A motor drive apparatus includes a power converter including an inverter having an upper arm and a lower arm, the inverter being configured to control an operation of an electric motor, and a drive controller configured to apply a dead time for preventing a short circuit between the upper arm and the lower arm, and to control the power converter. The drive controller is configured to control the power converter by switching a first mode in which a first correction value representing a time used to correct a voltage drop due to the dead time is employed to control the power converter, and a second mode in which a second correction value smaller than the first correction value is employed to control the power converter.

An HVAC system includes a compressor, condenser, and evaporator. A sensor measures a value associated with the refrigerant in the condenser or the evaporator, and a controller is communicatively coupled to the compressor and the sensor. The controller determines, based on an operational history the compressor, that pre-requisite criteria are satisfied for entering a sensor validation mode. After determining the pre-requisite criteria are satisfied, an initial sensor measurement value is determined. Following determining the initial sensor measurement value, the compressor is operated according to a sensor-validation mode. Following operating the compressor according to the sensor-validation mode for at least a minimum time, a current sensor measurement value is determined. The controller determines whether validation criteria are satisfied for the current sensor value. In response to determining that the validation criteria are satisfied, the controller determines that the sensor is validated.

Technologies are provided for preventing a working fluid leak from pooling and thus diluting any leaked working fluid from air within a condenser and/or evaporator compartment of the CCU. This can include a computer-readable medium that stores executable instructions that, upon execution, prevent a working fluid leak from pooling within a climate-control unit (CCU) of a transport climate control system. This also includes detecting fulfillment of activation threshold conditions in connection with the CCU. Also, this includes activating a fan in at least one of a condenser unit and an evaporator unit included in the CCU to dilute leaked working fluid from air within the CCU. Further, this includes detecting fulfillment of de-activation threshold conditions and de-activation of an activated fan.

A method of performing a defrost operation in a heating, ventilation and air conditioning (HVAC) system having a first heat exchanger and a second heat exchanger, the method including determining that the defrost operation is needed; determining a capacity for the defrost operation in response to one or more prior defrost operations; beginning the defrost operation at the determined capacity; monitoring a defrost parameter; determining if the defrost parameter indicates a need for increased capacity; and increasing the capacity of the defrost operation when the defrost parameter indicates the need for increased capacity.

Disclosed are a compressor control method, control apparatus and control system. The method includes: receiving a cylinder switching instruction, and detecting operating parameters of a compressor; determining whether a cylinder switching operation is completed according to the operating parameters of the compressor; and after it is determined that the cylinder switching operation is completed, performing torque compensation.

A method for controlling cold storage of an air conditioner includes acquiring an ambient temperature around the air conditioner and a pipe temperature of an exhaust pipe of a compressor of the air conditioner, acquiring a target opening degree corresponding to a current cold storage mode of the air conditioner according to the ambient temperature and the pipe temperature, and adjusting an opening degree of a throttle device of the air conditioner to be the target opening degree. The throttle device is arranged at a pipe between a cold storage box of the air conditioner and a condenser of the air conditioner.

Disclosed are climate systems and methods for control the climate systems. A climate system includes a plurality of compressors, a first heat exchanger disposed downstream of the compressors and a second heat exchanger disposed downstream of the first heat exchanger. The compressors and heat exchangers are fluidly connected by refrigerant lines to form a refrigerant circuit. The climate system also includes a controller that controls the operation of the compressors to draw back lubricant to the compressors without use of an oil equalization system.

An HVAC system includes a compressor, condenser, and evaporator. A sensor measures a value associated with the refrigerant in the condenser or the evaporator, and a controller is communicatively coupled to the compressor and the sensor. The controller determines, based on an operational history the compressor, that pre-requisite criteria are satisfied for entering a sensor validation mode. After determining the pre-requisite criteria are satisfied, an initial sensor measurement value is determined. Following determining the initial sensor measurement value, the compressor is operated according to a sensor-validation mode. Following operating the compressor according to the sensor-validation mode for at least a minimum time, a current sensor measurement value is determined. The controller determines whether validation criteria are satisfied for the current sensor value. In response to determining that the validation criteria are satisfied, the controller determines that the sensor is validated.

The invention provides an air-conditioner for maintaining a temperature of a conditioned space at or near a set temperature. The air-conditioner comprises at least one rotating or reciprocating element adapted to rotate or reciprocate at a variable frequency. The variable frequency including one or more nuisance frequencies at which vibration or noise within the air-conditioner or the conditioned space causes a nuisance. A processor programmed to control variation of the variable frequency in response to operational requirement. The processor is configured to operate the at least one rotating or reciprocating element so as to substantially exclude operation at the one or more nuisance frequencies.

The following invention relates to a dual loop conventional chiller plant, hereafter referred to as the enhanced air conditioning chiller. Where the first loop, primary circuit, typifies refrigeration compression closed loop containing the air conditioning companion stabilizer (“aka” stabilizer); establishing efficiency enhancements. The refrigeration loop is configured to provide refrigerant at a set point temperature amenable to the charging, ice production or freezing brine solution, contained within the ice storage tank static reservoir. The enhanced air conditioning chiller air handler(s) provides space/zones climate control via a fluid at a prescribed temperature, hereafter referred to as a hydronic solution, maintaining the air temperature to the space/zones.