Motor Drive Apparatus Series-Parallel Inverter Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional motor drive apparatuses face challenges in efficiently controlling power source voltage with complex circuitry and redundancy, leading to increased inverter loss and cost, especially when switching multiple inverter circuits between serial and parallel connections.
Innovation Solution
A motor drive apparatus with a control circuit and power converters, each including an inverter circuit and an interrupter circuit, where the inverter circuits are connected in series, and the control circuit switches them based on the motor's operating state and temperature, allowing for efficient power distribution and reducing switching loss by switching to different power converters when temperatures exceed thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple inverter circuits are switched between serial and parallel connections to control power source voltage, then output and efficiency are improved, but circuit complexity and inverter loss increase
Solution Approach 1:
The system segments the inverter circuits into multiple independent units (first inverter circuit and second inverter circuit) that can be independently controlled. Each inverter circuit has its own switching elements and control logic, allowing granular control over circuit configuration without requiring complex interconnections between circuits.
Solution Approach 2:
The system dynamically switches between series and parallel connections of inverter circuits based on motor operating conditions (speed and torque). The control circuit adjusts the connection configuration in real-time, enabling the system to adapt to varying load requirements while maintaining optimal efficiency and output performance.
2Productivity
If multiple inverter circuits are switched between serial and parallel connections to control power source voltage, then output and efficiency are improved, but inverter loss increases
Solution Approach 1:
The system dynamically selects series or parallel connection modes based on motor operating conditions. At low speeds, series connection is used to reduce switching loss by operating at lower voltage. At high speeds, parallel connection is used to provide sufficient voltage while maintaining current capacity. This dynamic adaptation minimizes inverter loss across the entire operating range.
Solution Approach 2:
The system changes operating parameters (voltage and current distribution) by switching between series and parallel configurations. In series connection, voltage is divided between circuits while current remains the same. In parallel connection, voltage remains the same while current is divided. This parameter adaptation allows optimal efficiency at different operating points.
3Adaptability or versatility
If switching elements are added to enable switching between parallel and series connection, then circuit adaptability is improved, but inverter loss and cost increase
Solution Approach 1:
Each inverter circuit is designed with universal switching capability that allows it to function in both series and parallel configurations. The switching elements within each circuit can operate in different modes (series switching or parallel switching) depending on the overall system configuration, eliminating the need for dedicated switching components for each mode and reducing total inverter loss.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration simplifies the circuitry, reduces inverter loss, and extends the useful life of power converters, improving the reliability and efficiency of the motor drive apparatus by dynamically adjusting power distribution based on operating conditions.
Implementation Method 1
Phase inversion is desired in order to increase output and voltage. The motor drive apparatus performs switching according to a motor turn count, so as to use one of inverter circuits provided as a series-connected pair and inverter circuits provided as a parallel-connected pair.
Implementation Method 2
The pair of series-connected inverter circuits split a source voltage such that each inverter circuit generates split voltage (1/2 of the source voltage) and supplies the split voltage to drive the motor.
Implementation Method 3
the parallel-connected pair of inverter circuits each generate power without splitting the source voltage to supply power to the motor. Accordingly, the motor is continually made to rotate despite high back-voltage occurring in motor coils when the motor turn count grows large.
Implementation Method 4
a temperature detector, the inverter circuits are connected in series to the DC power source and, while not in a short-circuit mode, each inverter circuit supplies electric power to the excitation coil of a corresponding phase
Data Source
AI summary
A motor drive apparatus receiving power from a power source and driving a motor with independent polyphase systems of excitation coils, comprises: a control circuit and power converters each corresponding to one system, each including an inverter circuit, an interrupter circuit, and a temperature detector, the inverter circuits being connected in series to the power source and, while not short-circuited, supplying power to the excitation coil, wherein the control circuit detects an operating state of the motor, short-circuits the inverter circuits and interrupts the interrupter circuits for a subset of power converters defined according to the operating state, such that a source voltage is supplied to non-short-circuited inverter circuits, and, when a power converter exceeds a predetermined temperature, the control circuit short-circuits the inverter circuit and interrupts the interrupter circuit thereof, and, in another power converter not exceeding the predetermined temperature, operates the inverter circuit and connects the interrupter circuit.