Energy Converters

Design and manufacturing of variable speed drives (VSD) and power-supply systems are of high importance within VNII Signal scope of activity.

Generators, motors, and static power converters (SPC) are the key component parts to provide energy conversion in VSD and PSS.

Types of available synchronous motor control:

• V/f control, that makes it possible to set the required rotation speed and torque output by impressing stator currents;
• vector control, that makes it possible to keep maximum torque output;
• subordinate control, i.e. outer circuit controls every inner circuit. Easy calculations and adjustment are provided by this type of architecture.

SDM motors have built-in measurement instrumentation to gauge electromagnetic parameters to improve the adjustment characteristics, accuracy and operation speed of adjusted drives. Excitation of SDM motor by high-coercivity magnet provides motor efficiency factor of 94-97% and increases power density by 2-4 times as compared to a hydraulic drive or a CD motor. Brushless design enlarges operational life by 3-5 times as compared to a hydraulic drive and by 8-10 times as compared to EDM low-mass CD motor.

SPC comprises microintegrated system (MIS), which is combined with built-in sensors of SDM motor to provide use of the most efficient algorithms to control, check and adjust both SPC and the drive as a whole.

Modular blocks, which comprise SDM motor, electromagnetic brake, angle sensors, speed sensors and intermediate gear placed between SDM motor and adjusted device, have been designed for a number of artillery systems and azimuth rotary systems. This design decision eliminates backlashes, kinematic errors, and elastic strain between component parts and results in actuator weight reduction.

Specification of SDM Synchronous Motors and SDM-Based Assembly Units:

IGBT–based power converters, which are used to control synchronous motors, together with an SDM motor provide the increase of efficiency factor of the drive as a whole up to 88-90% (50-60% as far as a hydraulic drive is concerned) and ensure improved reliability.

SPC comprises microintegrated system (MIS), which is combined with built-in sensors of SDM motor to provide use of the most efficient algorithms to control, check and adjust SPC and the drive as a whole.

Built-in controlled rectifiers and inverters make another large group of SPC designed by VNII Signal.

SPC Control and Support Devices

• Secondary power supplies
• Matching filters
• Braking choppers
• Microcomputer units
• Voltage regulators
• Interface units
• Torque and speed controllers

Power Supply Regulators

• Number of input voltage phases: 3
• Output voltage: (540 to 750) V
• Regulation accuracy: better than ± 4%
• Nominal output current: 150 А
• Switching frequency: up to 15 kHz
• Overvoltage ratio: 2
• Energy output to the mains
• Built-in current transducers
• Galvanic isolation of control

IGBT–Based Voltage Inverters

• Phase number: 3
• Nominal output current: 50/ 75/ 100/ 150 А
• Switching frequency: up to 15 kHz
• Overvoltage ratio: 2
• Built-in current transducers
• Galvanic isolation of control

10 kW PNVK power converter for railway car air conditioner is one of the most popular SPC of VNII Signal design.

The converter was designed according to the statement of work of Teploobmennik JSC (N. Novgorod) to provide power supply for air cooling compressor of passenger railway cars (“MAB-II” railway car air conditioners for railway cars of 47k and RIC-160 type).

The main advantages of PNVK power converter are its enhanced performances, and in particular, its operating temperature range, which is up to + 60°C, while other similar articles of Russian design can operate only up to + 45°C.

Performance Specifications of PNVK Power Converter:

VNII Signal JSC has developed several hybrid power-supply systems (HPSS) that supply energy to power consumers from three sources: primary power supply (gas turbine, windwheel, drive motor shaft of mobile carrier), standby power supply (diesel engine, gas turbine engine, etc.), electric energy storage (accumulator battery, EDLC (super capacitor), etc.). Hybrid power-supply system comprises generator, required electric power converters, and digital control system to provide controlled optimal power distribution between power consumers.

One of the most important HPSS components is an electric generator (EG), which provides optimal matching of input shaft velocity with primary motor shaft velocity, and of output signals with primary SPC signals.

HPSS EPG Performance Specification:

During the designing of HPSS and its components the main attention is paid to optimal matching of all the components to primary power supplies and energy consumers, high efficiency factor and reliability.

Various HPSS design decisions ensure efficient methods of autonomous and uninterruptable electric power supply.

For example, hybrid power supply systems, which comprise turbogenerators, make it possible to get electric power at any gas distribution station (GDS), gas dispenser (GD), boiler plant, or heat-electric generating plant without extra consumption of natural resources due to the conversion of energy, releasing during natural gas decompression. At the same time, there is no more need in the design and endorsement of plans of GDS and GD connections to electricity network and building of long power lines. Non-electrified GDS/GD can be automated; the number of duty officers and the costs for GDS/GD inspecting rides can be reduced significantly.

Hybrid power supply systems, which take primary power off the traction motor shaft, are in need for almost every mobile industrial/ defense systems that provide control over a great number of members using only the energy of primary traction motor.

Hybrid power supply systems, which take primary power off the windwheel, are in great demand nowadays, but the fact is that the design of an efficient system of this type has not been accomplished yet.

HPSS of VNII Signal design is used in Zhavoronok wind-diesel system.

Wind mill PSS comprises:

• Synchronous generator
• Voltage converter
• Accumulator battery unit
• Transformer

Application: PSS is used to generate electric power by means of energy conversion of HS rotor rotation and of standby and battery backup power supplies to provide external and internal consumers with 3-phase AC, 50 Hz, 380 V (through four-wire circuit with solidly earthed neutral), complying with GOST 13822-82 at any operation mode.

High requirements to advanced systems such as available power rise, flexibility and reliability improvement, weight and size minimization, fuel consumption reduction specify the task to design highly integrated, jam-resistant, and efficient power supply systems and their components.

Being an expert in SPC and PSS design, VNII Signal is ready to cooperate in this field with Russian and foreign customers.