JPH07102990A - Exhaust energy recovery device - Google Patents

Abstract

PURPOSE:To dispense with a DC-DC converter, reduce a cost, and energy loss by providing a controller which so controls an inverter that the generating voltage of a rotary electric machine and a turbine generator are substantially a battery voltage. CONSTITUTION:A rotary electric machine 11 is arranged on a turbocharger 7 and driven as a generator or a motor. A turbine generator 16 of an inductor is driven by exhaust gas. A first flat circuit 36 is connected to a dc side of a first inverter 19. A second flat circuit 37 is connected to a dc side of a second inverter 33. A circuit switcher 38 is provided for switching the connection between the first and second flat circuits 36, 37 and a battery 29. A controller 30 so controls the first and second inverters 19, 33 that generation voltages of the rotary electric machine 11 and the turbine generator 16 are substantially a battery voltage. Operation of the circuit switcher 38 is controlled. It is thus possible to dispense with a voltage converter for raising and lowering the voltage so as to reduce a cost, and reduce energy loss.

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 system for recovering exhaust energy by providing a plurality of generators in the exhaust system of an engine.

[0002]

2. Description of the Related Art In recent years, an adiabatic engine has been developed in which ceramics are used for various parts of the engine, such as the outer wall of the exhaust manifold, the cylinder liner, the heat insulating plate for the cylinder head, and the piston. In this engine, since it is not necessary to dissipate the heat generated inside to cool the engine, the exhaust gas has a high temperature and has a large amount of energy. Since it is unavoidable to release this to the atmosphere as it is, it is proposed to collect it while flowing through the exhaust pipe.

As a conventionally proposed recovery device, in addition to a turbocharger with a rotating electric machine in which a rotating electric machine that can also be used as a generator and a motor is attached to the rotating shaft of the turbocharger, a turbine as a prime mover is driven by exhaust gas. There is a device equipped with a turbine generator. A synchronous machine is used for both the rotating electric machine and the turbine generator.

Even if the high-temperature exhaust gas passes through the turbocharger with a rotating electric machine, it still has a large amount of energy, so that the turbine generator can be sufficiently driven. Therefore, power generation is performed not only by the rotary electric machine of the turbocharger with a rotary electric machine but also by the turbine generator. The electric power recovered by the power generation is used not only for charging the battery and supplying power to the vehicle load, but also for arranging a motor (assist motor) in which torque is transmitted to the crankshaft or vehicle drive shaft of the vehicle. ) Is used to drive.

FIG. 2 is a diagram showing a conventional exhaust energy recovery system as described above. In FIG. 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 rotating electric machine, 8 is a compressor blade, 9 is a turbine blade, 10 is a rotation sensor, 11
Is a rotating electric machine, 12 is a rotor, 13 is a stator winding, 14 is a turbine blade, 15 is a rotation sensor, 16 is a turbine generator, 17 is a rotor, 18 is a stator winding, 19 is an inverter, and 20 is Rectifying and smoothing circuits 21, 22 are DC-DC
Converter, 23 smoothing circuit, 24 regulator, 25 inverter, 26 motor, 27 crankshaft, 28 regulator, 29 battery, 30 controller,
Reference numeral 31 is an accelerator opening sensor, and 32 is a boost pressure sensor.

The motor 26 is for giving a torque for assisting the rotation of the crankshaft 27 when the engine load is large. A synchronous machine is also used as the motor 26. As the motor drive voltage, a voltage obtained by boosting the battery voltage by the DC-DC conversion unit 22 and converting it to AC by the inverter 25 is used. If the electric power recovered from the exhaust energy is used to drive the motor 26,
The exhaust energy is utilized in the form of torque that assists the rotation of the crankshaft 27.

The stator winding 13 of the rotating electric machine 11 is connected to the inverter 19, and the DC side of the inverter 19 is D
It is connected to the battery 29 via the C-DC converter 21, and is also connected to the battery 29 via the smoothing circuit 23 and the regulator 24. The path of the DC-DC converter 21 is
This is the case when electric power is sent from the battery 29 or the like to the rotary electric machine 11, and the path of the regulator 24 is that when electric power generated by the rotary electric machine 11 is sent to the battery 29.

Also, the stator winding 1 of the turbine generator 16
8 is connected to the battery 29 via the rectifying / smoothing circuit 20 and the regulator 28. The low voltage side of the DC-DC converter 22 (the side that is not the inverter 25 side) is connected to the battery 29. A well-known structure is used as each DC-DC converter.

The controller 30 detects signals from various sensors, for example, a rotation speed detection signal, a boost pressure detection signal,
With reference to the accelerator opening detection signal, etc., the inverter 1
9, DC-DC converters 21, 22, regulator 24,
28 etc. are controlled. For example, the boost pressure detected by the boost pressure sensor 32 is checked to determine whether or not the rotary electric machine 11 needs to be driven by a motor, and if there is, the DC-DC converter 21 and the inverter 19 are controlled. The detection signal of the accelerator opening sensor 31 reflects the driver's intention to accelerate or not, and accordingly, the rotating electric machine 11 is driven by a motor or a generator.

The regulator 2 of the controller 30
The control for 4, 28 is control for operating them or stopping them, and not for controlling the voltage to the value of the battery voltage.

FIG. 3 is a diagram showing a configuration example of the inverter. This configuration is known, and D is a diode and S
Is a switching element. For example, a transistor is used as the switching element S. Diode D
Are connected in antiparallel to the switching element S. This plays a role of providing a path through which the flywheel current that must be processed when the switching element S performs the switching operation is provided. In this example, six sets of antiparallel connection units of the switching element S and the diode D are used to obtain a three-phase alternating current. The switching control of each switching element S is
It is performed by the controller 30.

When the exhaust gas of the engine 1 flows through the exhaust pipe 6 in the exhaust energy recovery system having the above-mentioned structure, the turbine blades 9 and 14 are rotated, and the rotors 12 and 17 are rotated. Turbine generator 1
6 literally operates only as a generator. Rotating electric machine 1
1 is operated as a generator or a motor according to the condition of the engine 1 (in other words, the condition of the vehicle in which the engine 1 is mounted). For example,
In a situation where the boost pressure is large enough and it is not necessary to supercharge any more, it is operated as a generator. In the situation where the boost pressure is insufficient, it is operated as a motor. Next, the above operation will be described in more detail.

The generated voltage induced in the stator winding 18 of the turbine generator 16 passes through the rectifying / smoothing circuit 20 and is then controlled by the regulator 28 to have a voltage suitable for charging the battery 29. It is used for charging, supplying power to a vehicle load (not shown), or driving the motor 26.

When the rotary electric machine 11 is operated as a generator, a DC-command is issued by the controller 30.
The operation of the DC converter 21 is stopped (that is, off). The generated voltage induced in the stator winding 13 is the inverter 19
The voltage is rectified by a rectifying element (D in FIG. 3) built in, and is controlled to a voltage suitable for charging the battery 29 via the smoothing circuit 23 and the regulator 24. This voltage is also the same as the voltage from the regulator 28.
Used to charge the 9.

When it is desired to operate the rotating electric machine 11 as a motor, the regulator 2 is instructed by the controller 30.
4 is turned off. The voltage from the battery 29 (and the voltage from the regulator 28 if the voltage from the regulator 28 has risen to the battery voltage) is boosted by the DC-DC converter 21 and converted into an AC voltage by the inverter 19. It is applied to the rotating electric machine 11. A control signal for boosting operation is given from the controller 30.

Incidentally, as a conventional document relating to this type of exhaust energy recovery system, there is, for example, Japanese Patent Laid-Open No. 62-284923.

[0017]

However, in the conventional exhaust energy recovery system described above, the rotary electric machine 11,
Since a synchronous machine is used as the turbine generator 16, D
There are problems that a large number of voltage conversion units such as a C-DC conversion unit and a regulator are required, the cost becomes high, and energy is lost there.

(Explanation of Problems) As is well known, in a synchronous machine, the generated voltage (motor drive voltage in the case of motor operation) that is induced increases as the rotational speed increases.
Therefore, a voltage converter such as a regulator or a DC-DC converter is required to reduce the generated voltage to the battery voltage or to raise the battery voltage to the required motor drive voltage.

However, if these voltage conversion units are provided,
As a matter of course, this leads to an increase in cost and some energy is lost there. For example, DC-DC
Since the energy conversion efficiency of the converter is 70 to 80%, an energy loss of about 20 to 30% occurs. An object of the present invention is to solve the above problems.

[0020]

In order to solve the above-mentioned problems, in the exhaust energy recovery system of the present invention, a rotary electric machine of an induction machine mounted on a turbocharger and operated as a generator or a motor, and driven by exhaust gas. A turbine generator of an induction machine, a first inverter connected to the rotating electric machine, a first excitation power supply unit and a first smoothing circuit sequentially connected to the DC side of the first inverter,
A second inverter connected to the turbine generator;
A second excitation power source section and a second smoothing circuit that are sequentially connected to the DC side of the second inverter; and a circuit switching section that switches at least the connection between the first and second smoothing circuits and the battery. A controller that controls the switching of the circuit switching unit while controlling the first and second inverters so that the generated voltage of the rotating electric machine and the turbine generator is excited to become a substantially battery voltage. did.

[0021]

[Operation] Synchronous machines have been conventionally used for rotary electric machines that are attached to turbochargers and operate as generators or motors, and for turbine generators that are driven by exhaust gas. Use an induction machine.
Then, the magnitude of the generated voltage is set to a value substantially equal to the battery voltage by controlling the exciting power supply with the inverter. Therefore, it is not necessary to step down the generated voltage to charge the battery.

Further, since the rotating electric machine uses an induction machine, when the motor is operated, it is not necessary to increase the motor drive voltage even if the number of rotations increases. Therefore,
There is no need to boost the battery voltage. As described above, since it is not necessary to provide the voltage conversion unit, it is possible to avoid cost increase and energy loss due to the provision of the voltage conversion unit.

[0023]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a diagram showing an exhaust energy recovery system of the present invention. Reference numerals correspond to those of FIG. 2, 33 is an inverter, 34 and 35 are excitation power supply units, 36 and 37 are smoothing circuits, 38 is a circuit switching unit, and 39 is an excitation power supply unit. Since the same reference numerals as those in FIG. 2 operate in the same manner as in the conventional case,
The description is omitted.

FIG. 4 is a diagram showing a connection relationship between the induction machine, the inverter, and the excitation power source section in FIG.
1, the inverter 19, and the excitation power supply 34 are drawn as examples (the same applies to the turbine generator 16 and the motor 26). The excitation power supply unit 34 includes the excitation power supply 34-1.
And a reverse current blocking diode 34-2.
The excitation power source 34-1 can be obtained by using the battery 29. The AC side of the inverter 19 is connected to the stator winding of the induction machine.

In the present invention, the rotating machine used (rotary electric machine 1
1, an induction machine is used as the turbine generator 16 and the motor 26). When the induction machine is operating as a generator, the generated voltage does not increase even if the rotation speed increases (in the conventional example of FIG. 2, since the synchronous machine is used, the rotation speed increases). Then the power generation voltage was also large).
The power generation voltage of the induction machine 11 (IM ... Induction Machine) is controlled by controlling the voltage from the excitation power supply unit 34 by the inverter 19. Similarly, when the generator operates as a motor, a large motor speed does not require a large motor drive voltage.

Therefore, in the present invention, by controlling the exciting current, the generated voltage is set to be approximately the value of the battery voltage. In this way, the voltage conversion unit for boosting the battery voltage to a high voltage or for dropping the battery voltage from the high voltage to the battery voltage becomes unnecessary. Therefore, the cost will be lower,
Energy loss is reduced.

The circuit switching unit 38 is composed of a plurality of switches, and switches the circuit connection in response to a signal from the controller 30. For example, when the battery 29 is to be charged with the generated voltage of the turbine generator 16, the smoothing circuit 37
And the battery 29 are connected. In addition, the rotating electric machine 11
When the motor is driven by the generated voltage of the turbine generator 16 and the battery 29, the smoothing circuit 37 and the battery 29
Are connected to the smoothing circuit 36. When the motor 26 is driven by the battery 29, the battery 29 and the inverter 2
And 5 are connected.

Next, the operation of the exhaust energy recovery system having the above structure will be described. Since the turbine generator 16 only performs a power generation operation, the rotating electric machine 11 will be described separately for the case of the power generation operation and the case of the motor operation.

First, the case where the rotary electric machine 11 also performs a power generation operation will be described. The generated voltages of the rotating electric machine 11 and the turbine generator 16 are rectified by the rectifying elements (D in FIG. 3) of the inverters 19 and 33, and smoothed by the smoothing circuits 36 and 37. Since the generated voltage is set to approximately the battery voltage by the exciting current from the exciting power supply units 34 and 35, the output voltage of the smoothing circuits 36 and 37 is approximately the battery voltage. When the motor 26 is not driven, the circuit switching unit 38 connects the smoothing circuits 36 and 37 to the battery 29 according to a command from the controller 30. When driving the motor 26,
It is connected to the battery 29 and also to the inverter 25.

Next, a case where the rotary electric machine 11 is operated by a motor will be described. The power source at this time is the battery 29 and the turbine generator 16. The battery 29, the smoothing circuit 37, and the smoothing circuit 36 are connected by a command from the controller 30. The motor drive voltage is applied to the rotary electric machine 11 via the inverter 19. Since the rotating electric machine 11 uses an induction machine, a large voltage does not require a large voltage even if the number of rotations becomes large.

When the motor 26 is driven, the voltage of the battery 29 or the generated voltage of the rotary electric machine 11 or the turbine generator 16 is supplied to the inverter 25 via the circuit switching unit 38. When the vehicle runs with the engine brake applied, the motor 26 is rotated by the rotational force of the crankshaft 27. Therefore, it is also possible to use it as a driving force for power generation operation. To do so, it is necessary to connect a smoothing circuit to the DC side of the inverter 25. The generated power is used to charge the battery 29 via the circuit switching unit 38.

[0032]

As described above, according to the present invention, an induction machine, not a synchronous machine, is used as a rotary electric machine or a turbine generator used in an exhaust energy recovery system, and its excitation voltage is controlled by controlling its excitation. The size should be approximately the battery voltage. Therefore, the voltage conversion unit for stepping down or boosting the voltage is not required, and the cost can be reduced and the energy loss can be reduced.

[Brief description of drawings]

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

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

FIG. 3 is a diagram showing a configuration example of an inverter.

FIG. 4 is a diagram showing a connection relationship between the induction machine, the inverter, and the excitation power supply section in FIG. 1.

[Explanation 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 ... Turbine blade, 15 ... Rotation sensor, 16
… Turbine generator, 17… Rotor, 18… Stator winding,
19 ... Inverter, 20 ... Rectification smoothing circuit 21, 22, ...
DC-DC converter, 23 ... Smoothing circuit, 24 ... Regulator, 25 ... Inverter, 26 ... Motor, 27 ... Crankshaft, 28 ... Regulator, 29 ... Battery, 30 ... Controller, 31 ... Accelerator opening sensor, 32 ... Boost Pressure sensor, 33 ... Inverter, 34, 35 ... Excitation power supply section, 36, 37 ... Smoothing circuit, 38 ... Circuit switching section, 39 ...
Excitation power supply

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication H02J 1/00 306 A 7509-5G H02K 23/52 7706-5H

Claims (1)

[Claims] 1. A rotary electric machine of an induction machine mounted on a turbocharger and operated as a generator or a motor, a turbine generator of an induction machine driven by exhaust gas, and a first inverter connected to the rotary electric machine. A first excitation power supply unit and a first smoothing circuit sequentially connected to the direct current side of the first inverter, a second inverter connected to the turbine generator, and a direct current of the second inverter. Second excitation power source section and a second smoothing circuit sequentially connected to the side, a circuit switching section that switches connection between at least the first and second smoothing circuits and the battery, the rotating electric machine and turbine power generation. And a controller for controlling the switching of the circuit switching unit while controlling the first and second inverters so that the power generation voltage of the machine is approximately the battery voltage. And an exhaust energy recovery device.