Abstract: Motor overload protection device is equipped with a thermal monitor that can determine expected rotor temperature rise from rotor resistance estimates. The thermal monitor determines expected rotor temperature rise by using a correlation between rotor temperature rise computed from rotor resistance estimates, and motor thermal state estimates. The correlation can be derived by fitting a line to a plurality of points, with each point defined by an ordered pair composed of a rotor temperature rise estimate and a corresponding motor thermal state estimate, and determining a slope of the line. This rotor temperature slope can then be used by the thermal monitor to determine a rotor temperature rise given a rotor resistance estimate and a corresponding motor thermal state estimate. If the rotor temperature rise exceeds an expected rotor temperature rise by more than a predefined threshold, the thermal monitor issues an alarm and/or takes corrective actions in some embodiments.

Abstract: Motor overload protection device is equipped with a thermal monitor that can determine expected rotor temperature rise from rotor resistance estimates. The thermal monitor determines expected rotor temperature rise by using a correlation between rotor temperature rise computed from rotor resistance estimates, and motor thermal state estimates. The correlation can be derived by fitting a line to a plurality of points, with each point defined by an ordered pair composed of a rotor temperature rise estimate and a corresponding motor thermal state estimate, and determining a slope of the line. This rotor temperature slope can then be used by the thermal monitor to determine a rotor temperature rise given a rotor resistance estimate and a corresponding motor thermal state estimate. If the rotor temperature rise exceeds an expected rotor temperature rise by more than a predefined threshold, the thermal monitor issues an alarm and/or takes corrective actions in some embodiments.

Abstract: A method of automatically detecting an anomalous condition relative to a nominal operating condition in a vapor compression system. An expected input power function in the form of a hyperplane is calculated based on three temperature readings: an intake temperature from an intake area of the condenser unit, a return temperature from an intake area of an evaporator unit, and a supply temperature from a supply output area of the evaporator unit. The function produces an estimate of the expected input power consumed by the compressor unit, and this expected input power is compared with an actual input power measured from the compressor unit. If the expected input power deviates from the measured input power by more than a predetermined tolerance, an indication is stored and communicated that an anomalous condition, such as a refrigerant loss, condenser unit fouling, or a malfunctioning fan, exists in the vapor compression system.

Abstract: A system and method of measuring atmospheric parameters in an enclosed space using instrumented objects having measurement sensors. The instrumented objects travel through the space randomly or along defined flight paths. As the instrumented objects travel through the space, the measurement sensors measure atmospheric parameters and store the measurements to a memory. The devices periodically upload the measured atmospheric parameters to a controller circuit. By using self-propelled objects to carry measurement sensors, the system and method disclosed herein allow for periodically sampling atmospheric parameters in the interior of an enclosed space at a number of locations greater than the number of measurement devices employed. With data points taken from various locations within a volume of an enclosed space, the system and method can realize a more efficient utilization of energy by adjusting mechanical controls of an HVAC system or a ventilation system, for example.

Abstract: A system and method of measuring atmospheric parameters in an enclosed space using instrumented objects having measurement sensors. The instrumented objects travel through the space randomly or along defined flight paths. As the instrumented objects travel through the space, the measurement sensors measure atmospheric parameters and store the measurements to a memory. The devices periodically upload the measured atmospheric parameters to a controller circuit. By using self-propelled objects to carry measurement sensors, the system and method disclosed herein allow for periodically sampling atmospheric parameters in the interior of an enclosed space at a number of locations greater than the number of measurement devices employed. With data points taken from various locations within a volume of an enclosed space, the system and method can realize a more efficient utilization of energy by adjusting mechanical controls of an HVAC system or a ventilation system, for example.

Abstract: A method of automatically detecting an anomalous condition relative to a nominal operating condition in a vapor compression system. An expected input power function in the form of a hyperplane is calculated based on three temperature readings: an intake temperature from an intake area of the condenser unit, a return temperature from an intake area of an evaporator unit, and a supply temperature from a supply output area of the evaporator unit. The function produces an estimate of the expected input power consumed by the compressor unit, and this expected input power is compared with an actual input power measured from the compressor unit. If the expected input power deviates from the measured input power by more than a predetermined tolerance, an indication is stored and communicated that an anomalous condition, such as a refrigerant loss, condenser unit fouling, or a malfunctioning fan, exists in the vapor compression system.

Abstract: Devices and methods of commodity usage monitoring determine the amount of commodity used by individual elements of multi-element systems having a common source. An amount of commodity drawn from the source by all the users is determined. A user-state that indicates use of the commodity by each user is determined. Individual user consumption of the commodity for each of the users is determined using repeated determinations of the amount of the commodity and the user-state, for a number of repetitions greater than or equal to the number of users. Determining individual consumption can be performed using minimum least square estimation, singular value decomposition, discriminant function analysis, or other computational or analytical solution method. Duration and consumption information can be used to calculate the total amount of the commodity consumed by the particular user. Useful commodities include, but are not limited to, gas, electricity, mechanical, pneumatic, hydraulic, and water.

Abstract: A phase locked loop (PLL) circuit provides ac devices, such as power inverters and power measurement devices, with a reliable means for synchronizing to ac electrical systems. In an exemplary embodiment, the PLL circuit is configured for operation with single-phase electrical systems and offers substantial noise immunity by basing its locking operations on measured fundamental components, i.e., measured x-y phasors, of the electrical system voltage. Further, with its phasor-based locking operations and with its timer/counter-based operation, the PLL circuit can be implemented partly or wholly in digital processing logic.

Abstract: An induction motor having a rotor and a stator is protected during running overloads by connecting the motor to an overload protection relay that can be tripped to interrupt power to the motor in the event of an overload, tracking the stator winding temperature of the motor during running overloads with a hybrid thermal model by online adjustment in the hybrid thermal model, and tripping the overload protection relay in response to a predetermined running overload condition represented by the tracked stator winding temperature. In one embodiment of the invention, the stator winding temperature is tracked by use of an online hybrid thermal model that uses the resistance of the rotor as an indicator of rotor temperature and thus of the thermal operating conditions of the motor. The hybrid thermal model incorporates rotor losses and heat transfer between the rotor and the stator, and approximates the thermal characteristics of the rotor and stator.

Abstract: A control circuit synchronizes an ac power inverter to the mains voltage of an electrical grid by matching the fundamental phasor components of the inverter's output voltage to the fundamental phasor components of the mains voltage. Once such matching meets an acceptable voltage error threshold, the control circuit initiates contactor closure, verifies contactor closure, and then initiates a changeover from voltage-mode control used in synchronization operations to a current-mode control of the inverter's output. The control circuit provides corresponding disconnection control when disconnection from the grid is desired, wherein the regulated power of the inverter is ramped down in controlled fashion until it reaches a lower threshold whereupon contactor opening is initiated. Once contactor opening is verified, regulation control reverts to stand-alone voltage mode control or to shut down, as needed or desired.

Abstract: A power inverter includes a regulator circuit that controls real and reactive power output by the inverter. The regulator measures real and reactive output power by calculating x-phasor components of the inverter's voltage and current output waveforms. Phasor calculation can be adapted for one or more pairs of single-phase voltages and currents. Determining the fundamental in-phase and quadrature components of output voltage and current reduces computational complexity by permitting the regulator to perform its power control processing largely in a dc signal domain, and enables separate real and reactive power control. The power inverter can include islanding detection logic, which exploits the ability to separately control reactive power. Exemplary islanding detection logic is based on determining whether changing the amount of reactive power output by the inverter induces an output frequency shift.

Abstract: A method for calculating a first and second gain for a controller circuit for a plant is disclosed. The method comprises the steps of providing a reference model circuit with desired circuit characteristics, providing a reference model adaptive circuit, setting the second gain to zero, supplying a spectrally rich input signal to the reference model and to the controller circuit, determining the first gain by continuously adjusting the first gain until an output of the reference model and an output of the controller circuit are substantially equal, setting the first gain to the previously determined value, determining the second gain by continuously adjusting the second gain until an output of the reference model and an output of the controller circuit are substantially equal and setting the second gain to the previously determined value.

Abstract: A self-commissioning controller 7 for a field-oriented elevator motor controller 14 includes calculating an integral gain K.sub.I, a proportional gain Kp, and an overall gain (Gc) for the motor controller; obtaining initial values of a rotor time constant .tau..sub.R, magnetizing current Id, and motor torque constant K.sub.T for the motor controller 14, and obtaining a value of a motor transient inductance L.sigma.; calculating final values for said rotor time constant .tau..sub.R and magnetizing current Id, using said transient inductance L.sigma.; and calculating a system inertia J* parameter for speed loop compensation 16 within the motor controller 14. The controller 7 may also include calculating the initial values for .tau..sub.R, Id, and K.sub.T *, and performing self-commissioning automatically upon receiving a command from a service tool 80.

Abstract: An elevator controller 7 is provided with logic 48 which automatically calculates a motor time constant (.tau..sub.R) for a field-oriented current regulator/motor drive 20 by running the elevator up and down while computing a loss component VDX and while varying .tau..sub.R and determining the value of .tau..sub.R at which VDX for the up and down elevator runs are the same within a predetermined tolerance and which automatically calculates a magnetizing current (Id) by running the elevator in a predetermined direction while calculating a motor voltage Vm and varying Id and determining a new value of .tau..sub.R by performing the up/down elevator run until Vm is within a predetermined tolerance of a target voltage V.sub.T.

Abstract: An elevator controller 7 is provided with logic 48 which automatically calculates a motor time constant (.tau..sub.R) for a field-oriented current regulator/motor drive 20 by running the elevator up and down while computing an average of a sign-adjusted error signal DXD.sub.ERR for the up/down run and while varying .tau..sub.R and determining the value of .tau..sub.R at which the average of DXD.sub.ERR for the up and down runs equals zero within a predetermined tolerance. Alternatively, instead of computing the average of DXD.sub.ERR, a single elevator run may be used to determine the value of .tau..sub.R at which DXD.sub.ERR equals zero within a predetermined tolerance.

Abstract: An elevator controller 7 is provided with logic 48 which automatically calculates a motor time constant (.tau..sub.R), a torque constant (K.sub.T *), and a magnetizing current (Id) for a field-oriented motor/drive system by calculating a transient inductance L.sigma., injecting a variable input frequency sinewave into a q-axis reference current I.sub.qREF and varying the input frequency while calculating an imaginary part of a rotor impedance Imag(Z.sub.R) to obtain a frequency (F.sub.PEAK) at which the maximum value of Imag(Z.sub.R) occurs, then calculating .tau..sub.R from F.sub.PEAK. K.sub.T *, Id, and a total motor voltage V.sub.M are calculated and Id is varied until a ratio of rated motor voltage (Vph.sub.-- RATED) to V.sub.M is within a predetermined tolerance of one. The procedure is performed with the rotor locked.

Abstract: An elevator controller 7 is provided with logic 48 which automatically calculates a proportional gain (K.sub.P), an integral gain (K.sub.I), and an overall gain (Gc) for a current regulator/motor drive 20 by injecting a sinewave having a predetermined test frequency (F.sub.OL, F.sub.CL) into a reference current I.sub.qREF, measuring the open and closed loop transfer functions and adjusting K.sub.P and K.sub.I until the desired open and closed loop responses are achieved with Gc set based on F.sub.OL. First, with the test frequency at F.sub.OL, K.sub.I is set to zero and K.sub.P is varied until the open loop gain response at F.sub.OL is equal to one. Then, with the test frequency at F.sub.CL and K.sub.P set per the previous step, K.sub.I is varied until the closed loop gain response at F.sub.CL is equal to one. The procedure is performed with the rotor locked.

Abstract: An elevator controller 7 is provided with logic 48 which automatically calculates a motor speed loop gain (J*) of an elevator motor controller 14 by running the elevator up and down while computing an average of a model speed reference signal W.sub.MRE for the up/down run and while varying J* and determining the value of J* at which the average of W.sub.MRE equals zero within a predetermined tolerance.