A control device (2) includes a shot-pulse control unit (5) that provides, at a time of starting a synchronous motor (3), a predetermined current to each phase of the motor stator (3) for a short time; a detecting unit (6) that detects a current flowing through each phase; an estimating unit (7) that estimates a position of the motor rotor by comparing detected values; a voltage control unit that controls application of a voltage to the synchronous motor (3) based on a high-pressure side pressure of the compressor when the compressor is failed to be started due to any cause; and a magnetism-resistant section having a conductive layer sandwiched by insulating layers. The magnetism-resistant section covers a portion of a substrate of the control device, and a portion at which the conductive layer is exposed is in contact with, the housing or a part conducting heat to the housing.

In a delivery conduit for a compressor or an aspiration conduit for an aspirator, which connects the compressor or the aspirator to a closed environment (3), a first valve (4) is inserted, and opening and a closing of which is commanded by a temperature of an external environment. The valve is normally closed for external temperatures which are lower than a predetermined level and open, placing the conduit in communication with the outside environment, when the external temperature exceeds the predetermined level.

A control device (3) and a method for controlling speed of an electric motor (4) arranged to drive a rotary air compressor (2) comprised in an air system (14) of a vehicle (1). The control device (3) comprises a control unit (8) configured to determine a duty cycle of the rotary air compressor (2), determine speed control data of the rotary air compressor (2) based on the determined duty cycle according to a predetermined rule and to control the speed of the rotary air compressor (2) based on the determined speed control data. The disclosure also relates to a vehicle (1) comprising the device (3), to a computer program and to a computer program product.

A control device for an electric compressor comprising a magnetism-resistant section (45) formed in a sheet shape by sandwiching a conductive layer (46) having an electric conductivity and a thermal conductivity, with insulating layers (47, 48), and configured to cover a portion of a substrate of the control device. The magnetism-resistant section (45) includes a portion at which the conductive layer (46) is exposed, and is arranged such that the portion is in contact with any one of a housing of the electric compressor and a part conducting heat to the housing.

A control device (2) includes a shot-pulse control unit (5) that provides, at a time of starting a synchronous motor (3), a predetermined current to each phase of the motor stator (3) for a short time; a detecting unit (6) that detects a current flowing through each phase; an estimating unit (7) that estimates a position of the motor rotor by comparing detected values; a voltage control unit that controls application of a voltage to the synchronous motor (3) based on a high-pressure side pressure of the compressor when the compressor is failed to be started due to any cause; and a magnetism-resistant section having a conductive layer sandwiched by insulating layers. The magnetism-resistant section covers a portion of a substrate of the control device, and a portion at which the conductive layer is exposed is in contact with, the housing or a part conducting heat to the housing.

An objective of the present invention is to reduce the total power consumption of a compressor. In a control device (20) for an air conditioner having a two-stage-compression refrigerating cycle, first information in which a rotational speed, an intermediate pressure, and an efficiency are associated with each other for a lower-stage compressor (3a) is stored in a low-pressure-side storage section (31), and second information in which a rotational speed, an intermediate pressure, and an efficiency are associated with each other for a higher-stage compressor (3b) is stored in a high-pressure-side storage section (32). A target setting section (33) sets a target intermediate pressure in accordance with a predetermined algorithm. An intermediate-pressure determination section (34) determines, from the rotational speed of the lower-stage compressor (3a), the rotational speed of the higher-stage compressor (3b), the first information and the second information, an intermediate pressure at which the overall efficiency of the compressor becomes equal to or higher than the present overall efficiency. A target changing section (35) changes the target intermediate pressure set by the target setting section (33) to the intermediate pressure determined by the intermediate-pressure determination section (34).

A vacuum pump system comprising a vacuum pump and associated motor to drive a rotor therein, means to measure the rotational torque and/or the current of the motor, whereby pump monitoring can be effected.