An electric motor system is described. The electric motor system includes a drive circuit including an inverter configured to supply variable frequency current and a contactor configured to supply line frequency current. The electric motor system also includes an electric motor coupled to the drive circuit wherein the electric motor is communicatively coupled to a controller. The controller is configured to control the inverter to supply variable frequency current to the electric motor, thereby operating the electric motor at a motor speed, and determine, based upon at least one input parameter, a maximum potential motor speed the inverter can achieve. The controller is also configured to receive a command to operate the electric motor at line frequency current and control the drive circuit to transition from supplying variably frequency current to supplying line frequency current before the maximum potential motor speed the inverter can achieve is reached.

A cooling system is designed to generally allow for one or more compressors to be bypassed when ambient temperatures are low. The system includes a bypass line and valve that opens when ambient temperatures are low and/or when the pressure of the refrigerant in the system is low. In this manner, the refrigerant can flow through the bypass line instead of through one or more compressors. These compressors may then be shut off. To supply any needed pressure to cycle the refrigerant, the system may include a pump that turns on when the bypass line is open. When ambient temperatures are extremely low, thermosiphon may be used to cycle the refrigerant.

A method of feedthrough and overcurrent protection of a sealed compressor used in a transport climate control system (“TCCS”) is provided. The TCCS includes a climate control circuit with a sealed compressor. The sealed compressor includes an outer housing and an electrical motor within the outer housing. The method includes operating the sealed compressor to compress a working fluid by supplying electrical power to the electric motor of the sealed compressor via a sealed electrical feedthrough in the outer housing of the sealed compressor. The method also includes detecting an operating parameter of the sealed electrical feedthrough, and determining whether the sealed electrical feedthrough is in a melting condition based on the detected operating parameter. Also, the method includes adjusting operation of the climate control circuit upon determining that the sealed electrical feedthrough is in the melting condition until the sealed electrical feedthrough is no longer in the melting condition.

A power conversion apparatus includes a rectifier circuit, an inverse conversion circuit, and a capacitor. The rectifier circuit rectifies alternating current power of the alternating current power supply. The inverse conversion circuit inversely converts a voltage Vdc rectified by the rectifier circuit into an alternating current voltage having a certain frequency and applies the alternating current voltage to a motor whose maximum power consumption Pmax is 2 kW or larger. The capacitor is provided between the rectifier circuit and the inverse conversion circuit and has a capacitance C that satisfies a condition of a following expression in relation to an alternating current voltage Vac of the alternating current power supply and the maximum power consumption Pmax. $\begin{array}{cc}C\le 350\times {10}^{-6}\frac{P\max }{{\mathrm{Vac}}^2}.& \left(1\right)\end{array}$

Provided are a programmable motor and a household appliance having the same. The programmable motor comprises a main body (21) and a driving device (22) comprising a reprogramming interface. When performing reprogramming on the programmable motor, the reprogramming interface communicates with a programming device to receive a motor parameter or a motor software program, to transmit the same to the driving device (22), and to update the motor parameter or the motor software program in the driving device (22). The method realizes rewriting of a motor software program and realizes reprogramming of a motor by directly inserting a programming device into a reprogramming interface of a driving device (22) without having to disassemble the driving device (22), thereby effectively reducing post-sale costs associated with a motor, and improving post-sale efficiency associated with the motor.

In a power converter, an inductance L of a reactor and a capacitance C of a capacitor satisfy a condition of the expression (1) below. In the power converter, a current-limiting circuit between an AC power source and the capacitor is unnecessary. Herein, αm ([A.Math.s]) is a value of a ratio of a maximum rated current squared time product to a maximum rated output current of diodes of a rectifier circuit, Pmax is a maximum power consumption of the motor, Vac is a voltage value of a three-phase AC voltage, and a value of a constant a is 4.3

[00001]$\begin{array}{cc}a.C.\sqrt{\frac{C}{L}}.Math.\frac{{\mathrm{Vac}}^3}{P_{\max }}\le {\alpha }_m.& \left(1\right)\end{array}$

Provided are a heat sink capable of suppressing overcooling of an electronic component which should not be overcooled and highly efficiently cooling only an electronic component which should be cooled, and a circuit device including the same. A heat sink includes a pipe and a cooling block. At least one projection is formed in the cooling block. The pipe is in contact with the projection. The pipe is arranged with a spacing from a portion of the cooling block other than the projection.

Disclosed is a driver IC circuit of an intelligent power module including an upper bridge control signal input end, a lower bridge control signal input end, a PFC control signal input end, a logic input buffer circuit, a first upper bridge driver circuit, a second upper bridge driver circuit, a first lower bridge driver circuit, a second lower bridge driver circuit and a PFC driver circuit. The logic input buffer circuit performs full-wave filtering on control signals. The first upper bridge driver circuit, the first lower bridge driver circuit, the second upper bridge driver circuit and the second lower bridge driver circuit each drives a switch transistor corresponding to a first or second external motor according to one of the control signals. The PFC driver circuit drives an external PFC switch transistor according to one of the control signals. An intelligent power module and an air conditioner are also disclosed.

A heat pump configured by connecting a circuit including a variable capacity compressor, a condenser, an expansion valve, and an evaporator through a closed refrigerant line, includes a condenser fan, an evaporator fan, a refrigerant amount adjusting means for charging or recovering a refrigerant in or from the circuit, and a controller. Roles of the controller include setting a target pressure inside an outdoor heat exchanger y referring to an outside temperature and a load, setting a target pressure inside an indoor heat exchanger by referring to an inside temperature and a set temperature, setting a target sub-cooling degree and a target super-heating degree, and controlling both of the fans to either adjust temperature or adjust pressure.

A heat pump apparatus includes: a compression mechanism that compresses a refrigerant; a motor that drives the compression mechanism; an inverter that applies a voltage to the motor; and an inverter control unit that generates a drive signal for driving the inverter, based on a carrier signal, in which the inverter control unit periodically changes a carrier frequency of the carrier signal in a heating operation mode in which the refrigerant is heated, and generates the drive signal such that a period of time during which a voltage represented as a real vector is applied to the motor is kept constant regardless of the changed carrier frequency.