SK42018A3 - System of AC power transmission in hybrid electric vehicle - Google Patents

Abstract

The alternating power transmission circuit of a hybrid electric vehicle consists of a group of devices consisting of one internal combustion engine (1) that powers an electric generator (2) and two traction electric motors - the left traction electric motor (4) and the right traction electric motor (5). they are supplied in parallel from the AC traction converter (3). The AC traction converter (3) is powered from two sources. One source is an electric generator (2), the other source is an auxiliary traction converter (6), which is powered by the traction battery (7). Control of the whole system is provided by a control system (8) which senses the parameters of the electric generator (2), the AC traction converter (3), the left traction motor (4), the right traction motor (5), the auxiliary traction converter (6) and the traction battery ( 7) and, as required, controls the internal combustion engine (1), the ac traction converter (3) and the auxiliary traction converter (6).

Description

N E 4-2018 Α3

Technical field

It is an object of the invention to provide an alternating power transmission for a hybrid electric vehicle. The invention relates to the field of hybrid electric vehicles, i.e. the field of automotive technology, electrical engineering and power electronics.

BACKGROUND OF THE INVENTION

In principle, hybrid electric vehicles (HEVs) work with either serial or parallel transmission of traction power. In HEVs with parallel transmission of traction power, both the internal combustion engine and the electric motor operate simultaneously (in parallel) and their power is added together in the mechanical transmission of the drive axle. Most hybrid electric vehicles use a series power transmission to drive the traction motor and an AC / DC / AC power converter system with a rectifier, DC link and Voltage Source Inverter (VSI) inverters with one central motor and mechanical differential transmission. The generator serves simultaneously as a starting electric motor for the internal combustion engine. HEV vehicles with electric motor-wheels can work with mechanical or electronic differentials and power splitting. The electric motors of the drive wheels are supplied from separate inverters, which ensure the electric power distribution for the electric motors. The disadvantage of such a series HEV vehicle with an electric AC / DC / AC converter transmission is the need for a traction rectifier in this transmission chain and the associated voltage drops and its power losses, which adversely affects the overall energy efficiency of the vehicle HEV transmission. The disadvantage of HEV vehicles with an electronic differential is the necessity of using two with independent converters.

SUMMARY OF THE INVENTION

In the alternating power transmission of a hybrid electric vehicle, alternating electric power (not DC), at a frequency proportional to the speed of the electric generator, is used to transmit electric power from the electric generator to the traction motors. It does not feature a rectifier in the transmission chain, so the wiring achieves higher efficiency.

The wiring for the alternating power transmission of a hybrid electric vehicle consists of three parts. The first part consists of an internal combustion engine flexibly connected via a shaft to an electric generator. The internal combustion engine drives the electric generator to form an AC power supply that supplies power to the rest of the hybrid electric vehicle. A parallel traction converter is connected in parallel to this supply network, which supplies the traction battery with energy if necessary, or in the case of an excess of energy in this supply network, supplies it with the traction battery. The second part consists of an alternating traction converter, which generates the required voltages for parallel connected traction motors - left and right. The traction motors used must be four-phase, resp. multiphase. The use of three-phase electric motors allows only two combinations of phase connections (direct and reverse rotation). Electric motors with higher number of phases (more than 3 phases - optimal number is five phases) have more combinations of phase wiring. This allows for more advantageous mutual regulation of the speed of one engine against the other. In the case of regeneration (vehicle braking, downhill driving), the AC traction motor from the traction motors is supplied back to the mains and is subsequently accumulated in the traction battery via the auxiliary traction converter, or the internal combustion engine is braked by it.

The last part consists of a control system whose task is to read the parameters of electric generator, AC traction converter, left and right traction motor, auxiliary traction converter and traction battery and to control internal combustion engine, ac traction converter and auxiliary traction converter.

Connecting to the AC power of a hybrid electric vehicle brings many advantages over the prior art, for example:

• implemented electronic differential - the absence of a mechanical differential increases the efficiency of mechanical energy transfer and reduces the possibility of mechanical failure;

• direct transmission of AC power without changing it to DC in the rectifier, which also increases the efficiency of the whole system;

• parallel operation of the electric generator and traction battery, allowing the system to operate in different stand-alone operating modes;

• parallel connection of traction motors - only one traction converter is required.

N E 4-2018 Α3

BRIEF DESCRIPTION OF THE DRAWINGS

In FIG. 1 shows a block circuit for alternating power transmission of a hybrid electric vehicle.

DETAILED DESCRIPTION OF THE INVENTION

The alternating power transmission circuit of the hybrid electric vehicle of FIG. 1 consists of an internal combustion engine 1 and an electric generator 2 which are resiliently connected via shafts. The alternating traction converter 3 and the auxiliary traction converter 6 are connected in parallel to the electric generator 2 by means of power conductors. The traction battery 7 is connected to the auxiliary traction converter 6 by means of the power conductors. The control system 8 is connected via signal wires to the internal combustion engine 1, the electric generator 2, the alternating traction converter 3, the left traction motor 4, the right traction motor 5, the auxiliary traction converter 6 and the traction battery 7 and based on system requirements. it controls the internal combustion engine 1, the alternating traction converter 3 and the auxiliary traction converter 6.

Industrial usability

The connection to the alternating power transmission of a hybrid electric vehicle can be used in all electric vehicles (HEV - Hybrid Electric Vehicle, BEV - Battery Electric Vehicle, FEV - Fuel Cell Electric Vehicle, ...). This connection can also be used in diesel-electric locomotives, e-trucks, handling machines, etc.

N E 4-2018 Α3

List of reference marks

- Combustion engine

-electric generator

3 - AC traction converter

- left traction electric motor

- Right traction electric motor

- Auxiliary traction converter

- traction battery

8 - steering system

Claims (1)

N E 4-2018 Α3 PATENT CLAIMS Circuit for alternating power transmission of a hybrid electric vehicle consisting of an internal combustion engine (1), an electric generator (2), an ac traction converter (3), a left traction electric motor 5 (4), a right traction electric motor (5), an auxiliary traction converter (6) , a traction battery (7) and a control system (8), characterized in that the internal combustion engine shaft (1) is resiliently coupled to the shaft of the electric generator (2), further comprising an AC traction converter (3) and an auxiliary traction converter (6) are connected in parallel to power generators (2) by means of power conductors, the auxiliary traction converter (6) being connected to the traction battery (7) by means of power conductors, furthermore that the left traction motor 10 (4) and the right traction motor (5) are by means of power conductors connected in parallel to the AC traction converter (3), further that the control system (8) is connected by means of signal conductors to an internal combustion engine (1), an electric generator (2), an AC traction converter (3), a left traction electric motor (4), a right traction electric motor (5), an auxiliary traction converter (6) and a traction battery (7).