After studying the material in this chapter, the student should:
know
- control principles used in the implementation of control systems for power electronic devices;
- the structure of the power electronic device control system;
- principles of operation of transistor and thyristor control pulse shapers, methods of providing galvanic isolation;
- basic circuits of current and voltage sensors;
- general information about the element base of control systems;
be able to
- choose pulse shapers (drivers) to control power electronic switches;
- choose sensors for measuring currents and voltages in power electronic devices;
own
The skills of selecting elements of the control system of a power electronic device that correspond to its functional purpose.
Basic principles of management and regulation
The main task of the control system (CS) of a power electronic device (PSD) is to provide a given quality and control its output parameters, which stabilizes or changes them according to a given law. Traditional control systems are divided into systems with regulation according to the deviation of the controlled parameter and (or) the disturbance that causes this deviation. In SEU, as a rule, the controlled parameter is the value of the output voltage or current. The most pronounced disturbing parameters are the input voltage of the power source and the magnitude and (or) nature of the load.
On fig. 2.1, b/ shows a block diagram of the control system with deviation control. Information about the value of the output function / out (0 of the power unit (MF) is taken by the sensor (D) and enters the comparison device with the set value / 0. The mismatch signal of these values is sent to the control device (CU), which restores the set value of the output function with a certain In this case, we have an example of regulation implemented on the basis of the classical principle of negative feedback(OS). The main advantage of this principle is
Rice. 2.1.
a - by deviation; b - out of indignation
It turns out that it provides compensation in static modes for almost all types of disturbances that occur in the device, including the influence of changes in various gain factors, temperature, etc. At the same time, ensuring the required quality and stable operation in dynamic modes is often a difficult task.
On fig. 2.1 , b a block diagram corresponding to the disturbance control principle is presented. For example, if the value of the output function / o (0) directly depends on the input / in (?), then this dependence can be eliminated by introducing a feed-forward loop (PS) containing a compensation block (BC). The output signal of the latter together
with the reference reference signal / () enters the control device, which generates a control signal that ensures the invariance of the value of the output function. As a result, the dependence of the change / in (?) on the value / B1X (?) is excluded. Such a control system is also called invariant, i.e. indifferent to the effects of perturbation. Obviously, in the case under consideration, invariance to one type of perturbation is ensured. To expand the invariance region, it is necessary to introduce direct connections with correction blocks for all types of disturbances. In practice, such connections are introduced for the main explicit perturbations. However, the impact of unaccounted disturbances will disrupt the stability of the controlled parameter. On the other hand, direct connections increase the speed and stability of the system. Therefore, if necessary, a combined system is used that combines the principles of regulation by deviation and disturbance. In such cases, the feedback loop that provides regulation by deviation is more inertial and has a small gain, since it performs the function of correcting the controlled parameter in the steady-state operating modes of the power plant.
A feature of the SPP as control objects is that the processes in them proceed under the influence of switching power switches and are discrete in nature. To smooth currents and voltages in the SEU, filters are used, consisting of reactive elements (inductive or capacitive). Therefore, in the general case, the power part of the SPP can be represented in the form of nonlinear key elements and linear circuits containing reactive and resistive elements. In this regard, the control methods of the SPP and their analysis are diverse and are selected for each type of SPP, taking into account its circuit design, operating modes and requirements for the characteristics of the main parameters. According to the principle of control of the control system, the EMS can be conditionally divided into two groups:
- systems with phase control;
- systems with impulse control.
Phase control is used in SPPs connected to the AC network and using thyristors operating with natural switching as keys. Such SPPs include rectifiers, dependent inverters, direct frequency converters, etc. Systems with pulse regulation can currently be used in almost all types of converters and regulators made on the basis of switches with full controllability - transistors, lockable thyristors, etc. Common to these systems is the use of power keys as executive bodies regulators.
Systems with phase control (FC), in turn, can be divided into synchronous and asynchronous.
In synchronous systems, the moments of formation of control pulses are always synchronized with the voltage of the supply network to which the key is connected. In the process of regulation, the pulse formation phase changes so that the controlled parameter of the SEA remains at a given level. The traditional simplest way to shift the phase during regulation is the method of vertical phase control (VFC). On fig. 2.2, a presented structural scheme one control channel
Rice. 2.2.
a - structural scheme; 6 - diagrams of the formation of pulses by a thyristor based on VFU. The input of the phase-shifting device (FSU) through an isolation transformer (Tr) receives an alternating mains voltage and s. The main element of the FSU is the sawtooth voltage generator (SPG), which begins to form at the initial moment of the passage of the sinusoid through zero 9 = 0 and ends at the moment 9 = i (Fig. 2.2, b).
Such a duration of the GPN voltage is necessary if the range of the control pulse phase change is equal to half the period of the mains voltage. In some cases, for example, with small changes in the phase angle, it is possible to eliminate the GPN by using directly the input voltage of a sinusoidal shape to form the pulse k T u c . Voltage and g, generated GPN is compared with the mismatch signal r, coming, for example, through the feedback circuit in the ECS (see Fig. 2.1, a) to the comparator (K). At the moment of equal stress and g and e at the output a pulse is formed and and, which is then converted into a control signal and at thyristor using a control pulse shaper (FYU). From fig. 2.2, b it can be seen that the value of the signal in determines the value of the angle a, i.e. pulse shaping phase and at. So, for example, when e \u003d angle a \u003d a p and when e \u003d e 9, the angle a \u003d a 9.
Usually the number of thyristors in the SEU is more than one, for example, there are six of them in a bridge three-phase rectifier circuit. In this case, the synchronous control system can have the number of channels equal to the number of thyristors, or use one common channel to control the phase of the control pulses. The first type of synchronous system is called multichannel. The disadvantages of such a system are obvious. Technological dispersion of individual functional units across channels leads to asymmetry of switching intervals and, consequently, the appearance of undesirable current or voltage harmonics as a function of the output voltage or current. In addition, setting up a multi-channel SU is more complex. However, a synchronous system can also be created in a single-channel version (Fig. 2.3, a). At the same time, the input of the FSU of one common channel receives the voltage of a three-phase voltage system, from which the synchronization of the GPN with the moments corresponding to the switching of all thyristors with an angle a = 0 is possible, which corresponds to the switching of diodes in an uncontrolled rectifier. In this case, the GPN will operate at six times the frequency of the mains / and = 6 / s. Accordingly, with such a frequency, pulses will be formed and y, which are then fed through the pulse distributor (RI) to the thyristors (Fig. 2.3, b). The phase of the pulses in this case also changes depending on the signal 8, which is compared with the voltages and Mr. With such an organization of the control system, the range of angle regulation in each channel is limited by the value l/3. There are various circuit solutions that allow you to expand this range to a = k.
In asynchronous systems, the frequency of generation of control pulses becomes synchronous with respect to the frequency of the mains voltage only in the steady state when closed circuit phase control. The main types of such systems are "tracking" systems, the principle of which is based on comparing the average values of the controlled parameter and the master signal at interswitching intervals, as well as systems with phase locked loop.
Rice. 2.3.
a - structure; b- control pulse diagrams
The principle of pulse control is the main one in power electronics devices for the formation of currents and voltages of a given shape and the required quality. It is the basis various kinds pulse modulation of converted parameters in power electronic devices of various types. The main methods of pulse modulation of SEA are considered in Ch. 5.
The executive bodies of the SEU are power electronic keys operating in switching modes. In converters with pulse control, the switching frequency usually significantly exceeds the frequencies of the fundamental harmonics of the generated currents and voltages. In pulse DC converters, the operating frequency of the keys is also sought to be increased to values limited mainly by technical and economic criteria.
Increasing the operating frequency of the keys makes it possible to bring the pulsed transformation of the energy flow closer to continuous. This allows you to increase the controllability of the output parameters according to the required laws with a minimum delay in their implementation. The control of discrete values of small portions of energy as a whole increases the technical and economic efficiency of the electric power converter by improving the weight and size indicators of the converter per unit of power. Due to this, pulse conversion has been widely used in the creation of many types of SPP, especially DC-to-DC converters (see Chap. 6).
Description of the enterprise
Enterprise organized October 29, 1997.
At the end of 2006, as a result of the last restructuring of the group of companies in order to optimize business and unified management the HydraPac holding structure was created, management company which is ZAO GidraPak Holding.
Enterprise specialization- supply of complex technical solutions and components for manufacturers of mobile equipment and industrial equipment
Products
+ Components for mobile technology:
Hydrostatic transmissions
Volumetric hydraulic machines
Guiding and regulating hydraulic devices
Working fluid conditioners
Control and brake systems
Cabins and accessories
+ Components for industrial equipment
Pumping stations
hydraulic motors
Auxiliary and diagnostic equipment
Control systems
+ Engines and Mechanical Transmissions Division
Diesel engines and spare parts
Gearboxes
Bridges
cardan shafts
+ Electronics division
Electroproportional joysticks
Potentiometers
Electronic remote control panels
+ Technologies for the production of hydraulic cylinders
Equipment for the production of
stocks
Pipes
Seals
Pistons
Boxes
eyelets
+ Technologies for the production of high pressure hoses
Equipment for the production of.
Hoses
Quick connectors
Fitting
Pipeline equipment
Precision tubes
+ System for lifting bodies, dump trucks and Binotto mechanisms
Telescopic hydraulic cylinders
Hydraulic systems
Oil tanks
Hydraulic valves
End stops
Power take-offs
Gear and piston pumps
Fitting
Hoses
Pneumatic control devices
+ Services
Development of a hydraulic scheme, adjustment of an existing scheme.
Assistance in the selection of components.
Supply of a full range of hydraulic components, diesel engines, mechanical transmissions.
Assistance in preparation project documentation.
Assistance in binding, installation and adjustment of equipment. Tracking the development of prototype machines to launch in mass production.
Supply of spare parts.
Warranty and post-warranty repair.
Determination of the actual state of components and assemblies of hydraulic systems (pumps, hydraulic motors, hydraulic distributors, etc.) in laboratory conditions at stands of domestic and imported production (stand "MARUMA" Japan).
Diagnostics of hydraulic systems of machines and equipment using the latest technical means manufactured by Webtec, England. In order to prevent failures in a timely manner, options for planned repairs that require the least cost (replacement of components only if it is really necessary).
Comprehensive diagnostics of hydraulic systems of experimental or experimental samples of new equipment.
Maintenance of hydraulic systems.
Performing repairs on an aggregate basis.
Advice on issues Maintenance and repair of hydraulic systems. Efficiency in the departure of the brigade to carry out work directly at the facility within a radius of 200 km from Moscow, optimal prices and an individual approach to each client, a guaranteed system of discounts for spare parts. Works are carried out both under one-time requests and under service contracts. The work is carried out by highly qualified specialists with many years of experience, all types of work are guaranteed.
Activity type:
production
Branches:
- Production services, repair of equipment of machine-building plants
- Power Engineering
Additional contacts
Technological possibilities
Users from this enterprise
LIMITED LIABILITY COMPANY "GIDRAPAK POWER AND CONTROL SYSTEMS" 7720572519 is registered at 111123, MOSCOW CITY, 56 ENTUZIASTOV SHOSSE, STR.32. The management of the organization is carried out by the GENERAL DIRECTOR NATALIA IGOREVNA PURCHINSKAYA. In accordance with registration documents the main activity is Manufacture of hydraulic and pneumatic power equipment. The company was registered on 12/23/2006. The company has been assigned the All-Russian State Registration Number - 1067761568324. For more detailed information, you can go to the organization's card and check the counterparty for reliability.
12/23/2006 Interdistrict Inspectorate of the Federal Tax Service No. 46 for the city of Moscow registered the organization "HYDRAPACK POWER AND CONTROL SYSTEMS" LLC. On December 28, 2006, the procedure for registration with the State Institution - the Main Directorate of the Pension Fund of the Russian Federation No. 7 for Moscow and the Moscow Region was initiated municipal area Perovo, Moscow. Registered in Branch No. 38 State institution- Moscow regional branch of the Fund social insurance Russian Federation the company LLC "HYDRAPACK POWER AND CONTROL SYSTEMS" became 01/29/2018 0:00:00. In the Unified State Register of Legal Entities, the last entry about the organization has the following content: Termination legal entity(exclusion from the Unified State Register of Legal Entities of an inactive legal entity).