JP3166450B2 - Exhaust energy recovery device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust energy recovery apparatus for recovering exhaust energy by a rotating electric machine mounted on a turbocharger.

[0002]

2. Description of the Related Art An engine turbocharger is rotated at high speed by exhaust gas. A rotating electric machine which can be used as a generator and a motor is mounted on this rotating shaft, boost pressure is increased when the motor is operating, and exhaust is increased when the generator is operating. Exhaust energy recovery devices that recover energy are known.

FIG. 2 shows such an exhaust energy recovery apparatus. 2, 1 is an engine, 2 is an intake manifold, 3 is an exhaust manifold, 4 is an engine rotation sensor, 5 is an intake pipe, 6 is an exhaust pipe, 7 is a turbocharger with a rotating electric machine, 8 is a compressor blade, and 9 is a turbine. Blade 10, a rotation sensor, 11 a rotating electric machine, 12 a rotor, 13 a stator winding, 14 an inverter, 15 a DC-DC converter, 16 a battery, 17 a smoothing circuit, 18 a regulator, 19 Is the controller,
Reference numeral 20 denotes an accelerator opening sensor, and reference numeral 21 denotes a boost pressure sensor.

The stator winding 13 of the rotating electric machine 11 is connected to a battery 16 via an inverter 14 and a DC-DC converter 15. The DC side of the inverter 14 is connected to the battery 16 through the smoothing circuit 17 and the regulator 18.
Is connected to The DC-DC converter 15 is provided to boost the voltage of the battery 16 and send it to the inverter 14 when the rotating electric machine 11 is operated as a motor.
The smoothing circuit 17 and the regulator 18 are provided to smooth the generated voltage rectified by the inverter 14 and reduce the voltage to the battery voltage when the rotating electric machine 11 operates as a generator.

The controller 19 receives detection signals from various sensors, for example, a rotation speed detection signal, a boost pressure detection signal,
While referring to the accelerator opening detection signal, etc., the inverter 1
4, to control the DC-DC converter 15, the regulator 18, and the like. The controller 19 controls the regulator 18 to operate the regulator 18 or stop the operation, but not to control the voltage to the value of the battery voltage. The regulator 18 is operated when the rotating electric machine 11 operates as a generator, and is stopped when operating the motor.

The rotating electric machine 11 is operated as a generator or a motor depending on the condition of the engine 1 (in other words, the condition of a vehicle in which the engine is mounted). In situations where the boost pressure is large enough that no further supercharging is required, it is operated as a generator. When the boost pressure is insufficient, the motor is operated as a motor. The boost pressure is detected by the boost pressure sensor 25.

FIG. 6 shows an inverter used in the conventional example.
FIG. 3 is a diagram showing an example of the configuration. In FIG.
Switching unit, D_FIs flywheel
Do, D _AIs an additional diode, and S is a switching element.
You. As the switching element S, for example, a MOSFET
(A field effect transistor) is used. Fly Hoi
Diode D_FIs inverse to the switching element S
They are connected in parallel. This is because the switching element S
Flags that must be processed during switching operation
It is intended to provide a path for passing wheel current.
You.

Normally, a commercially available inverter in which the switching element S and the flywheel diode _DF are connected in anti-parallel is one switching unit 14-.
1 is formed. In this example, six sets of switching units 14-1 are used to obtain three-phase alternating current. The switching control of each switching element S is performed by the controller 19.

The flywheel diode D _F is originally
Since this is for flowing the flywheel current of the switching element S, it is made to have a current capacity enough to flow the flywheel current. The flywheel current is only about half or one third of the switching current of the switching element S.

[0010] However, the power generation current of the rotary electric machine 11, since it becomes larger than the flywheel current of the switching element S is often, attempts rectifies the generated current by utilizing a flywheel diode D _F of the inverter 14 Then, the current capacity becomes insufficient. Therefore, in order to make up for it, in parallel to the switching unit 14-1 it has been made to separately connect the additional diode D _A.

When the rotating electric machine 11 is operated as a generator, the generated voltage induced in the stator winding 13 is:
It is rectified by a diode built in the inverter 14 and smoothed by a smoothing circuit 17. Then, the voltage is lowered to a voltage suitable for charging the battery 16 by the regulator 18, and is used to charge the battery 16 and supply power to a vehicle load (not shown).

When it is desired to operate the rotating electric machine 11 as a motor, the voltage of the battery 16 is
, And is converted into an AC voltage by the inverter 14 and applied to the rotating electric machine 11. Note that a control signal for the boosting operation is provided from the controller 19.

As a conventional document relating to this type of exhaust energy recovery apparatus, there is, for example, JP-A-62-284923.

[0014]

However, in the conventional exhaust energy recovery apparatus described above, an additional diode must be mounted on the inverter in order to compensate for the shortage of current capacity during rectification. In addition, there is a problem that the inverter cannot be made compact because of the space for the installation. An object of the present invention is to solve such a problem.

[0015]

According to the present invention, there is provided a rotating electric machine which is mounted on a turbocharger and which is operated as a generator or a motor, and which supplies a DC voltage to the motor when the rotating electric machine is operated. An exhaust energy recovery device comprising: an inverter that converts the driving voltage to a driving voltage and rectifies the generated voltage when the generator is operated; and a regulator that controls the generated voltage from the rotating electric machine to a battery voltage and charges the battery during power generation. A switching element of the switching unit which is a component of the inverter, a bidirectional conduction switching element, and a power generation switching control for generating a switching signal for conducting the switching element together with a flywheel diode attached thereto when the generator is operating. Part was provided.

[0016]

[Operation] In an exhaust energy recovery system, an inverter is used to operate a rotating electric machine attached to a turbocharger with a motor or to rectify a generated voltage. A switching element used in a switching unit of the inverter is used. It is a bidirectional conduction switching element. When the generator is operated, when the flywheel diode paired with the switching element conducts, the switching element also turns on. As a result, the current that can flow during rectification increases, so that it is not necessary to add a diode to increase the capacity of the rectification current.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing an exhaust energy recovery device of the present invention. The reference numerals correspond to those in FIG. 2 operate in the same manner as in the prior art.
The description is omitted. The drawing is different from FIG. 2 in that a signal line for leading a voltage detection signal is connected to the controller 19 from each line on the AC side of the inverter 14. FIG. 4 is a diagram showing an inverter used in the present invention. The reference numerals correspond to those in FIG.

[0018] Conventional Example and first point of difference is that the so inverter 14 does not install additional diode D _A. The second point is that an element capable of conducting bidirectionally is used as the switching element S of the inverter 14, and bidirectional switching is performed (in the conventional example, an element capable of conducting bidirectionally is used. Even if the inverter is used, the current flows only in one direction by switching.)

FIG. 4 shows an inverter used in the present invention. The reference numerals correspond to FIG. This inverter is constructed using only the switching unit 14-1, expansion diode D _A is not connected. And
When the switching element S is turned on, the bidirectional conduction switching element (eg, M) capable of flowing current in either direction according to the polarity of the voltage applied to both ends.
OSFET).

In order to increase the boost pressure, the rotating electric machine 1
When the motor 1 is operated by a motor, a normal inverter control is performed, and a direct current is converted into an alternating current and supplied to the rotating electric machine 11.
During the inverter control, the polarity of the voltage applied to both ends of the switching unit 14-1 when the switching element S is turned on is opposite to the polarity of the flywheel diode _DF . The flywheel diode _DF provides a path for flowing a flywheel current.

When the rotating electric machine 11 is operated as a generator, when the forward voltage is applied to the flywheel diode _DF , the switching element S in the same switching unit 14-1 is controlled to be turned on. Therefore, the switching element S also flows a current in the same direction as the current flowing through the flywheel diode _DF . That is, since current flows in both directions in the same direction, it is as if the current capacity of the flywheel diode _DF is increased, and rectification of a large current can be performed.

FIG. 5 is a diagram showing the relationship between the generated voltage and the switching signal. FIG. 5A shows an inter-phase voltage of one of the three-phase generated voltages, and FIG. 5B shows a switching signal for the switching element S to be turned on when it has a positive polarity. (C) shows a switching signal for the switching element S to be turned on when it has a negative polarity. Such a switching signal is output from the controller 23, and its generation will be described with reference to FIG.

FIG. 3 is a diagram showing the power generation-time switching control unit 22. This is a portion that generates a switching signal during operation of the generator, and is configured in the controller 23. The inter-phase voltage generation unit 22-1 generates an inter-phase voltage based on the U-phase, V-phase, and W-phase voltages detected and guided from the stator winding 13 of the rotating electric machine 11. The diode applied voltage polarity determination unit 22-2 determines whether the polarity of the applied voltage to the flywheel diode _DF of the inverter is based on the inter-phase voltage,
Determine whether it is positive or negative. When the applied polarity is positive, the switching signal generator 22-3 generates an ON signal for the switching element S in the switching unit 14-1 that is the same as the flywheel diode _DF .

[0024]

As described above, according to the present invention, when the rotating electric machine is operated by the generator, the switching element of the inverter is turned on when the corresponding flywheel diode is turned on, and the rectified current is reduced. Therefore, it is no longer necessary to attach an additional diode which has been attached in the conventional example. Therefore, troublesome mounting work is not required, and it is not necessary to secure a space to be occupied by the additional diode, so that the inverter can be made compact.

[Brief description of the drawings]

FIG. 1 is a diagram showing an exhaust energy recovery device of the present invention.

FIG. 2 is a diagram showing a conventional exhaust energy recovery device.

FIG. 3 is a diagram showing a switching controller during power generation.

FIG. 4 is a diagram showing an inverter used in the present invention.

FIG. 5 is a diagram showing a relationship between a generated voltage and a switching signal.

FIG. 6 is a diagram showing an inverter used in a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Intake manifold, 3 ... Exhaust manifold, 4 ... Engine rotation sensor, 5 ... Intake pipe, 6 ... Exhaust pipe, 7 ... Turbocharger with rotary electric machine, 8 ... Compressor blade, 9 ... Turbine blade, 10 ... Rotation sensor, 11: rotating electric machine, 12: rotor, 13: stator winding, 14: inverter, 15: DC-DC converter, 16
... Battery, 17 ... Smoothing circuit, 18 ... Regulator, 1
9 ... controller, 20 ... accelerator opening sensor, 21 ...
Boost pressure sensor, 22: power generation switching control unit,
22-1: Correlation voltage generator, 22-2: Diode applied voltage polarity determiner, 22-3: Switching signal generator,
D _F ... flywheel diode, D _A ... additional diodes, S ... switching element

Claims (1)

(57) [Claims] 1. A rotating electric machine attached to a turbocharger and operated as a generator or a motor, a DC voltage is converted into a motor driving voltage when the rotating electric machine is operated by a motor, and the generated voltage is converted when the generator is operated by the motor. In an exhaust energy recovery device including a rectifying inverter and a regulator that controls a generated voltage from the rotating electric machine to a battery voltage during power generation and charges the battery, both a switching element of a switching unit that is a component of the inverter is used. An exhaust energy recovery apparatus, comprising: a forward conduction switching element; and a power generation switching control unit for generating a switching signal for conducting when the generator is in operation together with a flywheel diode attached to the switching element.