Patent Application
20100073980
The present invention generally relates to power converters, and more particularly relates to an automotive power converter with an isolated gate drive circuit.
In recent years, advances in technology, as well as ever-evolving tastes in style, have led to substantial changes in the design of automobiles. One of the changes involves the complexity of the electrical systems within automobiles, particularly alternative fuel vehicles, such as hybrid, electric, and fuel cell vehicles. Such alternative fuel vehicles typically use one or more electric motors, perhaps in combination with another actuator, to drive the wheels. Additionally, such automobiles may also include other motors, as well as other high voltage components, to operate the other various systems within the automobile, such as the air conditioner.
Due to the fact that alternative fuel automobiles typically include only direct current (DC) power supplies, direct current-to-alternating current (DC/AC) inverters (or power inverters) are provided to convert the DC power to alternating current (AC) power, which is generally required by the motors. Such vehicles, particularly fuel cell vehicles, also often use two separate voltage sources, such as a battery and a fuel cell, to power the electric motors that drive the wheels. Thus, power converters, such as direct current-to-direct current (DC/DC) converters, are typically also provided to manage and transfer the power from the two voltage sources.
It is desirable to provide a power converter with improved performance as related to the characteristics described above, as well as a layout that allows for advanced thermal management. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent description taken in conjunction with the accompanying drawings and the foregoing technical field and background.
A power converter assembly is provided. The power converter includes at least one switch, a high frequency oscillator coupled to the at least one switch and configured to generate a high frequency waveform based on direct current (DC) power provided thereto, and a power buffer coupled to the at least one switch and the high frequency oscillator and configured to control the operation of the at least one switch based on the high frequency waveform.
An automotive power converter assembly is provided. The automotive power converter includes at least one transistor, a substrate comprising a plurality of ceramic layers and passive electronic components, the passive electronic components at least partially forming a high frequency oscillator coupled to the at least one transistor and configured to generate a high frequency waveform based on direct current (DC) power provided thereto, and a power buffer coupled to the at least one transistor and the high frequency oscillator, the power buffer being configured to control the operation of the at least one transistor based on the high frequency waveform
An automotive drive system is provided. The automotive drive system includes an electric motor, a power inverter coupled to the electric motor and comprising at least one switch, a direct current (DC) power supply configured to generate DC power, a high frequency oscillator coupled to the DC power supply and configured to generate a high frequency waveform based on the DC power, control circuitry configured to generate a control signal, and a power buffer coupled to the high frequency oscillator, the control circuitry, and the power inverter and configured to control the operation of the at least one switch within the power inverter based on the high frequency waveform and the control signal such that alternating current (AC) power is provided to the electric motor.
The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and
The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, and brief summary, or the following detailed description.
The following description refers to elements or features being “connected” or “coupled” together. As used herein, “connected” may refer to one element/feature being mechanically joined to (or directly communicating with) another element/feature, and not necessarily directly. Likewise, “coupled” may refer to one element/feature being directly or indirectly joined to (or directly or indirectly communicating with) another element/feature, and not necessarily mechanically. However, it should be understood that although two elements may be described below, in one embodiment, as being “connected,” in alternative embodiments similar elements may be “coupled,” and vice versa. Thus, although the schematic diagrams shown herein depict example arrangements of elements, additional intervening elements, devices, features, or components may be present in an actual embodiment.
Further, various components and features described herein may be referred to using particular numerical descriptors, such as first, second, third, etc., as well as positional and/or angular descriptors, such as horizontal and vertical. However, such descriptors may be used solely for descriptive purposes relating to drawings and should not be construed as limiting, as the various components may be rearranged in other embodiments. It should also be understood that
The automobile 10 may be any one of a number of different types of automobiles, such as, for example, a sedan, a wagon, a truck, or a sport utility vehicle (SUV), and may be two-wheel drive (2WD) (i.e., rear-wheel drive or front-wheel drive), four-wheel drive (4WD), or all-wheel drive (AWD). The automobile 10 may also incorporate any one of, or combination of, a number of different types of engines, such as, for example, a gasoline or diesel fueled combustion engine, a “flex fuel vehicle” (FFV) engine (i.e., using a mixture of gasoline and alcohol), a gaseous compound (e.g., hydrogen and/or natural gas) fueled engine, a combustion/electric motor hybrid engine, and an electric motor.
In the exemplary embodiment illustrated in
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The switch network comprises three pairs (a, b, and c) of series switches with antiparallel diodes (i.e., antiparallel to each switch) corresponding to each of the phases of the motor 30. Each of the pairs of series switches comprises a first switch, or transistor, (i.e., a “high” switch) 40, 42, and 44 having a first terminal coupled to a positive electrode of the voltage source 22 and a second switch (i.e., a “low” switch) 46, 48, and 50 having a second terminal coupled to a negative electrode of the voltage source 22 and a first terminal coupled to a second terminal of the respective first switch 40, 42, and 44. As is commonly understood, each of the switches 40-50 may be in the form of individual semiconductor devices such as insulated gate bipolar transistors (IGBTs) within integrated circuits formed on semiconductor (e.g. silicon) substrates (e.g., die).
The power supply 54 includes a high frequency (HF) oscillator 60, a HF coupled circuit 62, and a rectifier 64. The HF oscillator 60 includes an integrated circuit 66 configured to control the HF oscillator 60 to keep the operation thereof at the resonant frequency of an LC circuit formed by a capacitor 68 and an inductor 70 within the HF oscillator 60. Through the LC circuit, the HF oscillator 60 delivers high frequency AC power to the HF coupled circuit 62. In one embodiment, the oscillator is a resonant cavity oscillator and likewise also includes a resonator cavity, as is commonly understood. The HF coupled circuit 62 includes two coils 72 which jointly form a transformer. In one embodiment, the transformer does not include a ferromagnetic core within either of the coils 72. The rectifier 64 (e.g., 20 VDC) includes one or more (e.g., two) diodes 74 and one or more (e.g., two) capacitors 76. In one embodiment, the power to operate the power supply 54 (Vdc) is provided by a low voltage (e.g., 12V) battery (not shown), as the high voltage battery, 22, is electrically isolated from the low voltage system.
The logic control circuitry 56 includes an HF electromagnetic transmitter 78 and an HF electromagnetic receiver 80. Although not shown, the transmitter 78 and the receiver 80 may include various passive electronic components, such as inductors, resistors, capacitors, and diodes, as is commonly understood. The logic control circuitry 56 may serve, at least in part, to electrically isolate the control or switching signal (ON/OFF) from the high voltage and to deliver the signal to the drive amplifier.
The power buffer (or drive amplifier) 58, in one embodiment, includes one or more (e.g., two) metal-oxide-semiconductor field-effect transistors (MOSFETs) 82 that are in operable communication with (or electrically connected to) the rectifier 64 and the HF receiver 80, as is commonly understood. The MOSFETs 82 are also electrically connected to the inverter 24 (and/or one of the switches in the inverter 24). As will be appreciated by one skilled in the art, other devices that are capable of delivering sufficiently high peak current for the switching action of the inverter 24 (i.e., switches 40-50 in
In one embodiment, various components of the inverter gate drive power and logic control subsystem 52 are implemented within a multi-layer ceramic substrate, such as a low temperature co-fired ceramic (LTCC) substrate 84, an example of which is shown in
Referring to
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During operation, referring to
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One advantage is that the use of the HF oscillator allows for the AC waveform to be generated at significantly higher frequencies, which in turn allows for a significant reduction in the size of the passive components (and the substrate overall). As a result, the distance between the circuitry used to drive the gates of the transistors and the inverter itself (i.e., the transistors) may be reduced. This reduction in size, in some embodiments, may allow the gate drive circuitry to be located within, and implemented as part of, one of the inverter modules, resulting in a reduction of external components and the wiring harnesses required between components.
The gate drive circuit described above may be used in various types of systems other than inverters used for motor drive, as it may be used in any application with a power switching transistor. For example, the circuit may be used in direct current-to-direct current (DC/DC) converters, such as boost converters, and it may be used to drive a single switch chopper that controls a heating element.
While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the exemplary embodiment or exemplary embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof.
