This application claims priority to China application no. 201210334374.8 filed on Sep. 11, 2012, which is hereby incorporated by reference in its entirety.
This invention relates to the drive technique of a synchronous motor and inductance motor. More particularly, this invention relates to an electric motor driver which can output drive signals with different phase numbers, phases and shapes as well as with a continuous or discrete amplitude. Further, this invention relates to an energy regeneration circuit formed by a function selection switch or by the combination of a function selection switch and a full-bridge rectifier circuit, wherein the function selection switch has a function of selecting a single-phase or multi-phase stator coil.
Motors are widely used in various fields, such as in machinery, petrochemistry and electricity. Generally, a motor comprises of basic parts including a stator, a rotor and a casing, and it can be categorized into direct current motors, synchronous motors and asynchronous motors according to its structure and working principle. In recent years, the performance requirement on the motor has steadily increased with the rapid development of industry. Many inventions related to motor manufacture have been emerging therewith. For example, patent document CN101752921A discloses a rotor which is used in a synchronous motor. Herein, the rotor comprises a plurality of inductive conductors, a first permanent magnet unit and a second permanent magnet unit. In the operational process of the motor, the rotor is firstly rotated by means of the induction motor theory, and then it is rotated at a synchronous speed through magnetic force generated between the conductor of the stator and the permanent magnet of the rotor. Patent document CN101562386B discloses a permanent magnet brushless DC motor, in which the drive circuit of the motor is a three-phase full-bridge circuit. The motor can output six drive pulses and close the six drive outputs when an over current occurs due to its function of over current protection.
At present, the majority of motor systems used in emerging fields (such as electric automobiles and hybrid powered vehicles) include an energy regeneration circuit, which collects reverse electromotive forces generated when the motor is in a non-drive state (i.e. the rotor is rotated by external force) or a phase commutation takes place so as to promote the operational efficiency of the motor system. Patent document CN1237028A discloses a multi-functional permanent magnet DC brushless motor, which consists of an electric motor, a position sensor and a control circuit. In such patent document, each motor winding can be controlled to switch on by turns, and an energy recovery circuit consisting of a backward diode and a load is also included. Patent document CN101889382A discloses a brushless DC motor, in which a circuit for achieving and stopping the power supply for a rotor winding is used. Such circuit is the type providing renewable energy to the power source, such as the circuit using a self-arc extinction component.
However, the following shortages exist in the above-mentioned motor systems: 1) the operation mode of the motor is limited; 2) the electric motor driver can only control the electric motor through changing the frequency and the duty cycle of the drive signal, while it cannot control the shape and the continuity of the drive signal as well as the drive phase number of the electric motor; 3) when the electric motor is driven by a DC signal, it only passively regenerates the reverse electromotive force generated during phase commutation while it cannot actively control phase commutation time according to the operation mode and (or) the operation state of the electric motor in order to achieve a higher operational efficiency for the electric motor; 4) thus the efficiency of the existing energy regeneration circuit is not high because of the above-mentioned reasons.
An object of this invention is to provide a hybrid motor with a higher operational efficiency, aiming at the above-mentioned drawbacks and shortages in the prior art.
To solve the above-mentioned technical problems, a hybrid motor is provided in this invention, which comprises an electric motor (EM), an electric motor driver (EMR) and an energy regeneration circuit (ERC). A rotor of the electric motor is comprised of a pair of permanent magnetic poles, or comprised of a pair of permanent magnetic poles and a pair of induction magnetic poles simultaneously.
The electric motor driver comprises a controller and at least one independent full-bridge drive circuit. The latter is constituted by a half-bridge drive circuit to construct the independent full-bridge drive circuit with a single phase, three phases or other phase numbers. In the case of more than one independent full-bridge drive circuit of the electric motor driver, their combination modes are the same or different. Meanwhile, the controller determines outputting a DC or a sine drive signal according to an operation mode and (or) an operation state of the electric motor. When a drive phase number of the electric motor is more than one, a same kind of drive signal is used to drive the electric motor by all the drive circuits.
The independent full-bridge drive circuit is used to drive an independent single phase or multi phases constituted by stator coils, and each group of the independent full-bridge drive circuit has a function selection switch which functions as selecting the independent single-phase or multi-phase stator coil. When the drive phase number of the electric motor is more than one, the controller will adjust the phase difference between the drive signals according to the number of the drive signal. At the same time, it also detects whether the electric motor meets the load requirement through a rotor position sensor and (or) a current/voltage sensing circuit of the electric motor. In this case, it is determined whether to change the drive phase number of the electric motor by changing the switch-on sequence and (or) the number of the switching element in a single or several half-bridge drive circuits which are used to constitute the independent full-bridge drive circuit. The drive signal is applied to the stator coil of the motor, and the magnetic field generated by the stator coil of the motor is used to drive a pair of magnetic poles in the rotor of the electric motor. When the rotor contains both the pair of permanent magnetic poles and the pair of induction magnetic poles, the electric motor can operate in an induction or a synchronous manner; when the rotor only contains the pair of permanent magnetic poles, the electric motor can only operate in a synchronous manner.
The controller determines whether to output the drive signal with a discrete amplitude according to the operation mode and (or) the operation state of the electric motor. The discrete amplitude and the discrete time of the discrete drive signal are determined by the controller based on the operation mode and (or) the operation state of the electric motor.
The energy regeneration circuit is constituted by the function selection switch or by the combination of the function selection switch and a full-bridge rectifier circuit, wherein the function selection switch has a function of selecting the independent single-phase or multi-phase stator coil. The function selection switch is switched on by the controller when all of the half-bridge drive circuits for constituting a single group of the independent full-bridge drive circuit are closed, aiming to collect the current which is generated through the relative movement between the permanent magnet poles in the rotor of the electric motor and the independent single-phase or multi-phase stator coil, wherein such current is supplied to an electrical load or utilized by a storage system.
In the above-mentioned hybrid motor, the electric motor driver and (or) the energy regeneration circuit are (is) applicable to all devices that contain the permanent magnetic pole and convert electrical energy into mechanical energy by way of electromagnetic induction.
In the hybrid motor provided in an embodiment of this invention, the following electric motor driver and energy regeneration circuit are employed, wherein the electric motor driver can output drive signals with different phase numbers, phases and shapes as well as with a continuous or discrete amplitude; the energy regeneration circuit is constituted by the function selection switch or by the combination of the function selection switch and the full-bridge rectifier circuit, and the function selection switch functions as selecting the independent single-phase or multi-phase stator coil. In this way, the motor overcomes the shortage of limited operation mode of the existing motor, and the electric motor driver can control the electric motor not only by changing the frequency and the duty cycle of the drive signal but also by controlling the shape and the continuity of the drive signal and the drive phase number of the electric motor. Moreover, when the electric motor is driven by the DC signal, the phase commutation time can be controlled automatically according to the operation mode and (or) the operation state of the electric motor. Accordingly, the electric motor of the hybrid motor in this invention can have higher operational efficiency.
This invention will be further described with reference to the accompanying drawings and embodiments in the following. In the figures,
a and 1b are structural block diagrams for a hybrid motor according to embodiments of the present invention;
a and 2b are structural diagrams for the electric motor in the hybrid motor according to embodiments of the present invention;
a and
Referring to
As shown in
Referring to
Referring to
There are two optional rotors in the above-mentioned two electric motors:
(1) The rotor (M4, A4) comprises four pairs of permanent magnetic poles, wherein each pair of the magnetic poles is apart by 45°.
(2) The rotor (M3, A5) comprise two pairs of permanent magnetic poles and two pairs of induction magnetic poles, wherein the pair of permanent magnetic poles is apart from the pair of induction magnetic poles by 45°.
Therefore, there are four different combinations of the electric motor in the embodiment of the hybrid motor in this invention. In the above-mentioned four combinations of the electric motor for illustration, the sensing of the rotor position can also be obtained without a sensor except that it is obtained through the position sensor (M7, A8) in the above-mentioned embodiment. For example, it can be obtained through a field oriented control (FOC).
Referring to
The electric motor driver B4 in
Similarly,
In an embodiment of the hybrid motor in this invention, the controller drives the electric motor by controlling the on and off of the switching element (which is the MOSFET in this example) of the half-bridge drive circuit in the electric motor driver. The controller determines outputting a DC or a sine drive signal according to the operation mode and (or) the operation state of the electric motor. When the drive phase number of the electric motor is more than one, the controller adjusts the phase difference between the drive signals according to the number of the drive signal (for example: the phase difference of a three-phase sine drive signal is 120°, and the phase difference of a two-phase sine drive signal is 90° or 180°). Meanwhile, the controller detects whether the electric motor meets the load requirement through a rotor position sensor and (or) a current/voltage sensing circuit of the electric motor. In this case, whether to change the drive phase number of the electric motor is determined by changing the switch-on sequence and (or) the number of the switching element in a single or several half-bridge drive circuits which are used to constitute the independent full-bridge drive circuit. The controller also determines whether to output the drive signal with a discrete amplitude according to the operation mode and (or) the operation state of the electric motor, wherein the discrete amplitude and the discrete time of the discrete drive signal are determined by the controller based on the operation mode and (or) the operation state of the electric motor. When the half-bridge drive circuits constituting the single group of independent full-bridge drive circuit are all closed, the function selection switch of the independent full-bridge drive circuit is switched on by the controller. In this case, the independent single-phase or multi-phase stator coil driven by the independent full-bridge drive circuit is changed from a drive coil to an induction coil, aiming to collect the current which is generated through the relative movement between the permanent magnet of the rotor in the electric motor and the single-phase or multi-phase stator coil. The current is injected into the DC bus once again by passing through the rectifier circuit and a DC regulator so that it can be utilized by the electric motor driver once more.
Illustrated in
As shown in
As shown in
Referring to
In accordance with the embodiments of the hybrid motor in this invention, the above-mentioned different electric motors, electric motor drivers and energy regeneration circuits can be included herein, wherein different combinations thereof can constitute different embodiments of the hybrid motor in this invention.
a and 11b are flowcharts for the operation of the hybrid motor system in this invention. In particular,
Referring to
Referring to
The hybrid motor provided in this invention comprises the electric motor B5, the electric motor driver B4 and the energy regeneration circuit B6, wherein the rotor can simultaneously comprise the pair of permanent magnetic poles and the pair of induction magnetic poles. When the magnetic field generated by the stator coil of the electric motor is used to drive the pair of permanent magnetic poles of the rotor, the electric motor operates as the synchronous motor; but when the magnetic field is used to drive the pair of induction magnetic poles of the rotor, the electric motor will operate as the induction motor. According to the operation mode and (or) the operation state of the electric motor, the controller outputs the DC or sine drive signal with discrete or continuous amplitude and changes the drive phase number of the electric motor by changing the switch-on sequence and (or) the number of the switching element in the half-bridge drive circuits of the electric motor driver B4, wherein the half-bridge drive circuits are used to constitute the independent full-bridge drive circuit. Such energy regeneration circuit and the hybrid motor are applicable to all motors that contain the permanent magnetic pole and convert the electrical energy into the mechanical energy by way of electromagnetic induction, wherein the energy regeneration circuit is comprised of the function selection switch or by the combination of the function selection switch and the full-bridge rectifier circuit, and the hybrid motor comprises the electric motor driver and the electric motor for achieving the above-mentioned functions.
In addition, the above-mentioned electric motor driver or the energy regeneration circuit is not limited to use in the hybrid motor in such embodiments. Instead, they are applicable to all devices that contain the permanent magnetic pole and convert electrical energy into mechanical energy by way of electromagnetic induction.
The ordinary skilled in the art may make various changes and modifications to the above-mentioned description according to the technical solution and technical conception of this invention, and all these changes and modifications should fall within the scope of the appended claims of this invention.
Number | Date | Country | Kind |
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201210334374.8 | Sep 2012 | CN | national |