Abstract: A brake system which can secure quietness in a passenger compartment is provided. A vehicle brake system 1 includes a brake assist device 2 which boosts a pressing force on a brake pedal 5 by drive of a motor 31, and an assist control unit 6 which controls the motor 31. The assist control unit 6 changes responsiveness of the motor 31 in accordance with a vehicle speed, and sets a dead zone amount and a filtering value to large values in a region with a low vehicle speed. Thereby, responsiveness of a boosting operation of the motor 31 to the operation of the brake pedal is made low, and a rotational variation and a vibration are prevented from occurring to the motor 31 by a minute variation of a detection signal of a stroke sensor 14 during low-speed traveling or stoppage of traveling.

Abstract: An objective of the present invention is to improve current detection accuracy and to reduce noise of carrier frequency. A motor apparatus and a motor drive apparatus calculate motor currents Iu, Iv, and Iw using a DC bus current detected value Idc of an inverter and control a magnitude and a phase of an applied voltage of a motor to drive the motor. A carrier adjuster decreases a carrier frequency Fc of the inverter if a motor output is relatively larger and that increases the carrier frequency Fc of the inverter if the motor output is relatively smaller. A pulse shift adjuster shifts an interphase waveform of a PWM pulse according to the carrier frequency Fc.

Abstract: An inverter device that controls a motor using a signal from a position sensor for detecting a rotor rotational position of the motor includes an initial adjustment unit that outputs a phase of current for designating a motor rotational position by rotating the motor in a clockwise direction of the motor and a phase of current for designating the motor rotational position by rotating the motor in a counter-clockwise direction of the motor.

Abstract: A motor drive device inputs two detection signals from a rotation position sensor thereby to detect a rotation position, and controls a voltage to be applied to a motor according to the detected rotation position. The motor drive device has a control unit for outputting a first voltage in a first state in which the square sum of sampling values sampled from the two detection signals is a predetermined value, and outputting a second voltage in a second state in which the square sum is not the predetermined value.

Abstract: In related art technique, an average neutral point voltage is detected via a low-pass filter. Time constant of the low-pass filter must be set to cover the entire output frequency band of an inverter and voltage fluctuation due to modulated signal must be separated from that due to a short circuit to ground. According to the present invention, whether abnormality such as a short circuit to ground or to supply occurs in output lines can be determined based on an actual neutral point voltage of a motor, which changes in a stepwise fashion in conformity to a PWM pulse pattern output by an inverter device, and a normal neutral point voltage which depends on a PWM pattern output by the inverter device. Highly reliable abnormality detection in accordance with the waveform of the neutral point voltage and stable abnormality detection not depending on the inverter output frequency are feasible.

Abstract: An oil-flooded screw compressor drives a pair of rotors at a rotational speed which is low enough not to increase torque for a short amount of time after start-up and accelerates the pair of rotors up to a normal-operation rotational speed after oil discharge. Alternatively, the oil-flooded screw compressor rotates the pair of rotors for a short amount of time after the remaining compressed gas is discharged after a halt, thereby allowing the oil accumulated inside the working chambers to be discharged and ensuring smooth start-up after the halt.

Abstract: Provided is a power converting apparatus which suppresses noise caused by a square wave voltage that is sharply changed according to switching of the power converting apparatus. The invention has a power converting apparatus including a first inverter circuit connected to a DC power supply side; and a second inverter circuit connected to a load side, wherein the first inverter circuit converts DC power from the DC power supply into power having an absolute waveform of an AC waveform, and the second inverter circuit converts the power of the absolute waveform every single cycle thereof into AC power by alternately inverting the power.

Abstract: An oil-flooded screw compressor drives a pair of rotors at a rotational speed which is low enough not to increase torque for a short amount of time after start-up and accelerates the pair of rotors up to a normal-operation rotational speed after oil discharge. Alternatively, the oil-flooded screw compressor rotates the pair of rotors for a short amount of time after the remaining compressed gas is discharged after a halt, thereby allowing the oil accumulated inside the working chambers to be discharged and ensuring smooth start-up after the halt.

Abstract: According to the present invention, limited electric power is consumed so as to achieve long-lasting use of electric power during brake control with the use of an auxiliary power supply source when there is a malfunction of a vehicle power supply source. In addition, a brake control device for ensuring responsivenss at the beginning of braking or when emergency braking is necessary is provided. The brake control device of the present invention is a brake control device for detecting electric signals generated depending on the degree of brake-pedal operation and calculating the driver's demanded braking force based on the electric signals so as to generate the demanded braking force, which comprises an auxiliary power supply source for supplying electric power to the brake control device when there is a malfunction of a vehicle power supply source and controls braking deppending on the charged capacity of the auxiliary power supply source.

Abstract: A brake system which can secure quietness in a passenger compartment is provided. A vehicle brake system 1 includes a brake assist device 2 which boosts a pressing force on a brake pedal 5 by drive of a motor 31, and an assist control unit 6 which controls the motor 31. The assist control unit 6 changes responsiveness of the motor 31 in accordance with a vehicle speed, and sets a dead zone amount and a filtering value to large values in a region with a low vehicle speed. Thereby, responsiveness of a boosting operation of the motor 31 to the operation of the brake pedal is made low, and a rotational variation and a vibration are prevented from occurring to the motor 31 by a minute variation of a detection signal of a stroke sensor 14 during low-speed traveling or stoppage of traveling.

Abstract: A position detecting device which can increase accuracy in detecting the pole position of a motor used to perform quick acceleration and deceleration over the range from a zero speed to a high rotation speed, and a synchronous motor driving device using the position detecting device. A position detector detects basic-wave component signals in sensor signals and executes position calculation. A correcting unit calculates signal information representing at least one of a gain, an offset and a phase by a phase detector from the basic-wave component signals detected by an error calculator, and makes correction based on the calculated signal information such that a position detection error is zero.

Abstract: A position detecting device which can increase accuracy in detecting the pole position of a motor used to perform quick acceleration and deceleration over the range from a zero speed to a high rotation speed, and a synchronous motor driving device using the position detecting device. A position detector detects basic-wave component signals in sensor signals and executes position calculation. A correcting unit calculates signal information representing at least one of a gain, an offset and a phase by a phase detector from the basic-wave component signals detected by an error calculator, and makes correction based on the calculated signal information such that a position detection error is zero.

Abstract: When an oil-flooded screw compressor is started up in a cold environment after a long halt, start-up torque increases due to the increased viscosity of the oil that has long stayed inside the working chambers of the compressor. This has necessitated drive means with a larger capacity than that required for normal operation. An oil-flooded screw compressor according to the invention comprises: a casing; a pair of rotors each having screw-thread-shaped groove and being housed in the casing; an electric motor for rotationally driving the pair of rotors; a control device for controlling the electric motor; an oil feeding mechanism for feeding oil into working chambers formed by being enclosed by the casing and the pair of rotors in which teeth thereof are meshed to each other; and an oil separating mechanism for separating the oil from compressed gas discharged from the working chambers.

Abstract: In such a product that torque of a motor is continuously generated when a rotation number of the motor is nearly equal to zero, since an output voltage is kept at a constant value in accordance with a rotation position of the motor, such a condition that currents are concentrated in a specific element are maintained. As a result, a temperature of the specific element is increased, so that there are problems that a temperature fail of an inverter apparatus may readily occur, and thus, lifetimes of elements are lowered. In a power converter of a motor drive apparatus, windings are energizing-controlled in such a manner that only 1 phase of a switching circuit is pulse-width-controlled when the motor is under motor locking condition.

Abstract: In an apparatus using an inverter as a motor drive apparatus, continuous operation can be permitted during a motor open-phase without providing any additional switching element. Especially, in an electric brake apparatus, higher security can be assured. When a motor winding of one phase occurs an open-phase, currents are conducted to the remaining normal phases while taking the position of a rotor of motor into account to thereby generate torque of the motor. Since the motor torque can be generated continuously in the event of a phase malfunction, reliability of apparatus such as the electric brake apparatus can be improved.

Abstract: A rotary sensor that outputs two analog signals, such as one sine wave and one cosine wave and has multiple periods within one period of the electrical angle of a motor is employed. The motor is energized at each position for a specified length of time upon its startup by using multiple electrical angles corresponding to the multiple candidate absolute angles obtained from the rotary sensor signal as the initial position of the motor, and the electrical angle at which the motor acceleration becomes maximum is determined as the absolute angle. While the motor drive is in operation, on the other hand, the phase difference ?? between the phase of the motor at the counter electromotive voltage and the control phase is directly computed from the parameters of the motor, sensed current, voltage command and angle speed so as to correct the shifted position.

Abstract: The AC motor driving apparatus comprises an inverter for supplying power to an AC motor, current sensors for detecting current that flows in the motor or inverter, a rotation sensor for detecting the rotation of the rotor in the motor, and a control unit for controlling the driving of the inverter. A current detection value detected by the current sensor and a rotor rotational position are used to estimate three-phase motor current values. The estimated motor current values are used to control the inverter. Thereby, an inexpensive, space-saving AC motor driving apparatus as well as an AC motor controller, electric actuator, or vehicle that can perform highly precise torque control from zero speed to high-speed rotation without depending on the PWM pulse pattern are provided.

Abstract: In such a product that torque of a motor is continuously generated when a rotation number of the motor is nearly equal to zero, since an output voltage is kept at a constant value in accordance with a rotation position of the motor, such a condition that currents are concentrated in a specific element are maintained. As a result, a temperature of the specific element is increased, so that there are problems that a temperature fail of an inverter apparatus may readily occur, and thus, lifetimes of elements are lowered. In a power converter of a motor drive apparatus, windings are energizing-controlled in such a manner that only 1 phase of a switching circuit is pulse-width-controlled when the motor is under motor locking condition.

Abstract: A position detecting device which can increase accuracy in detecting the pole position of a motor used to perform quick acceleration and deceleration over the range from a zero speed to a high rotation speed, and a synchronous motor driving device using the position detecting device. A position detector detects basic-wave component signals in sensor signals and executes position calculation. A correcting unit calculates signal information representing at least one of a gain, an offset and a phase by a phase detector from the basic-wave component signals detected by an error calculator, and makes correction based on the calculated signal information such that a position detection error is zero.

Abstract: The AC motor driving apparatus comprises an inverter for supplying power to an AC motor, current sensors for detecting current that flows in the motor or inverter, a rotation sensor for detecting the rotation of the rotor in the motor, and a control unit for controlling the driving of the inverter. A current detection value detected by the current sensor and a rotor rotational position are used to estimate three-phase motor current values. The estimated motor current values are used to control the inverter. Thereby, an inexpensive, space-saving AC motor driving apparatus as well as an AC motor controller, electric actuator, or vehicle that can perform highly precise torque control from zero speed to high-speed rotation without depending on the PWM pulse pattern are provided.