WO2013038612A1

WO2013038612A1 - Inverter device, electrically-operated compressor and vehicle

Info

Publication number: WO2013038612A1
Application number: PCT/JP2012/005555
Authority: WO
Inventors: 康文倉橋; 尚美後藤
Original assignee: パナソニック株式会社
Priority date: 2011-09-12
Filing date: 2012-09-03
Publication date: 2013-03-21
Also published as: JPWO2013038612A1

Abstract

[Problem] To provide an inverter device in which noise (vibration) during positional location of the magnetic rotor is reduced. [Solution] There are provided: an inverter circuit (10) comprising a switching element (2) connected with respectively the plus side and the minus side of a battery (1); a shunt resistance (6) that detects the current between the battery (1) and the aforementioned inverter circuit (10); and a control circuit (7) that outputs drive current to the inverter circuit (10), passing PWM-modulated current to a sensor-less DC brushless motor (11), performs correction of this current which is thus passed, and detects the phase current produced by the shunt resistance (6). The control circuit (7) can suppress noise during positional location, which has a large effect on correction of this current which is thus passed, since it performs correction of this current which is thus passed and phase current detection for only part of the positional location period in which positional location of the magnetic rotor (5) is performed, prior to operation of the sensor-less DC brushless motor (11).

Description

Inverter device, electric compressor and vehicle

The present invention relates to an inverter device that detects a phase current by a current sensor provided between a DC power source, an electric compressor, and a vehicle.

Conventionally, an inverter device that detects a phase current using a current sensor provided between a DC power supply and the like has been proposed (see, for example, Patent Document 1). The conventional inverter device described in Patent Document 1 will be described with reference to FIGS.

First, the state where the motor is driven and the rotor is rotating is defined as “operation”. FIG. 10 shows a conventional inverter device and its peripheral electric circuit.

The control circuit 12 of the conventional 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).

Based on these current values, the induced voltage by the magnet rotor 5 constituting the sensorless DC brushless motor 11 (hereinafter referred to as “motor 11”) is calculated, and its position is detected. Then, based on this position detection, communication speed command signal (not shown), etc., the switching element 2 (IGBT, FET, transistor, etc.) constituting the inverter circuit 10 is controlled via the connection line 18. To do.

Thereby, 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, upper arm switching elements are defined as U, V, W, and lower arm switching elements are defined as X, Y, Z, and correspond to the switching elements U, V, W, X, Y, Z. The diode is defined as 3U, 3V, 3W, 3X, 3Y, 3Z.

FIG. 11 shows a waveform characteristic diagram in 50% modulation of three-phase modulation. A U-phase terminal voltage 41, a V-phase terminal voltage 42, a W-phase terminal voltage 43, and a neutral point voltage 29 are shown. In the three-phase modulation, the modulation increases in both directions of 0% and 100% centering on Duty 50% as the modulation increases. These terminal voltages are realized by duty (%) indicated on the vertical axis by PWM modulation. The neutral point voltage 29 is a value obtained by calculating the sum of the terminal voltages of each phase and dividing by 3. The phase voltage is a value obtained by subtracting the neutral point voltage from the terminal voltage, and is a sine wave.

In FIG. 12, the ON periods (Duty) of the upper arm switching elements U, V, and W within one carrier (carrier cycle) in the phase of 270 to 330 degrees indicated by the broken line in FIG. 11 are displayed symmetrically from the center. ing. 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. When the upper arm switching element does not have an ON phase, it does not flow (non-energized, downward circulation). When only one phase is ON, the current of that phase flows (energized). When two phases are ON, the remaining phase currents Flows (energized) and does not flow when all three phases are ON (non-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 Further, 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. It is defined as a state in which all of the arm switching elements U, V, W are turned on and current is circulating between the upper arm and the motor 11.

In FIG. 12, the period during which current detection by the shunt resistor 6 can be performed is set as a detection period, and is indicated by a solid line arrow. In this case, the detection period of the U-phase current is indicated as U, and the detection period of the W-phase current is indicated as W.

At phase 270 degrees, only U-phase current can be detected. Further, at the phase of 330 degrees, only the W-phase phase current can be detected. An example of a response to the fact that only the phase current for one phase can be detected is shown in FIG.

FIG. 13A shows the case of the phase of 330 degrees in FIG. 12 as it is. In FIG. 13B, a predetermined value δ is added to the ON period (Duty) of the upper arm switching element U in FIG. 13A so that the phase current of the V phase can also be detected. FIG. 13C is a diagram in which the ON period (Duty) of the upper arm switching element U in FIG. 13A is reduced by a predetermined value δ so that the U-phase phase current can also be detected.

In this way, the addition or reduction of the PWM original ON period (Duty) so that the phase current can be detected is defined as energization correction. Further, the value to be added or reduced is defined as an energization correction amount.

These make it possible to detect the phase current for two phases. By executing both FIG. 13B and FIG. 13C, the addition or reduction of the predetermined value δ of the ON period (Duty) of the upper arm switching element U is cancelled. In other words, executing both FIG. 13B and FIG. 13C is equivalent to executing twice in FIG.

Next, the positioning of the magnet rotor 5 before the operation of the motor 11 will be described below.

In order to start rotation of the magnet rotor 5, it is necessary to position the magnet rotor 5 before energization (for example, refer to Patent Document 2). An example will be described below.

FIG. 14A shows a case where the magnet rotor 5 is positioned with the U phase and the 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. 14B, a current flows from the W phase to the U phase and the V phase of the stator winding 4.

15 ((B) and (C)) and FIG. 16 ((B) and (C)), the ON period of the upper arm switching elements U, V and W in one carrier (carrier cycle) in the above positioning. (Duty) is displayed in the same manner as in FIGS. FIG. 17 shows the W-phase current from positioning to operation.

FIG. 15A shows a case where the energization period is set small in order to gradually increase the current at the initial stage of positioning shown in FIG. The period from the start of positioning until the current rises is defined as the initial positioning. In the initial stage of positioning, this energization period is gradually increased. In this state, current detection by the shunt resistor 6 cannot be performed. The correspondence example for that is FIG. 15 (B) and FIG. 15 (C).

FIG. 15B shows that the U-phase current can be detected by adding a predetermined value δ or more to the second half (right side) of the carrier period in the ON period (Duty) of the upper arm switching element U in FIG. Further, a predetermined value δ or more is added to the first half (left side) of the carrier period in the ON period (Duty) of the upper arm switching element W in FIG. 15A so that the phase current of the W phase can be detected. . Thereby, the phase current for two phases can be detected.

FIG. 15C shows that the ON period (Duty) of the upper arm switching element U and the upper arm switching element W in FIG. 15A is reduced by a predetermined value δ or more, and the U-phase phase current and the W-phase phase current are reduced. It can be detected. Thereby, the phase current for two phases can be detected.

The above reduction of the ON period (Duty) by a predetermined value δ or more cancels the addition of the ON period (Duty) of the ON period (Duty) or more by a predetermined value δ. That is, by executing both FIG. 15B and FIG. 15C, the PWM modulation result becomes equivalent to the two executions of FIG.

15B and 15C are executed, the current at the initial stage of positioning can be increased while detecting phase currents for two phases. The energization period shown in FIG. 15A is gradually increased. Then, at the initial stage of positioning, approximately 50 mS is executed. When the carrier frequency is 10 kHz and the carrier cycle is 100 μS, the carrier cycle is 500 times.

FIG. 16A shows a case where the energization period is set so that a predetermined constant current flows in the stationary positioning period shown in FIG. The period during which the current is constant after the current rising at the initial stage of positioning is defined as the stationary positioning period.

Compared with FIG. 13A, the energization period is short, but this is because the magnet rotor 5 is stopped, no induced voltage is generated in the stator winding 4, and the energization period is used to flow the same current. This is because it may be short. In this state, the current detection by the shunt resistor 6 can detect only the W-phase current. The correspondence example for that is FIG. 16 (B) and FIG. 16 (C). The method is basically the same as FIG. 13 during operation.

FIG. 16B is a diagram in which a predetermined value δ is added to the ON period (Duty) of the upper arm switching element U in FIG. 16A so that the V-phase current can also be detected. FIG. 16C shows a case where the ON period (Duty) of the upper arm switching element U in FIG. 16A is reduced by a predetermined value δ so that the U-phase phase current can also be detected. Thereby, the phase current for two phases can be detected. Then, by executing both FIG. 16B and FIG. 16C, the addition or reduction of the predetermined value δ to the ON period (Duty) of the upper arm switching element U is cancelled.

16B and 16C are executed, it is possible to flow a constant current in the stationary stationary phase while detecting phase currents for two phases. 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. 17 shows the phase current of the W phase 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.

¡Sine wave alternating current during operation flows following this steady-state current. When the waveform in FIG. 11 is replaced with a sinusoidal alternating current (41 is a U-phase current, 42 is a V-phase current, and 43 is a W-phase current), the phase 330 degrees is a positioning steady-state current, that is, an operation start. Corresponds to current.

The reason why the current in the stationary positioning period 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. When the magnet rotor 5 starts rotating, an induced voltage is generated in the stator winding 4 by the magnet rotor 5 and the phase of the current with respect to the phase of the induced voltage is appropriately controlled. The current value of becomes smaller.

JP 2003-189670 A Japanese Patent Laid-Open No. 11-356088

The conventional inverter device using the phase current detection method with only one current sensor is smaller in size because there are fewer components compared to other methods that directly detect the phase current using two or three current sensors. There is an advantage that reliability such as vibration resistance can be improved.

However, when phase currents for two phases cannot be detected, energization correction that increases or decreases the ON period of the upper arm switching element in some phases is necessary. By this energization correction, a ripple current is generated as compared with the original PWM modulation current. This ripple current becomes an electromagnetic force, acts on the stator winding 4 of the motor 11, the mechanism, the housing, and the like, and generates noise (vibration). The addition and reduction of the ON period are canceled and the PWM modulation result does not change, but a ripple current is generated within the carrier period.

Especially, the effect of energization correction is significant during positioning before operation. For one thing, the magnet rotor 5 does not rotate, so there is no operating noise and noise due to ripple current is easily noticeable.

Secondly, the energization period is short (because the magnet rotor 5 is stopped and no induced voltage is generated in the stator winding 4 and the energization period may be short to allow the same current to flow). This is because the correction amount becomes relatively large (the minimum predetermined time δ necessary for detecting the current to be added or reduced with respect to the original energization period of PWM modulation becomes relatively large).

¡In the initial stage of positioning, the energization period is shorter and the influence is greater than in the stationary period.

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 phase (U phase in the conventional example) is connected. , V phase) is also connected to the positive side of the DC power source, and the current ratio between the three phases changes instantaneously. This is because the position of the magnet rotor 5 instantaneously fluctuates and noise (vibration) is generated.

When an electric compressor used for an air conditioner is driven by an inverter device, it is difficult to use a device such as a soundproof box for a vehicle due to restrictions such as mounting space and weight.

The present invention solves such a conventional problem, and an object of the present invention is to provide an inverter device with low noise during positioning, an electric compressor with low noise, and a vehicle.

In order to solve the above-described conventional problems, an inverter device according to the present invention includes an upper arm switching element connected to the positive side of a DC power supply and a lower arm switching element connected to the negative side of the DC power supply. A circuit, a current sensor for detecting a current between the DC power source and the inverter circuit, and a drive current is output to the motor by energization of the PWM modulation to the inverter circuit, and the current sensor corrects the energization and outputs a phase by the current sensor. A control circuit for detecting current, and the control circuit performs phase current detection by correcting energization only during a part of the positioning period for positioning the magnet rotor before operation of the motor. Thus, it is possible to suppress noise during positioning that is greatly affected by the energization correction.

The electric compressor of the present invention includes a compression mechanism section and a motor that drives the compression mechanism section, and the motor is driven by the inverter device of the present invention, and noise generated by the electric compressor is reduced. Since the electric compressor is used for a device in which noise is easily recognized, such as a room air conditioner and a car air conditioner, the effect of reducing noise is great.

Further, the vehicle of the present invention is equipped with the electric compressor of the present invention. For vehicles, the mounting space of the electric compressor is limited, and it is necessary to reduce the size, and vibration resistance against vibration caused by traveling is also necessary. Therefore, an electric compressor using an inverter device that detects current with a single current sensor such as a shunt resistor is useful. Moreover, since noise is easily recognized in the vehicle, the low noise effect by using the electric compressor of the present invention is great.

The inverter device of the present invention can detect the phase current with a single current sensor while suppressing noise during positioning by energization correction, and can achieve both low noise and downsizing. Moreover, the electric compressor and vehicle of the present invention are low noise.

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 at the time of positioning of the inverter device, (B) Current explanatory diagram of stator winding at the time of positioning (A) 1st explanatory drawing which shows electricity supply in the positioning initial stage of the inverter apparatus, B) 2nd explanatory drawing which shows electricity supply in the initial stage of positioning, (C) 3rd explanatory drawing which shows electricity supply in the initial stage of the positioning (A) 1st explanatory drawing which shows the example of electricity supply in the positioning regular period of the inverter apparatus, (B) 2nd explanatory drawing which shows the example of electricity supply in the same positioning stationary period, (C) The example of electricity supply in the same positioning stationary period Third explanatory diagram shown Illustration of phase current of W phase from positioning to operation of the inverter device (A) An explanatory diagram showing an example of energization at the initial stage of positioning of the inverter device in Embodiment 2 of the present invention, (B) an explanatory diagram showing an example of energization at the initial stage of positioning, and (C) an explanation showing energization correction of the inverter device Figure Illustration of phase current of W phase from positioning to operation of the inverter device Sectional drawing of the electric compressor in Embodiment 3 of this invention Schematic diagram of the vehicle in the fourth embodiment of the present invention Conventional inverter device and peripheral electrical circuit diagram Waveform diagram showing the modulation of each phase in the maximum modulation 50% three-phase modulation of the inverter device Characteristic diagram showing the upper arm ON period and detection period in the phase of 270 to 330 degrees of the maximum modulation 50% three-phase modulation (A) An explanatory view showing an example before energization correction during operation of the inverter device, (B) an explanatory view showing an example of the energization correction, and (C) an explanatory view showing another example of the energization correction. (A) Positional relationship diagram of stator winding and magnet rotor at the time of positioning of the inverter device, (B) Current explanatory diagram of stator winding at the time of positioning (A) Explanatory diagram showing an example before energization correction at the initial stage of positioning of the inverter device, (B) explanatory diagram showing an example of the energization correction, (C) explanatory diagram showing another example of the energization correction (A) Explanatory diagram showing an example before energization correction in the stationary positioning period of the inverter device, (B) explanatory diagram showing an example of the energization correction, (C) explanatory diagram showing another example of the energization correction Illustration of phase current of W phase from positioning to operation of the inverter device

1 Battery (DC power supply)
2 Switching element 3 Diode 4 Stator winding 5 Magnet rotor 6 Shunt resistance (current sensor)
7 Control circuit 10 Inverter circuit 11 Sensorless DC brushless motor (motor)
DESCRIPTION OF SYMBOLS 12 Control circuit 22 Inverter apparatus 40 Electric compressor 60 Vehicle 61 Inverter apparatus integrated electric compressor

According to a first aspect of the present invention, there is provided an inverter circuit including an upper arm switching element connected to a plus side of a DC power source and a lower arm switching element connected to a minus side of the DC power source, and between the DC power source and the inverter circuit And a control circuit that outputs a drive current to the motor by energization of PWM modulation to the inverter circuit, corrects the energization, and detects a phase current by the current sensor, The control circuit detects the phase current by performing energization correction only during a part of the positioning period in which the magnet rotor is positioned before the motor is operated. Noise can be suppressed.

In the second invention, in particular, the control circuit of the first invention does not perform the energization correction when the phase current detected by the energization correction exceeds a predetermined value. Since it can be controlled to a predetermined current value, stable start-up can be performed.

In the third aspect of the invention, in particular, the control circuit of the second aspect of the invention does not perform the energization correction in the stationary positioning period among the initial positioning period and the stationary stationary period as the positioning period. Noise during positioning can be suppressed.

In the fourth invention, in particular, the energization correction start of the second invention is after the latter half of the initial stage of positioning. At the time of positioning, the energization correction amount is relatively large compared to the original energization period of PWM modulation. For this reason, the effect of current correction on noise is large. Among them, since the current rising period in the initial stage of positioning is set to be shorter than the stationary period in order to gradually increase the current, and it is necessary to correct energization not only in one phase but also in two phases. In addition, the effect of current correction on noise is large. Therefore, noise during positioning can be greatly suppressed by starting energization correction after the latter half of the rising of the positioning current.

In the fifth invention, in particular, the current sensor of the second invention is a shunt resistor, and the control circuit detects a phase current based on a voltage from the shunt resistor. It is easy to realize. *

An electric compressor according to a sixth aspect of the present invention comprises a compression mechanism section and a motor that drives the compression mechanism section, and the motor is driven by the inverter device of the first to fifth aspects of the invention. Since the noise generated in the machine is reduced, the use of this electric compressor in equipment that easily recognizes noise, such as room air conditioners and car air conditioners, has the effect of reducing noise.

The vehicle according to the seventh invention is equipped with the electric compressor according to the sixth invention, and for vehicles, there is a limitation in the mounting space of the electric compressor, and it is necessary to reduce the size. Therefore, an electric compressor using an inverter device that detects current using a single current sensor such as a shunt resistor is useful. Moreover, since noise is easily recognized in the vehicle, the low noise effect by using the electric compressor of the present invention 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)
An inverter device according to Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 shows an inverter device according to the present embodiment and a peripheral electric circuit.

In FIG. 1, the control circuit 7 of the inverter device 22 in the present embodiment detects the phase current based on the voltage from the shunt resistor 6. If phase currents for two phases are detected, the phase currents for the remaining phases can be calculated from the two current values (Kirchhoff's current law is applied at the neutral point of the stator winding 4).

During operation, 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 detects the position of the magnet rotor 5. Do. 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, so that a sine wave shape is obtained. 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, upper arm switching elements are defined as U, V, W, and lower arm switching elements are defined as X, Y, Z, and diodes corresponding to the switching elements U, V, W, X, Y, Z Is defined as 3U, 3V, 3W, 3X, 3Y, 3Z.

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 the shunt resistor 6 is used, it is easy to reduce the size and improve the 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.

The energization at the time of positioning of the magnet rotor 5 before the operation of the motor 11 will be described below. About the electricity supply at the time of the driving | operation which the magnet rotor 5 of the motor 11 is rotating, it is the same as that of the prior art.

FIG. 2 (A) shows a case where the magnet rotor 5 is positioned with the U and V phases of the stator winding 4 as the S pole and the W phase as the N pole in the case of 4 poles. Positioning is performed by stopping the north pole of the magnet rotor 5 on the south pole of the stator winding 4 and the south pole of the magnet rotor 5 facing each other on the north pole of the stator winding 4. Is done.

At this time, 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 as shown in FIG. However, the period during which the current correction is performed and the phase current is detected is limited to a part of the period.

3 ((B) and (C)) and FIG. 4 ((B) and (C)), the ON period of the upper arm switching elements U, V, W within one carrier (carrier cycle) in the positioning ( Duty) is displayed. FIG. 5 shows the W-phase current from the positioning to the operation.

FIG. 3A shows a case where the energization period is set small in order to gradually increase the current in the initial positioning shown in FIG. The period from the start of positioning until the current rises is defined as the initial positioning. In the initial stage of positioning, this energization period is gradually increased. In this state, current detection by the shunt resistor 6 cannot be performed. The correspondence example for that is FIG. 3 (B) and FIG. 3 (C).

FIG. 3B shows that the U-phase current can be detected by adding a predetermined value δ or more to the latter half (right side) of the carrier period in the ON period (Duty) of the upper arm switching element U in FIG. In addition, a predetermined value δ or more is added to the first half (left side) of the carrier period in the ON period (Duty) of the upper arm switching element W in FIG. 3A so that the phase current of the W phase can be detected. . Thereby, the phase current for two phases can be detected.

FIG. 3C shows that the ON period (Duty) of the upper arm switching element U and the upper arm switching element W in FIG. 3A is reduced by a predetermined value δ or more, and the U-phase phase current and the W-phase phase current are reduced. It can be detected.

This makes it possible to detect the phase current for two phases. The reduction of the ON period (Duty) by a predetermined value δ or more cancels the addition of the ON period (Duty) by a predetermined value δ or more in FIG. That is, by executing both FIG. 3 (B) and FIG. 3 (C), the PWM modulation result becomes equivalent to the two executions of FIG. 3 (A).

3B and 3C are executed, the current at the initial stage of positioning can be increased while detecting the phase current for two phases. The energization period shown in FIG.

通電 The energization correction is stopped when the energization period gradually increases and the detected phase current exceeds a predetermined value. The initial positioning is performed for approximately 50 ms. When the carrier frequency is 10 kHz and the carrier cycle is 100 μS, the carrier cycle is 500 times.

FIG. 4A shows a case where the energization period is set so that a predetermined constant current flows in the stationary positioning period shown in FIG. A period in which the current is constant after the current rising at the initial stage of positioning is defined as a stationary positioning period. During this period, energization correction is not performed. That is, FIG. 4B and FIG. 4C are the same as FIG.

Then, it is executed for about 100 ms. When the carrier frequency is 10 kHz and the carrier cycle is 100 μS, the carrier cycle is 1000 times.

¡By not conducting the energization correction in the stationary period during the initial period and the stationary period, which is the positioning period, the positioning current can be controlled while suppressing noise, so that reliable startup can be performed.

(Embodiment 2)
6A is an explanatory diagram showing an example of energization at the initial stage of positioning of the inverter device according to Embodiment 2 of the present invention, FIG. 6B is an explanatory diagram showing an example of energization at the initial stage of positioning, and FIG. ) Is an explanatory diagram showing current correction of the inverter device, and FIG. 7 is an explanatory diagram of a W-phase phase current from positioning to operation of the inverter device. The same parts as those of the inverter device in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

Since the stationary stationary period in the inverter device in the present embodiment is the same as that in the first embodiment (see FIG. 4), the initial positioning will be described.

FIG. 6A shows a case where the energization period is set to be small in order to gradually increase the current at the initial stage of positioning. In the initial stage of positioning, this energization period is gradually increased as shown in FIGS. 6 (B) and 6 (C).

That is, the initial positioning is configured by FIG. 6 (A), FIG. 6 (B), and FIG. 6 (C). In particular, FIGS. 6A and 6B are defined as the first half of the initial positioning, and FIG. 6C is defined as the second half of the initial positioning. Here, the time until the current rises up (initial positioning) is approximately 50 mS, but this is the time until the current value in the stationary phase is reached.

Here, the first 25 mS in the first half of positioning is the first half of the initial positioning, and the second half 25 mS is the second half of the initial positioning. FIG. 7 shows the phase current at this time. In the initial period of positioning, since the energization period is set to be shorter than that in the stationary period, the effect of the energization correction on the noise is even greater.

The noise during positioning can be greatly suppressed by setting the initial first half of the positioning as a period during which no energization correction is performed. In the second half of the initial positioning, the period for performing energization correction is set. However, since the energization correction is stopped after the positioning current reaches the predetermined current, the positioning current can be controlled while suppressing noise, so that reliable start-up is performed. Can do.

In the first and second embodiments, 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. However, the present invention is not limited to this, and the phase of the S pole and the N pole of the stator winding 4 is arbitrary, and the current flows only to the two poles, the six poles, and the two phases of the stator winding 4. (If the two phases are the W phase and the U phase, for example, it corresponds to a phase of 300 degrees). 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. In addition, the first half of positioning and the second half of initial positioning are defined by time, but the same is true if they are defined by DUTY values.

(Embodiment 3)
FIG. 8 is a cross-sectional view of the electric compressor according to Embodiment 3 of the present invention. In addition, the same code | symbol is attached | subjected to the same part as the inverter apparatus in the said embodiment, and the description is abbreviate | omitted.

In FIG. 8, the compression mechanism 28, the motor 11, and the like are installed in the metal casing 32 of the electric compressor 40 in the present embodiment, and the above-described implementation is provided on the right side surface of the electric compressor 40. The case 30 containing the inverter device 22 in the form is attached in close contact.

The refrigerant is sucked from the suction port 33 and is compressed by driving the compression mechanism 28 (in this example, scroll) 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 circuit 10 serving as a heat source is cooled by the low-pressure refrigerant via the low-pressure pipe 38. Inside the electric compressor 40, the terminal 39 connected to the stator winding 4 of the motor 11 is connected to the output part of the inverter circuit 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 (not shown) to an air conditioner controller (not shown) that transmits a rotation speed signal.

Since the electric compressor 40 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 one current sensor such as the shunt resistor 6 and low noise is realized.

In the above-described embodiment, the compression mechanism 28 of the electric compressor 40 is a scroll. However, the present invention is not limited to this. Moreover, although the compressed refrigerant showed about the high pressure type which cools the motor 11, a low pressure type may be sufficient.

(Embodiment 4)
FIG. 9 is a schematic diagram of a vehicle in the fourth embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same part as the inverter apparatus or electric compressor in the said embodiment, and the description is abbreviate | omitted.

The vehicle 60 in the present embodiment includes an inverter device integrated electric compressor 61 in which the electric compressor 40 and the inverter device 22 in the third embodiment are integrated, an outdoor heat exchanger 63, and an outdoor fan 62. It is mounted in the engine room 68 (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 arranged in the vehicle interior 69. 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.

In the vehicle 60, particularly an electric vehicle and a hybrid car, the vehicle air conditioner is required to be small and light from the viewpoint of securing traveling performance and mounting properties, and among them, the weight is heavy, and the interior of the engine room 68 and other spaces are small. It is important to reduce the size and weight of the electric compressor attached to the motor. In addition, when traveling by a motor (not shown), the quietness 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 22 used in the inverter device-integrated electric compressor 61 in the present embodiment can achieve downsizing and vibration resistance due to the configuration of one current sensor such as the shunt resistor 6 shown in the above embodiments, Low noise can also be achieved. Therefore, the inverter device 22 in the above embodiment is very suitable for the vehicle 60.

In each of the above embodiments, 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 11 is a sensorless DC brushless motor, it can be applied to a motor that requires positioning, such as a reluctance motor. The present invention is not limited to sinusoidal driving, and can be applied to a driving method that requires detection of phase current during positioning. It can also be applied to PWM two-phase modulation.

As described above, the inverter device according to the present invention can detect a phase current with a single current sensor while suppressing noise during positioning by energization correction, and can perform stable start-up. 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.

Claims

An inverter circuit comprising an upper arm switching element connected to the positive side of the DC power source and a lower arm switching element connected to the negative side of the DC power source;
A current sensor for detecting a current between the DC power supply and the inverter circuit;
A drive circuit that outputs a drive current to the motor by energization of PWM modulation to the inverter circuit, and a control circuit that corrects the energization and detects a phase current by the current sensor;
The control device performs phase current detection by performing energization correction only during a part of a positioning period in which the magnet rotor is positioned before the motor is operated.
The inverter device according to claim 1, wherein the control circuit does not perform the energization correction when the phase current detected by the energization correction becomes a predetermined value or more.
3. The inverter device according to claim 2, wherein the control circuit does not perform the energization correction in the stationary positioning period among the initial positioning period and the stationary stationary period, which are the positioning periods.
The inverter device according to claim 2, wherein the energization correction is started after the latter half of the initial positioning.
The current sensor is a shunt resistor;
The inverter device according to claim 2, wherein the control circuit detects a phase current based on a voltage from the shunt resistor.
A compression mechanism, and a motor that drives the compression mechanism,
An electric compressor, wherein the motor is driven by the inverter device according to any one of claims 1 to 5.
A vehicle equipped with the electric compressor according to claim 6.