC power source and a lower arm switching element connected to a negative side, and a current for detecting a current between the DC power source and the inverter circuit A sensor and a control circuit that causes the inverter circuit to output a drive current to the motor are provided. The control circuit causes the inverter circuit to output a direct current to the motor by energizing the PWM modulation before positioning the magnet rotor before the motor is operated. At the same time, the phase current is detected by the current sensor by correcting the energization only immediately before the positioning current is stabilized, only immediately after the stabilization, or just before and after the stabilization.

  Thereby, since the time for performing energization correction is short, it is possible to suppress noise and vibration during positioning that are greatly affected by the energization correction. The energization can be adjusted so that a predetermined positioning current flows by detecting the current by performing energization correction only immediately before the stabilization of the positioning current, just after the stabilization, or just before and after the stabilization. Therefore, appropriate positioning can be performed.

  According to a second invention, in the inverter device of the first invention, the energization is corrected immediately before the end of the positioning current, and the phase current is detected by the current sensor. As a result, the operation current continues from the positioning current, and stable starting can be performed.

  According to a third invention, in the inverter device of the first or second invention, the duty of the energization period is gradually increased at the initial stage of positioning, and the timing immediately before or immediately after the stabilization of the positioning current is based on the duty of the energization period. Judgment. As a result, the timing immediately before and after the stabilization of the positioning current can be easily and accurately determined.

  According to a fourth aspect of the invention, in the inverter device of the first to third aspects, the duty of the energization period when the energization correction is not performed is corrected by the temperature of the motor. As a result, an almost accurate current can be passed without detecting the current.

  According to a fifth aspect of the present invention, in the inverter device according to the first to fourth aspects of the invention, the PWM modulation is three-phase modulation. Compared to the two-phase modulation, the three-phase modulation has a smooth current waveform and low noise, so that noise caused by the ripple current is easily noticeable, and the effect of the present invention is great.

  A sixth invention drives the motor of the electric compressor in the inverter device of the first to fifth inventions. Since electric compressors are used in room air conditioners, car air conditioners, etc., their noise is easily recognized. Therefore, the effect of the present invention that can reduce noise is great.

  A seventh invention is an inverter device according to the first to sixth inventions, which is mounted on a vehicle. In the case of a vehicle, since the mounting space is limited and downsizing is required and vibration resistance against vibration due to traveling is also required, the present inverter device that detects current with one current sensor such as a shunt resistor is useful. Further, since the noise is easily recognized, the effect of the present invention that can reduce the noise is great.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiment.

(Embodiment 1)
FIG. 1 shows an inverter device 22 according to Embodiment 1 of the present invention and an electric circuit around it. The control circuit 7 of the inverter device 22 detects the phase current based on the voltage from the shunt resistor 6. If phase currents for two phases are detected, the phase currents of the remaining phases can be calculated from the two current values.

  During operation of the motor 11, the control circuit 7 calculates the induced voltage of the stator winding 4 by the magnet rotor 5 constituting the motor 11 based on the current values for these three phases, and the magnet rotor 5 Perform position detection. Then, based on this position detection, rotation speed command signal (not shown), etc., the switching element 2 constituting the inverter circuit 10 is controlled, and the DC voltage from the battery 1 is switched by PWM modulation. An alternating current is output to the stator winding 4 of the motor 11. The diode 3 constituting the inverter circuit 10 serves as a circulation route for the current flowing through the stator winding 4. For the switching element 2, the upper arm switching element is defined as U, V, W, and the lower arm switching element is defined as X, Y, Z. The current sensor is not limited to the shunt resistor 6 and may be any sensor that can detect an instantaneous peak current, such as a current sensor using a Hall element. Further, it may be provided on the positive side of the power supply line. If it is a shunt resistor, it is easy to realize miniaturization and improvement of vibration resistance. The control circuit 7 is connected to the upper arm switching elements U, V, W and the lower arm switching elements X, Y, Z by a connection line 18 via a drive circuit or the like, and controls each switching element. When the switching element 2 is an IGBT or a power MOSFET, the gate voltage is controlled. When the switching element 2 is a power transistor, the base current is controlled.

  An example of energization during positioning of the magnet rotor 5 before the motor 11 is operated will be described below. FIG. 2A shows a case where the magnet rotor 5 is positioned with the U phase and V phase of the stator winding 4 set to the S pole and the W phase set to the N pole in the case of four poles. The N pole of the magnet rotor 5 is positioned on the S pole of the stator winding 4 and the S pole of the magnet rotor 5 is positioned on the N pole of the stator winding 4 so as to be opposed to each other. . At this time, as shown in FIG. 2B, the control circuit 7 controls the switching element 2 so that current flows from the W phase to the U phase and the V phase of the stator winding 4.

  In FIG. 3A, the ON periods (Duty) of the upper arm switching elements U, V, W within one carrier (carrier cycle) in the above positioning example are displayed symmetrically from the center.

  FIG. 3A shows the energization period set so that a predetermined constant current flows in the stationary positioning period when the positioning current is stable.

  As an example, the DC voltage of the battery 1 is set to DC 300 V, the resistance value of each phase of the stator winding 4 is set to 1Ω, and the carrier frequency is set to 10 kHz (carrier cycle 100 μS). Here, in order to set the phase current value of the W phase in the stationary positioning period to a predetermined 20 A, the equivalent resistance value of the stator winding 4 becomes 1.5Ω (Y connection: refer to FIG. 2B), which corresponds to DC 30V. Must be applied. DC30V is 10% of DC300V. Therefore, the duty of the energization period may be 10% (10 μS). That is, the sum of the left and right energization periods is set to Duty 10% (10 μS).

  In this state, if the minimum predetermined time δ necessary for current detection is 7 μS, the predetermined time δ cannot be secured and current detection by the shunt resistor 6 cannot be performed. The correspondence example for that is FIG. 3 (B) and FIG. 3 (C). In FIGS. 3B and 3C, the period in which the current can be detected by the shunt resistor 6 is set as a detection period, which is indicated by a solid line arrow, and which phase current is detected in the vicinity of the solid line arrow. Show. In this case, the detection period of the V-phase current is indicated as V, and the detection period of the U-phase current is indicated as U. 10 μS can be secured for each.

  FIG. 3B increases the ON period of the upper arm switching element U and the ON period of the upper arm switching element W in FIG. 3A to the right so that the phase current of the V phase can be detected. . Further, FIG. 3C is a diagram in which the amount of increase in FIG. 3B is reduced from FIG. 3A so that the U-phase phase current can be detected. Thereby, the phase current for two phases can be detected. Then, the phase current for the remaining one phase (phase current of the W phase) can be calculated. By executing both FIG. 3B and FIG. 3C, addition and reduction to the ON period of the upper arm switching element U and the ON period of the upper arm switching element W are cancelled.

  By executing FIG. 3 (B) and FIG. 3 (C) instead of FIG. 3 (A), while detecting the phase current for two phases, the constant current in the stationary stationary phase intended in FIG. 3 (A) Can flow. For example, it is executed for a short time (approximately 1 mS) only immediately after the positioning current is stabilized (at the beginning of the stationary positioning period). When the carrier frequency is 10 kHz and the carrier cycle is 100 μS, the carrier cycle is 10 times. In the other period, FIG. 3A without energization correction is executed for approximately 99 mS. For this reason, almost no noise and vibration are generated by the energization correction.

And based on the said current detection, electricity supply can be adjusted so that a predetermined positioning current may flow. Therefore, appropriate positioning can be performed. As an example, the DC voltage of the battery 1 drops to 280 V DC, and the resistance value of each phase of the stator winding 4 becomes 1.2 due to the temperature rise.
When it is increased to Ω, the phase current value of the W phase is 15A. For this reason, in order to obtain the predetermined 20 A, the equivalent resistance value of the stator winding 4 is 1.8Ω, and therefore it is necessary to apply a voltage equivalent to 36 VDC. DC36V is 12.9% of DC280V. Therefore, the duty of the energization period may be set to 12.9% (12.9 μS). That is, the sum of the left and right energization periods is set to Duty 12.9% (12.9 μS).

  FIG. 4 shows an example of a W-phase phase current from positioning to operation. Positioning includes an initial stage in which the current gradually increases and a stationary period in which the current is constant. The initial positioning time until the stationary phase when the current is constant can be calculated from the inductance and resistance value of the stator winding 4. The current may be detected after this calculation time. Further, the current detection may be performed by the shunt resistor 6 by correcting the energization not only immediately after the stabilization of the positioning current in the embodiment but also immediately before the stabilization, or immediately before and after the stabilization.

  In the above-described embodiment, the DC power source is a battery. However, the present invention is not limited to this, and a DC power source rectified from a commercial AC power source may be used. Although the motor is a sensorless DC brushless motor, it need not be sensorless and can be applied to a motor that requires positioning, such as a reluctance motor. Although the case where the U-phase and V-phase of the stator winding 4 are set to the S pole and the W-phase is set to the N-pole and the 4-pole magnet rotor 5 is positioned has been shown, the present invention is not limited to this. The phase of the S pole and the N pole of the wire 4 is arbitrary, and the present invention can be applied to two poles, six poles, etc., and also when a current is passed through only two phases of the stator winding 4. The present invention is not limited to sinusoidal driving, and can be applied to a driving method that requires detection of a phase current during positioning. The energization correction for detecting the phase current is not limited to the above, but may be any detection such as detection for three phases, detection only in the first half of the carrier cycle. Although the case of PWM three-phase modulation has been shown, the present invention can also be applied to PWM two-phase modulation. Although the current detection time is set to 1 mS, the present invention is not limited to this, and it is sufficient that appropriate current detection and positioning can be performed.

(Embodiment 2)
FIG. 5 shows an example of a W-phase phase current from positioning to operation according to the second embodiment. Compared to the case of FIG. 4 according to the first embodiment, the energization is corrected immediately before the end of the positioning current, and the phase current is detected by the shunt resistor 6. As a result, the current control can be continued to the current in the stationary positioning period, and a sinusoidal alternating current during operation can be supplied. The current in the stationary positioning period corresponds to the current at the start of operation. The reason why the current in the stationary stationary phase is continued is to start up stably. This is because once the positioning current is turned OFF, the position of the positioned magnet rotor 5 may move.

(Embodiment 3)
In order to gradually increase the current in the initial stage of positioning, it is conceivable to gradually increase the energization period. This is preferable when current detection is not performed and current feedback control is not performed. When the example of the first embodiment is applied, the duty of the energization period is 0% (0 μS) to 2.5% (2.5 μS) to 5% (5 μS) to 7.5% (7.5 μS) to 10 % (10 μS). Thus, if the time when the duty of the energization period becomes 10% (10 μS) is set as the stable time of the positioning current, the timing immediately before and immediately after the stabilization of the positioning current can be easily and accurately determined.

In this initial stage of positioning, the duty of the energization period is smaller than that in the stationary positioning period. Therefore, if the energization correction is performed, the influence on noise is even greater. Therefore, noise during positioning can be greatly suppressed by setting the current rising period at the initial stage of the positioning to a period in which the energization correction is not performed. However, immediately before reaching the stationary phase from the initial positioning (immediately before stabilization), the energization period is long, and if it is short, the influence on noise is small. In addition, it is important in adjusting the energization so that a predetermined positioning current flows by detecting the current. Therefore, it is preferable to correct the energization immediately before the stabilization of the positioning current and detect the current with the shunt resistor 6.

(Embodiment 4)
FIG. 6 shows a view in which the inverter device 22 is attached in close contact with the right side of the electric compressor 40. The compression mechanism 28, the motor 11, and the like are installed in the metal casing 32. The refrigerant is sucked from the suction port 33 and compressed by the compression mechanism 28 (scroll in this example) being driven by the motor 11. The compressed refrigerant cools the motor 11 when passing through the motor 11 and is discharged from the discharge port 34.

  The inverter device 22 uses a case 30 so as to be attached to the electric compressor 40. The inverter circuit unit 10 serving as a heat source is cooled by the low-pressure refrigerant through the low-pressure pipe 38. A terminal 39 connected to the stator winding 4 of the motor 11 inside the electric compressor 40 is connected to the output section of the inverter circuit section 10. The connection line 36 fixed to the inverter device 22 by the holding unit 35 includes a power line to the battery 1 and a signal line to an air conditioner controller (not shown) that transmits a rotation speed signal.

  Since the electric compressor is used for a room air conditioner, a car air conditioner, etc., the noise is easily recognized by the user. Therefore, the effect of the present invention that can reduce noise is great. Moreover, in the inverter apparatus integrated electric compressor as described above, the inverter apparatus 22 needs to be small and resistant to vibration. Therefore, it is suitable as an embodiment of the present invention in which current is detected by a single current sensor such as a shunt resistor to realize low noise.

  In the above embodiment, the compression mechanism of the electric compressor is a scroll. However, the present invention is not limited to this. Moreover, although the compressed refrigerant showed about the high voltage | pressure type which cools a motor, a low voltage | pressure type may be sufficient.

(Embodiment 5)
In the inverter apparatus integrated electric compressor of FIG. 6, a motor temperature sensor 8 for detecting the temperature of the motor 11 is attached in the vicinity of the stator winding 4. The duty correction of the energization period depending on the temperature of the motor 11 will be described. The duty of the energization period at the initial stage of positioning in the third embodiment is 0% (0 μS) to 2.5% (2.5 μS) to 5% (5 μS) to 7.5% (7.5 μS) to 10% (10 μS). ). These are set values when the temperature of the motor 11 is 20 ° C., and the temperature coefficient of resistance of the stator winding 4 is 0.4% / ° C.

  If the temperature of the motor 11 detected by the motor temperature sensor 8 is 70 ° C, the temperature of the motor 11 is 50 ° C higher than 20 ° C. The resistance value of the stator winding 4 is increased by 50 ° C. * 0.4% / ° C. = 20%. Therefore, in order to achieve a predetermined current value, it is necessary to increase the duty of the energization period by 20%. That is, it may be changed from 0% (0 μS) to 3% (3 μS) to 6% (6 μS) to 9% (9 μS) to 12% (12 μS). As a result, an almost accurate current can be passed without detecting the current. The duty of the energization period in the stationary positioning period may also be corrected by the temperature of the motor 11 as described above.

  An inverter temperature sensor 9 for detecting the temperature of the inverter is attached in the vicinity of the inverter circuit 10. When the temperature is balanced at the time of startup, the temperature of the motor detected by the motor temperature sensor 8 and the temperature of the inverter device detected by the inverter temperature sensor 9 are substantially equal. Therefore, when there is no motor temperature sensor 8, the inverter temperature sensor 9 can be substituted. In the above embodiment, the temperature sensor is a motor temperature sensor or an inverter temperature sensor. However, the temperature sensor is not limited to this and may be a discharge temperature sensor provided near the refrigerant discharge port.

(Embodiment 6)
FIG. 7 shows an example in which the inverter device of the present invention is configured integrally with a compressor (Embodiment 43) and is applied to an air conditioner and mounted on a vehicle 60. The inverter device-integrated electric compressor 61, the outdoor heat exchanger 63, and the outdoor fan 62 are mounted in an engine room (or motor room) in front of the vehicle 60. On the other hand, an indoor fan 65, an indoor heat exchanger 67, and an air conditioner controller 64 are disposed in the vehicle compartment. Air outside the vehicle is sucked from the air inlet 66 and the air heat-exchanged by the indoor heat exchanger 67 is blown out into the vehicle interior.

  Vehicles, particularly electric vehicles and hybrid cars, are required to have a small and lightweight vehicle air conditioner from the viewpoint of ensuring running performance and mounting properties. Among them, there is a heavy weight, and in a narrow motor room (or engine room) Reduction in size and weight of the electric compressor mounted in other spaces is an important issue. In addition, when running with a motor, silence is high, and low noise is required for the electric compressor. It is also necessary to have vibration resistance against vibration during traveling.

  The inverter device of the present invention can achieve downsizing and vibration resistance and low noise by the configuration of one current sensor such as the shunt resistor 6 shown in the above embodiments. Therefore, the inverter device of the present invention is very suitable for these vehicles. In each of the above embodiments, the DC voltage of the battery 1 may be detected, and the current accuracy may be increased by adjusting the duty of the energization period (multiplying the reciprocal of the ratio) based on the ratio to the reference voltage (DC 300 V in the above example). .

  As described above, the inverter device according to the present invention can detect a phase current by a single current sensor while suppressing noise during positioning by energization correction, and can perform appropriate positioning. In addition, since it is small and can improve reliability such as vibration resistance, it can be applied to various consumer products and various industrial equipment.

The inverter apparatus which concerns on Embodiment 1 of this invention, and its surrounding electric circuit diagram (A) Positional relationship diagram of stator winding and magnet rotor during positioning according to Embodiment 1 of the present invention, (B) Current explanatory diagram of stator winding during positioning (A) Explanatory drawing which shows the example of electricity supply at the time of positioning which concerns on Embodiment 1 of this invention, (B) Explanatory drawing which shows the same electricity supply correction | amendment, (C) Explanatory drawing which shows the same electricity supply correction | amendment Illustration of phase current of W phase from the same positioning to operation W-phase current explanatory diagram from positioning to operation according to Embodiment 2 of the present invention Sectional drawing of the inverter apparatus integrated electric compressor which concerns on Embodiment 4 and Embodiment 5 of this invention Schematic diagram of a vehicle equipped with an inverter device according to Embodiment 6 of the present invention Inverter device that detects phase current with a current sensor connected to a conventional DC power supply and its surrounding electrical circuit diagram (A) Positional relationship diagram of stator winding and magnet rotor during positioning, (B) Current explanatory diagram of stator winding during positioning (A) An explanatory view showing an example before energization correction at the time of positioning, (B) an explanatory diagram showing the same energization correction, (C) an explanatory diagram showing another energization correction Illustration of phase current of W phase from positioning to operation

Explanation of symbols

1 Battery 2 Switching Element 3 Diode 4 Stator Winding 5 Magnet Rotor 6 Shunt Resistance (Current Sensor)
7 Control Circuit 8 Motor Temperature Sensor 9 Inverter Temperature Sensor 10 Inverter Circuit 11 Sensorless DC Brushless Motor 22 Inverter Device 40 Electric Compressor 60 Vehicle

Claims (7)

An inverter circuit comprising an upper arm switching element connected to the positive side of a DC power source and a lower arm switching element connected to the negative side; a current sensor for detecting a current between the DC power source and the inverter circuit; And a control circuit for outputting a drive current to the DC brushless motor in the inverter circuit, wherein the control circuit generates a direct current by applying PWM modulation to the inverter circuit in positioning the magnet rotor before the motor is operated. And an inverter device that corrects the energization and detects the phase current by the current sensor only immediately before the positioning current is stabilized, immediately after the stabilization, or just before and immediately after the stabilization. The inverter apparatus according to claim 1, wherein the energization is corrected immediately before the positioning current is ended and the phase current is detected by the current sensor. 3. The inverter device according to claim 1, wherein the duty of the energization period is gradually increased in the initial stage of positioning, and the timing immediately before or immediately after the stabilization of the positioning current is determined based on the duty of the energization period. The inverter device according to any one of claims 1 to 3, wherein a duty of an energization period when energization correction is not performed is corrected by a temperature of the motor. The inverter device according to any one of claims 1 to 4, wherein the PWM modulation is three-phase modulation. The inverter apparatus as described in any one of Claims 1-5 which drives the motor of an electric compressor. The inverter apparatus as described in any one of Claims 1-6 mounted in a vehicle.