1. Field of the Invention
The invention relates to a daughter circuit board of an electronically commutated motor (ECM) for interface signal conversion.
2. Description of the Related Art
As shown in FIGS. 1 and 2, a conventional ECM includes a main body and a controller. The main body has a stator assembly and a rotor assembly. The controller should correspond with both the main body and a control interface of a control system of a user terminal. Different control systems of user terminals correspond with different control signals. For example, both a control system of an air-conditioner and a control system of a washing-machine belong to control system of user terminals, but the control signals thereof are completely different. Conventionally, for each specific control system of a user terminal, a motor and a controller thereof are developed accordingly, which, however, brings about the following disadvantages: 1) a variety of motors have to be manufactured, which results in inconvenient management and standardization; 2) the development for motors takes time and increases the production costs; and 3) the newly-developed motor has a narrow application scope and is inconvenient for popularization.
To solve the above-described problems, a motor controller including a mother circuit board and a daughter circuit board butted therewith has been introduced. Main functional circuits of the motor controller are disposed on the mother circuit board. Different interface circuit units and identify circuits are disposed on different daughter circuit boards. When one daughter circuit board is butted with the mother circuit board, the identify circuit of the daughter circuit board sends messages to a central control and process unit of the mother circuit board. Thereafter, the central control and process unit automatically assigns an input/output port for the daughter circuit board. Thus, through cooperation with various daughter circuit boards, the motor controller can be applied to various occasions, i.e., has a wide application. Consequently, the motor manufactures do not need to produce a large number of motors, thereby reducing the management and development costs, simplifying the production process, and improving the efficiency.
Specifically, as shown in FIGS. 3-5, a motor controller includes a microprocessor unit, a signal interface unit, and an identify circuit. The microprocessor unit is disposed on a mother circuit board. The signal interface unit and the identify circuit are disposed on a daughter circuit board. The mother circuit board and the daughter circuit board are butted with each other to form an electric connection. The identify circuit inputs an identify signal to the microprocessor unit, and then the microprocessor unit automatically assigns an input/output port for the signal interface unit according to the identify signal.
Identify circuits corresponding with different signal interface units output different signals, whereby forming different daughter circuit boards. An output end of the microprocessor unit is connected to a power inverter unit. An input end of the microprocessor unit is connected to an output end of a rotor position sensing circuit. The power inverter unit and the rotor position sensing unit are disposed on the mother circuit board. A power supply circuit and an analog sensing unit are also disposed on the mother circuit board. The analog sensing unit detects currents, voltages, and analog signals like NTC of the mother circuit lines on the mainboard. The power supply circuit supplies power to all the circuits. The microprocessor unit is a CPU, a micro control unit (MCU), or a digital signal processor (DSP). A port 3 is disposed on the mother circuit board and includes eleven terminal lugs E, N, L, M1, M2, M3, M4, M5, M6, M7, and M8, of which, the terminal lugs E, N, L are inputs of power supply, M1, M2, M3, M4, M5, M6, M7, M8 are interface signals output from the control system of the user terminal to daughter circuit boards. There may be a plurality of daughter circuit boards. A slot 1 is disposed on the mother circuit board, and a plug connector 2 is disposed on the daughter circuit board. The plug connector 2 is received in the slot 1 whereby electrically connecting the daughter circuit board with the mother circuit board.
However, disadvantages exist in applications of conventional ECMs, which are summarized below, 1) when too many signals interfaces are employed, multiple electric isolations must be designed between daughter circuit boards and the mother circuit board, which results in complicated circuits and high production cost; 2) interface signals need too much resource of the microprocessor unit MCU to process, which affects the running speed; 3) excessive types of daughter circuit boards make the ECM not convenient to be managed and popularized.