226 results about "Excitation controller" patented technology

A position detecting device is provided. The position detecting device includes a position pointer which transmits a position-pointing signal using a power supply stored in a rechargeable power storage unit, and a tablet which detects a position pointed to by the position pointer when receiving the position-pointing signal. The position pointer includes a coil, a charging circuit for charging the power storage unit, and a transmitter for transmitting the position-pointing signal. The tablet includes an excitation coil wound around a periphery of a position detecting area of the tablet, an excitation circuit for supplying an alternating voltage to the excitation coil, a position-pointing signal detector for detecting the position-pointing signal received from the position pointer, and an excitation controller for controlling a supply of the alternating voltage to the excitation coil based on the detected position-pointing signal.

Mobile electronic devices and methods are disclosed that operate an electroactive polymer (EAP) transducer to provide tactile indications to a user. A mobile electronic device can include a housing with at least one EAP transducer that is at least partially disposed in a surface of the housing. The EAP transducer has first and second electrodes with an EAP material coupled therebetween. An EAP excitation controller controls an electric field across the first and second electrodes to regulate deformation of the EAP material. The mobile electronic device can include a communication controller that communicates with a wireless communication device using at least one wireless communication protocol. The communication controller generates an alert signal in response to receiving a phone call / data message from the wireless communication device. The EAP excitation controller responds to the alert signal by repetitively varying the electric field across the EAP transducer to generate a vibration therefrom.

The invention relates to a brushless doubly-fed motor excitation control system, which is characterized by comprising a PWM (Pulse-Width Modulation) rectifying unit, a first current sensor, a smoothing reactor, a contactor, an excitation controller and an inverter unit, an operation and display unit, an energy storage device, a BOOST reactor, a soft start circuit, a first voltage detection circuit and a second voltage detection circuit. The brushless doubly-fed motor excitation control system can always keep a speed-variable load-variable constant-frequency and constant-voltage power generation state when a brushless doubly-fed motor is at an electric operating state, the rotating speed of a brushless rotor rapidly changes and the load condition is within a larger range; and when the brushless doubly-fed motor is at the electric operating state, the brushless doubly-fed motor excitation control system can finish rapid adjustment of the rotating speed of the brushless rotor by excitation control and realizes multiple electric operating modes, such as synchronous operating, asynchronous operating and doubly-fed speed adjustment. When the load condition changes in a larger range, the brushless doubly-fed motor excitation control system can always keep the hard mechanical property of a synchronous motor. The invention also comprises the control method using the brushless doubly-fed motor excitation control system.

The invention discloses an inverter secondary-frequency-regulation control circuit based on a virtual synchronous generator. The inverter secondary-frequency-regulation control circuit comprises an inverter, an LC filter and a power measurement module, and also comprises a voltage loop and a VSG controller. The input end of the VSG controller is connected with the output end of the power measurement module, the output end of the VSG controller is connected with the input end of the voltage loop, and the output end of the voltage loop is connected with the inverter; the VSG controller comprises a power frequency controller and an excitation controller, the power frequency controller is used for simulating a rotor motion equation of the synchronous generator, the excitation controller is used for reactive-voltage droop control, the amplitude information of command voltage generated by the excitation controller and the phase information of command voltage generated by the power frequency controller are synthesized, and an input command signal em of the voltage loop cam be obtained. According to the inverter secondary-frequency-regulation control circuit, the VSG control strategy can automatically track load fluctuation and change output force of inverter secondary-frequency-regulation control circuit under the island model, and frequency support is provided for a micro grid.

A starter-generator system supplies a controllable torque to a gas turbine engine, to thereby assist in starting the gas turbine engine, by independently controlling excitation frequency and / or voltage magnitude. The starter-generator includes a multi-phase exciter stator, a rotationally mounted multi-phase exciter rotor, a multi-phase main stator, a rotationally mounted multi-phase main rotor, and an exciter controller. The rotationally mounted multi-phase exciter rotor has a plurality of exciter rotor windings wound thereon that, upon excitation thereof with a rotating electromagnetic exciter flux generated by the exciter stator, have non-rectified excitation currents induced therein. The rotationally mounted multi-phase main rotor has a plurality of main rotor windings wound thereon that are electrically connected to receive the non-rectified excitation currents induced in the exciter rotor windings and that, upon excitation thereof with a rotating electromagnetic flux and in response to the non-rectified excitation currents supplied thereto, have currents induced therein that generate a main rotor torque to thereby cause the multi-phase main rotor and the multi-phase exciter rotor to rotate. The exciter controller is electrically coupled to at least the exciter stator and is configured to selectively supply the electrical excitation thereto, to thereby selectively control the generated main rotor torque.

The invention discloses a control method for a virtual synchronous generator capable of being adapted to imbalanced power grid and load conditions. The control method comprises the following steps that 1) an active ring simulates the mechanical characteristics of a speed controller and a rotor to obtain an output positive sequence voltage frequency and a phase position instruction; 2) a reactive ring simulates a n excitation controller to obtain an output positive sequence voltage amplitude value instruction; 3) a voltage-control and virtual synchronous impedance ring simulates the electrical characteristics of a stator; 4) positive and negative sequence current rings carry out accurate tracking on the positive and negative sequence current instructions respectively, and eliminates the negative sequence current output; and 5) a modulation signal is obtained by the combination of the positive and negative sequence current rings, and then the modulation signal is subjected to PWM to obtain a switching signal. Compared with the prior art, the output active power fluctuation and frequency fluctuation caused by imbalance of the power grid can be eliminated; and in addition, it is ensured that the output current of the virtual synchronous generator is balanced constantly, so that overhigh electrical stress of a certain bridge arm of the inverter can be avoided.

A position sensing apparatus (300) derives rotor position of a synchronous machine (200) from signals output from the machine (200). In one embodiment, the position sensing apparatus (300) comprises: a bandpass filter (322) that filters phase voltage signals output from main stator windings (216) of the synchronous machine (200) during AC excitation, thereby extracting a rotor position-indicating component from the phase voltage signals; a converter (324) that converts the filtered phase voltages into balanced two-phase quadrature signals, the balanced two-phase quadrature signals indicating positioning of the rotor (212); and an excitation controller (204) for controlling AC excitation frequency as a function of rotor speed.

The invention relates to a structure of an excitation control system of a brushless doubly-fed shaft generator used for a marine diesel and a control method thereof. The structure comprises a contactor, a step-up transformer, a rectification feedback unit, a direct current compensation unit, a inverter unit, an operation panel, an excitation controller, an AB phase voltage sensor, a CA phase voltage sensor, and a BC phase voltage sensor; the method based on the control system structure can realize the excitation, constant-voltage control, constant-frequency control, under-voltage protection and over-voltage protection of the brushless doubly-fed shaft generator of the marine diesel.

A micro power grid frequency control method and a system are provided, wherein the method comprises the steps of obtaining d-axis and q-axis components of an output voltage, an output current and a filtering inductance current of an LC filter at the grid side of an inversion power supply; obtaining the output reactive power, the output active power and an output voltage amplitude of the LC filter in combination with the d-axis and the q-axis components of the output voltage and the output current; obtaining a virtual excitation electromotive force by taking the output reactive power and the output voltage amplitude as the input of a virtual excitation controller; obtaining an active power increment by inputting an output angular frequency of a virtual synchronous generator controller into a frequency controller; and obtaining a d-axis and a q-axis reference instruction value and an output angular frequency of the inverter output voltage by taking the output active power, the virtual excitation electromotive force, the active power increment and the d-axis component and the q-axis component of the filtering inductance current as the input of the virtual synchronous generator controller. According to the invention, the micro power grid frequency change caused by load disturbance can be effectively inhibited; and the island micro power grid can be operated stably.

The invention discloses a configurable on-chip testing module supporting the encapsulation of a chip through different pins, which consists of an encapsulation form controller (101), a pin converter (102), a pin signal controller (103) and a bus signal selector (104). The testing module can support the encapsulation form of the multifunctional chip that the different pins are adopted for different pieces of application. The configurable on-chip testing module supporting the encapsulation of the chip through the different pins is characterized in that: 1, the testing module is strong in universality and wide in testing range and can almost test all other functional modules except an internal CPU; 2, the testing module is less logical and can ignore influence on the area of the chip, thus the production cost of the chip is not increased; and 3, a virtual CPU (an excitation controller) adopted in testing is arranged outside the chip, thus the development on testing programs is more flexible and more relevant.

An excitation controller sets an output terminal reference voltage of a synchronous machine from a reactive current output from the synchronous machine and a high side reference voltage of a transformer, and controls the field current supplied to the field winding of the synchronous machine in response to the deviation between the reference voltage and the output terminal voltage. Although a conventional excitation controller can maintain the transmission voltage on the transmission bus at a fixed value, an expensive potential detector is needed for detecting the transmission voltage on the transmission bus, which increases the manufacturing cost of the excitation controller.

The invention discloses a mixed excitation magnetoelectric machine adopting harmonic excitation, comprising a machine shell (1), a stator core (2), a stator winding (3), a permanent magnet pole (4), aferromagnetic pole (5), a rotating shaft (6), a rotor core (7) and a rotor winding (8), wherein, a rotor magnet pole is composed of the permanent magnet pole (4) and the ferromagnetic pole (5) whichis provided with the rotor winding (8); the rotor winding (8) consists of a harmonic winding (14) and an excitation winding (13); the stator winding (3) comprises a main winding (11) and a harmonic excitation winding (12), and is distributed in a stator groove; the pole distance of the main winding and the pole distance of the rotor excitation winding are identical; the pole distance of the harmonic excitation winding and the pole distance of the rotor harmonic winding are identical; the harmonic excitation winding is connected with an excitation controller; when the motor runs, the current inthe harmonic excitation winding can be controlled to achieve the functions of adjusting magnetic field and voltage. Compared with the prior art, the invention has no electric brush, collecting electric ring, additional air gap, axial magnetic circuit, has simple structure, little magnetic-flux leakage, less excitation loss, high efficiency of the motor and strong ability of adjusting the main magnetic field.

The invention relates to an auxiliary detection device and a method of image processing for the on-line flaw detection of rails. In the on-line running process of a train, an embedded type control system controls a light source excitation controller to enable two auxiliary light sources to irradiate the surfaces of rails, an industrial CCD line array camera collects image information at the surfaces of the rails by the control of a digital line array image collection interface, the information is transmitted to the embedded type system, and the embedded type system processes the collected rail image by an image processing technology; the flaw information and the inherent structure information of the surfaces of the rails are calculated from the processed rail image; then, the obtained flaw information of the surfaces of the rails is classified, and the flaw degree is calculated; and finally, the flaw classification and degree information is transmitted to an on-line rail flaw detection device by a communication interface, and then information integration is carried out on the transmitted information and a collection signal of the on-line rail flaw detection device, thereby reducing the interference degree of surface flaws to the on-line rail flaw detection device when detecting flaws inside the rails.

The invention provides a system for testing linear motor characteristics with linear linear device, which belongs to the technical field of motors and solves the problems that the conventional system for testing the linear motor characteristics can be used for testing in a single direction and a loading force cannot be changed continuously. A stator of the motor and a stator of a linear electromagnetic damper are simultaneously arranged on a system platform; the power output end of a motor driver is connected with the armature winding input end of a tested motor; the armature winding output end of the tested motor is connected with the current input end and the voltage input end of a power analyzer respectively; a force sensor is used for detecting a mutual acting force between a rotor of the tested motor and a rotor of the linear electromagnetic damper; the force signal output end of the force sensor is connected with the force signal input end of the power analyzer; a speed sensor is used for detecting the speed of the rotor of the motor or the stator of the damper; the speed signal output end of the speed sensor is connected with the speed signal input end of the power analyzer; and the linear electromagnetic damper consists of a primary, a secondary and an excitation controller. The invention is used as the test system of the linear motor.

The invention relates to a multi-path high-energy ultrasonic field treatment device for regulating and controlling a welding residual stress. The device sends a control instruction by matching with regulating-controlling system software and via an industrial personal computer; an ultrasonic signal excitation controller receives the control instruction, and then sends a regulating-controlling signal to a high-power ultrasonic amplifier; the high-power ultrasonic amplifier drives a high-energy ultrasonic transducer according to the regulating-controlling signal to generate a high-energy ultrasonic beam; and the energy of the high-energy ultrasonic beam is injected in a residual stress concentrated area in the surrounding of a weld joint according to set requirements, and then is used for regulating the residual stress. The device is simple in structure and good in regulating-controlling effect, can effectively solve the various adverse effects of a residual stress on the dimensional stability, the fatigue strength and the like of a welding workpiece at the present stage, has the characteristics of being efficient, energy-saving, environment-friendly and the like, and is very wide in application prospect.

A position sensing apparatus (300) derives rotor position of a synchronous machine (200) from signals output from the machine (200). In one embodiment, the position sensing apparatus (300) comprises: a bandpass filter (322) that filters phase voltage signals output from main stator windings (216) of the synchronous machine (200) during AC excitation, thereby extracting a rotor position-indicating component from the phase voltage signals; a converter (324) that converts the filtered phase voltages into balanced two-phase quadrature signals, the balanced two-phase quadrature signals indicating positioning of the rotor (212); and an excitation controller (204) for controlling AC excitation frequency as a function of rotor speed.

A position detecting device is provided. The position detecting device includes a position pointer which transmits a position-pointing signal using a power supply stored in a rechargeable power storage unit, and a tablet which detects a position pointed to by the position pointer when receiving the position-pointing signal. The position pointer includes a coil, a charging circuit for charging the power storage unit, and a transmitter for transmitting the position-pointing signal. The tablet includes an excitation coil wound around a periphery of a position detecting area of the tablet, an excitation circuit for supplying an alternating voltage to the excitation coil, a position-pointing signal detector for detecting the position-pointing signal received from the position pointer, and an excitation controller for controlling a supply of the alternating voltage to the excitation coil based on the detected position-pointing signal.

The invention relates to a magnetic levitation self-driven double-spiral-wing flying saucer, which consists of a saucer housing, a saucer cabin, a double-spiral-wing system, an excitation system and a spiral wing positioning system. Upper and lower magnetic levitation spiral wing wheels in the double-spiral-wing system rotate relatively through interactive magnetic forces generated by a magnetic field generated by -inductive current in inductive coils to realize self-driven rotation. An excitation controller in the excitation system controls the speed of the self-driven rotation by measuring relative position change of a positioned magnetic field on the upper and lower magnetic levitation spiral wing wheels and changes the direction of -control current in a control circuit -to change the direction of the inductive magnetic field in the spiral wing wheels so as to control steering of the self-driven rotation. The magnetic levitation self-driven double-spiral-wing flying saucer has the advantages of compact design structure, reasonable layout, light weight, and high power conversion efficiency, overcomes the reverse torque deficiency of the spiral wing flying saucer at the same time, and realizes positioning control of the spiral wing and guarantees safe operation of the flying saucer.

The invention relates to a control method and system based on a virtual synchronous generator. In the grid-connected pre-synchronization stage, phase-locked loop control is performed on grid voltage to obtain a grid voltage amplitude; the phase-locked loop control is conducted on the terminal voltage of a virtual synchronous generator, and the amplitude of the terminal voltage is obtained; the grid voltage amplitude is taken as a given value, the terminal voltage amplitude is taken as a feedback value, closed-loop control is conducted, the amplitude synchronization amount is obtained, and theamplitude synchronization amount is superimposed on a voltage control loop of an excitation controller. When the phase-locked loop control is performed on the grid voltage, the frequency adjustment amount is obtained, and the frequency adjustment amount is superimposed on a power frequency controller. The method adaptively compensates the deviation of bridge arm voltage phase and terminal voltagephase caused by an LC / LCL filter, thereby achieving the synchronization of the terminal voltage phase and the grid voltage phase and amplitude synchronization.

A vibration characteristic measuring apparatus includes a magnetic bearing that generates magnetic force on the rotating body of a multi-stage centrifugal compressor, a displacement sensor that measures the vibration amplitude of the rotating body, a current amplifier that supplies a current to the magnetic bearing, and an excitation controller which outputs an excitation control signal for applying vibration to the rotating body and which measures the response characteristics of the vibration of the rotating body to the excitation control signal. The excitation controller outputs a rotating body control signal obtained by adding a vibration eliminating signal for eliminating unbalance vibration of the rotating body to the excitation control signal when measuring the response characteristics, and the current amplifier supplies a current that generates magnetic force in accordance with the rotating body control signal to the magnetic bearing.

A high-power brushless double fed motor variable frequency speed regulation system comprises a power winding of the high-power brushless double fed motor and a control winding, a first contactor, an input power distribution unit, an entry switch, a soft start circuit, a alternating current or direct current rectifying unit, a energy-storage capacitor, an operation and display unit, and an excitation control and inverter module which is composed of a excitation controller, an inverter unit, a first current detection unit, a second current detection unit and a voltage detection unit. After the power winding is connected with the first contactor in series, the power winding is connected with the input power distribution unit, the entry switch, the alternating current or direct current rectifying unit, the energy-storage capacitor, and the inverter module, then the power winding is connected with the control winding. The soft start circuit is connected with a circuit between the alternating current or direct current rectifying unit and a three-phase output end of the entry switch in series or the soft start circuit is connected with a circuit between the alternating current or direct current rectifying unit and the energy-storage capacitor. Whole course frequency speed regulation of the brushless double fed motor can be achieved. The invention further comprises a fundamental control timing sequence and a method.

The invention discloses a photovoltaic power generation system control method for tracking through maximum power point spinning reserve capacity in the technical field of power electronic control. The method comprises the following steps: acquiring photovoltaic cell performance parameters, and converting a photovoltaic cell circuit into an equivalent circuit; determining an initial discriminant relation between output power and output voltage under the condition of tracking the maximum power point of the photovoltaic cell according to the condition that a photovoltaic array output characteristic curve is a single peak curve; changing the power tracking point according to the selection standard of the spinning reserve capacity of the system; simulating mechanical inertia of a synchronous generator, frequency modulator and excitation controller characteristics and a double closed loop control by taking inductive current as inner loop feedback by adopting a VSG power controller according to the relation between the external environment and the photovoltaic array output characteristic curve, and determining the PV-VSG inertia and damping parameters. The maximum power point of the power generation load of a real-time synchronous tracking system at the spinning reserve capacity and the real-time tracking function in a transient stable state can be realized.

The invention discloses a third-harmonic excitation synchronous motor. The third-harmonic excitation synchronous motor comprises a motor case, a stator core, a stator armature winding, a stator third-harmonic winding, a rotor core, a rotor excitation winding, a rotor harmonic winding and a rotary shaft, wherein the armature winding and the third-harmonic winding are arranged in a stator groove, a magnetic pole body is sleeved with the excitation winding, the harmonic winding is arranged in a rotor groove, the short circuit of the third-harmonic winding is achieved through an anti-parallel thyristor, the phase position of trigger pulses of the thyristor is given by an excitation controller, and the excitation winding and the harmonic winding are connected through a diode rectification circuit. According to the third-harmonic excitation synchronous motor, electromotive force induced by the third-harmonic winding is transmitted to the excitation winding for excitation through the magnetic coupling between the stator third-harmonic winding and the rotor harmonic winding, an electric brush and a collecting ring or an alternating-current exciter are omitted, and the third-harmonic excitation synchronous motor has the advantages of being high in reliability, small in maintenance amount, low in manufacturing cost and the like; adjustment of the voltage of a motor end is achieved by controlling the phase position of the trigger pulses of the anti-parallel thyristor, and the third-harmonic excitation synchronous motor further has the advantages of being convenient to control and easy to adjust.

The invention discloses a proportional-integral-differential (PID) prediction function-based excitation control method, which is used for an excitation control system for a synchronous generator. By combining characteristics of PID and prediction function control, a PID form-based prediction function controlled target function is provided, and the optimized controlled quantity is obtained by optimized calculation, and is taken as a control end input signal of a silicon controlled (or a full-control device) in the excitation control system so as to control the excitation current of the synchronous generator and further influence the terminal voltage thereof. An excitation controller acquired by the method has structural characteristics of proportion, integral and differential in a broad sense, has respective advantages of the PID and the prediction function control, and is convenient to implement. The method overcomes the defects that the conventional prediction control method has high on-line calculated amount and the PID control method has a limited regulating range, and is a novel and effective control strategy for stabilizing a power system.

The invention is a DSP-based excitation controller data collecting and processing system and the operating method thereof, and it comprises on-off collecting circuit, AC analogue preprocessing circuit, frequency measuring circuit, A / D converter-DSP interface circuit, on-off output circuit, and phase shifted pulse forming and power output circuit. And its advantages: 1. simplifying hardware design; 2. using DSP chip with respect to motor and motion control field; 3. simplifying hardware overhead and reducing system maintaining workload by adopting AC sampling and omitting the electrical transducer from the excitation controller; 4. improving data collecting speed and accuracy and response real-time property of the excitation controller by data calculating and processing ability of DSP.

The invention discloses an alternating current and direct current coordination control method improving the system stability, and belongs to the field of electric power system operation control. The method comprises the steps of carrying out quadratic polynomial curve fitting on the power of a connecting line after smoothing and stopping are carried out on the power of the connecting line under the condition that an alternating current and direct current series-parallel power grid goes wrong, judging whether the power increase condition or the power decrease condition is met and then increasing or decreasing the direct current power. Meanwhile, the effect is more remarkable with cooperation with an additional PSS4B excitation controller. According to the alternating current and direct current coordination control method, the regional power balance relation in the swinging process of a generator set can be effectively controlled, power angle swinging can be restrained, generator tripping can be reduced, and the transient stability level and the dynamic stability level of an alternating current and direct current system can be increased.

The invention provides an airplane power supply system experiment platform device. The airplane power supply system experiment platform device comprises a motor speed regulation control system, a generator excitation control system, a PC end host computer, an inverter and an aviation storage battery. According to the airplane power supply system experiment platform device, the motor speed regulation control system is utilized to replace an aviation engine system to provide power for rotation of a rotor when an AC generator provides power supply, a DSP speed regulation controller in the motor speed regulation control system is used for adjusting a rotation speed of a permanent-magnet synchronous motor, an excitation current of an excitation winding of the AC generator is controlled through an STM32 excitation controller in the generator excitation control system to make an end voltage outputted by the generator be constant, the PC end host computer is used for controlling and displaying data parameters of two systems, and the inverter is used for converting a 28V DC current into 200V / 115V 400Hz AC current needed by an aviation AC load. Through the airplane power supply system experiment platform device, a verifiable platform is provided for theoretical researches on airplane power supply systems, and great importance to popularization of experiment platforms and research and development of modern airplane power supply systems is realized.

A generator wide area damping control system closed-loop testing method based on an ADPSS comprises the following steps that S1, an electromechanical-electromagnetic grid dividing scheme of a power grid to be tested is set up through an ADPSS system; S2, an important call wire in the grid dividing scheme is defined, voltage signals or current signals on the important call wire are used as wide area analog acquisition, and are converted into wide area damping control signals, and the wide area damping control signals and local PSS signals are used as new PSS signals to act on an excitation controller model after being superposed; S3, the ADPSS system is utilized for simulating various fault modes, and the functions of a generator wide area damping controller are measured. A real power grid model is set up through the real-time simulation platform ADPSS, damping control modes under the various fault modes are simulated, the measurement result is obtained, and a firm foundation is established for popularization and application of the wide area damping control technology in the power grid.

A 60 t mine dumping vehicle control system comprises a diesel engine set, a convertor, a main generator, a storage battery, a whole vehicle controller, a driver controller, a display screen, a combined instrument, and six motors for driving wheels, wherein the diesel engine set comprises a diesel engine and a 24 V generator; the converter comprises a generator excitation controller, four variable current controllers DCU, an AC / DC converter and six DC / AC converters; the diesel engine is connected with the 24 V generator and the main generator respectively; the 24 V generator provides DC 24 V voltage to the storage battery; the storage battery provides DC 24 V voltage to the whole vehicle controller, the display screen, the combined instrument, the variable current controllers DCU and the excitation controller ECU; the alternative current from the main generator is converted into intermediate direct current by one AC / DC converter, and then the intermediate direct current is converted into three-phase alternative current by six DC / AC converters and the three-phase alternative current provides the power supply to the six motors. Communication based on CAN bus makes the control wiring of the whole vehicle simpler, and the control system is stable and reliable.

A flywheel energy storage system for preventing power interruptions to a load from interruptions of primary power includes a flywheel supported for rotation about an axis on a bearing system, and a motor-generator having a rotor coupled with the flywheel, and having a stator with multiple armature windings and a field coil. The field coil generates flux that passes through the armature windings as the rotor rotates to produce torque for accelerating the flywheel during charging, and produces electrical power from the flywheel during discharge. The armature windings are energized by a DC buss that is supplied by a rectifier connected to primary power. The flywheel system provides instantaneous full power capability along with output control for extracting more energy from the flywheel. The field coil is oversized and is powered in standby operation to produce an armature back emf that is at least 75% of the DC buss voltage. The current to the field coil remains substantially constant during a period including immediately before an interruption and immediately after and interruption of primary power. The flywheel system uniquely utilizes an extremely large field coil, which is preferably 25-50% of the weight of the flywheel. The increased field coil size allows for both full standby energization without overheating and also reduces the armature reaction such that full power is available during a power interruption without requiring instantaneous increasing of the field coil current. In one embodiment, the field controller has a speed sensor for monitoring rotational speed of the flywheel and for varying electrical power to the field coil, without monitoring the primary power for interruptions. The field controller varies electrical current to the field coil approximately inverse linearly with the rotational speed of the flywheel during both standby and discharging operation to govern power to the field coil during standby operation such that the back emf of the armature remains substantially constant during an interruption of power.