Variable-frequency drive

About: Variable-frequency drive is a research topic. Over the lifetime, 837 publications have been published within this topic receiving 5691 citations. The topic is also known as: VFD.

Spindle box four-gear variable frequency drive structure of numerically controlled lathe

Abstract: The utility model discloses a spindle box four-gear variable frequency drive structure of a numerically controlled lathe. The spindle box four-gear variable frequency drive structure of the numerically controlled lathe comprises a spindle box body, a spindle and a belt plate arranged on one side of the spindle box body. A first shaft, a second shaft, a third shaft and a fourth shaft are arranged in the spindle box body. The spindle box four-gear variable frequency drive structure of the numerically controlled lathe is reasonable in design, simple in structure and convenient to install. Therefore, four gears of speed are generated on the spindle in all, meanwhile, a rotating speed of a motor is adjusted through a frequency converter, and finally four-gear gear shifting and frequency conversion stepless speed regulation of a spindle box are achieved. The spindle box four-gear variable frequency drive structure of the numerically controlled lathe has the advantages of being simple in structure, greatly improving drive efficiency, and meanwhile being low in noise, and low in fault rate. The greatest advantage of the spindle box four-gear variable frequency drive structure of the numerically controlled lathe is that low-speed output torque is large.

Repetitive scheme plugged-in parallel with Deadbeat controller for VFD fed by cascaded multilevel inverter

Abstract: This paper proposes an experimental Real Time Digital Feedback Controller (RTDFBC) combined with a Repetitive technique to control a Variable Frequency Drive (VFD) fed by a cascaded Multi-Level Inverter (MLI). The proposed controller is Deadbeat type compensating for non-cyclical disturbances while the repetitive controller compensates for cyclical fluctuations (Dead-time effect, DC voltage imbalance effect) by generating proper compensating d-q voltages. This digital control is characterized by a very fast transient response, low switching losses, and a proper compensation for load disturbances and cyclical fluctuations. Theoretical analysis, simulation, and experimental results are described in this paper.

Mixing machine with VFD based diagnostics

Abstract: A mixing machine includes a head extending over a bowl receiving location, a rotatable output shaft for receiving a mixer tool, and a gear system for effecting rotation of the rotatable output shaft about its axis and orbiting of the shaft axis about another axis. An electric motor includes an output operatively connected to drive the gear system. A variable frequency drive is connected to deliver 3-phase power to the electric motor to achieve variable speed and torque. The variable frequency drive includes a plurality of embedded sensors, including embedded current sensors and embedded voltage sensors. A diagnostic control is configured and operable to analyze outputs from the embedded sensors and produce an alert indication upon identification of a characteristic indicative of at least one of input power brownout, input power surge, machine short circuit, motor phase insulation arch, motor phase to ground arch or motor loss of phase.

Dc power supply systems and methods

Abstract: DC power supply systems and methods are disclosed. A power supply system includes a variable frequency drive (VFD) configured to convert AC power at a VFD input to controlled AC power at a VFD output, and the VFD is configured to control a frequency and voltage of the controlled AC power responsive to a control input. The power supply system also includes a transformer including a primary side coupled to the VFD output and a secondary side and a rectifier coupled to the secondary side of the transformer, and one or more sensors are coupled to the output of the rectifier to monitor the DC power. A controller is coupled to the one or more sensors, and the controller is configured to provide the control input to the VFD to adjust the controlled AC in response to changes to the one or more characteristics of the DC power.