RU2467892C1 - Method of increasing ac electric locomotive power efficiency and quality of electric power at locomotive current collector, and device to this end - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to electric rolling stock, particularly, to voltage rectifier-inverter converters. Proposed method of different-phase control (DPC) allows rejecting using α_tr for α₀, and incorporates adaptive functions. ADPC system comprises control unit, transducer supply unit, analog-to-digital transducer unit (ADT), digital filters, unit to compute delays and unit of programmable timers, two units of switches (SU), power supply (PS), sets of control units. Unit of switches comprises set of input converters for signals traction/recovery (t/r) and synchronisation. Control unit serves to convert and filter transducer signal. Two units of switches are intended for galvanic isolation of ADPC-001 from electric locomotive circuits, amplification of signals to magnitude required for operation of "СФИ ВИП", switching of signals between I/O. It comprises input unit of matching and unit of input amplifiers. Power supply unit generates voltages required for operation of APDC system and galvanic isolation of t/r signal from locomotive circuits and decreases amplitude of voltage distortion harmonics corresponding to frequencies of there oscillations.

EFFECT: reduced post-switching voltage oscillations at current collector.

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Description

The method is intended for use on an electrically rolling stock and relates to an actuator control algorithm — a rectifier-inverter voltage converter.

The use of thyristor rectifiers in static converters of single-phase direct current electric locomotives (a different formulation of a single-phase sinusoidal current of an industrial frequency of 50 Hz) in Russia and abroad made it possible to control collector traction motors by continuously adjusting the voltage across them. This is done by changing the unlocking moments of the corresponding arms of the rectifier-inverter converter (VIP-4000) of the electric locomotive within the period of the supply voltage [1,4].

However, the operation of such electric locomotives, along with the advantages of power circuits of thyristor converters, revealed a number of their disadvantages compared to electric locomotives equipped with uncontrolled semiconductor diodes. The reliability issues of technical equipment of electric locomotives have always been relevant, and they received great attention in scientific research [1].

According to the standard algorithm of the control system of electric locomotives with smooth voltage regulation (VL80R, VL85 and other electric locomotives with thyristor converters), the current switching of all VIPs of both sections occurs simultaneously. At the beginning of switching, part of the windings of the traction transformer of each section of the electric locomotive begins to work in short circuit mode. The simultaneous start of switching of all converters causes a sharp decrease in voltage at the current collector. However, an instantaneous voltage drop does not occur, since due to the presence of distributed inductors and capacitance in the traction network, free voltage fluctuations occur (the first switching law) [4, p. 115].

A known method of controlling thyristor converters of an electric locomotive [2], using a discharge diode arm, which allows to reduce electromagnetic voltage fluctuations in the natural switching zone (switching basis). But when using this algorithm, the problem of improving the quality of voltage in the contact network was solved only when the main switching current of the thyristors of the VIP arms was flowing, and with phase regulation in each zone, free oscillations remained unchanged and could reach the voltage of the mains in amplitude.

The closest technical solution was the multi-phase control method (RFU), proposed by the staff of the All-Russian Scientific Research Institute of Railway Transport (VNIIZhT), consisting in the separation in time of the beginnings, as well as the ends of the switching of various groups of converters (8-9 electrical degrees at the angles α ₀ and α _p ). In theory, this was supposed to reduce the forced voltage jump when turning on and off each group of converters and the amplitude of free voltage fluctuations at the current collector [3].

However, in practice, the method proposed by VNIIZHT was not widely used due to the presence of significant shortcomings.

The main disadvantages of the existing method of RFU:

- different-phase control is achieved by a constant increase in the opening angle of the thyristors of the converter by 8–9 electrical degrees (both at the angles α ₀ and α _p ), and this, in turn, significantly reduces the external characteristics of the converter (VIP);

- reduction of the power factor of the electric locomotive when implementing the proposed algorithm;

- the power of the electric locomotive in the hourly and continuous mode is slightly lower than with the typical control method, there is also a slight decrease in speed;

- the constancy of the shift of the opening angle of the thyristors of the converter by 8-9 electrical degrees does not give the full effect of reducing high-frequency fluctuations in the voltage of the contact network due to changes in the inductance and capacity of the traction network (depending on the distance from the traction substation).

Known control unit of the rectifier-inverter converter (BUVIP-133) [4, p.123], containing the block frame, electronic control cassettes, clamps for connecting a diagnostic device, is designed to control VIP-4000.

However, the unit has the disadvantage associated with the simultaneous switching of the thyristor arms of all VIP-4000 electric locomotives. Thus, the switching and post-switching oscillations arising from this have a high power.

An RFU method is proposed using a discharge diode arm, which makes it possible to abandon the use of α _rfu (phase angle at RFU) in the control algorithm for α ₀ , and using an adaptive system, as well as with the combined use of the double-circuit simultaneous switching method of the shoulders of VIP thyristors (Fig. 3). It is proposed to delay the control of the shoulders of the transducer equal to the half-cycle of the natural oscillations of the voltage of the traction network.

Adaptive multi-phase control system (ARFU), which is an addition to BUVIP-133, is designed to create a phase shift (α _rff ) in the angle of regulation (α _r ), relative to two VIPs with the aim of overlapping the resulting voltage fluctuations and reducing them.

ARFU should provide the implementation of management in accordance with the presented new control algorithm (figure 4).

Functional diagram of the ARFU is shown in figure 1. The system contains the following blocks:

- a control unit (CU) containing a normalizing amplifier, a sensor power supply, an analog-to-digital converter (ADC) unit, digital filters, a delay calculation unit, and a programmable timer unit;

- two blocks of keys (BC), containing an input matching unit, a block of input amplifiers and a relay block;

- a power supply unit (PSU), blocks BU, BK, which includes a node input converters for signals thrust / recovery (t / r) and synchronization.

A schematic diagram of the connection of the ARFU to the electric locomotive circuits is shown in Fig.2.

The control unit BU is designed to convert the sensor signal, filter it, extract the maximum harmonic, calculate the delay time from the harmonic number, delay the VIP control signals for the estimated time, and also control the other nodes of the ARPU and contain a board for collecting, transmitting and processing information of the multi-phase VIP control electric locomotive (based on a microprocessor type ADuC842BS) (Fig. 1). The control unit contains the following elements:

- connector for programming FPGA configuration memory;

- a connector for communication with other ARFU units;

- a connector for connecting a voltage sensor;

- connector for communication of the unit with the computer and programming of the microprocessor;

- OP27FG-type operational amplifiers that convert current signals from the sensor to voltages, amplifying them to the level necessary for the operation of an analog-to-digital converter (ADC);

- the reference voltage source, with which the voltage from the normalizing amplifier is compared, and the ADC generates a corresponding digital code;

- a microprocessor of the type ADuC842BS, which includes an ADC, a block of software-implemented digital band-pass filters tuned to 15, 17, 19, 21, 23 harmonics of the mains voltage, a block for extracting the maximum harmonic, a computation unit that calculates shoulder switching delay times according to a given algorithm VIP depending on the harmonic number, the node for generating the relay control signal;

- A programmable logic integrated circuit (FPGA) of the XC2S30-VSQ100-6I type, containing programmable timers for generating the obtained delay time, a logic unit that controls the operation of the timers, processes the T / P and synchronization signals and generates control signals for switching the VIP arms;

- memory chip type XCF01S, providing storage of FPGA configuration firmware for the duration of a power outage;

- a chip like ADM232AARW, which is a standard RS-232 interface driver for communication with a computer and programming a microprocessor;

- microcircuit type IN74HC245D - buffer amplifiers, amplify the signals from the FPGA for transmission to the BC;

- LM217 type microcircuit - voltage stabilizer for supplying FPGAs and memory microcircuits;

- a generator that generates clock pulses of a given frequency for FPGA operation.

The operation of the BU-001 in the traction mode of an electric locomotive is as follows: when the power is turned on, the configuration is overwritten from the memory chip of the XCF01S type to the FPGA. Upon arrival of the synchronization pulse, the processor gives a signal to turn on the relay and records zero delays in the FPGA. Upon the arrival of control pulses from BUVIP, they are transmitted without delay to the output amplifiers and to the SFI VIP. At the same time, data is read from the voltage sensor and the delay of the phase angle control pulses is calculated on the corresponding arms of the VIP.

At the end of the calculation and the formation of the next synchronization pulse from the LVS-100 voltage sensor, either zero or calculated delays of the control phase angles are recorded in the timers of the control unit, depending on the number of the half-cycle. At the end of the delay time, phase control pulses are output to the output amplifiers. When collecting the recovery scheme, the corresponding signal from the electric locomotive circuits enters the control unit and switches the relay to the direct passage of signals from the BUVIP to the SFI VIP without delays (regenerative braking mode is standard).

The key block BK (2 pcs.) Is designed for galvanic isolation of the ARFU-001 from the electric locomotive circuits, amplifying the signals to the value necessary for the operation of the SFI VIP, switching the signals between the input and output and contains an input matching unit and a block of input amplifiers (Fig. 1) .

Functionally, BK-001 consists of four identical blocks of input shapers and eight blocks of output keys, it contains the following nodes:

- a connector designed for communication with other blocks of the system;

- a connector designed for communication with electric locomotive circuits;

- optocouplers of type ADuM1400AARW for galvanic isolation of output amplifiers from control units;

- galvanic isolation power source;

- optocouplers of type AOuM1400AARW for galvanic isolation of input signals from electric locomotive circuits (input shaper blocks);

- eight output amplifiers (blocks of output shapers);

- eight relays designed for direct supply of signals to the shoulders of the VIP in the event of a malfunction of the multi-phase control system and operation in the recovery mode.

The power supply unit BP is designed to generate voltages necessary for the operation of the ARFU system and galvanic isolation of the T / P signal from the electric locomotive circuits (Fig. 1).

The BP-001 block contains the following nodes:

- a connector designed for communication with other blocks of the system;

- a connector designed for communication with electric locomotive circuits;

- optocouplers of the HCPL4503 type for galvanic isolation of thrust recovery signals (T / P) and synchronization from electric locomotive circuits;

- a module of type WPN20R48SC, which is a bipolar switching power supply with an output voltage of + 15V and -15V, designed to power the analog nodes of the ARFU system;

- a module of type WPN20R48S05C, which is a switching power supply with an output voltage of + 5V, which provides power to the digital circuits of the ARFU system;

- module type WPN20R48SC, which is a bipolar switching power supply with an output voltage of + 15V and -15V, designed to power a voltage sensor of type LVS-100.

The created adaptive system of different-phase control of the VIP of an electric locomotive allows, regardless of the location of the electric locomotive on the feeder zone (changing the contact network parameters), to minimize the amplitudes of voltage-distorting harmonics corresponding to the frequencies of these oscillations, which leads to a decrease in the distortion coefficient of the sinusoidality of the voltage curve and, in general, to increase quality of electrical energy in the contact network.

In order for the external characteristic of the converter to decrease slightly, it is necessary, as in the prototype method [3], to alternate the deviations of the adjustable angle for each section in different half-periods (Fig. 4).

The work of the proposed algorithm (figure 4) is as follows.

On the 1st regulation zone:

At first TTI for the first section of the electric supply voltage to half thyristor shoulder VS3 VS6 and a pulse control α _p, a shoulder corresponding to the second pulse supplied VIP α _rrfu. At α _{0, the} delayed pulse is not supplied, because the negative voltage section closes on the discharge diode arm and this reduces the switching voltage jump [3]. In the second half-period, so that the external characteristic of the converter does not decrease, on the contrary, the control pulse α _rfu is applied to the first VIP on the thyristor arm VS4, VS5, at the same time, the pulse α _p is applied to the same VIP on the same arms (Fig. 4) .

On the 2nd regulation zone:

For the first VIP in the first half-cycle of the supply voltage, the control pulse α _{r is} applied to the thyristor arm VS1, and the pulse α _rfu is fed to the corresponding arm of the second VIP. In the second half-cycle, so that the external characteristic of the converter does not decrease, on the contrary, the control pulse α _rfp is applied to the first VIP on the thyristor arm VS2, while the pulse α _p is applied to the second VIP on the same arm (Fig. 4).

On the 3rd regulation zone:

At first VCSEL in the first half cycle of the supply voltage to the thyristor shoulder VS3 α _p supplied control pulse, and the corresponding arm of the second pulse supplied VIP α _rrfu. In the second half-period, so that the external characteristic of the converter does not decrease, on the contrary, the control pulse α _rfu is applied to the first VIP on the thyristor arm VS4, at the same time, the pulse a _p is applied to the second VIP on the same arm (Fig. 4).

On the 4th regulation zone:

For the first VIP in the first half-cycle of the supply voltage, the control pulse α _r is supplied to the thyristor arm VS1, and the pulse _rrf is supplied to the corresponding arm of the second VIP. In the second half-cycle, so that the external characteristic of the converter does not decrease, on the contrary, the control pulse α _rfp is applied to the first VIP on the thyristor arm VS2, while the pulse α _p is applied to the second VIP on the same arm (Fig. 4).

When implementing this algorithm, a double-circuit simultaneous switching method is also used (switching of large and small circuits is realized simultaneously, without the participation of the thyristor arms of the VIP of the previous voltage control zones) (Figure 3).

The proposed method for the implementation of the RFU will eliminate the above disadvantages.

The technical result when implementing the proposed method of reducing post-switching voltage fluctuations on the current collector of an electric locomotive:

- improves the quality of voltage in the contact network;

- the insulation service life of electric machines and apparatuses will be extended;

- the reliability of operation of signaling, centralization, blocking (STB) devices, continuous automatic locomotive signaling (ALSN), control systems for electric locomotive converters, relay protection, automation, communications and computer technology will increase.

Information sources

1. Tikhmenev B.N., Kuchumov V.A. Electric locomotives of alternating current with thyristor converters. - M .: Transport, 1988 .-- 311 p.

2. A method of controlling a multi-zone rectifier single-phase alternating current. Pat. No. 2322749, Ros. Federation: IPC Н02М 5/42 / №2006140957 / 09; declared 11/20/06; publ. 04/20/2008.

3. Kuchumov V. A., Nakhodkin V. V., Shirochenko N. N. Technical and economic indicators of thyristor electric locomotives of alternating current with different-phase control // Bulletin of the All-Russian Research and Design Institute of Electric Locomotive. 1987, No. 3, S.15-18.

4. Electric locomotive VL85: Operation manual / B.A. Tushkanov, N.G. Pushkarev, L.A. Pozdnyakova, etc. - Moscow: Transport, 1995. - 480 p.

Claims (2)

1. A way to increase the energy indicators of an alternating current electric locomotive and the quality of electric energy at a current collector, which is an algorithm for different-phase control of a rectifier-inverter converter of an electric locomotive in the angle α ₀ and α _p with constant time diversity of the beginning, as well as the endings of switching of various groups of converters (delay angle - α of the _{Russian Federation} ) by 8–9 electrical degrees and by alternating the delay in sections of the electric locomotive for various half-periods of voltage, characterized in that the adaptive different-phase control of the converter arms with a variable delay angle (α _rfpu ) equal to the half-cycle of natural oscillations of the traction network voltage, and only by the angle of regulation α _p , the duration of which is proposed to be _determined using an adaptive control system with the use of a control algorithm with simultaneous dual-circuit switching of shoulders rectifier-inverter converter using a diode discharge arm. 2. A device for reducing post-switching voltage fluctuations on a current collector of an electric locomotive for implementing the claimed method, comprising a block frame, electronic control cassettes, clamps for connecting a diagnostic device that controls the thyristor arms of a rectifier-inverter converter with α _r control pulses, characterized in that an additional adaptive block is installed raznofaznogo control system that provides the shift control pulses to the variable α _p value α _rrfu, depending ty from the position of the electric locomotive in the area of the feeder zone, containing the position block of the electric locomotive in the area of the feeder zone, containing a control unit (BU) containing a normalizing amplifier, a sensor power supply, an analog-to-digital converter (ADC) unit, digital filters, a delay calculation unit, and a block programmable timers, two blocks of keys (BC), containing an input matching block, a block of input amplifiers and a relay block, a power supply (BP) of blocks BU, BC, which includes a node of input converters for thrust / recovery signals (t / r) synchronization BU given algorithm performs a spectral analysis of harmonic oscillations of the mains supply, allocates harmonic with the highest amplitude, and calculates the phase change (α _rrfu) adjusting the angle (α _p) supplied to the shoulders of the inverter rectifier converter.

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