JPH08308291A - Inverter controlling method for energy recovering apparatus - Google Patents

Abstract

PURPOSE: To easily control the low rotation region of a motor which has been difficult by a PAM control by conducting the PWM control if the generated voltage of a generator is sufficiently higher than the driving voltage of an engine or conducting the PAM control if the difference is small. CONSTITUTION: The gas exhausted from an exhaust manifold 4 is supplied to a turbine 5 to rotate the turbine 5. Thus, a compressor 7 and a motor generator 6 provided at the coaxial shaft 8 are rotated by the turbine 5. The generated power is converted to DC power by an inverter 11, a battery 10 is charged, while three-phase AC power is output to drive an alternator 3 as a motor. The air sucked from an air cleaner 13 is supercharged by a compressor 7, and supplied to an engine 1 via a suction manifold 9. When the quantity and pressure of the gas exhausted from the manifold 4 are lowered, the three-phase AC power is supplied from the battery 10 to the generator 6 via a controller 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an inverter of an energy recovery system for an automobile equipped with two motor / generators.

[0002]

2. Description of the Related Art A system has been proposed in which an exhaust pipe of an automobile engine is provided with a turbocharger with a motor / generator to effectively recover the energy of exhaust gas from the engine. In Japanese Patent Laid-Open No. 4-276132 (hereinafter referred to as a prior art), in the above system, when the electric motor / generator operates as an electric motor, a generator provided in the engine and driven by a belt by the engine (hereinafter,
It is called an alternator. ), PWM control or PAM control is performed by the inverter to convert DC to three-phase AC, and the motor / generator is driven as an electric motor.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The above-mentioned prior art discloses a PW as a control method for an inverter when converting the power generated by the alternator into three-phase AC power.
M control or PAM control is used. However, P
In the WM control, switching loss occurs due to the carrier frequency, and in the PAM control, it is difficult to drive the alternator at a low rotation speed due to the influence of the generated voltage. In addition, there is a problem that a DC-DC converter capable of stepping down the voltage is required and the cost becomes high.

[0004]

In order to solve the above problems, the present invention provides an energy recovery system having a generator and an electric motor, in which the generated voltage of the generator is sufficiently higher than the drive voltage of the driven electric motor. Performs PWM control,
There is provided a method for controlling an inverter of an energy recovery system, wherein PAM control is performed when a difference between a generated voltage of a generator and a drive voltage of a driven motor is small.

[0005]

According to the present invention, with the above configuration, the control of the inverter of the electric motor can be shifted from the PAM control to the PWM control and from the PWM control to the PAM control, which is difficult in the PAM control. It is easy to control the low rotation range of the electric motor.

[0006]

EXAMPLE Next, an example of the present invention will be described in detail with reference to FIG. In FIG. 1, an engine 1 is provided with an alternator 3 driven via a belt 2 that transmits the driving force of the engine 1. A turbine 5 is connected to an exhaust manifold 4 of the engine 1, and a compressor 7 is provided coaxially with a shaft 8 of the turbine 5. A motor / generator 6 is provided on the shaft 8 between the turbine 5 and the compressor 7. Reference numeral 9 is an intake manifold connected to the compressor 7. The electric current generated by the alternator 3 is connected so as to charge the battery 10. The alternator 3 is a three-phase AC machine and operates as an electric motor when three-phase AC power is applied from the outside. When the motor / generator 6 is operating as a motor, the controller 11 converts the DC power of the battery 10 into three-phase AC power and supplies power to the motor / generator 6, and when the motor / generator 6 is operating as a generator. Is an inverter control device that converts the power generated by the motor / generator 6 into DC power, charges the battery 10, and supplies three-phase AC power that drives the alternator 3 as a motor. Although not shown, an engine rotation detection sensor, an accelerator opening detection sensor, and a boost pressure detection sensor are provided, and each is electrically connected to the control device 11. 12 is a silencer and 13 is an air cleaner.

First, the basic operation of the embodiment of the present invention will be described with reference to FIG. The exhaust gas exhausted from the exhaust manifold 4 is supplied to the turbine 5 and the turbine 5 rotates.
As a result, the compressor 7 and the motor / generator 6 provided on the coaxial 8 also rotate, and the electric power generated by the motor / generator 6 is converted into DC power by the inverter 11.
While the battery 10 is being charged, three-phase AC power is output and becomes power for driving the alternator 3 as an electric motor. Further, the air taken in from the air cleaner 13 is supercharged by the compressor 7 and is supplied to the engine 1 via the intake manifold 9. When the amount and pressure of the exhaust gas exhausted from the exhaust manifold 4 decrease and the rotation of the turbine 5 becomes insufficient, three-phase AC power is generated from the battery 10 via the control device 11 to generate electric power. The electric motor / generator 6 is supplied to the machine 6 to operate as an electric motor to rotate the compressor 7 and supercharge the intake air.

Next, FIG. 2 shows a block diagram of the inverter 11 of this embodiment, and FIG. 3 shows the input and output waveforms of the inverter 11 for explaining the operation of the inverter 11 of this embodiment. Show. Further, FIG. 4 shows a detailed block diagram of the inverter 11 of the present embodiment. The operation of this embodiment will be described below with reference to these drawings. 2 and 4, in FIG.
The same numbers are attached to those common to. Motor / generator 6
Is operating in electric motor mode, the inverter
The converter 14 is controlled by the control circuit 18 so as to perform three-phase full-wave rectification or step-up power generation. Specifically, in the three-phase full-wave rectification, a signal is sent from the control circuit 18 so that all the transistors of the inverter / converter 14 shown in FIG. The three-phase full-wave rectification circuit is formed by the diode. In step-up power generation, the three upper-arm transistors in the transistor of FIG. 4 are turned off, and the lower-arm three transistors are switched so that booster power generation is performed with the armature reactor of the generator. To be done. The electric power generated by the alternator 3 which has been full-wave rectified or boosted by the inverter / converter 14 is smoothed by the smoothing circuit 15 and applied to the battery 10 through the insulation type voltage regulator 17. It On the other hand, the output of the smoothing circuit 15 is converted into a three-phase AC power by the inverter converter 16 and applied to the alternator 3. Inverter / converter 1
6 is controlled by the control circuit 18 as an inverter. That is, the transistors of the inverter / converter 16 in FIG. 4 are PWM or PAM controlled to convert DC power into three-phase AC power. The current sensor 19 is a sensor for feedback control with respect to a current target value, which will be described later, detects the current of the smoothing circuit 15, and a signal corresponding to the current value is input to the control device 18. The voltage dividing circuit 20 divides the voltage of the smoothing circuit 15 to divide the voltage into the control device 18.
This signal is used for voltage feedback. In addition, a signal for detecting the phase of each of the three phases is input to the control circuit 18 from the three-phase output lines of the inverter / converters 14, 16.

The operating modes of the inverter converters 14 and 16 are set as follows. 1) When the alternator voltage is higher than the motor / generator voltage, the inverter / converter 14 rectifies,
The converter 16 is PWM controlled. 2) When the alternator voltage is lower than the motor / generator voltage, the inverter / converter 14 boosts the power generation and the inverter.
The converter 16 is controlled by PAM. 3) When the alternator voltage is substantially equal to the motor / generator voltage, the inverter / converter 14 is rectified, and the inverter / converter 16 is PAM controlled. Here, when the control is shifted from the above 1) to 2), as shown in FIG.
As shown in, the ON / OFF duty ratio of each pulse of PWM control is set to 100%, so that the transition from PWM to PAM control can be performed smoothly. On the contrary, the transition from 2) to 1) is performed with the duty ratio reduced from 100%, so that the transition is smooth.

The operation of the inverter converter 16 will be described with reference to the control block diagram of the inverter converter shown in FIG. 25 is an operation control diagram showing the operation of duty control, and a to f show control elements. Now, if the motor / generator 6 is driven by an electric motor,
An instruction of the drive current is issued, and the difference between the instruction value and the actual current detected by the current detector 26 is obtained (a in 25),
The current deviation is amplified (25b). Next, the amplified current deviation is compared with the reference voltage by the comparator (25 c) which is feedback controlled by the signal of the voltage detector 27, and a duty wave corresponding to the magnitude of the current deviation is generated. Is generated. Here, the signal of the voltage detector 27 has a duty of 100 when the voltage of the smoothing circuit 15 is lower than the set value.
Change the reference voltage so that it becomes%. That is, PWM
Control switches from control to PAM control. In addition, PAM
The voltage control during control is performed by boosting the alternator 3 to generate electric power. Next, the signal in which the duty ratio is set and the signal of the current detector 26 are differentiated and integrated (25
E, f) of the triangular wave signal generated by the subtracter (25
Is applied to the gate array 18 for PWM control, and a signal of 6 steps is generated.
This 6-step signal is applied to each phase excitation circuit 29 to generate a 3-phase 6-step signal. The output signal is output to the inverter converter 16. Each phase excitation circuit 29 is supplied with the respective phase signals of the inverter / converter 16 and the phase detection circuit 30 for detecting the phase of each phase. It is used as a synchronization signal for distributing the step signal into three phases.
The duty control can be realized by software using a microcomputer, or can be realized by an operational amplifier or the like.

[0011]

According to the present invention, control of the motor inverter is performed from PAM control to PWM control and from PWM control to P control.
Since the control shifts to the AM control, it is possible to easily control the low rotation range of the electric motor, which was difficult with the PAM control, and it is possible to select an operation mode with high efficiency. Furthermore, from PAM control to PW
Shift from M control and PWM control to PAM control by PWM
Since it is realized by changing the ON / OFF duty ratio of each control pulse, the control shift is smooth and can be realized by the PWM control circuit without a special additional circuit.

[Brief description of drawings]

FIG. 1 is an overall system diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram of an inverter according to an embodiment of the present invention.

FIG. 3 is a diagram showing an output waveform of an inverter according to an embodiment of the present invention.

FIG. 4 is a detailed drawing of an inverter converter according to an embodiment of the present invention.

FIG. 5 is a block diagram for explaining the control operation of the inverter / converter of the present invention.

[Explanation of symbols]

1 ... Engine, 2 ... Belt, 3 ... Alternator, 4 ... Manifold, 5 ... Turbin, 6 ... Motor / generator, 7 ... Compressor, 8 ... Shaft, 9 ... Intake manifold, 10 ... Battery, 11 ... Power part, 12 ... Silencer, 13 ... Air cleaner, 14 ... Inverter / converter, 15 ... Smoothing circuit, 16 ... Inverter / converter, 17 ... Insulated voltage regulator, 18 ... Control circuit, 19 ... Current sensor, 20 ... Voltage dividing circuit, 21 ... Transistor, 22 ... Diode, 23, 24 ... Phase detection line, 25 ... Duty control, 26 ... Current detector, 27 ... Voltage Detector, 28 ...
PWM control gate array, 29 ... Exciter for each phase, 30 ... Phase detector

Claims (2)

[Claims] 1. In an energy recovery system having a generator and an electric motor, PWM control is performed when the generated voltage of the generator is sufficiently higher than the drive voltage of the driven motor, and the generated voltage of the generator is When the difference between the driving voltage of the driven electric motor and the driving voltage of the electric motor is small, PAM control is performed. 2. The energy control method according to claim 1, wherein the PWM control switches only the upper arm or the lower arm in synchronism with the phase of the induced voltage of the electric motor.
A method of controlling the inverter of the recovery system.