Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Naomi Goto

Makoto Yoshida

Yasufumi Kurahashi

Norio Yoshida

Nobuyuki Nishii

Masafumi Nishimiya

Susumu Yamano

Minoru Fukumoto

Keizo Matsui

Hideo Nishihata

Katsunori Makino

The inverter device contains the following structure: an inverter circuit which has upper-arm switching elements that are connected on a positive side of a DC power source and lower-arm switching elements that are connected on a negative side of the DC power source; a current sensor that detects current flowing between the DC power source and the inverter circuit; and a control circuit that controls the inverter circuit by a PWM driving so that the inverter circuit outputs AC current to the motor. The control circuit provides a carrier cycle with a first correction and provides the successive cycle with a second correction, by which the current sensor can detect phase current of the motor. A ripple current caused by the first correction and a ripple current caused by the second correction are opposite in polarity.

Inverter device

An inverter has an inverter circuit and a current detector. In the inverter circuit, upper-arm switching elements and lower-arm switching elements, which are connected to DC power supply, provide DC with pulse-width modulation (PWM) so as to output AC to a load. The current detector detects current of the load. With the structure above, the inverter calculates an average value of DC that flows between the DC power supply and the inverter circuit according to a product of an ON-period in which any one of the switching elements maintains ON and a current value detected by the current sensor.

Inverter that calculates an average value of direct current DC

The inverter device contains three sets of series circuit formed by connecting two switching elements () in series between a positive terminal and a negative terminal of DC power supply (). Connecting points of the two switching elements are connected to motor (). DC voltage of DC power supply () is switched by PWM 3-phase modulation so that a sinusoidal wave-shaped AC current is fed to the motor. Upper-arm switching elements connected to the positive terminal of the DC power supply increase or decrease an ON period equally in all phases for a carrier cycle in the PWM 3-phase modulation so as to provide two conducting period in the carrier cycle.

Inverter device with improved 3-phase pulse width modulation and vehicle air conditioner using the same

An inverter contains the following structure: an inverter circuit having upper-arm switching elements connected on the positive side of a DC power source and lower-arm switching elements connected on the negative side of the DC power source; a current sensor that detects current flowing between the DC power source and the inverter circuit; and a control circuit that not only effects control of the inverter circuit so that AC is fed to a motor from the inverter circuit according to an ON-period controlled by a PWM system, but also makes a correction to the ON-period so as to allow the current sensor to detect phase current. The control circuit determines an amount of the correction by judging a direction of current of a phase having an intermediate length of the ON-period.

Inverter

A small and highly vibration-proof inverter capable of detecting a phase current without requiring the development of complicated control software and without causing any current distortion is provided. Shunt resistors () serving as a kind of current detector are provided, respectively, between lower arm switching elements X, Y, Z) in only two phases&#x2014;and the minus side of a DC power supply. An identical ON period is reduced from the ON periods of upper arm switching elements (U, V, W) in the carrier cycle entirely for three phases. Consequently, phase current is detected for the two phases provided with the shunt resistors (). The inverter can detect the phase current without complicating the control software and without causing any current distortion, by controlling inverter circuit () with control software incorporated in control circuit () through connection lines ().

Three phase inverter control circuit detecting two phase currents and deducting or adding identical ON periods

A current sensor for detecting a power supply current is commonly used for detecting a current of a stator winding to detect a rotational position of a magnet rotor, so that a sinusoidal driving is realized without adding two current sensors for detection of a phase current, and also a phase shift circuit and a comparator needed in the conventional 120-degree current feeding are not required, and the number of components can be reduced. Therefore, an inverter device with a low noise and low vibration, having a small size, light weight and high reliability is obtained.

Inverter device and air conditioner using inverter device

A compressor driver for a compressor is provided, wherein at the start of the compressor, a phase of the current flowing in the motor is controlled to be ahead of an induction voltage, then the advancement of the phase is controlled to decrease. Under an unstable condition to detect a position, such as at the start under pressure-difference, the foregoing control allows the phase to advance up to the current-phase where the max. torque can be produced, thereby drawing the instantaneous max. torque of the motor for starting the compressor. Then the control reduces the advancement for obtaining a stable operation.

Driver of electric compressor

An electric vehicle includes a drive-motor driving device and a compressor-driving device for air-conditioning. Both of these driving devices share a smoothing capacitor and a radiator. The drive-motor driving devices, the compressor-driving device, and the smoothing capacitor are disposed in a shielding case against electromagnetic wave, so that the electric circuit of the vehicle can be downsized and light-weighted.

Electric circuit of electric vehicle

An air conditioner includes a direct-current (DC) power supply, a compressor, and a compressor driving device that converts a current supplied from the DC power supply into an alternate-current (AC) for driving the compressor. The DC power supply energizes the driving device through a center conductor and an outer conductor of a shield cable. This structure allows the driving device not to include a capacitor for smoothing a power current, and to suppress surge voltages and electromagnetic-wave radiation, thus providing an air-conditioner including a compact size and light-weighted compressor driving device.

Air conditioner

In an air conditioner including a control unit receiving a power from a switching power supply, the switching power supply is connected to a DC power source without passing through a switch device or power application device. The output of the switching power supply is connected to a capacitor via a diode. The control unit is able to operate even when the capacitor to be charged via the power application device is not charged. Accordingly, the motor-driven compressor may start to operate quickly.

Air conditioner including a control unit powered by a switching power supply

In an air conditioner having a control unit receiving a power from a switching power supply, a supplied voltage for the control unit is reduced to a possible lowest voltage for the unit to operate. This arrangement provides the air conditioner with less electromagnetic wave noise of the switching power supply, with a quick check and repair, and with having a motor-driven compressor quick start.

An automobile air conditioner having a charging device for charging a power source capacitor preliminarily before driving a motor-driven compressor, which comprises a discharge circuit for discharging the electric charge in the capacitor through a power feeding device, and a controller for controlling the discharge by the discharge circuit. Further by comprising a cut-off detecting circuit for detecting when the battery is cut off, it is discharged automatically. Moreover, the voltage of the battery is converted, and supplied as a power source for the controller.

Automobile air conditioner

An electric compressor, a four-way valve driving unit and an outside heat exchanger fan driving unit of an automotive electric compressor driving apparatus which are located in an engine room are connected to an electric compressor driving unit disposed outside a passenger compartment of an automobile and are controlled by an air conditioner controller disposed in a passenger compartment and connected to the electric compressor driving unit by one communication cable transmitting serial signals. In addition, the detection output of an outside temperature sensor is supplied to the air conditioner controller via the electric compressor driving unit and the communication cable.

Automotive electric compressor driving apparatus

A hermetic electric compressor includes a motor unit having a stator coil and a compressor unit driven by the motor unit for compressing refrigerant gas. A temperature sensor is provided at the stator coil for monitoring a temperature of the stator coil. A control unit is further provided to control a rotational frequency or speed of the motor unit via the stator coil depending on the monitored temperature of the stator coil. The temperature sensor and the control unit are connected via a shielded cable or a twisted pair. The shielded cable or the twisted pair may be grounded via a capacitor. Further, a thermostat may also be provided at the stator coil and connected in series to the temperature sensor.

Hermetic electric compressor with improved temperature responsive motor

An apparatus for controlling a DC brush-less motor includes a switching circuit which switches a DC voltage to convert the DC voltage into first pulses and a controller which controls the switching circuit. The controller has a voltage detector which detects a voltage of second pulses induced in the windings, a duty ratio control which controls a duty ratio of the first pulse depending upon the induced voltage detected by the voltage detector, and a carrier cycle control which controls a cycle of the first pulse depending upon the duty ratio or a width of the second pulse.

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Shiga, Japan

Naomi Goto