Abstract: An estimation method for estimating a rotor frequency of a motor during freewheeling, includes: applying a fixed input voltage and one selected from a plurality of stator frequencies to the motor sequentially so as to perform frequency scanning; detecting a stator current value of the motor corresponding to the selected stator frequency; calculating a stator current slope of the stator current values sequentially; defining a target period from a start point where the stator current slope varies from positive to negative to an end point where the stator current slope varies from negative to positive; and determining that a difference between the scanned stator frequency and the rotor frequency is within a preset value, then designating any of the corresponding stator frequencies during the target period as an estimated value of the rotor frequency.

Abstract: A motor demagnetization detection method includes the following steps. The speed of a motor is calculated according to the rotation angle of the motor. When determining that the motor respectively maintains a first and second steady state according to the speed, the three-phase current values of the motor are received to obtain first and second steady-state data. An equivalent magnetic flux is calculated according to the first and second steady-state data. The motor is repeatedly driven to maintain the first and second steady states, the first and second steady-state data are updated according to the three-phase current values, and the equivalent magnetic flux is again calculated to generate equivalent magnetic fluxes. A magnetic flux change is calculated according to equivalent magnetic fluxes. A demagnetization warning is issued according to a comparison of the magnetic flux change and a demagnetization warning value.

Abstract: An estimating method includes the following steps. Firstly, if the electrical machine control system is in the generator mode, a bus voltage of the bus capacitor is monitored continuously. Then, if the switch is turned to an on state, a first current value of a current flowing through the bus capacitor during an off state of the switch is calculated. Then, the switch is turned to the on state. Then, if the switch is turned to the off state, a second current value of a current flowing through the bus capacitor during the on state of the switch is calculated, and a resistance value of the braking resistor is estimated according to the first current value and the second current value.

Abstract: A diarylethene compound reversibly convertible under photochromic and electrochromic conditions between a ring-open isomer of Formula (1A) and a ring-closed isomer of Formula (IB) wherein R5 is a substituted phenyl ring and Re is a substituted thiophene ring is provided. The photochromic-electrochromic diarylethene compound of Formula (1A)/(1B) have improved photochromic, electrochromic or photochromic and electrochromic properties, and is useful to provide variation of the light transmission properties of optical filters. The compound also possesses improved solubility making it suitable for incorporation in commercial products.

Abstract: An encrypted hard disk device is provided, including a near-field communication (NFC) sensing module, a processor, a storage unit, and a power switch. The NFC sensing module is configured to read a user identification (UID) of at least one sensor element. The processor is electrically connected to the NFC sensing module and the storage unit. The processor receives the UID and generates a control signal when the UID is approved. The power switch is electrically connected to the processor and the storage unit and maintains a conducting state according to the control signal and supplies power to the storage unit for accessing the storage unit.

Abstract: A motor driving method includes steps of: at an open loop phase and in response to a motor being operated under a steady-state, calculating an angle difference between an estimation coordinate axis of the motor and an actual coordinate axis by a controller, according to an estimation voltage value, an estimation current value and at least one electrical parameter feedback from the motor and in reference with the estimation coordinate axis of the motor; calculating an actual current value in reference with the actual coordinate axis according to the angle difference by the controller; calculating a load torque estimation value associated with the motor according to the actual current value by the controller; and, in response to the open loop phase being switched to a close loop phase, compensating an output torque of the motor according to the load torque estimation value by the controller.

Abstract: A current sensing correction method for a driving system is provided. Firstly, the detection values of a three-phase current are acquired through the measuring unit. When the three-phase current is maintained at the DC state, the DC values of the three-phase current are acquired and recorded as three-phase demagnetization values. When the detection values are zero, a d-axis current and a q-axis current are calculated according to the three-phase demagnetization values, a d-axis correction current command and a q-axis correction current command are calculated according to a proportional constant, the d-axis current and the q-axis current, and a three-phase demagnetization current is generated to the measuring unit according to the d-axis correction current command and the q-axis correction current command. When the demagnetization time reaches the first predetermined time, the three-phase demagnetization current is not generated.

Abstract: A method of detecting a connection fault of an electric motor, applies to a driving mechanism of an inverter, and includes: measuring a three-phase stator current of the electric motor; transforming the three-phase stator current to acquire dual-axis current components in a stationary coordinate; calculating an angle of rotation of the electric motor according to the dual-axis current components; calculating an angular velocity according to the angle of rotation; comparing a frequency of the angular velocity with a frequency of an output voltage of the inverter; and determining that the electric motor occurs a connection fault if a difference between the frequency of the angular velocity and the frequency of the output voltage is greater than a predetermined frequency difference value.

Abstract: A fault detection method is used to determine whether a power switch coupled to a DC bus of a power conversion circuit is faulted. The method includes: detecting a bus voltage to provide a voltage signal and acquiring at least one detection value according to the voltage signal; providing control signals sequentially to turn off or turn on the power switch; determining that the power switch is a short-circuit fault if a first detection value is greater than or equal to a first threshold value when the power switch is turned off; determining that the power switch is an open-circuit fault if a second detection value is less than a second threshold value when the power switch is turned on; and providing an alarm signal or a disable signal when the power switch is the short-circuit fault or the open-circuit fault.

Abstract: An estimation method for estimating a rotor frequency of a motor during freewheeling, includes: applying a fixed input voltage and one selected from a plurality of stator frequencies to the motor sequentially so as to perform frequency scanning; detecting a stator current value of the motor corresponding to the selected stator frequency; calculating a stator current slope of the stator current values sequentially; defining a target period from a start point where the stator current slope varies from positive to negative to an end point where the stator current slope varies from negative to positive; and determining that a difference between the scanned stator frequency and the rotor frequency is within a preset value, then designating any of the corresponding stator frequencies during the target period as an estimated value of the rotor frequency.

Abstract: An electric machine control system adapted to a motor includes a voltage detector, a power module, a current detector and a controller. The voltage detector detects a bus voltage to generate a voltage detection signal. The power module generates a first phase current, a second phase current and a third phase current to drive the motor according to the bus voltage and a PWM signal. To generate the current detection signal, the current detector detects at least two of the following: the first phase current, the second phase current and the third phase current. When the motor is operating in a steady state and blocked, the controller calculates the DC offset error of the motor according to the voltage detection signal and the current detection signal.

Abstract: An electronic device is provided. The electronic device includes a metal housing, an insulation element, and an antenna unit. The insulation element is disposed on the metal housing and includes a first heat dissipation hole. The antenna unit is disposed on the insulation element and includes a radiation portion and a feeding portion. The radiation portion is composed of a conductor. The feeding portion is electrically connected to the radiation portion and a grounding plane. In this way, according to the electronic device, space configuration inside the electronic device is saved and a shielding effect of the metal housing is prevented from affecting stability of sending and receiving a signal.

Abstract: An antenna device and its control method is provided. The antenna device includes: a ground layer; a feeding element, connecting to the ground layer; a first radiating element, extending along a first direction and connected to the ground layer; a second radiating element, extending along a second direction which is orthogonal to the first direction, and connected the ground layer; a first switching element, coupled between the feeding element and the first radiating element, and configured to electrically connect or disconnect the feeding element and the first radiating element; and a second switching element disposed between the feeding element and the second radiating element, and configured to electrically connect or disconnect the feeding element and the second radiating element.

Abstract: An estimating method includes the following steps. Firstly, if the electrical machine control system is in the generator mode, a bus voltage of the bus capacitor is monitored continuously. Then, if the switch is turned to an on state, a first current value of a current flowing through the bus capacitor during an off state of the switch is calculated. Then, the switch is turned to the on state. Then, if the switch is turned to the off state, a second current value of a current flowing through the bus capacitor during the on state of the switch is calculated, and a resistance value of the braking resistor is estimated according to the first current value and the second current value.

Abstract: An electric machine control system adapted to a motor includes a voltage detector, a power module, a current detector and a controller. The voltage detector detects a bus voltage to generate a voltage detection signal. The power module generates a first phase current, a second phase current and a third phase current to drive the motor according to the bus voltage and a PWM signal. To generate the current detection signal, the current detector detects at least two of the following: the first phase current, the second phase current and the third phase current. When the motor is operating in a steady state and blocked, the controller calculates the DC offset error of the motor according to the voltage detection signal and the current detection signal.

Abstract: An electronic device is provided. The electronic device includes a metal housing, an insulation element, and an antenna unit. The insulation element is disposed on the metal housing and includes a first heat dissipation hole. The antenna unit is disposed on the insulation element and includes a radiation portion and a feeding portion. The radiation portion is composed of a conductor. The feeding portion is electrically connected to the radiation portion and a grounding plane. In this way, according to the electronic device, space configuration inside the electronic device is saved and a shielding effect of the metal housing is prevented from affecting stability of sending and receiving a signal.

Abstract: A surface-enhanced Raman scattering (SERS) detection method is provided for detecting a target analyte in a sample. The SERS detection method generally includes the steps of: (a). preparing an extract of the sample; (b). introducing the sample extract onto a SERS substrate, causing the target analyte to be absorbed in the SERS substrate; (c). introducing a volatile organic solvent onto the SERS substrate to have the target analyte of the sample extract dissolved and comes out of the SERS substrate; (d). irradiating the SERS substrate with light to evaporate the volatile organic solvent, leaving a more condensed target analyte on the SERS substrate; (e). irradiating the condensed target analyte with laser light to have the target analyte penetrate deeply into the SERS substrate; and (f). performing Raman measurement with a laser beam focusing on the SERS substrate to analyze the target analyte.

Abstract: An antenna device and its control method is provided. The antenna device includes: a ground layer; a feeding element, connecting to the ground layer; a first radiating element, extending along a first direction and connected to the ground layer; a second radiating element, extending along a second direction which is orthogonal to the first direction, and connected the ground layer; a first switching element, coupled between the feeding element and the first radiating element, and configured to electrically connect or disconnect the feeding element and the first radiating element; and a second switching element disposed between the feeding element and the second radiating element, and configured to electrically connect or disconnect the feeding element and the second radiating element.

Abstract: A polysaccharide based aerogel comprising a network of polysaccharide fibers with pores therebetween, wherein the sizes of the pores are in the micrometer range.

Abstract: A method and system for detecting pesticide residue in agricultural products. The system includes a chromatographic and mass-spectrometric system and a computer. The system inspects first and second sample solutions prepared from two identical extracts of an agricultural product. The first sample solution includes no additives while the second sample is added with a pesticide standard which is intended to be detected by the system for comparison. The computer compares the mass chromatograms of the first and second sample solutions, and calculate an increased integral area by which the peak of the second sample solution in the second mass chromatogram exceeds the peak of the first sample solution in the first mass chromatogram at the same retention time. As such, the concentration of pesticide residue in the sample can be determined by a ratio between the increased integral area and the concentration of the pesticide standard.