A sensor-less detection circuit includes a first voltage adjustment circuit providing a first output voltage at a first node using one of three input voltages. A second voltage adjustment circuit provides a second output voltage at a second node using all three, or only two, of the three input voltages. The second voltage adjustment circuit acts as an internal virtual neutral point for detecting a zero crossing event of the motor. A differential amplifier is coupled with the first and second nodes and outputs a third output voltage at a third node. A reference buffer has a reference voltage input and provides a fourth output voltage at a fourth node. A comparator is coupled with the third and fourth nodes and outputs a fifth output voltage at a fifth node, the fifth voltage indicating a zero cross event.

A method of driving a three-phase motor includes, while a first phase is energized, driving a second phase using a first drive function which is sinusoidal. The first phase is switched to a non-energized state and a back electromotive force (BEMF) voltage of the first phase is detected. For at least a portion of a time when the first phase is non-energized the driving of the second phase depends on the output of a second drive function different from the first drive function. The second drive function may be non-sinusoidal and may be a cosine function. The second drive function may drive the second phase when the output of the second drive function is a modulation ratio less than 1. When the output of the second drive function is a modulation ratio greater than or equal to 1 the second phase may be driven to a modulation ratio of 1.

An electronic device for controlling an LRA (Linear Resonant Actuator) includes a signal generator, a driver, a delay unit, a sensor, and a DSP (Digital Signal Processor). The signal generator generates a digital signal. The driver drives the LRA according to the digital signal. The delay unit delays the digital signal for a predetermined time, so as to generate an estimated voltage signal. The sensor detects the current flowing through the LRA, so as to generate a sensing current signal. The DSP controls the resonant frequency or the gain value of the signal generator according to the estimated voltage signal and the sensing current signal.

A method for determining zero crossing occurrence in an alternating current (AC) signal with constant frequency of a permanent magnet synchronous motor (PMSM) includes: sampling the AC signal to obtain a plurality of data points; starting to count a number of consecutive data points that have sampled values with a same sign in a detection range, to generate a count value, wherein the consecutive data points are included in the plurality of data points; determining whether the count value is equal to a zero crossing determination value; and in response to the count value being equal to the zero crossing determination value, determining that a zero crossing occurs at a last data point of the consecutive data points.

A control chip, a control system, and a control method for a motor are disclosed. The control chip comprises: an analog comparator comprising a first input terminal and a second input terminal, wherein the first input terminal receives a reference voltage of the motor, the second input terminal receives at least one back EMF (Electromotive Force) of the motor in turn, the analog comparator compares each of the at least one back EMF with the reference voltage in turn through a polling method, so as to produce at least one comparison result and control the motor according to the at least one comparison result. Thereby, the analog comparator is able to compare back EMF with the reference voltage without three comparators, and the cost is therefore saved.

A system is described in which a magnetic mover includes at least one mover identification device. The system also includes a stator defining a work surface and including an actuation coil assembly and at least one stator identification device operable to interact with the at least one mover identification device. One or more sensors are used to sense a position of the first magnetic mover. One or more stator driving circuits are used to drive the actuation coil assembly to thereby move the first magnetic mover over the work surface. The first magnetic mover includes one or more magnetic components positioned such that interaction of one or more magnetic fields emitted by the one or more magnetic components with one or more magnetic fields generated by the actuation coil assembly when driven by the one or more stator driving circuits enables movement of the first magnetic mover in at least two degrees of freedom.

Improved systems and methods for operating moveable architectural elements (e.g., furniture) are described. The system can include improved features implemented throughout various elements, including hardware elements, controller elements, and/or software elements. As one example, the system can feature the ability to map a characteristic load profile across a particular length of actuation and, if during operation a measured load exceeds the profile, adjust (e.g., stop) the system's motion. The system can also advantageously map its current draw to increase energy efficiency. In addition, the system can include a positioning system that enables it to automatically determine its position upon start up and during operation. In some implementations, the system includes multiple moveable elements (e.g., furniture items). In some cases, power is distributed to the moveable element(s) using a moveable power distribution module. Many other improvements and features are contemplated and described.

A high-voltage permanent magnet frequency conversion all-in-one machine according to an embodiment of the present disclosure includes a frequency converter configured to perform frequency conversion on a high-voltage alternating current, and output at least three alternating currents, a permanent magnet motor configured to receive the alternating currents subjected to the frequency conversion and output from the frequency converter, to drive the motor to operate, and a controller configured to control the frequency converter to perform the frequency conversion on the high-voltage alternating current, and control an operation state of the permanent magnet motor.

A high-voltage permanent magnet frequency conversion all-in-one machine according to an embodiment of the present disclosure includes a frequency converter configured to perform frequency conversion on a high-voltage alternating current, and output at least three alternating currents, a permanent magnet motor configured to receive the alternating currents subjected to the frequency conversion and output from the frequency converter, to drive the motor to operate, and a controller configured to control the frequency converter to perform the frequency conversion on the high-voltage alternating current, and control an operation state of the permanent magnet motor.

For determination of the position of a movable component with a plurality of position magnets relative to a stationary component with a plurality of position sensors, it is provided that the sensor responses are detected for a group of position sensors in the region of the movable component, sensor model responses of the group of position sensors are determined from a sensor model for a plurality of assumed different relative positions of the movable component relative to the stationary component, the sensor model responses are compared with the sensor responses and the assumed relative position with the smallest deviation between the sensor model responses and the sensor responses is used as the relative position of the movable component.